{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0595.html", "source_quote": "NIOSH REL TWA 500 ppm (4170 mg/m3)", "value": "TWA 500"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0595.html", "source_quote": "NIOSH REL TWA 500 ppm (4170 mg/m3)", "value": "4170"}], "cas_number": "76-11-9", "disagreements": [], "id": "1-1-1-2-tetrachloro-2-2-difluoroethane", "pel_mgm3": "4170", "pel_ppm": "500", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "1,1,1,2-Tetrachloro-2,2-difluoroethane | 76-11-9 | 500 | 4170 | - |", "substance": "1,1,1,2-Tetrachloro-2,2-difluoroethane", "url": "https://referencesource.org/workplace-exposure-limits/1-1-1-2-tetrachloro-2-2-difluoroethane/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "630-20-6", "id": "1-1-1-2-tetrachloroethane", "rel_statement": "Handle with caution in the workplace. See Appendix C (Chloroethanes)", "source": "https://www.cdc.gov/niosh/npg/npgd0597.html", "source_quote": "NIOSH REL Handle with caution in the workplace. See Appendix C (Chloroethanes)", "substance": "1,1,1,2-Tetrachloroethane", "url": "https://referencesource.org/workplace-exposure-limits/1-1-1-2-tetrachloroethane/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0596.html", "source_quote": "NIOSH REL TWA 500 ppm (4170 mg/m3)", "value": "TWA 500"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0596.html", "source_quote": "NIOSH REL TWA 500 ppm (4170 mg/m3)", "value": "4170"}], "cas_number": "76-12-0", "disagreements": [], "id": "1-1-2-2-tetrachloro-1-2-difluoroethane", "pel_mgm3": "4170", "pel_ppm": "500", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "1,1,2,2-Tetrachloro-1,2-difluoroethane | 76-12-0 | 500 | 4170 | - |", "substance": "1,1,2,2-Tetrachloro-1,2-difluoroethane", "url": "https://referencesource.org/workplace-exposure-limits/1-1-2-2-tetrachloro-1-2-difluoroethane/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0598.html", "source_quote": "NIOSH REL Ca TWA 1 ppm (7 mg/m3) [skin]", "value": "TWA 1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0598.html", "source_quote": "NIOSH REL Ca TWA 1 ppm (7 mg/m3) [skin]", "value": "7"}], "cas_number": "79-34-5", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "1,1,2,2-Tetrachloroethane | 79-34-5 | 5 | 35 | X |", "value": "5"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "79345 | S | 1,1,2,2-Tetrachloroethane; acetylene tetrachloride | 1 | 7", "value": "1"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "1,1,2,2-Tetrachloroethane | 79-34-5 | 5 | 35 | X |", "value": "35"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "79345 | S | 1,1,2,2-Tetrachloroethane; acetylene tetrachloride | 1 | 7", "value": "7"}]}], "id": "1-1-2-2-tetrachloroethane", "pel_mgm3": "35", "pel_ppm": "5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "1,1,2,2-Tetrachloroethane | 79-34-5 | 5 | 35 | X |", "substance": "1,1,2,2-Tetrachloroethane", "url": "https://referencesource.org/workplace-exposure-limits/1-1-2-2-tetrachloroethane/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-28", "field": "ceiling", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "76131 | | 1,1,2-Trichloro-1,2,2-trifluoroethane | 1000 | 7600 | 2000 ppm | 1250 | 9500", "value": "2000 ppm"}, {"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "76131 | | 1,1,2-Trichloro-1,2,2-trifluoroethane | 1000 | 7600 | 2000 ppm | 1250 | 9500", "value": "a ceiling value in addition to the TWA values"}, {"as_of": "2026-09-28", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "76131 | | 1,1,2-Trichloro-1,2,2-trifluoroethane | 1000 | 7600 | 2000 ppm | 1250 | 9500", "value": "1250"}, {"as_of": "2026-09-28", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "76131 | | 1,1,2-Trichloro-1,2,2-trifluoroethane | 1000 | 7600 | 2000 ppm | 1250 | 9500", "value": "9500"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0632.html", "source_quote": "NIOSH REL TWA 1000 ppm (7600 mg/m3) ST 1250 ppm (9500 mg/m3)", "value": "TWA 1000"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0632.html", "source_quote": "NIOSH REL TWA 1000 ppm (7600 mg/m3) ST 1250 ppm (9500 mg/m3)", "value": "7600"}], "cas_number": "76-13-1", "disagreements": [], "id": "1-1-2-trichloro-1-2-2-trifluoroethane", "pel_mgm3": "7600", "pel_ppm": "1000", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "1,1,2-Trichloro-1,2,2-trifluoroethane | 76-13-1 | 1000 | 7600 | - |", "substance": "1,1,2-Trichloro-1,2,2-trifluoroethane", "url": "https://referencesource.org/workplace-exposure-limits/1-1-2-trichloro-1-2-2-trifluoroethane/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0628.html", "source_quote": "NIOSH REL Ca TWA 10 ppm (45 mg/m3) [skin]", "value": "TWA 10"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0628.html", "source_quote": "NIOSH REL Ca TWA 10 ppm (45 mg/m3) [skin]", "value": "45"}], "cas_number": "79-00-5", "disagreements": [], "id": "1-1-2-trichloroethane", "pel_mgm3": "45", "pel_ppm": "10", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "1,1,2-Trichloroethane | 79-00-5 | 10 | 45 | X |", "substance": "1,1,2-Trichloroethane", "url": "https://referencesource.org/workplace-exposure-limits/1-1-2-trichloroethane/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0198.html", "source_quote": "NIOSH REL TWA 2 ppm (10 mg/m3)", "value": "TWA 2"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0198.html", "source_quote": "NIOSH REL TWA 2 ppm (10 mg/m3)", "value": "10"}], "cas_number": "594-72-9", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "1,1-Dichloro-1-nitroethane | 594-72-9 | (C)10 | (C)60 | - |", "value": "(C)10"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "594729 | | 1,1-Dichloro-1-nitroethane | 2 | 10", "value": "2"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "1,1-Dichloro-1-nitroethane | 594-72-9 | (C)10 | (C)60 | - |", "value": "(C)60"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "594729 | | 1,1-Dichloro-1-nitroethane | 2 | 10", "value": "10"}]}], "id": "1-1-dichloro-1-nitroethane", "pel_mgm3": "(C)60", "pel_ppm": "(C)10", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "1,1-Dichloro-1-nitroethane | 594-72-9 | (C)10 | (C)60 | - |", "substance": "1,1-Dichloro-1-nitroethane", "url": "https://referencesource.org/workplace-exposure-limits/1-1-dichloro-1-nitroethane/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0194.html", "source_quote": "NIOSH REL TWA 100 ppm (400 mg/m3)", "value": "TWA 100"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0194.html", "source_quote": "NIOSH REL TWA 100 ppm (400 mg/m3)", "value": "400"}], "cas_number": "75-34-3", "disagreements": [], "id": "1-1-dichloroethane", "pel_mgm3": "400", "pel_ppm": "100", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "1,1-Dichloroethane | 75-34-3 | 100 | 400 | - |", "substance": "1,1-Dichloroethane", "url": "https://referencesource.org/workplace-exposure-limits/1-1-dichloroethane/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0227.html", "source_quote": "NIOSH REL Ca C 0.06 ppm (0.15 mg/m3) [2-hr]", "value": "C 0.06"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0227.html", "source_quote": "NIOSH REL Ca C 0.06 ppm (0.15 mg/m3) [2-hr]", "value": "0.15"}], "cas_number": "57-14-7", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "1,1-Dimethylhydrazine | 57-14-7 | 0.5 | 1 | X |", "value": "0.5"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "57147 | S | 1,1-Dimethylhydrazine | 0.01 | 0.025", "value": "0.01"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "1,1-Dimethylhydrazine | 57-14-7 | 0.5 | 1 | X |", "value": "1"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "57147 | S | 1,1-Dimethylhydrazine | 0.01 | 0.025", "value": "0.025"}]}], "id": "1-1-dimethylhydrazine", "pel_mgm3": "1", "pel_ppm": "0.5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "1,1-Dimethylhydrazine | 57-14-7 | 0.5 | 1 | X |", "substance": "1,1-Dimethylhydrazine", "url": "https://referencesource.org/workplace-exposure-limits/1-1-dimethylhydrazine/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0631.html", "source_quote": "NIOSH REL Ca TWA 10 ppm (60 mg/m3) [skin]", "value": "TWA 10"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0631.html", "source_quote": "NIOSH REL Ca TWA 10 ppm (60 mg/m3) [skin]", "value": "60"}], "cas_number": "96-18-4", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "1,2,3-Trichloropropane | 96-18-4 | 50 | 300 | - |", "value": "50"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "96184 | | 1,2,3-Trichloropropane | 10 | 60", "value": "10"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "1,2,3-Trichloropropane | 96-18-4 | 50 | 300 | - |", "value": "300"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "96184 | | 1,2,3-Trichloropropane | 10 | 60", "value": "60"}]}], "id": "1-2-3-trichloropropane", "pel_mgm3": "300", "pel_ppm": "50", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "1,2,3-Trichloropropane | 96-18-4 | 50 | 300 | - |", "substance": "1,2,3-Trichloropropane", "url": "https://referencesource.org/workplace-exposure-limits/1-2-3-trichloropropane/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "526-73-8", "id": "1-2-3-trimethylbenzene", "rel_mgm3": "125", "rel_ppm": "TWA 25", "source": "https://www.cdc.gov/niosh/npg/npgd0637.html", "source_quote": "NIOSH REL TWA 25 ppm (125 mg/m3)", "substance": "1,2,3-Trimethylbenzene", "url": "https://referencesource.org/workplace-exposure-limits/1-2-3-trimethylbenzene/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0627.html", "source_quote": "NIOSH REL C 5 ppm (40 mg/m3)", "value": "C 5"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0627.html", "source_quote": "NIOSH REL C 5 ppm (40 mg/m3)", "value": "40"}], "cas_number": "120821", "ceiling_notation": "the values given in the PEL columns are ceiling values", "disagreements": [], "id": "1-2-4-trichlorobenzene", "pel_mgm3": "40", "pel_ppm": "5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "120821 | | 1,2,4-Trichlorobenzene | 5 | 40 | C", "substance": "1,2,4-Trichlorobenzene", "url": "https://referencesource.org/workplace-exposure-limits/1-2-4-trichlorobenzene/", "verified_fields": ["cas_number", "ceiling_notation", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "95-63-6", "id": "1-2-4-trimethylbenzene", "rel_mgm3": "125", "rel_ppm": "TWA 25", "source": "https://www.cdc.gov/niosh/npg/npgd0638.html", "source_quote": "NIOSH REL TWA 25 ppm (125 mg/m3)", "substance": "1,2,4-Trimethylbenzene", "url": "https://referencesource.org/workplace-exposure-limits/1-2-4-trimethylbenzene/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "96128 | | 1,2-Dibromo-3-chloropropane; DBCP; see Section 5212 | .001 | .01", "value": ".001"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "96128 | | 1,2-Dibromo-3-chloropropane; DBCP; see Section 5212 | .001 | .01", "value": ".01"}], "cas_number": "96-12-8", "disagreements": [], "id": "1-2-dibromo-3-chloropropane", "rel_statement": "Ca See Appendix A", "source": "https://www.cdc.gov/niosh/npg/npgd0184.html", "source_quote": "NIOSH REL Ca See Appendix A", "substance": "1,2-Dibromo-3-chloropropane", "url": "https://referencesource.org/workplace-exposure-limits/1-2-dibromo-3-chloropropane/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0195.html", "source_quote": "NIOSH REL TWA 200 ppm (790 mg/m3)", "value": "TWA 200"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0195.html", "source_quote": "NIOSH REL TWA 200 ppm (790 mg/m3)", "value": "790"}], "cas_number": "540-59-0", "disagreements": [], "id": "1-2-dichloroethylene", "pel_mgm3": "790", "pel_ppm": "200", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "1,2-Dichloroethylene | 540-59-0 | 200 | 790 | - |", "substance": "1,2-Dichloroethylene", "url": "https://referencesource.org/workplace-exposure-limits/1-2-dichloroethylene/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0201.html", "source_quote": "NIOSH REL TWA 1000 ppm (7000 mg/m3)", "value": "TWA 1000"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0201.html", "source_quote": "NIOSH REL TWA 1000 ppm (7000 mg/m3)", "value": "7000"}], "cas_number": "76142", "disagreements": [], "id": "1-2-dichlorotetrafluoroethane-fluorocarbon-114", "pel_mgm3": "7,000", "pel_ppm": "1,000", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "76142 | | 1,2-Dichlorotetrafluoroethane; Fluorocarbon 114 | 1,000 | 7,000", "substance": "1,2-Dichlorotetrafluoroethane; Fluorocarbon 114", "url": "https://referencesource.org/workplace-exposure-limits/1-2-dichlorotetrafluoroethane-fluorocarbon-114/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "2451629", "id": "1-3-5-triglycidyl-s-triazinetrione", "pel_mgm3": "0.005", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "2451629 | | 1,3,5-Triglycidyl-s-triazinetrione | | 0.005", "substance": "1,3,5-Triglycidyl-s-triazinetrione", "url": "https://referencesource.org/workplace-exposure-limits/1-3-5-triglycidyl-s-triazinetrione/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"cas_number": "108-67-8", "disagreements": [], "id": "1-3-5-trimethylbenzene", "rel_mgm3": "125", "rel_ppm": "TWA 25", "source": "https://www.cdc.gov/niosh/npg/npgd0639.html", "source_quote": "NIOSH REL TWA 25 ppm (125 mg/m3)", "substance": "1,3,5-Trimethylbenzene", "url": "https://referencesource.org/workplace-exposure-limits/1-3-5-trimethylbenzene/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "106990 | | 1,3-Butadiene (see also section 5201) | 1 | 2.2 | | 5 | 11", "value": "1"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "106990 | | 1,3-Butadiene (see also section 5201) | 1 | 2.2 | | 5 | 11", "value": "2.2"}, {"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "106990 | | 1,3-Butadiene (see also section 5201) | 1 | 2.2 | | 5 | 11", "value": "5"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "106990 | | 1,3-Butadiene (see also section 5201) | 1 | 2.2 | | 5 | 11", "value": "11"}], "cas_number": "106-99-0", "disagreements": [], "id": "1-3-butadiene", "rel_statement": "Ca See Appendix A", "source": "https://www.cdc.gov/niosh/npg/npgd0067.html", "source_quote": "NIOSH REL Ca See Appendix A", "substance": "1,3-Butadiene", "url": "https://referencesource.org/workplace-exposure-limits/1-3-butadiene/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "118525 | | 1,3-Dichloro-5,5-dimethyl hydantoin | -- | 0.2 | | -- | 0.4", "value": "0.4"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0193.html", "source_quote": "NIOSH REL TWA 0.2 mg/m3 ST 0.4 mg/m3", "value": "TWA 0.2"}], "cas_number": "118-52-5", "disagreements": [], "id": "1-3-dichloro-5-5-dimethyl-hydantoin", "pel_mgm3": "0.2", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "1,3-Dichloro-5,5-dimethyl hydantoin | 118-52-5 | - | 0.2 | - |", "substance": "1,3-Dichloro-5,5-dimethyl hydantoin", "url": "https://referencesource.org/workplace-exposure-limits/1-3-dichloro-5-5-dimethyl-hydantoin/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "542756 | S | Dichloropropene | 1 | 5", "value": "1"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "542756 | S | Dichloropropene | 1 | 5", "value": "5"}], "cas_number": "542-75-6", "disagreements": [], "id": "1-3-dichloropropene", "rel_mgm3": "5", "rel_ppm": "TWA 1", "source": "https://www.cdc.gov/niosh/npg/npgd0199.html", "source_quote": "NIOSH REL Ca TWA 1 ppm (5 mg/m3) [skin]", "substance": "1,3-Dichloropropene", "url": "https://referencesource.org/workplace-exposure-limits/1-3-dichloropropene/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"cas_number": "764410", "id": "1-4-dichloro-2-butene", "pel_mgm3": "0.025", "pel_ppm": "0.005", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "764410 | S | 1,4-Dichloro-2-butene | 0.005 | 0.025", "substance": "1,4-Dichloro-2-butene", "url": "https://referencesource.org/workplace-exposure-limits/1-4-dichloro-2-butene/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "124094", "id": "1-6-hexanediamine", "pel_mgm3": "2.3", "pel_ppm": "0.5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "124094 | | 1,6-Hexanediamine | 0.5 | 2.3", "substance": "1,6-Hexanediamine", "url": "https://referencesource.org/workplace-exposure-limits/1-6-hexanediamine/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "106945", "id": "1-bromopropane-n-propyl-bromide", "pel_mgm3": "25", "pel_ppm": "5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "106945 | S | 1-bromopropane, n-propyl bromide | 5 | 25", "substance": "1-bromopropane, n-propyl bromide", "url": "https://referencesource.org/workplace-exposure-limits/1-bromopropane-n-propyl-bromide/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0130.html", "source_quote": "NIOSH REL TWA 2 ppm (10 mg/m3)", "value": "TWA 2"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0130.html", "source_quote": "NIOSH REL TWA 2 ppm (10 mg/m3)", "value": "10"}], "cas_number": "600-25-9", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "1-Chloro-1-nitropropane | 600-25-9 | 20 | 100 | - |", "value": "20"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "600259 | | 1-Chloro-1-nitropropane | 2 | 10", "value": "2"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "1-Chloro-1-nitropropane | 600-25-9 | 20 | 100 | - |", "value": "100"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "600259 | | 1-Chloro-1-nitropropane | 2 | 10", "value": "10"}]}], "id": "1-chloro-1-nitropropane", "pel_mgm3": "100", "pel_ppm": "20", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "1-Chloro-1-nitropropane | 600-25-9 | 20 | 100 | - |", "substance": "1-Chloro-1-nitropropane", "url": "https://referencesource.org/workplace-exposure-limits/1-chloro-1-nitropropane/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "143-10-2", "id": "1-decanethiol", "rel_mgm3": "3.6", "rel_ppm": "C 0.5", "source": "https://www.cdc.gov/niosh/npg/npgd0176.html", "source_quote": "NIOSH REL C 0.5 ppm (3.6 mg/m3) [15-minute]", "substance": "1-Decanethiol", "url": "https://referencesource.org/workplace-exposure-limits/1-decanethiol/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"cas_number": "112-55-0", "id": "1-dodecanethiol", "rel_mgm3": "4.1", "rel_ppm": "C 0.5", "source": "https://www.cdc.gov/niosh/npg/npgd0249.html", "source_quote": "NIOSH REL C 0.5 ppm (4.1 mg/m3) [15-minute]", "substance": "1-Dodecanethiol", "url": "https://referencesource.org/workplace-exposure-limits/1-dodecanethiol/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"cas_number": "1639-09-4", "id": "1-heptanethiol", "rel_mgm3": "2.7", "rel_ppm": "C 0.5", "source": "https://www.cdc.gov/niosh/npg/npgd0313.html", "source_quote": "NIOSH REL C 0.5 ppm (2.7 mg/m3) [15-minute]", "substance": "1-Heptanethiol", "url": "https://referencesource.org/workplace-exposure-limits/1-heptanethiol/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"cas_number": "2917-26-2", "id": "1-hexadecanethiol", "rel_mgm3": "5.3", "rel_ppm": "C 0.5", "source": "https://www.cdc.gov/niosh/npg/npgd0318.html", "source_quote": "NIOSH REL C 0.5 ppm (5.3 mg/m3) [15-minute]", "substance": "1-Hexadecanethiol", "url": "https://referencesource.org/workplace-exposure-limits/1-hexadecanethiol/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"cas_number": "592416", "id": "1-hexene", "pel_mgm3": "180", "pel_ppm": "50", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "592416 | | 1-Hexene | 50 | 180", "substance": "1-Hexene", "url": "https://referencesource.org/workplace-exposure-limits/1-hexene/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0459.html", "source_quote": "NIOSH REL TWA 25 ppm (90 mg/m3)", "value": "TWA 25"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0459.html", "source_quote": "NIOSH REL TWA 25 ppm (90 mg/m3)", "value": "90"}], "cas_number": "108-03-2", "disagreements": [], "id": "1-nitropropane", "pel_mgm3": "90", "pel_ppm": "25", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "1-Nitropropane | 108-03-2 | 25 | 90 | - |", "substance": "1-Nitropropane", "url": "https://referencesource.org/workplace-exposure-limits/1-nitropropane/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "1455-21-6", "id": "1-nonanethiol", "rel_mgm3": "3.3", "rel_ppm": "C 0.5", "source": "https://www.cdc.gov/niosh/npg/npgd0467.html", "source_quote": "NIOSH REL C 0.5 ppm (3.3 mg/m3) [15-minute]", "substance": "1-Nonanethiol", "url": "https://referencesource.org/workplace-exposure-limits/1-nonanethiol/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"cas_number": "2885-00-9", "id": "1-octadecanethiol", "rel_mgm3": "5.9", "rel_ppm": "C 0.5", "source": "https://www.cdc.gov/niosh/npg/npgd0469.html", "source_quote": "NIOSH REL C 0.5 ppm (5.9 mg/m3) [15-minute]", "substance": "1-Octadecanethiol", "url": "https://referencesource.org/workplace-exposure-limits/1-octadecanethiol/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"cas_number": "111-88-6", "id": "1-octanethiol", "rel_mgm3": "3.0", "rel_ppm": "C 0.5", "source": "https://www.cdc.gov/niosh/npg/npgd0471.html", "source_quote": "NIOSH REL C 0.5 ppm (3.0 mg/m3) [15-minute]", "substance": "1-Octanethiol", "url": "https://referencesource.org/workplace-exposure-limits/1-octanethiol/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"cas_number": "110-66-7", "id": "1-pentanethiol", "rel_mgm3": "2.1", "rel_ppm": "C 0.5", "source": "https://www.cdc.gov/niosh/npg/npgd0487.html", "source_quote": "NIOSH REL C 0.5 ppm (2.1 mg/m3) [15-minute]", "substance": "1-Pentanethiol", "url": "https://referencesource.org/workplace-exposure-limits/1-pentanethiol/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"cas_number": "107-03-9", "id": "1-propanethiol", "rel_mgm3": "1.6", "rel_ppm": "C 0.5", "source": "https://www.cdc.gov/niosh/npg/npgd0526.html", "source_quote": "NIOSH REL C 0.5 ppm (1.6 mg/m3) [15-minute]", "substance": "1-Propanethiol", "url": "https://referencesource.org/workplace-exposure-limits/1-propanethiol/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"cas_number": "5332-52-5", "id": "1-undecanethiol", "rel_mgm3": "3.9", "rel_ppm": "C 0.5", "source": "https://www.cdc.gov/niosh/npg/npgd0649.html", "source_quote": "NIOSH REL C 0.5 ppm (3.9 mg/m3) [15-minute]", "substance": "1-Undecanethiol", "url": "https://referencesource.org/workplace-exposure-limits/1-undecanethiol/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0200.html", "source_quote": "NIOSH REL TWA 1 ppm (6 mg/m3)", "value": "TWA 1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0200.html", "source_quote": "NIOSH REL TWA 1 ppm (6 mg/m3)", "value": "6"}], "cas_number": "75990", "disagreements": [], "id": "2-2-dichloropropionic-acid", "pel_mgm3": "6", "pel_ppm": "1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75990 | | 2,2-Dichloropropionic acid | 1 | 6", "substance": "2,2-Dichloropropionic acid", "url": "https://referencesource.org/workplace-exposure-limits/2-2-dichloropropionic-acid/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "1746-01-6", "id": "2-3-7-8-tetrachloro-dibenzo-p-dioxin", "rel_statement": "Ca See Appendix A", "source": "https://www.cdc.gov/niosh/npg/npgd0594.html", "source_quote": "NIOSH REL Ca See Appendix A", "substance": "2,3,7,8-Tetrachloro-dibenzo-p-dioxin", "url": "https://referencesource.org/workplace-exposure-limits/2-3-7-8-tetrachloro-dibenzo-p-dioxin/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "2,4,5-T (2,4,5-trichlorophenoxyacetic acid) | 93-76-5 | - | 10 | - |", "value": "10"}], "cas_number": "93-76-5", "disagreements": [], "id": "2-4-5-t", "rel_mgm3": "TWA 10", "source": "https://www.cdc.gov/niosh/npg/npgd0583.html", "source_quote": "NIOSH REL TWA 10 mg/m3", "substance": "2,4,5-T", "url": "https://referencesource.org/workplace-exposure-limits/2-4-5-t/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "2,4,6-Trinitrotoluene (TNT) | 118-96-7 | - | 1.5 | X |", "value": "1.5"}], "cas_number": "118-96-7", "disagreements": [], "id": "2-4-6-trinitrotoluene", "rel_mgm3": "TWA 0.5", "source": "https://www.cdc.gov/niosh/npg/npgd0641.html", "source_quote": "NIOSH REL TWA 0.5 mg/m3 [skin]", "substance": "2,4,6-Trinitrotoluene", "url": "https://referencesource.org/workplace-exposure-limits/2-4-6-trinitrotoluene/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "94757 | | 2,4-D;2,4-dichlorophenoxyacetic acid | -- | 10", "value": "10"}], "cas_number": "94-75-7", "disagreements": [], "id": "2-4-d", "rel_mgm3": "TWA 10", "source": "https://www.cdc.gov/niosh/npg/npgd0173.html", "source_quote": "NIOSH REL TWA 10 mg/m3", "substance": "2,4-D", "url": "https://referencesource.org/workplace-exposure-limits/2-4-d/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"cas_number": "615-05-4", "id": "2-4-diaminoanisole-and-its-salts", "rel_statement": "Ca Minimize occupational exposure (especially skin exposures) See Appendix A", "source": "https://www.cdc.gov/niosh/npg/npgd0179.html", "source_quote": "NIOSH REL Ca Minimize occupational exposure (especially skin exposures) See Appendix A", "substance": "2,4-Diaminoanisole (and its salts)", "url": "https://referencesource.org/workplace-exposure-limits/2-4-diaminoanisole-and-its-salts/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0235.html", "source_quote": "NIOSH REL Ca TWA 1.5 mg/m3 [skin]", "value": "TWA 1.5"}], "cas_number": "25321146", "disagreements": [{"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "25321146 | S | 2,4-Dinitrotoluene | -- | 0.15", "value": "0.15"}, {"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Dinitrotoluene | 25321-14-6 | - | 1.5 | X |", "value": "1.5"}]}], "id": "2-4-dinitrotoluene", "pel_mgm3": "0.15", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "25321146 | S | 2,4-Dinitrotoluene | -- | 0.15", "substance": "2,4-Dinitrotoluene", "url": "https://referencesource.org/workplace-exposure-limits/2-4-dinitrotoluene/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0246.html", "source_quote": "NIOSH REL TWA 10 mg/m3", "value": "TWA 10"}], "cas_number": "128370", "disagreements": [], "id": "2-6-di-tert-butyl-p-cresol", "pel_mgm3": "10", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "128370 | | 2,6-Di-tert-butyl-p-cresol | -- | 10", "substance": "2,6-Di-tert-butyl-p-cresol", "url": "https://referencesource.org/workplace-exposure-limits/2-6-di-tert-butyl-p-cresol/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"cas_number": "53-96-3", "disagreements": [], "id": "2-acetylaminofluorene", "rel_statement": "Ca See Appendix A", "source": "https://www.cdc.gov/niosh/npg/npgd0007.html", "source_quote": "NIOSH REL Ca See Appendix A", "substance": "2-Acetylaminofluorene", "url": "https://referencesource.org/workplace-exposure-limits/2-acetylaminofluorene/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0026.html", "source_quote": "NIOSH REL TWA 0.5 ppm (2 mg/m3)", "value": "TWA 0.5"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0026.html", "source_quote": "NIOSH REL TWA 0.5 ppm (2 mg/m3)", "value": "2"}], "cas_number": "504-29-0", "disagreements": [], "id": "2-aminopyridine", "pel_mgm3": "2", "pel_ppm": "0.5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "2-Aminopyridine | 504-29-0 | 0.5 | 2 | - |", "substance": "2-Aminopyridine", "url": "https://referencesource.org/workplace-exposure-limits/2-aminopyridine/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "2-Butanone (Methyl ethyl ketone) | 78-93-3 | 200 | 590 | - |", "value": "200"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "2-Butanone (Methyl ethyl ketone) | 78-93-3 | 200 | 590 | - |", "value": "590"}, {"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "78933 | | Methyl ethyl ketone; MEK; 2-butanone; ethyl methyl ketone | 200 | 590 | | 300 | 885", "value": "300"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "78933 | | Methyl ethyl ketone; MEK; 2-butanone; ethyl methyl ketone | 200 | 590 | | 300 | 885", "value": "885"}], "cas_number": "78-93-3", "disagreements": [], "id": "2-butanone", "rel_mgm3": "590", "rel_ppm": "TWA 200", "source": "https://www.cdc.gov/niosh/npg/npgd0069.html", "source_quote": "NIOSH REL TWA 200 ppm (590 mg/m3) ST 300 ppm (885 mg/m3)", "substance": "2-Butanone", "url": "https://referencesource.org/workplace-exposure-limits/2-butanone/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0070.html", "source_quote": "NIOSH REL TWA 5 ppm (24 mg/m3) [skin]", "value": "TWA 5"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0070.html", "source_quote": "NIOSH REL TWA 5 ppm (24 mg/m3) [skin]", "value": "24"}], "cas_number": "111-76-2", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "2-Butoxyethanol | 111-76-2 | 50 | 240 | X |", "value": "50"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "111762 | S | 2-Butoxyethanol (EGBE) | 20 | 97", "value": "20"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "2-Butoxyethanol | 111-76-2 | 50 | 240 | X |", "value": "240"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "111762 | S | 2-Butoxyethanol (EGBE) | 20 | 97", "value": "97"}]}], "id": "2-butoxyethanol", "pel_mgm3": "240", "pel_ppm": "50", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "2-Butoxyethanol | 111-76-2 | 50 | 240 | X |", "substance": "2-Butoxyethanol", "url": "https://referencesource.org/workplace-exposure-limits/2-butoxyethanol/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "112-07-2", "id": "2-butoxyethanol-acetate", "rel_mgm3": "33", "rel_ppm": "TWA 5", "source": "https://www.cdc.gov/niosh/npg/npgd0071.html", "source_quote": "NIOSH REL TWA 5 ppm (33 mg/m3)", "substance": "2-Butoxyethanol acetate", "url": "https://referencesource.org/workplace-exposure-limits/2-butoxyethanol-acetate/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0136.html", "source_quote": "NIOSH REL TWA 10 mg/m3 (total) ST 20 mg/m3 (total) TWA 5 mg/m3 (resp)", "value": "TWA 10 mg/m3 (total) ST 20 mg/m3 (total) TWA 5 mg/m3 (resp)"}], "cas_number": "1929-82-4", "disagreements": [], "id": "2-chloro-6-trichloromethyl-pyridine", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "2-Chloro-6-(trichloromethyl) pyridine | 1929-82-4 | - | - | - |", "substance": "2-Chloro-6-(trichloromethyl) pyridine", "url": "https://referencesource.org/workplace-exposure-limits/2-chloro-6-trichloromethyl-pyridine/", "verified_fields": ["cas_number", "substance"]}
{"cas_number": "598787", "id": "2-chloropropionic-acid", "pel_mgm3": "0.44", "pel_ppm": "0.1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "598787 | S | 2-Chloropropionic acid | 0.1 | 0.44", "substance": "2-Chloropropionic acid", "url": "https://referencesource.org/workplace-exposure-limits/2-chloropropionic-acid/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0210.html", "source_quote": "NIOSH REL TWA 10 ppm (50 mg/m3) [skin]", "value": "TWA 10"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0210.html", "source_quote": "NIOSH REL TWA 10 ppm (50 mg/m3) [skin]", "value": "50"}], "cas_number": "100378", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "100378 | S | 2-(Diethylamino) ethanol | 2 | 9.6", "value": "2"}, {"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "2-Diethylaminoethanol | 100-37-8 | 10 | 50 | X |", "value": "10"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "100378 | S | 2-(Diethylamino) ethanol | 2 | 9.6", "value": "9.6"}, {"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "2-Diethylaminoethanol | 100-37-8 | 10 | 50 | X |", "value": "50"}]}], "id": "2-diethylamino-ethanol", "pel_mgm3": "9.6", "pel_ppm": "2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "100378 | S | 2-(Diethylamino) ethanol | 2 | 9.6", "substance": "2-(Diethylamino) ethanol", "url": "https://referencesource.org/workplace-exposure-limits/2-diethylamino-ethanol/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0258.html", "source_quote": "NIOSH REL TWA 0.5 ppm (1.8 mg/m3) [skin]", "value": "TWA 0.5"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0258.html", "source_quote": "NIOSH REL TWA 0.5 ppm (1.8 mg/m3) [skin]", "value": "1.8"}], "cas_number": "110805", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "110805 | S | 2-Ethoxyethanol | 5 | 18", "value": "5"}, {"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "2-Ethoxyethanol (Cellosolve) | 110-80-5 | 200 | 740 | X |", "value": "200"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "110805 | S | 2-Ethoxyethanol | 5 | 18", "value": "18"}, {"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "2-Ethoxyethanol (Cellosolve) | 110-80-5 | 200 | 740 | X |", "value": "740"}]}], "id": "2-ethoxyethanol", "pel_mgm3": "18", "pel_ppm": "5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "110805 | S | 2-Ethoxyethanol | 5 | 18", "substance": "2-Ethoxyethanol", "url": "https://referencesource.org/workplace-exposure-limits/2-ethoxyethanol/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0259.html", "source_quote": "NIOSH REL TWA 0.5 ppm (2.7 mg/m3) [skin]", "value": "TWA 0.5"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0259.html", "source_quote": "NIOSH REL TWA 0.5 ppm (2.7 mg/m3) [skin]", "value": "2.7"}], "cas_number": "111159", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "111159 | S | 2-Ethoxyethyl acetate | 5 | 27", "value": "5"}, {"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "2-Ethoxyethyl acetate (Cellosolve acetate) | 111-15-9 | 100 | 540 | X |", "value": "100"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "111159 | S | 2-Ethoxyethyl acetate | 5 | 27", "value": "27"}, {"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "2-Ethoxyethyl acetate (Cellosolve acetate) | 111-15-9 | 100 | 540 | X |", "value": "540"}]}], "id": "2-ethoxyethyl-acetate", "pel_mgm3": "27", "pel_ppm": "5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "111159 | S | 2-Ethoxyethyl acetate | 5 | 27", "substance": "2-Ethoxyethyl acetate", "url": "https://referencesource.org/workplace-exposure-limits/2-ethoxyethyl-acetate/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "2-Hexanone (Methyl n-butyl ketone) | 591-78-6 | 100 | 410 | - |", "value": "100"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "2-Hexanone (Methyl n-butyl ketone) | 591-78-6 | 100 | 410 | - |", "value": "410"}, {"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "591786 | S | Methyl n-butyl ketone; 2-hexanone | 1 | 4 | | 10 | 40", "value": "10"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "591786 | S | Methyl n-butyl ketone; 2-hexanone | 1 | 4 | | 10 | 40", "value": "40"}], "cas_number": "591-78-6", "disagreements": [], "id": "2-hexanone", "rel_mgm3": "4", "rel_ppm": "TWA 1", "source": "https://www.cdc.gov/niosh/npg/npgd0325.html", "source_quote": "NIOSH REL TWA 1 ppm (4 mg/m3)", "substance": "2-Hexanone", "url": "https://referencesource.org/workplace-exposure-limits/2-hexanone/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0339.html", "source_quote": "NIOSH REL TWA 0.5 ppm (3 mg/m3) [skin]", "value": "TWA 0.5"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0339.html", "source_quote": "NIOSH REL TWA 0.5 ppm (3 mg/m3) [skin]", "value": "3"}], "cas_number": "999611", "disagreements": [], "id": "2-hydroxypropyl-acrylate", "pel_mgm3": "3", "pel_ppm": "0.5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "999611 | S | 2-Hydroxypropyl acrylate | 0.5 | 3", "substance": "2-Hydroxypropyl acrylate", "url": "https://referencesource.org/workplace-exposure-limits/2-hydroxypropyl-acrylate/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "109591 | | Isopropoxyethanol | 25 | 105", "value": "25"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "109591 | | Isopropoxyethanol | 25 | 105", "value": "105"}], "cas_number": "109-59-1", "disagreements": [], "id": "2-isopropoxyethanol", "rel_statement": "See Appendix D", "source": "https://www.cdc.gov/niosh/npg/npgd0357.html", "source_quote": "NIOSH REL See Appendix D", "substance": "2-Isopropoxyethanol", "url": "https://referencesource.org/workplace-exposure-limits/2-isopropoxyethanol/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0401.html", "source_quote": "NIOSH REL TWA 0.1 ppm (0.3 mg/m3) [skin]", "value": "TWA 0.1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0401.html", "source_quote": "NIOSH REL TWA 0.1 ppm (0.3 mg/m3) [skin]", "value": "0.3"}], "cas_number": "109864", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "109864 | S | 2-Methoxyethanol | 5 | 16", "value": "5"}, {"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "2-Methoxyethanol (Methyl cellosolve) | 109-86-4 | 25 | 80 | X |", "value": "25"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "109864 | S | 2-Methoxyethanol | 5 | 16", "value": "16"}, {"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "2-Methoxyethanol (Methyl cellosolve) | 109-86-4 | 25 | 80 | X |", "value": "80"}]}], "id": "2-methoxyethanol", "pel_mgm3": "16", "pel_ppm": "5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "109864 | S | 2-Methoxyethanol | 5 | 16", "substance": "2-Methoxyethanol", "url": "https://referencesource.org/workplace-exposure-limits/2-methoxyethanol/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0402.html", "source_quote": "NIOSH REL TWA 0.1 ppm (0.5 mg/m3) [skin]", "value": "TWA 0.1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0402.html", "source_quote": "NIOSH REL TWA 0.1 ppm (0.5 mg/m3) [skin]", "value": "0.5"}], "cas_number": "110496", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "110496 | | 2-Methoxyethyl acetate | 5 | 24", "value": "5"}, {"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "2-Methoxyethyl acetate (Methyl cellosolve acetate) | 110-49-6 | 25 | 120 | X |", "value": "25"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "110496 | | 2-Methoxyethyl acetate | 5 | 24", "value": "24"}, {"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "2-Methoxyethyl acetate (Methyl cellosolve acetate) | 110-49-6 | 25 | 120 | X |", "value": "120"}]}], "id": "2-methoxyethyl-acetate", "pel_mgm3": "24", "pel_ppm": "5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "110496 | | 2-Methoxyethyl acetate | 5 | 24", "substance": "2-Methoxyethyl acetate", "url": "https://referencesource.org/workplace-exposure-limits/2-methoxyethyl-acetate/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "624419", "id": "2-methylbutyl-acetate-see-pentyl-acetate", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "624419 | | 2-Methylbutyl acetate; see Pentyl acetate", "substance": "2-Methylbutyl acetate; see Pentyl acetate", "url": "https://referencesource.org/workplace-exposure-limits/2-methylbutyl-acetate-see-pentyl-acetate/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0409.html", "source_quote": "NIOSH REL TWA 0.2 mg/m3 [skin]", "value": "TWA 0.2"}], "cas_number": "12108133", "disagreements": [], "id": "2-methylcyclopentadienyl-manganese-tricarbonyl-as-mn", "pel_mgm3": "0.2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "12108133 | S | 2-Methylcyclopentadienyl manganese tricarbonyl, as Mn | -- | 0.2", "substance": "2-Methylcyclopentadienyl manganese tricarbonyl, as Mn", "url": "https://referencesource.org/workplace-exposure-limits/2-methylcyclopentadienyl-manganese-tricarbonyl-as-mn/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0185.html", "source_quote": "NIOSH REL TWA 2 ppm (14 mg/m3) [skin]", "value": "TWA 2"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0185.html", "source_quote": "NIOSH REL TWA 2 ppm (14 mg/m3) [skin]", "value": "14"}], "cas_number": "102818", "disagreements": [], "id": "2-n-dibutylaminoethanol", "pel_mgm3": "14", "pel_ppm": "2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "102818 | S | 2-N-Dibutylaminoethanol | 2 | 14", "substance": "2-N-Dibutylaminoethanol", "url": "https://referencesource.org/workplace-exposure-limits/2-n-dibutylaminoethanol/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "581-89-5", "id": "2-nitronaphthalene", "rel_statement": "Ca* See Appendix A", "source": "https://www.cdc.gov/niosh/npg/npgd0458.html", "source_quote": "NIOSH REL Ca* See Appendix A", "substance": "2-Nitronaphthalene", "url": "https://referencesource.org/workplace-exposure-limits/2-nitronaphthalene/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0460.html", "source_quote": "NIOSH REL Ca See Appendix A", "value": "Ca See Appendix A"}], "cas_number": "79-46-9", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "2-Nitropropane | 79-46-9 | 25 | 90 | - |", "value": "25"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "79469 | | 2-Nitropropane | 10 | 35", "value": "10"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "2-Nitropropane | 79-46-9 | 25 | 90 | - |", "value": "90"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "79469 | | 2-Nitropropane | 10 | 35", "value": "35"}]}], "id": "2-nitropropane", "pel_mgm3": "90", "pel_ppm": "25", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "2-Nitropropane | 79-46-9 | 25 | 90 | - |", "substance": "2-Nitropropane", "url": "https://referencesource.org/workplace-exposure-limits/2-nitropropane/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "2-Pentanone (Methyl propyl ketone) | 107-87-9 | 200 | 700 | - |", "value": "200"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "2-Pentanone (Methyl propyl ketone) | 107-87-9 | 200 | 700 | - |", "value": "700"}, {"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "107879 | | Methyl propyl ketone; 2-pentanone | 200 | 700 | | 250 | 875", "value": "250"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "107879 | | Methyl propyl ketone; 2-pentanone | 200 | 700 | | 250 | 875", "value": "875"}], "cas_number": "107-87-9", "disagreements": [], "id": "2-pentanone", "rel_mgm3": "530", "rel_ppm": "TWA 150", "source": "https://www.cdc.gov/niosh/npg/npgd0488.html", "source_quote": "NIOSH REL TWA 150 ppm (530 mg/m3)", "substance": "2-Pentanone", "url": "https://referencesource.org/workplace-exposure-limits/2-pentanone/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0191.html", "source_quote": "NIOSH REL Ca See Appendix A", "value": "Ca See Appendix A"}], "cas_number": "91941", "disagreements": [], "id": "3-3-dichlorobenzidine-4-4-diamino-3-3-dichlorobiphenyl-see-section-5209", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "91941 | S | 3,3'-Dichlorobenzidine; 4,4'-diamino-3,3'-dichlorobiphenyl; see Section 5209", "substance": "3,3'-Dichlorobenzidine; 4,4'-diamino-3,3'-dichlorobiphenyl; see Section 5209", "url": "https://referencesource.org/workplace-exposure-limits/3-3-dichlorobenzidine-4-4-diamino-3-3-dichlorobiphenyl-see-section-5209/", "verified_fields": ["cas_number", "substance"]}
{"cas_number": "620111", "id": "3-amyl-acetate-see-pentyl-acetate", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "620111 | | 3-Amyl acetate; see Pentyl acetate", "substance": "3-Amyl acetate; see Pentyl acetate", "url": "https://referencesource.org/workplace-exposure-limits/3-amyl-acetate-see-pentyl-acetate/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0411.html", "source_quote": "NIOSH REL Ca TWA 0.003 mg/m3 [skin]", "value": "TWA 0.003"}], "cas_number": "101144", "disagreements": [], "id": "4-4-methylene-bis-2-chloroaniline-see-also-section-5215", "pel_mgm3": "0.01", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "101144 | S | 4,4′-Methylene bis(2-chloroaniline), see also Section 5215 | -- | 0.01", "substance": "4,4′-Methylene bis(2-chloroaniline), see also Section 5215", "url": "https://referencesource.org/workplace-exposure-limits/4-4-methylene-bis-2-chloroaniline-see-also-section-5215/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0415.html", "source_quote": "NIOSH REL Ca See Appendix A", "value": "Ca See Appendix A"}], "cas_number": "101779", "disagreements": [], "id": "4-4-methylene-dianiline-mda-see-also-sections-1535-5200", "pel_mgm3": "0.08", "pel_ppm": "0.01", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "101779 | S | 4,4′-Methylene dianiline; MDA (see also Sections 1535 & 5200) | 0.01 | 0.08 | | 0.1 | 0.8", "stel_mgm3": "0.8", "stel_ppm": "0.1", "substance": "4,4′-Methylene dianiline; MDA (see also Sections 1535 & 5200)", "url": "https://referencesource.org/workplace-exposure-limits/4-4-methylene-dianiline-mda-see-also-sections-1535-5200/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "stel_mgm3", "stel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0609.html", "source_quote": "NIOSH REL TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)", "value": "TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)"}], "cas_number": "96-69-5", "disagreements": [], "id": "4-4-thiobis-6-tert-butyl-m-cresol", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "4,4′-Thiobis (6-tert, Butyl-m-cresol) | 96-69-5 | - | - | - |", "substance": "4,4′-Thiobis (6-tert, Butyl-m-cresol)", "url": "https://referencesource.org/workplace-exposure-limits/4-4-thiobis-6-tert-butyl-m-cresol/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0234.html", "source_quote": "NIOSH REL TWA 0.2 mg/m3 [skin]", "value": "TWA 0.2"}], "cas_number": "534521", "disagreements": [], "id": "4-6-dinitro-o-cresol-2-methyl-4-6-dinitrophenol", "pel_mgm3": "0.2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "534521 | S | 4,6-Dinitro-o-cresol; 2-methyl-4,6-dinitrophenol | -- | 0.2", "substance": "4,6-Dinitro-o-cresol; 2-methyl-4,6-dinitrophenol", "url": "https://referencesource.org/workplace-exposure-limits/4-6-dinitro-o-cresol-2-methyl-4-6-dinitrophenol/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"cas_number": "92-67-1", "disagreements": [], "id": "4-aminodiphenyl", "rel_statement": "Ca See Appendix A", "source": "https://www.cdc.gov/niosh/npg/npgd0025.html", "source_quote": "NIOSH REL Ca See Appendix A", "substance": "4-Aminodiphenyl", "url": "https://referencesource.org/workplace-exposure-limits/4-aminodiphenyl/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"cas_number": "60-11-7", "disagreements": [], "id": "4-dimethylaminoazobenzene", "rel_statement": "Ca See Appendix A", "source": "https://www.cdc.gov/niosh/npg/npgd0220.html", "source_quote": "NIOSH REL Ca See Appendix A", "substance": "4-Dimethylaminoazobenzene", "url": "https://referencesource.org/workplace-exposure-limits/4-dimethylaminoazobenzene/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0390.html", "source_quote": "NIOSH REL TWA 5 mg/m3", "value": "TWA 5"}], "cas_number": "150765", "disagreements": [], "id": "4-methoxyphenol", "pel_mgm3": "5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "150765 | | 4-Methoxyphenol | -- | 5", "substance": "4-Methoxyphenol", "url": "https://referencesource.org/workplace-exposure-limits/4-methoxyphenol/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"cas_number": "92-93-3", "disagreements": [], "id": "4-nitrobiphenyl", "rel_statement": "Ca See Appendix A", "source": "https://www.cdc.gov/niosh/npg/npgd0451.html", "source_quote": "NIOSH REL Ca See Appendix A", "substance": "4-Nitrobiphenyl", "url": "https://referencesource.org/workplace-exposure-limits/4-nitrobiphenyl/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"cas_number": "100403", "id": "4-vinyl-cyclohexene", "pel_mgm3": "0.4", "pel_ppm": "0.1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "100403 | S | 4-Vinyl cyclohexene | 0.1 | 0.4", "substance": "4-Vinyl cyclohexene", "url": "https://referencesource.org/workplace-exposure-limits/4-vinyl-cyclohexene/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ethyl amyl ketone (5-Methyl-3-heptanone) | 541-85-5 | 25 | 130 | - |", "value": "25"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ethyl amyl ketone (5-Methyl-3-heptanone) | 541-85-5 | 25 | 130 | - |", "value": "130"}], "cas_number": "541-85-5", "disagreements": [], "id": "5-methyl-3-heptanone", "rel_mgm3": "130", "rel_ppm": "TWA 25", "source": "https://www.cdc.gov/niosh/npg/npgd0418.html", "source_quote": "NIOSH REL TWA 25 ppm (130 mg/m3)", "substance": "5-Methyl-3-heptanone", "url": "https://referencesource.org/workplace-exposure-limits/5-methyl-3-heptanone/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0119.html", "source_quote": "NIOSH REL TWA 0.3 mg/m3 (0.05 ppm)", "value": "0.05"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0119.html", "source_quote": "NIOSH REL TWA 0.3 mg/m3 (0.05 ppm)", "value": "TWA 0.3"}], "cas_number": "532-27-4", "disagreements": [], "id": "a-chloroacetophenone-phenacyl-chloride", "pel_mgm3": "0.3", "pel_ppm": "0.05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "a-Chloroacetophenone (Phenacyl chloride) | 532-27-4 | 0.05 | 0.3 | - |", "substance": "a-Chloroacetophenone (Phenacyl chloride)", "url": "https://referencesource.org/workplace-exposure-limits/a-chloroacetophenone-phenacyl-chloride/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75070 | | Acetaldehyde | 25 | 45 | C", "value": "the values given in the PEL columns are ceiling values"}, {"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0001.html", "source_quote": "NIOSH REL Ca See Appendix A See Appendix C (Aldehydes)", "value": "Ca See Appendix A See Appendix C (Aldehydes)"}], "cas_number": "75-07-0", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Acetaldehyde | 75-07-0 | 200 | 360 | - |", "value": "200"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75070 | | Acetaldehyde | 25 | 45 | C", "value": "25"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Acetaldehyde | 75-07-0 | 200 | 360 | - |", "value": "360"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75070 | | Acetaldehyde | 25 | 45 | C", "value": "45"}]}], "id": "acetaldehyde", "pel_mgm3": "360", "pel_ppm": "200", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Acetaldehyde | 75-07-0 | 200 | 360 | - |", "substance": "Acetaldehyde", "url": "https://referencesource.org/workplace-exposure-limits/acetaldehyde/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-28", "field": "ceiling", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "64197 | | Acetic acid | 10 | 25 | 40 ppm | 15 | 37", "value": "40 ppm"}, {"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "64197 | | Acetic acid | 10 | 25 | 40 ppm | 15 | 37", "value": "a ceiling value in addition to the TWA values"}, {"as_of": "2026-09-28", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "64197 | | Acetic acid | 10 | 25 | 40 ppm | 15 | 37", "value": "15"}, {"as_of": "2026-09-28", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "64197 | | Acetic acid | 10 | 25 | 40 ppm | 15 | 37", "value": "37"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0002.html", "source_quote": "NIOSH REL TWA 10 ppm (25 mg/m3) ST 15 ppm (37 mg/m3)", "value": "TWA 10"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0002.html", "source_quote": "NIOSH REL TWA 10 ppm (25 mg/m3) ST 15 ppm (37 mg/m3)", "value": "25"}], "cas_number": "64-19-7", "disagreements": [], "id": "acetic-acid", "pel_mgm3": "25", "pel_ppm": "10", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Acetic acid | 64-19-7 | 10 | 25 | - |", "substance": "Acetic acid", "url": "https://referencesource.org/workplace-exposure-limits/acetic-acid/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "108247 | | Acetic Anhydride | 5 | 20 | C", "value": "the values given in the PEL columns are ceiling values"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0003.html", "source_quote": "NIOSH REL C 5 ppm (20 mg/m3)", "value": "C 5"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0003.html", "source_quote": "NIOSH REL C 5 ppm (20 mg/m3)", "value": "20"}], "cas_number": "108-24-7", "disagreements": [], "id": "acetic-anhydride", "pel_mgm3": "20", "pel_ppm": "5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Acetic anhydride | 108-24-7 | 5 | 20 | - |", "substance": "Acetic anhydride", "url": "https://referencesource.org/workplace-exposure-limits/acetic-anhydride/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-28", "field": "ceiling", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "67641 | | Acetone | 500 | 1200 | 3000 ppm | 750 | 1780", "value": "3000 ppm"}, {"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "67641 | | Acetone | 500 | 1200 | 3000 ppm | 750 | 1780", "value": "a ceiling value in addition to the TWA values"}, {"as_of": "2026-09-28", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "67641 | | Acetone | 500 | 1200 | 3000 ppm | 750 | 1780", "value": "750"}, {"as_of": "2026-09-28", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "67641 | | Acetone | 500 | 1200 | 3000 ppm | 750 | 1780", "value": "1780"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0004.html", "source_quote": "NIOSH REL TWA 250 ppm (590 mg/m3)", "value": "TWA 250"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0004.html", "source_quote": "NIOSH REL TWA 250 ppm (590 mg/m3)", "value": "590"}], "cas_number": "67-64-1", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Acetone | 67-64-1 | 1000 | 2400 | - |", "value": "1000"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "67641 | | Acetone | 500 | 1200 | 3000 ppm | 750 | 1780", "value": "500"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Acetone | 67-64-1 | 1000 | 2400 | - |", "value": "2400"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "67641 | | Acetone | 500 | 1200 | 3000 ppm | 750 | 1780", "value": "1200"}]}], "id": "acetone", "pel_mgm3": "2400", "pel_ppm": "1000", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Acetone | 67-64-1 | 1000 | 2400 | - |", "substance": "Acetone", "url": "https://referencesource.org/workplace-exposure-limits/acetone/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-28", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75865 | | Acetone cyanohydrin as CN | 4.7 | 5 | C", "value": "4.7"}, {"as_of": "2026-09-28", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75865 | | Acetone cyanohydrin as CN | 4.7 | 5 | C", "value": "5"}, {"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75865 | | Acetone cyanohydrin as CN | 4.7 | 5 | C", "value": "the values given in the PEL columns are ceiling values"}], "cas_number": "75-86-5", "disagreements": [], "id": "acetone-cyanohydrin", "rel_mgm3": "4", "rel_ppm": "C 1", "source": "https://www.cdc.gov/niosh/npg/npgd0005.html", "source_quote": "NIOSH REL C 1 ppm (4 mg/m3) [15-minute]", "substance": "Acetone cyanohydrin", "url": "https://referencesource.org/workplace-exposure-limits/acetone-cyanohydrin/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75058 | S | Acetonitrile | 40 | 70 | | 60 | 105", "value": "60"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75058 | S | Acetonitrile | 40 | 70 | | 60 | 105", "value": "105"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0006.html", "source_quote": "NIOSH REL TWA 20 ppm (34 mg/m³)", "value": "TWA 20"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0006.html", "source_quote": "NIOSH REL TWA 20 ppm (34 mg/m³)", "value": "34"}], "cas_number": "75-05-8", "disagreements": [], "id": "acetonitrile", "pel_mgm3": "70", "pel_ppm": "40", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Acetonitrile | 75-05-8 | 40 | 70 | - |", "substance": "Acetonitrile", "url": "https://referencesource.org/workplace-exposure-limits/acetonitrile/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "98862", "id": "acetophenone", "pel_mgm3": "49", "pel_ppm": "10", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "98862 | | Acetophenone | 10 | 49", "substance": "Acetophenone", "url": "https://referencesource.org/workplace-exposure-limits/acetophenone/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0008.html", "source_quote": "NIOSH REL C 2500 ppm (2662 mg/m3)", "value": "C 2500"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0008.html", "source_quote": "NIOSH REL C 2500 ppm (2662 mg/m3)", "value": "2662"}], "cas_number": "74862", "disagreements": [], "id": "acetylene", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "74862 | | Acetylene | (h)", "substance": "Acetylene", "url": "https://referencesource.org/workplace-exposure-limits/acetylene/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0009.html", "source_quote": "NIOSH REL See Appendix D", "value": "See Appendix D"}], "cas_number": "79-27-6", "disagreements": [], "id": "acetylene-tetrabromide", "pel_mgm3": "14", "pel_ppm": "1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Acetylene tetrabromide | 79-27-6 | 1 | 14 | - |", "substance": "Acetylene tetrabromide", "url": "https://referencesource.org/workplace-exposure-limits/acetylene-tetrabromide/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "50782 | | Acetylsalicylic acid (Aspirin) | -- | 5", "value": "5"}], "cas_number": "50-78-2", "disagreements": [], "id": "acetylsalicylic-acid", "rel_mgm3": "TWA 5", "source": "https://www.cdc.gov/niosh/npg/npgd0010.html", "source_quote": "NIOSH REL TWA 5 mg/m3", "substance": "Acetylsalicylic acid", "url": "https://referencesource.org/workplace-exposure-limits/acetylsalicylic-acid/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "107028 | S | Acrolein | 0.1 | 0.25 | C", "value": "the values given in the PEL columns are ceiling values"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0011.html", "source_quote": "NIOSH REL TWA 0.1 ppm (0.25 mg/m3) ST 0.3 ppm (0.8 mg/m3)", "value": "TWA 0.1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0011.html", "source_quote": "NIOSH REL TWA 0.1 ppm (0.25 mg/m3) ST 0.3 ppm (0.8 mg/m3)", "value": "0.25"}], "cas_number": "107-02-8", "disagreements": [], "id": "acrolein", "pel_mgm3": "0.25", "pel_ppm": "0.1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Acrolein | 107-02-8 | 0.1 | 0.25 | - |", "substance": "Acrolein", "url": "https://referencesource.org/workplace-exposure-limits/acrolein/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0012.html", "source_quote": "NIOSH REL Ca TWA 0.03 mg/m3 [skin]", "value": "TWA 0.03"}], "cas_number": "79-06-1", "disagreements": [{"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Acrylamide | 79-06-1 | - | 0.3 | X |", "value": "0.3"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "79061 | S | Acrylamide | -- | 0.03", "value": "0.03"}]}], "id": "acrylamide", "pel_mgm3": "0.3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Acrylamide | 79-06-1 | - | 0.3 | X |", "substance": "Acrylamide", "url": "https://referencesource.org/workplace-exposure-limits/acrylamide/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0013.html", "source_quote": "NIOSH REL TWA 2 ppm (6 mg/m3) [skin]", "value": "TWA 2"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0013.html", "source_quote": "NIOSH REL TWA 2 ppm (6 mg/m3) [skin]", "value": "6"}], "cas_number": "79107", "disagreements": [], "id": "acrylic-acid", "pel_mgm3": "5.9", "pel_ppm": "2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "79107 | S | Acrylic acid | 2 | 5.9", "substance": "Acrylic acid", "url": "https://referencesource.org/workplace-exposure-limits/acrylic-acid/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "107131 | S | Acrylonitrile; see Section 5213 | 2 | 4.5", "value": "2"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "107131 | S | Acrylonitrile; see Section 5213 | 2 | 4.5", "value": "4.5"}], "cas_number": "107-13-1", "disagreements": [], "id": "acrylonitrile", "rel_ppm": "TWA 1", "source": "https://www.cdc.gov/niosh/npg/npgd0014.html", "source_quote": "NIOSH REL Ca TWA 1 ppm C 10 ppm [15-minute] [skin]", "substance": "Acrylonitrile", "url": "https://referencesource.org/workplace-exposure-limits/acrylonitrile/", "verified_fields": ["cas_number", "rel_ppm", "substance"]}
{"cas_number": "124049", "id": "adipic-acid", "pel_mgm3": "5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "124049 | | Adipic acid | -- | 5", "substance": "Adipic acid", "url": "https://referencesource.org/workplace-exposure-limits/adipic-acid/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0015.html", "source_quote": "NIOSH REL TWA 4 ppm (18 mg/m3)", "value": "TWA 4"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0015.html", "source_quote": "NIOSH REL TWA 4 ppm (18 mg/m3)", "value": "18"}], "cas_number": "111693", "disagreements": [], "id": "adiponitrile", "pel_mgm3": "8.8", "pel_ppm": "2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "111693 | S | Adiponitrile | 2 | 8.8", "substance": "Adiponitrile", "url": "https://referencesource.org/workplace-exposure-limits/adiponitrile/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0016.html", "source_quote": "NIOSH REL Ca TWA 0.25 mg/m3 [skin]", "value": "TWA 0.25"}], "cas_number": "309-00-2", "disagreements": [], "id": "aldrin", "pel_mgm3": "0.25", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Aldrin | 309-00-2 | - | 0.25 | X |", "substance": "Aldrin", "url": "https://referencesource.org/workplace-exposure-limits/aldrin/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "107186 | S | Allyl alcohol | 0.5 | 1.25 | | 4 | 10", "value": "4"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "107186 | S | Allyl alcohol | 0.5 | 1.25 | | 4 | 10", "value": "10"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0017.html", "source_quote": "NIOSH REL TWA 2 ppm (5 mg/m3) ST 4 ppm (10 mg/m3) [skin]", "value": "TWA 2"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0017.html", "source_quote": "NIOSH REL TWA 2 ppm (5 mg/m3) ST 4 ppm (10 mg/m3) [skin]", "value": "5"}], "cas_number": "107-18-6", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Allyl alcohol | 107-18-6 | 2 | 5 | X |", "value": "2"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "107186 | S | Allyl alcohol | 0.5 | 1.25 | | 4 | 10", "value": "0.5"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Allyl alcohol | 107-18-6 | 2 | 5 | X |", "value": "5"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "107186 | S | Allyl alcohol | 0.5 | 1.25 | | 4 | 10", "value": "1.25"}]}], "id": "allyl-alcohol", "pel_mgm3": "5", "pel_ppm": "2", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Allyl alcohol | 107-18-6 | 2 | 5 | X |", "substance": "Allyl alcohol", "url": "https://referencesource.org/workplace-exposure-limits/allyl-alcohol/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "107051 | | Allyl chloride | 1 | 3 | | 2 | 6", "value": "2"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "107051 | | Allyl chloride | 1 | 3 | | 2 | 6", "value": "6"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0018.html", "source_quote": "NIOSH REL TWA 1 ppm (3 mg/m3) ST 2 ppm (6 mg/m3)", "value": "TWA 1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0018.html", "source_quote": "NIOSH REL TWA 1 ppm (3 mg/m3) ST 2 ppm (6 mg/m3)", "value": "3"}], "cas_number": "107-05-1", "disagreements": [], "id": "allyl-chloride", "pel_mgm3": "3", "pel_ppm": "1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Allyl chloride | 107-05-1 | 1 | 3 | - |", "substance": "Allyl chloride", "url": "https://referencesource.org/workplace-exposure-limits/allyl-chloride/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Allyl glycidyl ether (AGE) | 106-92-3 | (C)10 | (C)45 | - |", "value": "(C)10"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Allyl glycidyl ether (AGE) | 106-92-3 | (C)10 | (C)45 | - |", "value": "(C)45"}], "cas_number": "106-92-3", "disagreements": [], "id": "allyl-glycidyl-ether", "rel_mgm3": "22", "rel_ppm": "TWA 5", "source": "https://www.cdc.gov/niosh/npg/npgd0019.html", "source_quote": "NIOSH REL TWA 5 ppm (22 mg/m3) ST 10 ppm (44 mg/m3) [skin]", "substance": "Allyl glycidyl ether", "url": "https://referencesource.org/workplace-exposure-limits/allyl-glycidyl-ether/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "2179591 | | Allyl propyl disulfide | 2 | 12 | | 3 | 18", "value": "3"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "2179591 | | Allyl propyl disulfide | 2 | 12 | | 3 | 18", "value": "18"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0020.html", "source_quote": "NIOSH REL TWA 2 ppm (12 mg/m3) ST 3 ppm (18 mg/m3)", "value": "TWA 2"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0020.html", "source_quote": "NIOSH REL TWA 2 ppm (12 mg/m3) ST 3 ppm (18 mg/m3)", "value": "12"}], "cas_number": "2179-59-1", "disagreements": [], "id": "allyl-propyl-disulfide", "pel_mgm3": "12", "pel_ppm": "2", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Allyl propyl disulfide | 2179-59-1 | 2 | 12 | - |", "substance": "Allyl propyl disulfide", "url": "https://referencesource.org/workplace-exposure-limits/allyl-propyl-disulfide/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0021.html", "source_quote": "NIOSH REL See Appendix D", "value": "See Appendix D"}], "cas_number": "1344-28-1", "disagreements": [], "id": "alpha-alumina", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "alpha-Alumina | 1344-28-1 | - | - | - |", "substance": "alpha-Alumina", "url": "https://referencesource.org/workplace-exposure-limits/alpha-alumina/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0429.html", "source_quote": "NIOSH REL TWA 50 ppm (240 mg/m3) ST 100 ppm (485 mg/m3)", "value": "TWA 50"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0429.html", "source_quote": "NIOSH REL TWA 50 ppm (240 mg/m3) ST 100 ppm (485 mg/m3)", "value": "240"}, {"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "98839 | | alpha-Methylstyrene; 1-methyl-1-phenylethene | 50 | 240 | | 100 | 485", "value": "100"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "98839 | | alpha-Methylstyrene; 1-methyl-1-phenylethene | 50 | 240 | | 100 | 485", "value": "485"}], "cas_number": "98-83-9", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "alpha-Methyl styrene | 98-83-9 | (C)100 | (C)480 | - |", "value": "(C)100"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "98839 | | alpha-Methylstyrene; 1-methyl-1-phenylethene | 50 | 240 | | 100 | 485", "value": "50"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "alpha-Methyl styrene | 98-83-9 | (C)100 | (C)480 | - |", "value": "(C)480"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "98839 | | alpha-Methylstyrene; 1-methyl-1-phenylethene | 50 | 240 | | 100 | 485", "value": "240"}]}], "id": "alpha-methyl-styrene", "pel_mgm3": "(C)480", "pel_ppm": "(C)100", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "alpha-Methyl styrene | 98-83-9 | (C)100 | (C)480 | - |", "substance": "alpha-Methyl styrene", "url": "https://referencesource.org/workplace-exposure-limits/alpha-methyl-styrene/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0395.html", "source_quote": "NIOSH REL TWA 1 ppm (3 mg/m³) [skin]", "value": "TWA 1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0395.html", "source_quote": "NIOSH REL TWA 1 ppm (3 mg/m³) [skin]", "value": "3"}], "cas_number": "126987", "disagreements": [], "id": "alpha-methylacrylonitrile", "pel_mgm3": "3", "pel_ppm": "1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "126987 | S | alpha-Methylacrylonitrile | 1 | 3", "substance": "alpha-Methylacrylonitrile", "url": "https://referencesource.org/workplace-exposure-limits/alpha-methylacrylonitrile/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "134-32-7", "disagreements": [], "id": "alpha-naphthylamine", "rel_statement": "Ca See Appendix A", "source": "https://www.cdc.gov/niosh/npg/npgd0441.html", "source_quote": "NIOSH REL Ca See Appendix A", "substance": "alpha-Naphthylamine", "url": "https://referencesource.org/workplace-exposure-limits/alpha-naphthylamine/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"cas_number": "7429-90-5", "disagreements": [], "id": "aluminum", "rel_statement": "TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)", "source": "https://www.cdc.gov/niosh/npg/npgd0022.html", "source_quote": "NIOSH REL TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)", "substance": "Aluminum", "url": "https://referencesource.org/workplace-exposure-limits/aluminum/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"id": "aluminum-alkyls-not-otherwise-classified", "pel_mgm3": "2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Aluminum, alkyls (not otherwise classified) | -- | 2", "substance": "Aluminum, alkyls (not otherwise classified)", "url": "https://referencesource.org/workplace-exposure-limits/aluminum-alkyls-not-otherwise-classified/", "verified_fields": ["pel_mgm3", "substance"]}
{"cas_number": "300925", "id": "aluminum-distearate", "pel_mgm3": "10", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "300925 | | Aluminum distearate | -- | 10", "substance": "Aluminum distearate", "url": "https://referencesource.org/workplace-exposure-limits/aluminum-distearate/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"id": "aluminum-pyro-powders", "pel_mgm3": "5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Aluminum pyro powders | -- | 5", "substance": "Aluminum pyro powders", "url": "https://referencesource.org/workplace-exposure-limits/aluminum-pyro-powders/", "verified_fields": ["pel_mgm3", "substance"]}
{"id": "aluminum-soluble-salts", "pel_mgm3": "2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Aluminum soluble salts | -- | 2", "substance": "Aluminum soluble salts", "url": "https://referencesource.org/workplace-exposure-limits/aluminum-soluble-salts/", "verified_fields": ["pel_mgm3", "substance"]}
{"cas_number": "7047849", "id": "aluminum-stearate", "pel_mgm3": "10", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7047849 | | Aluminum stearate | -- | 10", "substance": "Aluminum stearate", "url": "https://referencesource.org/workplace-exposure-limits/aluminum-stearate/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"cas_number": "637127", "id": "aluminum-tristearate", "pel_mgm3": "10", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "637127 | | Aluminum tristearate | -- | 10", "substance": "Aluminum tristearate", "url": "https://referencesource.org/workplace-exposure-limits/aluminum-tristearate/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"id": "aluminum-welding-fumes", "pel_mgm3": "5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Aluminum welding fumes | -- | 5", "substance": "Aluminum welding fumes", "url": "https://referencesource.org/workplace-exposure-limits/aluminum-welding-fumes/", "verified_fields": ["pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0027.html", "source_quote": "NIOSH REL Ca TWA 0.2 mg/m3", "value": "TWA 0.2"}], "cas_number": "61825", "disagreements": [], "id": "amitrole", "pel_mgm3": "0.2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "61825 | | Amitrole | -- | 0.2", "substance": "Amitrole", "url": "https://referencesource.org/workplace-exposure-limits/amitrole/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7664417 | | Ammonia | 25 | 18 | | 35 | 27", "value": "35"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7664417 | | Ammonia | 25 | 18 | | 35 | 27", "value": "27"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0028.html", "source_quote": "NIOSH REL TWA 25 ppm (18 mg/m3) ST 35 ppm (27 mg/m3)", "value": "TWA 25"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0028.html", "source_quote": "NIOSH REL TWA 25 ppm (18 mg/m3) ST 35 ppm (27 mg/m3)", "value": "18"}], "cas_number": "7664-41-7", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ammonia | 7664-41-7 | 50 | 35 | - |", "value": "50"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7664417 | | Ammonia | 25 | 18 | | 35 | 27", "value": "25"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ammonia | 7664-41-7 | 50 | 35 | - |", "value": "35"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7664417 | | Ammonia | 25 | 18 | | 35 | 27", "value": "18"}]}], "id": "ammonia", "pel_mgm3": "35", "pel_ppm": "50", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ammonia | 7664-41-7 | 50 | 35 | - |", "substance": "Ammonia", "url": "https://referencesource.org/workplace-exposure-limits/ammonia/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0029.html", "source_quote": "NIOSH REL TWA 10 mg/m3 ST 20 mg/m3", "value": "TWA 10"}], "cas_number": "12125029", "disagreements": [], "id": "ammonium-chloride-fume", "pel_mgm3": "10", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "12125029 | | Ammonium chloride fume | -- | 10 | | -- | 20", "stel_mgm3": "20", "substance": "Ammonium chloride fume", "url": "https://referencesource.org/workplace-exposure-limits/ammonium-chloride-fume/", "verified_fields": ["cas_number", "pel_mgm3", "stel_mgm3", "substance"]}
{"cas_number": "3825261", "id": "ammonium-perfluorooctanoate", "pel_mgm3": "0.01", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "3825261 | S | Ammonium perfluorooctanoate | -- | 0.01", "substance": "Ammonium perfluorooctanoate", "url": "https://referencesource.org/workplace-exposure-limits/ammonium-perfluorooctanoate/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"cas_number": "1002897", "id": "ammonium-stearate", "pel_mgm3": "10", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "1002897 | | Ammonium stearate | -- | 10", "substance": "Ammonium stearate", "url": "https://referencesource.org/workplace-exposure-limits/ammonium-stearate/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0030.html", "source_quote": "NIOSH REL TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)", "value": "TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)"}], "cas_number": "7773-06-0", "disagreements": [], "id": "ammonium-sulfamate", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ammonium sulfamate | 7773-06-0 | - | - | - |", "substance": "Ammonium sulfamate", "url": "https://referencesource.org/workplace-exposure-limits/ammonium-sulfamate/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0033.html", "source_quote": "NIOSH REL Ca See Appendix A", "value": "Ca See Appendix A"}], "cas_number": "62533", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "62533 | S | Aniline | 2 | 7.6", "value": "2"}, {"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Aniline and homologs | 62-53-3 | 5 | 19 | X |", "value": "5"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "62533 | S | Aniline | 2 | 7.6", "value": "7.6"}, {"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Aniline and homologs | 62-53-3 | 5 | 19 | X |", "value": "19"}]}], "id": "aniline", "pel_mgm3": "7.6", "pel_ppm": "2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "62533 | S | Aniline | 2 | 7.6", "substance": "Aniline", "url": "https://referencesource.org/workplace-exposure-limits/aniline/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "29191524 | S | Anisidine (ortho and para isomers) | 0.1 | 0.5", "value": "0.1"}], "cas_number": "29191-52-4", "disagreements": [], "id": "anisidine-o-p-isomers", "pel_mgm3": "0.5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Anisidine (o-, p-isomers) | 29191-52-4 | - | 0.5 | X |", "substance": "Anisidine (o-, p-isomers)", "url": "https://referencesource.org/workplace-exposure-limits/anisidine-o-p-isomers/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Antimony and compounds (as Sb) | 7440-36-0 | - | 0.5 | - |", "value": "0.5"}], "cas_number": "7440-36-0", "disagreements": [], "id": "antimony", "rel_mgm3": "TWA 0.5", "source": "https://www.cdc.gov/niosh/npg/npgd0036.html", "source_quote": "NIOSH REL TWA 0.5 mg/m3", "substance": "Antimony", "url": "https://referencesource.org/workplace-exposure-limits/antimony/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "86884 | | ANTU; 1-(1-naphthyl)-2-thiourea; Bantu; Rattrack | -- | 0.3", "value": "0.3"}], "cas_number": "86-88-4", "disagreements": [], "id": "antu", "rel_mgm3": "TWA 0.3", "source": "https://www.cdc.gov/niosh/npg/npgd0037.html", "source_quote": "NIOSH REL TWA 0.3 mg/m3", "substance": "ANTU", "url": "https://referencesource.org/workplace-exposure-limits/antu/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"cas_number": "7440371", "id": "argon", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7440371 | | Argon | (h)", "substance": "Argon", "url": "https://referencesource.org/workplace-exposure-limits/argon/", "verified_fields": ["cas_number", "substance"]}
{"cas_number": "7440382", "id": "arsenic-and-inorganic-arsenic-compounds-see-also-section-5214", "pel_mgm3": "0.01", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7440382 | | Arsenic and inorganic arsenic compounds; see also Section 5214 | | 0.01", "substance": "Arsenic and inorganic arsenic compounds; see also Section 5214", "url": "https://referencesource.org/workplace-exposure-limits/arsenic-and-inorganic-arsenic-compounds-see-also-section-5214/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"cas_number": "7440-38-2 (metal)", "id": "arsenic-inorganic-compounds-as-as", "rel_mgm3": "C 0.002", "source": "https://www.cdc.gov/niosh/npg/npgd0038.html", "source_quote": "NIOSH REL Ca C 0.002 mg/m3 [15-minute]", "substance": "Arsenic (inorganic compounds, as As)", "url": "https://referencesource.org/workplace-exposure-limits/arsenic-inorganic-compounds-as-as/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"cas_number": "7440-38-2", "id": "arsenic-inorganic-compounds-as-as-see-1910-1018", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Arsenic, inorganic compounds (as As); see 1910.1018 | 7440-38-2 | - | - | - |", "substance": "Arsenic, inorganic compounds (as As); see 1910.1018", "url": "https://referencesource.org/workplace-exposure-limits/arsenic-inorganic-compounds-as-as-see-1910-1018/", "verified_fields": ["cas_number", "substance"]}
{"cas_number": "7440-38-2", "disagreements": [{"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Arsenic, organic compounds (as As) | 7440-38-2 | - | 0.5 | - |", "value": "0.5"}, {"as_of": "2026-09-25", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Arsenic, organic compounds, as As | -- | 0.2", "value": "0.2"}]}], "id": "arsenic-organic-compounds-as-as", "pel_mgm3": "0.5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Arsenic, organic compounds (as As) | 7440-38-2 | - | 0.5 | - |", "substance": "Arsenic, organic compounds (as As)", "url": "https://referencesource.org/workplace-exposure-limits/arsenic-organic-compounds-as-as/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0040.html", "source_quote": "NIOSH REL Ca C 0.002 mg/m3 [15-minute]", "value": "C 0.002"}], "cas_number": "7784-42-1", "disagreements": [], "id": "arsine", "pel_mgm3": "0.2", "pel_ppm": "0.05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Arsine | 7784-42-1 | 0.05 | 0.2 | - |", "substance": "Arsine", "url": "https://referencesource.org/workplace-exposure-limits/arsine/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "1332-21-4", "disagreements": [], "id": "asbestos", "rel_statement": "Ca See Appendix A See Appendix C", "source": "https://www.cdc.gov/niosh/npg/npgd0041.html", "source_quote": "NIOSH REL Ca See Appendix A See Appendix C", "substance": "Asbestos", "url": "https://referencesource.org/workplace-exposure-limits/asbestos/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "8052424 | | Asphalt (petroleum) fumes | -- | 5", "value": "5"}], "cas_number": "8052-42-4", "disagreements": [], "id": "asphalt-fumes", "rel_mgm3": "C 5", "source": "https://www.cdc.gov/niosh/npg/npgd0042.html", "source_quote": "NIOSH REL Ca C 5 mg/m3 [15-minute]", "substance": "Asphalt fumes", "url": "https://referencesource.org/workplace-exposure-limits/asphalt-fumes/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0043.html", "source_quote": "NIOSH REL TWA 5 mg/m3", "value": "TWA 5"}], "cas_number": "1912249", "disagreements": [], "id": "atrazine", "pel_mgm3": "5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "1912249 | | Atrazine | -- | 5", "substance": "Atrazine", "url": "https://referencesource.org/workplace-exposure-limits/atrazine/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0681.html", "source_quote": "NIOSH REL TWA 0.2 mg/m3 [skin]", "value": "TWA 0.2"}], "cas_number": "86-50-0", "disagreements": [], "id": "azinphos-methyl", "pel_mgm3": "0.2", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Azinphos-methyl | 86-50-0 | - | 0.2 | X |", "substance": "Azinphos-methyl", "url": "https://referencesource.org/workplace-exposure-limits/azinphos-methyl/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"cas_number": "10361-37-2", "id": "barium-chloride-as-ba", "rel_mgm3": "TWA 0.5", "source": "https://www.cdc.gov/niosh/npg/npgd0045.html", "source_quote": "NIOSH REL TWA 0.5 mg/m3", "substance": "Barium chloride (as Ba)", "url": "https://referencesource.org/workplace-exposure-limits/barium-chloride-as-ba/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"cas_number": "10022-31-8", "id": "barium-nitrate-as-ba", "rel_mgm3": "TWA 0.5", "source": "https://www.cdc.gov/niosh/npg/npgd0046.html", "source_quote": "NIOSH REL TWA 0.5 mg/m3", "substance": "Barium nitrate (as Ba)", "url": "https://referencesource.org/workplace-exposure-limits/barium-nitrate-as-ba/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"cas_number": "7440-39-3", "disagreements": [], "id": "barium-soluble-compounds-as-ba", "pel_mgm3": "0.5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Barium, soluble compounds (as Ba) | 7440-39-3 | - | 0.5 | - |", "substance": "Barium, soluble compounds (as Ba)", "url": "https://referencesource.org/workplace-exposure-limits/barium-soluble-compounds-as-ba/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0047.html", "source_quote": "NIOSH REL TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)", "value": "TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)"}], "cas_number": "7727-43-7", "disagreements": [], "id": "barium-sulfate", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Barium sulfate | 7727-43-7 | - | - | - |", "substance": "Barium sulfate", "url": "https://referencesource.org/workplace-exposure-limits/barium-sulfate/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0048.html", "source_quote": "NIOSH REL See Appendix D", "value": "See Appendix D"}], "cas_number": "17804-35-2", "disagreements": [], "id": "benomyl", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Benomyl | 17804-35-2 | - | - | - |", "substance": "Benomyl", "url": "https://referencesource.org/workplace-exposure-limits/benomyl/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "71432 | S | Benzene; see also Section 5218 | 1 | | | 5 | --", "value": "1"}, {"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "71432 | S | Benzene; see also Section 5218 | 1 | | | 5 | --", "value": "5"}], "cas_number": "71-43-2", "disagreements": [], "id": "benzene", "rel_ppm": "TWA 0.1", "source": "https://www.cdc.gov/niosh/npg/npgd0049.html", "source_quote": "NIOSH REL Ca TWA 0.1 ppm ST 1 ppm", "substance": "Benzene", "url": "https://referencesource.org/workplace-exposure-limits/benzene/", "verified_fields": ["cas_number", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "108985 | | Phenyl mercaptan | 0.5 | 2", "value": "0.5"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "108985 | | Phenyl mercaptan | 0.5 | 2", "value": "2"}], "cas_number": "108-98-5", "disagreements": [], "id": "benzenethiol", "rel_mgm3": "0.5", "rel_ppm": "C 0.1", "source": "https://www.cdc.gov/niosh/npg/npgd0050.html", "source_quote": "NIOSH REL C 0.1 ppm (0.5 mg/m3) [15-minute]", "substance": "Benzenethiol", "url": "https://referencesource.org/workplace-exposure-limits/benzenethiol/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"cas_number": "92-87-5", "disagreements": [], "id": "benzidine", "rel_statement": "Ca See Appendix A See Appendix C", "source": "https://www.cdc.gov/niosh/npg/npgd0051.html", "source_quote": "NIOSH REL Ca See Appendix A See Appendix C", "substance": "Benzidine", "url": "https://referencesource.org/workplace-exposure-limits/benzidine/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"cas_number": "98884", "ceiling_notation": "the values given in the PEL columns are ceiling values", "id": "benzoyl-chloride", "pel_mgm3": "1.1", "pel_ppm": "0.2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "98884 | | Benzoyl chloride | 0.2 | 1.1 | C", "substance": "Benzoyl chloride", "url": "https://referencesource.org/workplace-exposure-limits/benzoyl-chloride/", "verified_fields": ["cas_number", "ceiling_notation", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0052.html", "source_quote": "NIOSH REL TWA 5 mg/m3", "value": "TWA 5"}], "cas_number": "94-36-0", "disagreements": [], "id": "benzoyl-peroxide", "pel_mgm3": "5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Benzoyl peroxide | 94-36-0 | - | 5 | - |", "substance": "Benzoyl peroxide", "url": "https://referencesource.org/workplace-exposure-limits/benzoyl-peroxide/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"cas_number": "140114", "id": "benzyl-acetate", "pel_mgm3": "61", "pel_ppm": "10", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "140114 | | Benzyl acetate | 10 | 61", "substance": "Benzyl acetate", "url": "https://referencesource.org/workplace-exposure-limits/benzyl-acetate/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0053.html", "source_quote": "NIOSH REL C 1 ppm (5 mg/m3) [15-minute]", "value": "C 1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0053.html", "source_quote": "NIOSH REL C 1 ppm (5 mg/m3) [15-minute]", "value": "5"}], "cas_number": "100-44-7", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Benzyl chloride | 100-44-7 | 1 | 5 | - |", "value": "1"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "100447 | | benzyl chloride; alpha-chlorotoluene | 0.03 | 0.16", "value": "0.03"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Benzyl chloride | 100-44-7 | 1 | 5 | - |", "value": "5"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "100447 | | benzyl chloride; alpha-chlorotoluene | 0.03 | 0.16", "value": "0.16"}]}], "id": "benzyl-chloride", "pel_mgm3": "5", "pel_ppm": "1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Benzyl chloride | 100-44-7 | 1 | 5 | - |", "substance": "Benzyl chloride", "url": "https://referencesource.org/workplace-exposure-limits/benzyl-chloride/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0054.html", "source_quote": "NIOSH REL Ca See Appendix A", "value": "Ca See Appendix A"}], "cas_number": "7440417", "ceiling": "0.025mg/M3", "ceiling_notation": "a ceiling value in addition to the TWA values", "disagreements": [], "id": "beryllium-and-beryllium-compounds", "pel_mgm3": "0.0002", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7440417 | | Beryllium, and beryllium compounds | -- | 0.0002 | 0.025mg/M3 | -- | 0.002", "stel_mgm3": "0.002", "substance": "Beryllium, and beryllium compounds", "url": "https://referencesource.org/workplace-exposure-limits/beryllium-and-beryllium-compounds/", "verified_fields": ["cas_number", "ceiling", "ceiling_notation", "pel_mgm3", "stel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0133.html", "source_quote": "NIOSH REL Ca C 1 ppm (3.6 mg/m3) [15-minute]", "value": "C 1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0133.html", "source_quote": "NIOSH REL Ca C 1 ppm (3.6 mg/m3) [15-minute]", "value": "3.6"}], "cas_number": "126-99-8", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "beta-Chloroprene | 126-99-8 | 25 | 90 | X |", "value": "25"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "126998 | S | Chloroprene; 2-chloro-1,3-butadiene | 10 | 36", "value": "10"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "beta-Chloroprene | 126-99-8 | 25 | 90 | X |", "value": "90"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "126998 | S | Chloroprene; 2-chloro-1,3-butadiene | 10 | 36", "value": "36"}]}], "id": "beta-chloroprene", "pel_mgm3": "90", "pel_ppm": "25", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "beta-Chloroprene | 126-99-8 | 25 | 90 | X |", "substance": "beta-Chloroprene", "url": "https://referencesource.org/workplace-exposure-limits/beta-chloroprene/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "91-59-8", "disagreements": [], "id": "beta-naphthylamine", "rel_statement": "Ca See Appendix A", "source": "https://www.cdc.gov/niosh/npg/npgd0442.html", "source_quote": "NIOSH REL Ca See Appendix A", "substance": "beta-Naphthylamine", "url": "https://referencesource.org/workplace-exposure-limits/beta-naphthylamine/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "57578 | | beta-Propiolactone, see Section 5209 | 0.5 | 1.5", "value": "0.5"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "57578 | | beta-Propiolactone, see Section 5209 | 0.5 | 1.5", "value": "1.5"}], "cas_number": "57-57-8", "disagreements": [], "id": "beta-propiolactone", "rel_statement": "Ca See Appendix A", "source": "https://www.cdc.gov/niosh/npg/npgd0528.html", "source_quote": "NIOSH REL Ca See Appendix A", "substance": "beta-Propiolactone", "url": "https://referencesource.org/workplace-exposure-limits/beta-propiolactone/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0239.html", "source_quote": "NIOSH REL TWA 1 mg/m3 (0.2 ppm)", "value": "0.2"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0239.html", "source_quote": "NIOSH REL TWA 1 mg/m3 (0.2 ppm)", "value": "TWA 1"}], "cas_number": "92524", "disagreements": [{"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "92524 | | Biphenyl; diphenyl; phenylbenzene | 0.2 | 1.5", "value": "1.5"}, {"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Diphenyl (Biphenyl) | 92-52-4 | 0.2 | 1 | - |", "value": "1"}]}], "id": "biphenyl-diphenyl-phenylbenzene", "pel_mgm3": "1.5", "pel_ppm": "0.2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "92524 | | Biphenyl; diphenyl; phenylbenzene | 0.2 | 1.5", "substance": "Biphenyl; diphenyl; phenylbenzene", "url": "https://referencesource.org/workplace-exposure-limits/biphenyl-diphenyl-phenylbenzene/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "3033623 | S | Bis (Dimethylaminoethyl) ether (DMAEE) | 0.05 | 0.328 | | 0.15 | 0.983", "value": "0.05"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "3033623 | S | Bis (Dimethylaminoethyl) ether (DMAEE) | 0.05 | 0.328 | | 0.15 | 0.983", "value": "0.328"}, {"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "3033623 | S | Bis (Dimethylaminoethyl) ether (DMAEE) | 0.05 | 0.328 | | 0.15 | 0.983", "value": "0.15"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "3033623 | S | Bis (Dimethylaminoethyl) ether (DMAEE) | 0.05 | 0.328 | | 0.15 | 0.983", "value": "0.983"}], "cas_number": "3033-62-3", "disagreements": [], "id": "bis-2-dimethylamino-ethyl-ether", "rel_statement": "See Appendix C (NIAX® Catalyst ESN)", "source": "https://www.cdc.gov/niosh/npg/npgd0221.html", "source_quote": "NIOSH REL See Appendix C (NIAX® Catalyst ESN)", "substance": "bis(2-(Dimethylamino)ethyl)ether", "url": "https://referencesource.org/workplace-exposure-limits/bis-2-dimethylamino-ethyl-ether/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "542881 | | bis-Chloromethyl ether, see also Section 5209 | 0.001 | 0.005", "value": "0.001"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "542881 | | bis-Chloromethyl ether, see also Section 5209 | 0.001 | 0.005", "value": "0.005"}], "cas_number": "542-88-1", "disagreements": [], "id": "bis-chloromethyl-ether", "rel_statement": "Ca See Appendix A", "source": "https://www.cdc.gov/niosh/npg/npgd0128.html", "source_quote": "NIOSH REL Ca See Appendix A", "substance": "bis-Chloromethyl ether", "url": "https://referencesource.org/workplace-exposure-limits/bis-chloromethyl-ether/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0056.html", "source_quote": "NIOSH REL TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)", "value": "TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)"}], "cas_number": "1304821", "disagreements": [], "id": "bismuth-telluride", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "1304821 | | Bismuth telluride", "substance": "Bismuth telluride", "url": "https://referencesource.org/workplace-exposure-limits/bismuth-telluride/", "verified_fields": ["cas_number", "substance"]}
{"id": "bismuth-telluride-selenium-doped", "pel_mgm3": "5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Bismuth telluride (selenium-doped) | -- | 5", "substance": "Bismuth telluride (selenium-doped)", "url": "https://referencesource.org/workplace-exposure-limits/bismuth-telluride-selenium-doped/", "verified_fields": ["pel_mgm3", "substance"]}
{"cas_number": "1330-43-4", "id": "borates-tetra-sodium-salts-anhydrous", "rel_mgm3": "TWA 1", "source": "https://www.cdc.gov/niosh/npg/npgd0057.html", "source_quote": "NIOSH REL TWA 1 mg/m3", "substance": "Borates, tetra, sodium salts (Anhydrous)", "url": "https://referencesource.org/workplace-exposure-limits/borates-tetra-sodium-salts-anhydrous/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"cas_number": "1303-96-4", "id": "borates-tetra-sodium-salts-decahydrate", "rel_mgm3": "TWA 5", "source": "https://www.cdc.gov/niosh/npg/npgd0058.html", "source_quote": "NIOSH REL TWA 5 mg/m3", "substance": "Borates, tetra, sodium salts (Decahydrate)", "url": "https://referencesource.org/workplace-exposure-limits/borates-tetra-sodium-salts-decahydrate/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"cas_number": "12179-04-3", "id": "borates-tetra-sodium-salts-pentahydrate", "rel_mgm3": "TWA 1", "source": "https://www.cdc.gov/niosh/npg/npgd0059.html", "source_quote": "NIOSH REL TWA 1 mg/m3", "substance": "Borates, tetra, sodium salts (Pentahydrate)", "url": "https://referencesource.org/workplace-exposure-limits/borates-tetra-sodium-salts-pentahydrate/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "1303862 | | Boron oxide | -- | 10", "value": "10"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0060.html", "source_quote": "NIOSH REL TWA 10 mg/m3", "value": "TWA 10"}], "cas_number": "1303-86-2", "disagreements": [], "id": "boron-oxide", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Boron oxide | 1303-86-2 | - | - | - |", "substance": "Boron oxide", "url": "https://referencesource.org/workplace-exposure-limits/boron-oxide/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0061.html", "source_quote": "NIOSH REL C 1 ppm (10 mg/m3)", "value": "C 1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0061.html", "source_quote": "NIOSH REL C 1 ppm (10 mg/m3)", "value": "10"}], "cas_number": "10294334", "ceiling_notation": "the values given in the PEL columns are ceiling values", "disagreements": [], "id": "boron-tribromide", "pel_mgm3": "10", "pel_ppm": "1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "10294334 | | Boron tribromide | 1 | 10 | C", "substance": "Boron tribromide", "url": "https://referencesource.org/workplace-exposure-limits/boron-tribromide/", "verified_fields": ["cas_number", "ceiling_notation", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7637072 | | Boron trifluoride | 1 | 3 | C", "value": "the values given in the PEL columns are ceiling values"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0062.html", "source_quote": "NIOSH REL C 1 ppm (3 mg/m3)", "value": "C 1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0062.html", "source_quote": "NIOSH REL C 1 ppm (3 mg/m3)", "value": "3"}], "cas_number": "7637-07-2", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Boron trifluoride | 7637-07-2 | (C)1 | (C)3 | - |", "value": "(C)1"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7637072 | | Boron trifluoride | 1 | 3 | C", "value": "1"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Boron trifluoride | 7637-07-2 | (C)1 | (C)3 | - |", "value": "(C)3"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7637072 | | Boron trifluoride | 1 | 3 | C", "value": "3"}]}], "id": "boron-trifluoride", "pel_mgm3": "(C)3", "pel_ppm": "(C)1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Boron trifluoride | 7637-07-2 | (C)1 | (C)3 | - |", "substance": "Boron trifluoride", "url": "https://referencesource.org/workplace-exposure-limits/boron-trifluoride/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0063.html", "source_quote": "NIOSH REL TWA 1 ppm (10 mg/m3)", "value": "TWA 1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0063.html", "source_quote": "NIOSH REL TWA 1 ppm (10 mg/m3)", "value": "10"}], "cas_number": "314409", "disagreements": [], "id": "bromacil", "pel_mgm3": "10", "pel_ppm": "1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "314409 | | Bromacil | 1 | 10", "substance": "Bromacil", "url": "https://referencesource.org/workplace-exposure-limits/bromacil/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7726956 | | Bromine | 0.1 | 0.7 | C", "value": "the values given in the PEL columns are ceiling values"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0064.html", "source_quote": "NIOSH REL TWA 0.1 ppm (0.7 mg/m3) ST 0.3 ppm (2 mg/m3)", "value": "TWA 0.1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0064.html", "source_quote": "NIOSH REL TWA 0.1 ppm (0.7 mg/m3) ST 0.3 ppm (2 mg/m3)", "value": "0.7"}], "cas_number": "7726-95-6", "disagreements": [], "id": "bromine", "pel_mgm3": "0.7", "pel_ppm": "0.1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Bromine | 7726-95-6 | 0.1 | 0.7 | - |", "substance": "Bromine", "url": "https://referencesource.org/workplace-exposure-limits/bromine/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0065.html", "source_quote": "NIOSH REL TWA 0.1 ppm (0.7 mg/m³)", "value": "TWA 0.1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0065.html", "source_quote": "NIOSH REL TWA 0.1 ppm (0.7 mg/m³)", "value": "0.7"}], "cas_number": "7789302", "disagreements": [], "id": "bromine-pentafluoride", "pel_mgm3": "0.7", "pel_ppm": "0.1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7789302 | | Bromine pentafluoride | 0.1 | 0.7", "substance": "Bromine pentafluoride", "url": "https://referencesource.org/workplace-exposure-limits/bromine-pentafluoride/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0066.html", "source_quote": "NIOSH REL TWA 0.5 ppm (5 mg/m3) [skin]", "value": "TWA 0.5"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0066.html", "source_quote": "NIOSH REL TWA 0.5 ppm (5 mg/m3) [skin]", "value": "5"}], "cas_number": "75-25-2", "disagreements": [], "id": "bromoform", "pel_mgm3": "5", "pel_ppm": "0.5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Bromoform | 75-25-2 | 0.5 | 5 | X |", "substance": "Bromoform", "url": "https://referencesource.org/workplace-exposure-limits/bromoform/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0068.html", "source_quote": "NIOSH REL TWA 800 ppm (1900 mg/m³)", "value": "TWA 800"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0068.html", "source_quote": "NIOSH REL TWA 800 ppm (1900 mg/m³)", "value": "1900"}], "cas_number": "106978", "disagreements": [], "id": "butane", "pel_mgm3": "1,900", "pel_ppm": "800", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "106978 | | Butane | 800 | 1,900", "substance": "Butane", "url": "https://referencesource.org/workplace-exposure-limits/butane/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0075.html", "source_quote": "NIOSH REL TWA 10 ppm (55 mg/m³)", "value": "TWA 10"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0075.html", "source_quote": "NIOSH REL TWA 10 ppm (55 mg/m³)", "value": "55"}], "cas_number": "141322", "disagreements": [], "id": "butyl-acrylate", "pel_mgm3": "11", "pel_ppm": "2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "141322 | | Butyl acrylate | 2 | 11", "substance": "Butyl acrylate", "url": "https://referencesource.org/workplace-exposure-limits/butyl-acrylate/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0083.html", "source_quote": "NIOSH REL C 0.5 ppm (1.8 mg/m3) [15-minute]", "value": "C 0.5"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0083.html", "source_quote": "NIOSH REL C 0.5 ppm (1.8 mg/m3) [15-minute]", "value": "1.8"}], "cas_number": "109-79-5", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Butyl mercaptan | 109-79-5 | 10 | 35 | - |", "value": "10"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "109795 | | n-Butyl mercaptan | 0.5 | 1.5", "value": "0.5"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Butyl mercaptan | 109-79-5 | 10 | 35 | - |", "value": "35"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "109795 | | n-Butyl mercaptan | 0.5 | 1.5", "value": "1.5"}]}], "id": "butyl-mercaptan", "pel_mgm3": "35", "pel_ppm": "10", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Butyl mercaptan | 109-79-5 | 10 | 35 | - |", "substance": "Butyl mercaptan", "url": "https://referencesource.org/workplace-exposure-limits/butyl-mercaptan/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "109739 | S | Butylamine | 5 | 15 | C", "value": "the values given in the PEL columns are ceiling values"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0079.html", "source_quote": "NIOSH REL C 5 ppm (15 mg/m3) [skin]", "value": "C 5"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0079.html", "source_quote": "NIOSH REL C 5 ppm (15 mg/m3) [skin]", "value": "15"}], "cas_number": "109-73-9", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Butylamine | 109-73-9 | (C)5 | (C)15 | X |", "value": "(C)5"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "109739 | S | Butylamine | 5 | 15 | C", "value": "5"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Butylamine | 109-73-9 | (C)5 | (C)15 | X |", "value": "(C)15"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "109739 | S | Butylamine | 5 | 15 | C", "value": "15"}]}], "id": "butylamine", "pel_mgm3": "(C)15", "pel_ppm": "(C)5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Butylamine | 109-73-9 | (C)5 | (C)15 | X |", "substance": "Butylamine", "url": "https://referencesource.org/workplace-exposure-limits/butylamine/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0087.html", "source_quote": "NIOSH REL Ca See Appendix A", "value": "Ca See Appendix A"}], "cas_number": "7440-43-9", "disagreements": [], "id": "cadmium-as-cd-see-1910-1027", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Cadmium (as Cd); see 1910.1027 | 7440-43-9 | - | - | - |", "substance": "Cadmium (as Cd); see 1910.1027", "url": "https://referencesource.org/workplace-exposure-limits/cadmium-as-cd-see-1910-1027/", "verified_fields": ["cas_number", "substance"]}
{"cas_number": "1306-19-0 (CdO)", "disagreements": [], "id": "cadmium-fume-as-cd", "rel_statement": "Ca See Appendix A", "source": "https://www.cdc.gov/niosh/npg/npgd0088.html", "source_quote": "NIOSH REL Ca See Appendix A", "substance": "Cadmium fume (as Cd)", "url": "https://referencesource.org/workplace-exposure-limits/cadmium-fume-as-cd/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"cas_number": "7778-44-1", "disagreements": [], "id": "calcium-arsenate-as-as", "rel_mgm3": "C 0.002", "source": "https://www.cdc.gov/niosh/npg/npgd0089.html", "source_quote": "NIOSH REL Ca C 0.002 mg/m3 [15-minute]", "substance": "Calcium arsenate (as As)", "url": "https://referencesource.org/workplace-exposure-limits/calcium-arsenate-as-as/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"cas_number": "1317-65-3", "id": "calcium-carbonate", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Calcium carbonate | 1317-65-3 | - | - | - |", "substance": "Calcium carbonate", "url": "https://referencesource.org/workplace-exposure-limits/calcium-carbonate/", "verified_fields": ["cas_number", "substance"]}
{"cas_number": "471-34-1 (synthetic) 1317-65-3 (natural)", "id": "calcium-carbonate-2", "rel_statement": "TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)", "source": "https://www.cdc.gov/niosh/npg/npgd0090.html", "source_quote": "NIOSH REL TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)", "substance": "Calcium carbonate", "url": "https://referencesource.org/workplace-exposure-limits/calcium-carbonate-2/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"cas_number": "471341", "id": "calcium-carbonate-see-particulates-not-otherwise-regulated", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "471341 | | Calcium carbonate; see Particulates not otherwise regulated | --", "substance": "Calcium carbonate; see Particulates not otherwise regulated", "url": "https://referencesource.org/workplace-exposure-limits/calcium-carbonate-see-particulates-not-otherwise-regulated/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0091.html", "source_quote": "NIOSH REL TWA 0.5 mg/m3", "value": "TWA 0.5"}], "cas_number": "156627", "disagreements": [], "id": "calcium-cyanamide", "pel_mgm3": "0.5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "156627 | | Calcium cyanamide | -- | 0.5", "substance": "Calcium cyanamide", "url": "https://referencesource.org/workplace-exposure-limits/calcium-cyanamide/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "1305620 | | Calcium hydroxide | -- | 5", "value": "5"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0092.html", "source_quote": "NIOSH REL TWA 5 mg/m3", "value": "TWA 5"}], "cas_number": "1305-62-0", "disagreements": [], "id": "calcium-hydroxide", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Calcium hydroxide | 1305-62-0 | - | - | - |", "substance": "Calcium hydroxide", "url": "https://referencesource.org/workplace-exposure-limits/calcium-hydroxide/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0093.html", "source_quote": "NIOSH REL TWA 2 mg/m3", "value": "TWA 2"}], "cas_number": "1305-78-8", "disagreements": [{"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Calcium oxide | 1305-78-8 | - | 5 | - |", "value": "5"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "1305788 | | Calcium oxide | -- | 2", "value": "2"}]}], "id": "calcium-oxide", "pel_mgm3": "5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Calcium oxide | 1305-78-8 | - | 5 | - |", "substance": "Calcium oxide", "url": "https://referencesource.org/workplace-exposure-limits/calcium-oxide/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0094.html", "source_quote": "NIOSH REL TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)", "value": "TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)"}], "cas_number": "1344-95-2", "disagreements": [], "id": "calcium-silicate", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Calcium silicate | 1344-95-2 | - | - | - |", "substance": "Calcium silicate", "url": "https://referencesource.org/workplace-exposure-limits/calcium-silicate/", "verified_fields": ["cas_number", "substance"]}
{"cas_number": "1592230", "id": "calcium-stearate", "pel_mgm3": "10", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "1592230 | | Calcium stearate | -- | 10", "substance": "Calcium stearate", "url": "https://referencesource.org/workplace-exposure-limits/calcium-stearate/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0095.html", "source_quote": "NIOSH REL TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)", "value": "TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)"}], "cas_number": "7778-18-9", "disagreements": [], "id": "calcium-sulfate", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Calcium sulfate | 7778-18-9 | - | - | - |", "substance": "Calcium sulfate", "url": "https://referencesource.org/workplace-exposure-limits/calcium-sulfate/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0096.html", "source_quote": "NIOSH REL TWA 2 mg/m3", "value": "TWA 2"}], "cas_number": "76-22-2", "disagreements": [], "id": "camphor-synthetic", "pel_mgm3": "2", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Camphor, synthetic | 76-22-2 | - | 2 | - |", "substance": "Camphor, synthetic", "url": "https://referencesource.org/workplace-exposure-limits/camphor-synthetic/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"cas_number": "105-60-2", "id": "caprolactam", "rel_statement": "Dust: TWA 1 mg/m3 ST 3 mg/m3 Vapor: TWA 0.22 ppm (1 mg/m3) ST 0.66 ppm (3 mg/m3)", "source": "https://www.cdc.gov/niosh/npg/npgd0097.html", "source_quote": "NIOSH REL Dust: TWA 1 mg/m3 ST 3 mg/m3 Vapor: TWA 0.22 ppm (1 mg/m3) ST 0.66 ppm (3 mg/m3)", "substance": "Caprolactam", "url": "https://referencesource.org/workplace-exposure-limits/caprolactam/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"cas_number": "105602", "id": "caprolactam-dust", "pel_mgm3": "1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "105602 | | Caprolactam dust | -- | 1 | | -- | 3", "stel_mgm3": "3", "substance": "Caprolactam dust", "url": "https://referencesource.org/workplace-exposure-limits/caprolactam-dust/", "verified_fields": ["cas_number", "pel_mgm3", "stel_mgm3", "substance"]}
{"cas_number": "105602", "id": "caprolactam-vapor", "pel_mgm3": "20", "pel_ppm": "5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "105602 | | Caprolactam vapor | 5 | 20 | | 10 | 40", "stel_mgm3": "40", "stel_ppm": "10", "substance": "Caprolactam vapor", "url": "https://referencesource.org/workplace-exposure-limits/caprolactam-vapor/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "stel_mgm3", "stel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0098.html", "source_quote": "NIOSH REL Ca TWA 0.1 mg/m3 [skin]", "value": "TWA 0.1"}], "cas_number": "2425061", "disagreements": [], "id": "captafol", "pel_mgm3": "0.1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "2425061 | S | Captafol | -- | 0.1", "substance": "Captafol", "url": "https://referencesource.org/workplace-exposure-limits/captafol/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0099.html", "source_quote": "NIOSH REL Ca TWA 5 mg/m3", "value": "TWA 5"}], "cas_number": "133062", "disagreements": [], "id": "captan", "pel_mgm3": "5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "133062 | | Captan | -- | 5", "substance": "Captan", "url": "https://referencesource.org/workplace-exposure-limits/captan/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "63252 | | Carbaryl; 1-naphthyl N-methylcarbamate | -- | 5", "value": "5"}], "cas_number": "63-25-2", "disagreements": [], "id": "carbaryl", "rel_mgm3": "TWA 5", "source": "https://www.cdc.gov/niosh/npg/npgd0100.html", "source_quote": "NIOSH REL TWA 5 mg/m3", "substance": "Carbaryl", "url": "https://referencesource.org/workplace-exposure-limits/carbaryl/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0101.html", "source_quote": "NIOSH REL TWA 0.1 mg/m3", "value": "TWA 0.1"}], "cas_number": "1563662", "disagreements": [], "id": "carbofuran", "pel_mgm3": "0.1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "1563662 | | Carbofuran | -- | 0.1", "substance": "Carbofuran", "url": "https://referencesource.org/workplace-exposure-limits/carbofuran/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0102.html", "source_quote": "NIOSH REL TWA 3.5 mg/m3 Ca TWA 0.1 mg PAHs/m3 [Carbon black in presence of polycyclic aromatic hydrocarbons (PAHs)]", "value": "TWA 3.5"}], "cas_number": "1333-86-4", "disagreements": [], "id": "carbon-black", "pel_mgm3": "3.5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Carbon black | 1333-86-4 | - | 3.5 | - |", "substance": "Carbon black", "url": "https://referencesource.org/workplace-exposure-limits/carbon-black/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "124389 | | Carbon dioxide | 5,000 | 9,000 | | 30,000 | 54,000", "value": "30,000"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "124389 | | Carbon dioxide | 5,000 | 9,000 | | 30,000 | 54,000", "value": "54,000"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0103.html", "source_quote": "NIOSH REL TWA 5000 ppm (9000 mg/m3) ST 30,000 ppm (54,000 mg/m3)", "value": "TWA 5000"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0103.html", "source_quote": "NIOSH REL TWA 5000 ppm (9000 mg/m3) ST 30,000 ppm (54,000 mg/m3)", "value": "9000"}], "cas_number": "124-38-9", "disagreements": [], "id": "carbon-dioxide", "pel_mgm3": "9000", "pel_ppm": "5000", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Carbon dioxide | 124-38-9 | 5000 | 9000 | - |", "substance": "Carbon dioxide", "url": "https://referencesource.org/workplace-exposure-limits/carbon-dioxide/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-28", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75150 | S | Carbon disulfide | 1 | 3 | 30 ppm | 12 | 36", "value": "1"}, {"as_of": "2026-09-28", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75150 | S | Carbon disulfide | 1 | 3 | 30 ppm | 12 | 36", "value": "3"}, {"as_of": "2026-09-28", "field": "ceiling", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75150 | S | Carbon disulfide | 1 | 3 | 30 ppm | 12 | 36", "value": "30 ppm"}, {"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75150 | S | Carbon disulfide | 1 | 3 | 30 ppm | 12 | 36", "value": "a ceiling value in addition to the TWA values"}, {"as_of": "2026-09-28", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75150 | S | Carbon disulfide | 1 | 3 | 30 ppm | 12 | 36", "value": "12"}, {"as_of": "2026-09-28", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75150 | S | Carbon disulfide | 1 | 3 | 30 ppm | 12 | 36", "value": "36"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0104.html", "source_quote": "NIOSH REL TWA 1 ppm (3 mg/m3) ST 10 ppm (30 mg/m3) [skin]", "value": "TWA 1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0104.html", "source_quote": "NIOSH REL TWA 1 ppm (3 mg/m3) ST 10 ppm (30 mg/m3) [skin]", "value": "3"}], "cas_number": "75-15-0", "disagreements": [], "id": "carbon-disulfide", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Carbon disulfide | 75-15-0 | - | (2) | - |", "substance": "Carbon disulfide", "url": "https://referencesource.org/workplace-exposure-limits/carbon-disulfide/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-09-28", "field": "ceiling", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "630080 | | Carbon monoxide | 25 | 29 | 200 ppm", "value": "200 ppm"}, {"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "630080 | | Carbon monoxide | 25 | 29 | 200 ppm", "value": "a ceiling value in addition to the TWA values"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0105.html", "source_quote": "NIOSH REL TWA 35 ppm (40 mg/m3) C 200 ppm (229 mg/m3)", "value": "TWA 35"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0105.html", "source_quote": "NIOSH REL TWA 35 ppm (40 mg/m3) C 200 ppm (229 mg/m3)", "value": "40"}], "cas_number": "630-08-0", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Carbon monoxide | 630-08-0 | 50 | 55 | - |", "value": "50"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "630080 | | Carbon monoxide | 25 | 29 | 200 ppm", "value": "25"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Carbon monoxide | 630-08-0 | 50 | 55 | - |", "value": "55"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "630080 | | Carbon monoxide | 25 | 29 | 200 ppm", "value": "29"}]}], "id": "carbon-monoxide", "pel_mgm3": "55", "pel_ppm": "50", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Carbon monoxide | 630-08-0 | 50 | 55 | - |", "substance": "Carbon monoxide", "url": "https://referencesource.org/workplace-exposure-limits/carbon-monoxide/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0106.html", "source_quote": "NIOSH REL TWA 0.1 ppm (1.4 mg/m3) ST 0.3 ppm (4 mg/m3)", "value": "TWA 0.1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0106.html", "source_quote": "NIOSH REL TWA 0.1 ppm (1.4 mg/m3) ST 0.3 ppm (4 mg/m3)", "value": "1.4"}], "cas_number": "558134", "disagreements": [], "id": "carbon-tetrabromide", "pel_mgm3": "1.4", "pel_ppm": "0.1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "558134 | | Carbon tetrabromide | 0.1 | 1.4 | | 0.3 | 4", "stel_mgm3": "4", "stel_ppm": "0.3", "substance": "Carbon tetrabromide", "url": "https://referencesource.org/workplace-exposure-limits/carbon-tetrabromide/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "stel_mgm3", "stel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-28", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "56235 | S | Carbon tetrachloride | 2 | 12.6 | 200 ppm | 10 | 63", "value": "2"}, {"as_of": "2026-09-28", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "56235 | S | Carbon tetrachloride | 2 | 12.6 | 200 ppm | 10 | 63", "value": "12.6"}, {"as_of": "2026-09-28", "field": "ceiling", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "56235 | S | Carbon tetrachloride | 2 | 12.6 | 200 ppm | 10 | 63", "value": "200 ppm"}, {"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "56235 | S | Carbon tetrachloride | 2 | 12.6 | 200 ppm | 10 | 63", "value": "a ceiling value in addition to the TWA values"}, {"as_of": "2026-09-28", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "56235 | S | Carbon tetrachloride | 2 | 12.6 | 200 ppm | 10 | 63", "value": "10"}, {"as_of": "2026-09-28", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "56235 | S | Carbon tetrachloride | 2 | 12.6 | 200 ppm | 10 | 63", "value": "63"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0107.html", "source_quote": "NIOSH REL Ca ST 2 ppm (12.6 mg/m3) [60-minute]", "value": "ST 2"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0107.html", "source_quote": "NIOSH REL Ca ST 2 ppm (12.6 mg/m3) [60-minute]", "value": "12.6"}], "cas_number": "56-23-5", "disagreements": [], "id": "carbon-tetrachloride", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Carbon tetrachloride | 56-23-5 | - | (2) | - |", "substance": "Carbon tetrachloride", "url": "https://referencesource.org/workplace-exposure-limits/carbon-tetrachloride/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0108.html", "source_quote": "NIOSH REL TWA 2 ppm (5 mg/m3) ST 5 ppm (15 mg/m3)", "value": "TWA 2"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0108.html", "source_quote": "NIOSH REL TWA 2 ppm (5 mg/m3) ST 5 ppm (15 mg/m3)", "value": "5"}], "cas_number": "353504", "disagreements": [], "id": "carbonyl-fluoride", "pel_mgm3": "5", "pel_ppm": "2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "353504 | | Carbonyl fluoride | 2 | 5 | | 5 | 15", "stel_mgm3": "15", "stel_ppm": "5", "substance": "Carbonyl fluoride", "url": "https://referencesource.org/workplace-exposure-limits/carbonyl-fluoride/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "stel_mgm3", "stel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "120809 | S | Catechol; pyrocatechol | 5 | 20", "value": "5"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "120809 | S | Catechol; pyrocatechol | 5 | 20", "value": "20"}], "cas_number": "120-80-9", "disagreements": [], "id": "catechol", "rel_mgm3": "20", "rel_ppm": "TWA 5", "source": "https://www.cdc.gov/niosh/npg/npgd0109.html", "source_quote": "NIOSH REL TWA 5 ppm (20 mg/m3) [skin]", "substance": "Catechol", "url": "https://referencesource.org/workplace-exposure-limits/catechol/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0110.html", "source_quote": "NIOSH REL TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)", "value": "TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)"}], "cas_number": "9004-34-6", "disagreements": [], "id": "cellulose", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Cellulose | 9004-34-6 | - | - | - |", "substance": "Cellulose", "url": "https://referencesource.org/workplace-exposure-limits/cellulose/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0111.html", "source_quote": "NIOSH REL TWA 2 mg/m3", "value": "TWA 2"}], "cas_number": "21351791", "disagreements": [], "id": "cesium-hydroxide", "pel_ppm": "2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "21351791 | | Cesium hydroxide | 2", "substance": "Cesium hydroxide", "url": "https://referencesource.org/workplace-exposure-limits/cesium-hydroxide/", "verified_fields": ["cas_number", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0112.html", "source_quote": "NIOSH REL Ca TWA 0.5 mg/m3 [skin]", "value": "TWA 0.5"}], "cas_number": "57-74-9", "disagreements": [], "id": "chlordane", "pel_mgm3": "0.5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Chlordane | 57-74-9 | - | 0.5 | X |", "substance": "Chlordane", "url": "https://referencesource.org/workplace-exposure-limits/chlordane/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0113.html", "source_quote": "NIOSH REL Ca [skin] See Appendix A", "value": "Ca [skin] See Appendix A"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "8001352 | S | Chlorinated camphene; toxaphene | -- | 0.5 | | -- | 1", "value": "1"}], "cas_number": "8001-35-2", "disagreements": [], "id": "chlorinated-camphene", "pel_mgm3": "0.5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Chlorinated camphene | 8001-35-2 | - | 0.5 | X |", "substance": "Chlorinated camphene", "url": "https://referencesource.org/workplace-exposure-limits/chlorinated-camphene/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"cas_number": "55720-99-5", "disagreements": [], "id": "chlorinated-diphenyl-oxide", "pel_mgm3": "0.5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Chlorinated diphenyl oxide | 55720-99-5 | - | 0.5 | - |", "substance": "Chlorinated diphenyl oxide", "url": "https://referencesource.org/workplace-exposure-limits/chlorinated-diphenyl-oxide/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7782505 | | Chlorine | 0.5 | 1.5 | | 1 | 3", "value": "1"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7782505 | | Chlorine | 0.5 | 1.5 | | 1 | 3", "value": "3"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0115.html", "source_quote": "NIOSH REL C 0.5 ppm (1.45 mg/m3) [15-minute]", "value": "C 0.5"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0115.html", "source_quote": "NIOSH REL C 0.5 ppm (1.45 mg/m3) [15-minute]", "value": "1.45"}], "cas_number": "7782-50-5", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Chlorine | 7782-50-5 | (C)1 | (C)3 | - |", "value": "(C)1"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7782505 | | Chlorine | 0.5 | 1.5 | | 1 | 3", "value": "0.5"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Chlorine | 7782-50-5 | (C)1 | (C)3 | - |", "value": "(C)3"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7782505 | | Chlorine | 0.5 | 1.5 | | 1 | 3", "value": "1.5"}]}], "id": "chlorine", "pel_mgm3": "(C)3", "pel_ppm": "(C)1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Chlorine | 7782-50-5 | (C)1 | (C)3 | - |", "substance": "Chlorine", "url": "https://referencesource.org/workplace-exposure-limits/chlorine/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "10049044 | | Chlorine dioxide | 0.1 | 0.3 | | 0.3 | 0.9", "value": "0.3"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "10049044 | | Chlorine dioxide | 0.1 | 0.3 | | 0.3 | 0.9", "value": "0.9"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0116.html", "source_quote": "NIOSH REL TWA 0.1 ppm (0.3 mg/m3) ST 0.3 ppm (0.9 mg/m3)", "value": "TWA 0.1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0116.html", "source_quote": "NIOSH REL TWA 0.1 ppm (0.3 mg/m3) ST 0.3 ppm (0.9 mg/m3)", "value": "0.3"}], "cas_number": "10049-04-4", "disagreements": [], "id": "chlorine-dioxide", "pel_mgm3": "0.3", "pel_ppm": "0.1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Chlorine dioxide | 10049-04-4 | 0.1 | 0.3 | - |", "substance": "Chlorine dioxide", "url": "https://referencesource.org/workplace-exposure-limits/chlorine-dioxide/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7790912 | | Chlorine trifluoride | 0.1 | 0.4 | C", "value": "the values given in the PEL columns are ceiling values"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0117.html", "source_quote": "NIOSH REL C 0.1 ppm (0.4 mg/m³)", "value": "C 0.1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0117.html", "source_quote": "NIOSH REL C 0.1 ppm (0.4 mg/m³)", "value": "0.4"}], "cas_number": "7790-91-2", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Chlorine trifluoride | 7790-91-2 | (C)0.1 | (C)0.4 | - |", "value": "(C)0.1"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7790912 | | Chlorine trifluoride | 0.1 | 0.4 | C", "value": "0.1"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Chlorine trifluoride | 7790-91-2 | (C)0.1 | (C)0.4 | - |", "value": "(C)0.4"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7790912 | | Chlorine trifluoride | 0.1 | 0.4 | C", "value": "0.4"}]}], "id": "chlorine-trifluoride", "pel_mgm3": "(C)0.4", "pel_ppm": "(C)0.1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Chlorine trifluoride | 7790-91-2 | (C)0.1 | (C)0.4 | - |", "substance": "Chlorine trifluoride", "url": "https://referencesource.org/workplace-exposure-limits/chlorine-trifluoride/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "107200 | | Chloroacetaldehyde | 1 | 3 | C", "value": "the values given in the PEL columns are ceiling values"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0118.html", "source_quote": "NIOSH REL C 1 ppm (3 mg/m3)", "value": "C 1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0118.html", "source_quote": "NIOSH REL C 1 ppm (3 mg/m3)", "value": "3"}], "cas_number": "107-20-0", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Chloroacetaldehyde | 107-20-0 | (C)1 | (C)3 | - |", "value": "(C)1"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "107200 | | Chloroacetaldehyde | 1 | 3 | C", "value": "1"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Chloroacetaldehyde | 107-20-0 | (C)1 | (C)3 | - |", "value": "(C)3"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "107200 | | Chloroacetaldehyde | 1 | 3 | C", "value": "3"}]}], "id": "chloroacetaldehyde", "pel_mgm3": "(C)3", "pel_ppm": "(C)1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Chloroacetaldehyde | 107-20-0 | (C)1 | (C)3 | - |", "substance": "Chloroacetaldehyde", "url": "https://referencesource.org/workplace-exposure-limits/chloroacetaldehyde/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "78955", "ceiling_notation": "the values given in the PEL columns are ceiling values", "id": "chloroacetone", "pel_mgm3": "3.8", "pel_ppm": "1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "78955 | S | Chloroacetone | 1 | 3.8 | C", "substance": "Chloroacetone", "url": "https://referencesource.org/workplace-exposure-limits/chloroacetone/", "verified_fields": ["cas_number", "ceiling_notation", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0120.html", "source_quote": "NIOSH REL TWA 0.05 ppm (0.2 mg/m³)", "value": "TWA 0.05"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0120.html", "source_quote": "NIOSH REL TWA 0.05 ppm (0.2 mg/m³)", "value": "0.2"}], "cas_number": "79049", "disagreements": [], "id": "chloroacetyl-chloride", "pel_mgm3": "0.2", "pel_ppm": "0.05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "79049 | S | Chloroacetyl chloride | 0.05 | 0.2 | | 0.15 | 0.69", "stel_mgm3": "0.69", "stel_ppm": "0.15", "substance": "Chloroacetyl chloride", "url": "https://referencesource.org/workplace-exposure-limits/chloroacetyl-chloride/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "stel_mgm3", "stel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0121.html", "source_quote": "NIOSH REL See Appendix D", "value": "See Appendix D"}], "cas_number": "108-90-7", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Chlorobenzene | 108-90-7 | 75 | 350 | - |", "value": "75"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "108907 | | Chlorobenzene; monochlorobenzene | 10 | 46", "value": "10"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Chlorobenzene | 108-90-7 | 75 | 350 | - |", "value": "350"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "108907 | | Chlorobenzene; monochlorobenzene | 10 | 46", "value": "46"}]}], "id": "chlorobenzene", "pel_mgm3": "350", "pel_ppm": "75", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Chlorobenzene | 108-90-7 | 75 | 350 | - |", "substance": "Chlorobenzene", "url": "https://referencesource.org/workplace-exposure-limits/chlorobenzene/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0123.html", "source_quote": "NIOSH REL TWA 200 ppm (1050 mg/m3)", "value": "TWA 200"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0123.html", "source_quote": "NIOSH REL TWA 200 ppm (1050 mg/m3)", "value": "1050"}], "cas_number": "74-97-5", "disagreements": [], "id": "chlorobromomethane", "pel_mgm3": "1050", "pel_ppm": "200", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Chlorobromomethane | 74-97-5 | 200 | 1050 | - |", "substance": "Chlorobromomethane", "url": "https://referencesource.org/workplace-exposure-limits/chlorobromomethane/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75456 | | Chlorodifluoromethane; Fluorocarbon 22 | 1,000 | 3,500", "value": "1,000"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75456 | | Chlorodifluoromethane; Fluorocarbon 22 | 1,000 | 3,500", "value": "3,500"}], "cas_number": "75-45-6", "disagreements": [], "id": "chlorodifluoromethane", "rel_mgm3": "3500", "rel_ppm": "TWA 1000", "source": "https://www.cdc.gov/niosh/npg/npgd0124.html", "source_quote": "NIOSH REL TWA 1000 ppm (3500 mg/m3) ST 1250 ppm (4375 mg/m3)", "substance": "Chlorodifluoromethane", "url": "https://referencesource.org/workplace-exposure-limits/chlorodifluoromethane/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0125.html", "source_quote": "NIOSH REL Ca TWA 0.001 mg/m3", "value": "TWA 0.001"}], "cas_number": "53469219", "disagreements": [], "id": "chlorodiphenyl-42-chlorine", "pel_mgm3": "1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "53469219 | S | Chlorodiphenyl (42% chlorine) | -- | 1", "substance": "Chlorodiphenyl (42% chlorine)", "url": "https://referencesource.org/workplace-exposure-limits/chlorodiphenyl-42-chlorine/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0126.html", "source_quote": "NIOSH REL Ca TWA 0.001 mg/m3", "value": "TWA 0.001"}], "cas_number": "11097691", "disagreements": [], "id": "chlorodiphenyl-54-chlorine", "pel_mgm3": "0.5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "11097691 | S | Chlorodiphenyl (54% chlorine) | -- | 0.5", "substance": "Chlorodiphenyl (54% chlorine)", "url": "https://referencesource.org/workplace-exposure-limits/chlorodiphenyl-54-chlorine/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Chloroform (Trichloromethane) | 67-66-3 | (C)50 | (C)240 | - |", "value": "(C)50"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Chloroform (Trichloromethane) | 67-66-3 | (C)50 | (C)240 | - |", "value": "(C)240"}], "cas_number": "67-66-3", "disagreements": [], "id": "chloroform", "rel_mgm3": "9.78", "rel_ppm": "ST 2", "source": "https://www.cdc.gov/niosh/npg/npgd0127.html", "source_quote": "NIOSH REL Ca ST 2 ppm (9.78 mg/m3) [60-minute]", "substance": "Chloroform", "url": "https://referencesource.org/workplace-exposure-limits/chloroform/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"cas_number": "107-30-2", "disagreements": [], "id": "chloromethyl-methyl-ether", "rel_statement": "Ca See Appendix A", "source": "https://www.cdc.gov/niosh/npg/npgd0129.html", "source_quote": "NIOSH REL Ca See Appendix A", "substance": "Chloromethyl methyl ether", "url": "https://referencesource.org/workplace-exposure-limits/chloromethyl-methyl-ether/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0131.html", "source_quote": "NIOSH REL TWA 1000 ppm (6320 mg/m3)", "value": "TWA 1000"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0131.html", "source_quote": "NIOSH REL TWA 1000 ppm (6320 mg/m3)", "value": "6320"}], "cas_number": "76153", "disagreements": [], "id": "chloropentafluoroethane", "pel_mgm3": "6,320", "pel_ppm": "1,000", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "76153 | | Chloropentafluoroethane | 1,000 | 6,320", "substance": "Chloropentafluoroethane", "url": "https://referencesource.org/workplace-exposure-limits/chloropentafluoroethane/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0132.html", "source_quote": "NIOSH REL TWA 0.1 ppm (0.7 mg/m3)", "value": "TWA 0.1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0132.html", "source_quote": "NIOSH REL TWA 0.1 ppm (0.7 mg/m3)", "value": "0.7"}], "cas_number": "76-06-2", "disagreements": [], "id": "chloropicrin", "pel_mgm3": "0.7", "pel_ppm": "0.1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Chloropicrin | 76-06-2 | 0.1 | 0.7 | - |", "substance": "Chloropicrin", "url": "https://referencesource.org/workplace-exposure-limits/chloropicrin/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0137.html", "source_quote": "NIOSH REL TWA 0.2 mg/m3 ST 0.6 mg/m3 [skin]", "value": "TWA 0.2"}], "cas_number": "2921882", "disagreements": [], "id": "chlorpyrifos", "pel_mgm3": "0.2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "2921882 | S | Chlorpyrifos | -- | 0.2", "substance": "Chlorpyrifos", "url": "https://referencesource.org/workplace-exposure-limits/chlorpyrifos/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"cas_number": "1333-82-0 (CrO3)", "id": "chromic-acid-and-chromates", "rel_mgm3": "TWA 0.0002", "source": "https://www.cdc.gov/niosh/npg/npgd0138.html", "source_quote": "NIOSH REL (as Cr): Ca TWA 0.0002 mg/m3 (8-hours)", "substance": "Chromic acid and chromates", "url": "https://referencesource.org/workplace-exposure-limits/chromic-acid-and-chromates/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"id": "chromite-ore-processing-chromate-as-cr", "pel_mgm3": "0.005", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Chromite ore processing (chromate), as Cr | -- | 0.005", "substance": "Chromite ore processing (chromate), as Cr", "url": "https://referencesource.org/workplace-exposure-limits/chromite-ore-processing-chromate-as-cr/", "verified_fields": ["pel_mgm3", "substance"]}
{"id": "chromium-ii-compounds-as-cr", "pel_mgm3": "0.5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Chromium (II) compounds, as Cr | -- | 0.5", "substance": "Chromium (II) compounds, as Cr", "url": "https://referencesource.org/workplace-exposure-limits/chromium-ii-compounds-as-cr/", "verified_fields": ["pel_mgm3", "substance"]}
{"id": "chromium-iii-compounds-as-cr", "pel_mgm3": "0.5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Chromium (III) compounds, as Cr | -- | 0.5", "substance": "Chromium (III) compounds, as Cr", "url": "https://referencesource.org/workplace-exposure-limits/chromium-iii-compounds-as-cr/", "verified_fields": ["pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0141.html", "source_quote": "NIOSH REL TWA 0.5 mg/m3", "value": "TWA 0.5"}], "cas_number": "7440473", "disagreements": [{"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7440473 | | Chromium metal | -- | 0.5", "value": "0.5"}, {"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Chromium metal and insol. salts (as Cr) | 7440-47-3 | - | 1 | - |", "value": "1"}]}], "id": "chromium-metal", "pel_mgm3": "0.5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7440473 | | Chromium metal | -- | 0.5", "substance": "Chromium metal", "url": "https://referencesource.org/workplace-exposure-limits/chromium-metal/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"ceiling": "0.1 mg/M3", "ceiling_notation": "a ceiling value in addition to the TWA values", "id": "chromium-vi-compounds-as-cr", "pel_mgm3": "0.005", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Chromium (VI) compounds, as Cr | -- | 0.005 | 0.1 mg/M3", "substance": "Chromium (VI) compounds, as Cr", "url": "https://referencesource.org/workplace-exposure-limits/chromium-vi-compounds-as-cr/", "verified_fields": ["ceiling", "ceiling_notation", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0142.html", "source_quote": "NIOSH REL Ca TWA 0.001 mg Cr(VI)/m3 See Appendix A See Appendix C", "value": "Ca TWA 0.001 mg Cr(VI)/m3 See Appendix A See Appendix C"}], "cas_number": "14977618", "disagreements": [], "id": "chromyl-chloride", "pel_mgm3": "0.15", "pel_ppm": "0.025", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "14977618 | | Chromyl chloride | 0.025 | 0.15", "substance": "Chromyl chloride", "url": "https://referencesource.org/workplace-exposure-limits/chromyl-chloride/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0143.html", "source_quote": "NIOSH REL TWA 10 mg/m3 (total) ST 20 mg/m3 (total) TWA 5 mg/m3 (resp)", "value": "TWA 10 mg/m3 (total) ST 20 mg/m3 (total) TWA 5 mg/m3 (resp)"}], "cas_number": "2971-90-6", "disagreements": [], "id": "clopidol", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Clopidol | 2971-90-6 | - | - | - |", "substance": "Clopidol", "url": "https://referencesource.org/workplace-exposure-limits/clopidol/", "verified_fields": ["cas_number", "substance"]}
{"cas_number": "65996-93-2", "id": "coal-tar-pitch-volatiles", "rel_mgm3": "TWA 0.1", "source": "https://www.cdc.gov/niosh/npg/npgd0145.html", "source_quote": "NIOSH REL Ca TWA 0.1 mg/m3 (cyclohexane-extractable fraction)", "substance": "Coal tar pitch volatiles", "url": "https://referencesource.org/workplace-exposure-limits/coal-tar-pitch-volatiles/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"cas_number": "65966-93-2", "id": "coal-tar-pitch-volatiles-benzene-soluble-fraction-anthracene-bap-phenanthrene-ac", "pel_mgm3": "0.2", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Coal tar pitch volatiles (benzene soluble fraction), anthracene, BaP, phenanthrene, acridine, chrysene, pyrene | 65966-93-2 | - | 0.2 | - |", "substance": "Coal tar pitch volatiles (benzene soluble fraction), anthracene, BaP, phenanthrene, acridine, chrysene, pyrene", "url": "https://referencesource.org/workplace-exposure-limits/coal-tar-pitch-volatiles-benzene-soluble-fraction-anthracene-bap-phenanthrene-ac/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"id": "coal-tar-pitch-volatiles-i", "pel_mgm3": "0.2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Coal tar pitch volatiles(i) | -- | 0.2", "substance": "Coal tar pitch volatiles(i)", "url": "https://referencesource.org/workplace-exposure-limits/coal-tar-pitch-volatiles-i/", "verified_fields": ["pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-25", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Cobalt carbonyl, as Co | -- | 0.1", "value": "0.1"}], "cas_number": "10210-68-1", "disagreements": [], "id": "cobalt-carbonyl-as-co", "rel_mgm3": "TWA 0.1", "source": "https://www.cdc.gov/niosh/npg/npgd0147.html", "source_quote": "NIOSH REL TWA 0.1 mg/m3", "substance": "Cobalt carbonyl (as Co)", "url": "https://referencesource.org/workplace-exposure-limits/cobalt-carbonyl-as-co/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0148.html", "source_quote": "NIOSH REL TWA 0.1 mg/m3", "value": "TWA 0.1"}], "cas_number": "16842038", "disagreements": [], "id": "cobalt-hydrocarbonyl-as-co", "pel_mgm3": "0.1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "16842038 | | Cobalt hydrocarbonyl, as Co | -- | 0.1", "substance": "Cobalt hydrocarbonyl, as Co", "url": "https://referencesource.org/workplace-exposure-limits/cobalt-hydrocarbonyl-as-co/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0146.html", "source_quote": "NIOSH REL TWA 0.05 mg/m3", "value": "TWA 0.05"}], "cas_number": "7440-48-4", "disagreements": [{"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Cobalt metal, dust, and fume (as Co) | 7440-48-4 | - | 0.1 | - |", "value": "0.1"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7440484 | | Cobalt, metal fume and dust, as Co | -- | 0.02", "value": "0.02"}]}], "id": "cobalt-metal-dust-and-fume-as-co", "pel_mgm3": "0.1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Cobalt metal, dust, and fume (as Co) | 7440-48-4 | - | 0.1 | - |", "substance": "Cobalt metal, dust, and fume (as Co)", "url": "https://referencesource.org/workplace-exposure-limits/cobalt-metal-dust-and-fume-as-co/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"id": "coke-oven-emissions-see-section-5211", "pel_mgm3": "0.15", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Coke oven emissions, see Section 5211 | -- | 0.15", "substance": "Coke oven emissions, see Section 5211", "url": "https://referencesource.org/workplace-exposure-limits/coke-oven-emissions-see-section-5211/", "verified_fields": ["pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0150.html", "source_quote": "NIOSH REL TWA 1 mg/m3", "value": "TWA 1"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7440508 | | Copper metal fume, as Cu | -- | 0.1", "value": "0.1"}], "cas_number": "7440-50-8", "disagreements": [], "id": "copper", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Copper | 7440-50-8 | - | - | - |", "substance": "Copper", "url": "https://referencesource.org/workplace-exposure-limits/copper/", "verified_fields": ["cas_number", "substance"]}
{"cas_number": "1317-38-0 (CuO)", "id": "copper-fume-as-cu", "rel_mgm3": "TWA 0.1", "source": "https://www.cdc.gov/niosh/npg/npgd0151.html", "source_quote": "NIOSH REL TWA 0.1 mg/m3", "substance": "Copper fume (as Cu)", "url": "https://referencesource.org/workplace-exposure-limits/copper-fume-as-cu/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"id": "copper-salts-dusts-and-mists-as-cu", "pel_mgm3": "1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Copper salts, dusts and mists, as Cu | -- | 1", "substance": "Copper salts, dusts and mists, as Cu", "url": "https://referencesource.org/workplace-exposure-limits/copper-salts-dusts-and-mists-as-cu/", "verified_fields": ["pel_mgm3", "substance"]}
{"id": "cotton-dust-see-also-section-5190", "pel_mgm3": "1(j)", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Cotton dust, see also Section 5190 | -- | 1(j)", "substance": "Cotton dust, see also Section 5190", "url": "https://referencesource.org/workplace-exposure-limits/cotton-dust-see-also-section-5190/", "verified_fields": ["pel_mgm3", "substance"]}
{"cas_number": "136-78-7", "disagreements": [], "id": "crag-herbicide", "rel_statement": "TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)", "source": "https://www.cdc.gov/niosh/npg/npgd0153.html", "source_quote": "NIOSH REL TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)", "substance": "Crag® herbicide", "url": "https://referencesource.org/workplace-exposure-limits/crag-herbicide/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"cas_number": "1319-77-3", "disagreements": [], "id": "cresol-all-isomers", "pel_mgm3": "22", "pel_ppm": "5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Cresol, all isomers | 1319-77-3 | 5 | 22 | X |", "substance": "Cresol, all isomers", "url": "https://referencesource.org/workplace-exposure-limits/cresol-all-isomers/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "14464461", "disagreements": [], "id": "cristobalite", "pel_mgm3": "0.05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "14464461 | | Cristobalite, | -- | 0.05", "substance": "Cristobalite,", "url": "https://referencesource.org/workplace-exposure-limits/cristobalite/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-28", "field": "ceiling", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "123739 | S | Crotonaldehyde; beta-methylacrolein | | | 0.3", "value": "0.3"}, {"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "123739 | S | Crotonaldehyde; beta-methylacrolein | | | 0.3", "value": "a ceiling value in addition to the TWA values"}], "cas_number": "4170-30-3", "disagreements": [], "id": "crotonaldehyde", "rel_mgm3": "6", "rel_ppm": "TWA 2", "source": "https://www.cdc.gov/niosh/npg/npgd0157.html", "source_quote": "NIOSH REL TWA 2 ppm (6 mg/m3)", "substance": "Crotonaldehyde", "url": "https://referencesource.org/workplace-exposure-limits/crotonaldehyde/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0158.html", "source_quote": "NIOSH REL TWA 5 mg/m3 ST 20 mg/m3", "value": "TWA 5"}], "cas_number": "299865", "disagreements": [], "id": "crufomate", "pel_mgm3": "5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "299865 | | Crufomate | -- | 5", "substance": "Crufomate", "url": "https://referencesource.org/workplace-exposure-limits/crufomate/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0159.html", "source_quote": "NIOSH REL TWA 50 ppm (245 mg/m3) [skin]", "value": "TWA 50"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0159.html", "source_quote": "NIOSH REL TWA 50 ppm (245 mg/m3) [skin]", "value": "245"}], "cas_number": "98-82-8", "disagreements": [], "id": "cumene", "pel_mgm3": "245", "pel_ppm": "50", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Cumene | 98-82-8 | 50 | 245 | X |", "substance": "Cumene", "url": "https://referencesource.org/workplace-exposure-limits/cumene/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0160.html", "source_quote": "NIOSH REL TWA 2 mg/m3", "value": "TWA 2"}], "cas_number": "420042", "disagreements": [], "id": "cyanamide", "pel_mgm3": "2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "420042 | | Cyanamide | -- | 2", "substance": "Cyanamide", "url": "https://referencesource.org/workplace-exposure-limits/cyanamide/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"id": "cyanide-as-cn", "pel_mgm3": "5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "S | Cyanide, as CN | -- | 5", "substance": "Cyanide, as CN", "url": "https://referencesource.org/workplace-exposure-limits/cyanide-as-cn/", "verified_fields": ["pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0161.html", "source_quote": "NIOSH REL TWA 10 ppm (20 mg/m3)", "value": "TWA 10"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0161.html", "source_quote": "NIOSH REL TWA 10 ppm (20 mg/m3)", "value": "20"}], "cas_number": "460195", "disagreements": [], "id": "cyanogen", "pel_mgm3": "20", "pel_ppm": "10", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "460195 | | Cyanogen | 10 | 20", "substance": "Cyanogen", "url": "https://referencesource.org/workplace-exposure-limits/cyanogen/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0162.html", "source_quote": "NIOSH REL C 0.3 ppm (0.6 mg/m3)", "value": "C 0.3"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0162.html", "source_quote": "NIOSH REL C 0.3 ppm (0.6 mg/m3)", "value": "0.6"}], "cas_number": "506774", "ceiling_notation": "the values given in the PEL columns are ceiling values", "disagreements": [], "id": "cyanogen-chloride", "pel_mgm3": "0.6", "pel_ppm": "0.3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "506774 | | Cyanogen chloride | 0.3 | 0.6 | C", "substance": "Cyanogen chloride", "url": "https://referencesource.org/workplace-exposure-limits/cyanogen-chloride/", "verified_fields": ["cas_number", "ceiling_notation", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0163.html", "source_quote": "NIOSH REL TWA 300 ppm (1050 mg/m3)", "value": "TWA 300"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0163.html", "source_quote": "NIOSH REL TWA 300 ppm (1050 mg/m3)", "value": "1050"}], "cas_number": "110-82-7", "disagreements": [], "id": "cyclohexane", "pel_mgm3": "1050", "pel_ppm": "300", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Cyclohexane | 110-82-7 | 300 | 1050 | - |", "substance": "Cyclohexane", "url": "https://referencesource.org/workplace-exposure-limits/cyclohexane/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "1569-69-3", "id": "cyclohexanethiol", "rel_mgm3": "2.4", "rel_ppm": "C 0.5", "source": "https://www.cdc.gov/niosh/npg/npgd0164.html", "source_quote": "NIOSH REL C 0.5 ppm (2.4 mg/m3) [15-minute]", "substance": "Cyclohexanethiol", "url": "https://referencesource.org/workplace-exposure-limits/cyclohexanethiol/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0165.html", "source_quote": "NIOSH REL TWA 50 ppm (200 mg/m3) [skin]", "value": "TWA 50"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0165.html", "source_quote": "NIOSH REL TWA 50 ppm (200 mg/m3) [skin]", "value": "200"}], "cas_number": "108-93-0", "disagreements": [], "id": "cyclohexanol", "pel_mgm3": "200", "pel_ppm": "50", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Cyclohexanol | 108-93-0 | 50 | 200 | - |", "substance": "Cyclohexanol", "url": "https://referencesource.org/workplace-exposure-limits/cyclohexanol/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0166.html", "source_quote": "NIOSH REL TWA 25 ppm (100 mg/m3) [skin]", "value": "TWA 25"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0166.html", "source_quote": "NIOSH REL TWA 25 ppm (100 mg/m3) [skin]", "value": "100"}], "cas_number": "108-94-1", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Cyclohexanone | 108-94-1 | 50 | 200 | - |", "value": "50"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "108941 | S | Cyclohexanone | 25 | 100", "value": "25"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Cyclohexanone | 108-94-1 | 50 | 200 | - |", "value": "200"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "108941 | S | Cyclohexanone | 25 | 100", "value": "100"}]}], "id": "cyclohexanone", "pel_mgm3": "200", "pel_ppm": "50", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Cyclohexanone | 108-94-1 | 50 | 200 | - |", "substance": "Cyclohexanone", "url": "https://referencesource.org/workplace-exposure-limits/cyclohexanone/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0167.html", "source_quote": "NIOSH REL TWA 300 ppm (1015 mg/m3)", "value": "TWA 300"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0167.html", "source_quote": "NIOSH REL TWA 300 ppm (1015 mg/m3)", "value": "1015"}], "cas_number": "110-83-8", "disagreements": [], "id": "cyclohexene", "pel_mgm3": "1015", "pel_ppm": "300", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Cyclohexene | 110-83-8 | 300 | 1015 | - |", "substance": "Cyclohexene", "url": "https://referencesource.org/workplace-exposure-limits/cyclohexene/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0168.html", "source_quote": "NIOSH REL TWA 10 ppm (40 mg/m3)", "value": "TWA 10"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0168.html", "source_quote": "NIOSH REL TWA 10 ppm (40 mg/m3)", "value": "40"}], "cas_number": "108918", "disagreements": [], "id": "cyclohexylamine", "pel_mgm3": "40", "pel_ppm": "10", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "108918 | S | Cyclohexylamine | 10 | 40", "substance": "Cyclohexylamine", "url": "https://referencesource.org/workplace-exposure-limits/cyclohexylamine/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "121824 | S | Cyclonite; RDX; cyclotrimethylenetrinitramine | -- | 0.07", "value": "0.07"}], "cas_number": "121-82-4", "disagreements": [], "id": "cyclonite", "rel_mgm3": "TWA 1.5", "source": "https://www.cdc.gov/niosh/npg/npgd0169.html", "source_quote": "NIOSH REL TWA 1.5 mg/m3 ST 3 mg/m3 [skin]", "substance": "Cyclonite", "url": "https://referencesource.org/workplace-exposure-limits/cyclonite/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0170.html", "source_quote": "NIOSH REL TWA 75 ppm (200 mg/m3)", "value": "TWA 75"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0170.html", "source_quote": "NIOSH REL TWA 75 ppm (200 mg/m3)", "value": "200"}], "cas_number": "542-92-7", "disagreements": [], "id": "cyclopentadiene", "pel_mgm3": "200", "pel_ppm": "75", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Cyclopentadiene | 542-92-7 | 75 | 200 | - |", "substance": "Cyclopentadiene", "url": "https://referencesource.org/workplace-exposure-limits/cyclopentadiene/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0171.html", "source_quote": "NIOSH REL TWA 600 ppm (1720 mg/m3)", "value": "TWA 600"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0171.html", "source_quote": "NIOSH REL TWA 600 ppm (1720 mg/m3)", "value": "1720"}], "cas_number": "287923", "disagreements": [], "id": "cyclopentane", "pel_mgm3": "1,720", "pel_ppm": "600", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "287923 | | Cyclopentane | 600 | 1,720", "substance": "Cyclopentane", "url": "https://referencesource.org/workplace-exposure-limits/cyclopentane/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "13121705 | | Cyhexatin; tricyclohexyltin hydroxide | | 5", "value": "5"}], "cas_number": "13121-70-5", "disagreements": [], "id": "cyhexatin", "rel_mgm3": "TWA 5", "source": "https://www.cdc.gov/niosh/npg/npgd0172.html", "source_quote": "NIOSH REL TWA 5 mg/m3", "substance": "Cyhexatin", "url": "https://referencesource.org/workplace-exposure-limits/cyhexatin/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "50293 | S | DDT; 1,1,1-trichloro-2,2-bis-(p-chlorophenyl)ethane | -- | 1", "value": "1"}], "cas_number": "50-29-3", "disagreements": [], "id": "ddt", "rel_mgm3": "TWA 0.5", "source": "https://www.cdc.gov/niosh/npg/npgd0174.html", "source_quote": "NIOSH REL Ca TWA 0.5 mg/m3", "substance": "DDT", "url": "https://referencesource.org/workplace-exposure-limits/ddt/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "17702419 | S | Decaborane | 0.05 | 0.3 | | 0.15 | 0.9", "value": "0.15"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "17702419 | S | Decaborane | 0.05 | 0.3 | | 0.15 | 0.9", "value": "0.9"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0175.html", "source_quote": "NIOSH REL TWA 0.3 mg/m3 (0.05 ppm) ST 0.9 mg/m3 (0.15 ppm) [skin]", "value": "0.05"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0175.html", "source_quote": "NIOSH REL TWA 0.3 mg/m3 (0.05 ppm) ST 0.9 mg/m3 (0.15 ppm) [skin]", "value": "TWA 0.3"}], "cas_number": "17702-41-9", "disagreements": [], "id": "decaborane", "pel_mgm3": "0.3", "pel_ppm": "0.05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Decaborane | 17702-41-9 | 0.05 | 0.3 | X |", "substance": "Decaborane", "url": "https://referencesource.org/workplace-exposure-limits/decaborane/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "8065483 | S | Demeton; a mixture of o,o-diethyl o-2(ethylthio)ethyl phosphorothloate and o,o'-diethyl S-2(ethylthio)ethyl phosphorothioate | 0.01 | 0.1", "value": "0.01"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "8065483 | S | Demeton; a mixture of o,o-diethyl o-2(ethylthio)ethyl phosphorothloate and o,o'-diethyl S-2(ethylthio)ethyl phosphorothioate | 0.01 | 0.1", "value": "0.1"}], "cas_number": "8065-48-3", "disagreements": [], "id": "demeton", "rel_mgm3": "TWA 0.1", "source": "https://www.cdc.gov/niosh/npg/npgd0177.html", "source_quote": "NIOSH REL TWA 0.1 mg/m3 [skin]", "substance": "Demeton", "url": "https://referencesource.org/workplace-exposure-limits/demeton/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "117817 | | Di-sec-octyl phthalate; bis(2 ethylhexyl) phthalate | -- | 5 | | --", "value": "5"}], "cas_number": "117-81-7", "disagreements": [], "id": "di-sec-octyl-phthalate", "rel_mgm3": "TWA 5", "source": "https://www.cdc.gov/niosh/npg/npgd0236.html", "source_quote": "NIOSH REL Ca TWA 5 mg/m3 ST 10 mg/m3", "substance": "Di-sec octyl phthalate", "url": "https://referencesource.org/workplace-exposure-limits/di-sec-octyl-phthalate/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Diacetone alcohol (4-Hydroxy-4-methyl-2-pentanone) | 123-42-2 | 50 | 240 | - |", "value": "50"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Diacetone alcohol (4-Hydroxy-4-methyl-2-pentanone) | 123-42-2 | 50 | 240 | - |", "value": "240"}], "cas_number": "123-42-2", "disagreements": [], "id": "diacetone-alcohol", "rel_mgm3": "240", "rel_ppm": "TWA 50", "source": "https://www.cdc.gov/niosh/npg/npgd0178.html", "source_quote": "NIOSH REL TWA 50 ppm (240 mg/m3)", "substance": "Diacetone alcohol", "url": "https://referencesource.org/workplace-exposure-limits/diacetone-alcohol/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "333415 | S | Diazinon; o,o-diethyl o-(2-isopropyl-6-methyl-4-pyrimidinyl) phosphorothioate | -- | 0.1", "value": "0.1"}], "cas_number": "333-41-5", "disagreements": [], "id": "diazinon", "rel_mgm3": "TWA 0.1", "source": "https://www.cdc.gov/niosh/npg/npgd0181.html", "source_quote": "NIOSH REL TWA 0.1 mg/m3 [skin]", "substance": "Diazinon®", "url": "https://referencesource.org/workplace-exposure-limits/diazinon/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0182.html", "source_quote": "NIOSH REL TWA 0.2 ppm (0.4 mg/m3)", "value": "TWA 0.2"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0182.html", "source_quote": "NIOSH REL TWA 0.2 ppm (0.4 mg/m3)", "value": "0.4"}], "cas_number": "334-88-3", "disagreements": [], "id": "diazomethane", "pel_mgm3": "0.4", "pel_ppm": "0.2", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Diazomethane | 334-88-3 | 0.2 | 0.4 | - |", "substance": "Diazomethane", "url": "https://referencesource.org/workplace-exposure-limits/diazomethane/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0183.html", "source_quote": "NIOSH REL TWA 0.1 ppm (0.1 mg/m3)", "value": "TWA 0.1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0183.html", "source_quote": "NIOSH REL TWA 0.1 ppm (0.1 mg/m3)", "value": "0.1"}], "cas_number": "19287-45-7", "disagreements": [], "id": "diborane", "pel_mgm3": "0.1", "pel_ppm": "0.1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Diborane | 19287-45-7 | 0.1 | 0.1 | - |", "substance": "Diborane", "url": "https://referencesource.org/workplace-exposure-limits/diborane/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "2528361", "id": "dibutyl-phenyl-phosphate", "pel_mgm3": "3.5", "pel_ppm": "0.3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "2528361 | S | Dibutyl phenyl phosphate | 0.3 | 3.5", "substance": "Dibutyl phenyl phosphate", "url": "https://referencesource.org/workplace-exposure-limits/dibutyl-phenyl-phosphate/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "107664 | | Dibutyl phosphate | 1 | 5 | | 2 | 10", "value": "2"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "107664 | | Dibutyl phosphate | 1 | 5 | | 2 | 10", "value": "10"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0186.html", "source_quote": "NIOSH REL TWA 1 ppm (5 mg/m3) ST 2 ppm (10 mg/m3)", "value": "TWA 1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0186.html", "source_quote": "NIOSH REL TWA 1 ppm (5 mg/m3) ST 2 ppm (10 mg/m3)", "value": "5"}], "cas_number": "107-66-4", "disagreements": [], "id": "dibutyl-phosphate", "pel_mgm3": "5", "pel_ppm": "1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Dibutyl phosphate | 107-66-4 | 1 | 5 | - |", "substance": "Dibutyl phosphate", "url": "https://referencesource.org/workplace-exposure-limits/dibutyl-phosphate/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0187.html", "source_quote": "NIOSH REL TWA 5 mg/m3", "value": "TWA 5"}], "cas_number": "84-74-2", "disagreements": [], "id": "dibutyl-phthalate", "pel_mgm3": "5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Dibutyl phthalate | 84-74-2 | - | 5 | - |", "substance": "Dibutyl phthalate", "url": "https://referencesource.org/workplace-exposure-limits/dibutyl-phthalate/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0188.html", "source_quote": "NIOSH REL Ca C 0.1 ppm (0.4 mg/m3)", "value": "C 0.1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0188.html", "source_quote": "NIOSH REL Ca C 0.1 ppm (0.4 mg/m3)", "value": "0.4"}], "cas_number": "7572294", "ceiling_notation": "the values given in the PEL columns are ceiling values", "disagreements": [], "id": "dichloroacetylene", "pel_mgm3": "0.4", "pel_ppm": "0.1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7572294 | | Dichloroacetylene | 0.1 | 0.4 | C", "substance": "Dichloroacetylene", "url": "https://referencesource.org/workplace-exposure-limits/dichloroacetylene/", "verified_fields": ["cas_number", "ceiling_notation", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-28", "field": "ceiling", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75718 | | Dichlorodifluoromethane | 1000 | 4950 | 6200 ppm", "value": "6200 ppm"}, {"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75718 | | Dichlorodifluoromethane | 1000 | 4950 | 6200 ppm", "value": "a ceiling value in addition to the TWA values"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0192.html", "source_quote": "NIOSH REL TWA 1000 ppm (4950 mg/m3)", "value": "TWA 1000"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0192.html", "source_quote": "NIOSH REL TWA 1000 ppm (4950 mg/m3)", "value": "4950"}], "cas_number": "75-71-8", "disagreements": [], "id": "dichlorodifluoromethane", "pel_mgm3": "4950", "pel_ppm": "1000", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Dichlorodifluoromethane | 75-71-8 | 1000 | 4950 | - |", "substance": "Dichlorodifluoromethane", "url": "https://referencesource.org/workplace-exposure-limits/dichlorodifluoromethane/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0196.html", "source_quote": "NIOSH REL Ca TWA 5 ppm (30 mg/m3) ST 10 ppm (60 mg/m3) [skin]", "value": "TWA 5"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0196.html", "source_quote": "NIOSH REL Ca TWA 5 ppm (30 mg/m3) ST 10 ppm (60 mg/m3) [skin]", "value": "30"}, {"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "111444 | S | Dichloroethyl ether; bis(2-chloroethyl) ether | 5 | 30 | | 10 | 60", "value": "10"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "111444 | S | Dichloroethyl ether; bis(2-chloroethyl) ether | 5 | 30 | | 10 | 60", "value": "60"}], "cas_number": "111-44-4", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Dichloroethyl ether | 111-44-4 | (C)15 | (C)90 | X |", "value": "(C)15"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "111444 | S | Dichloroethyl ether; bis(2-chloroethyl) ether | 5 | 30 | | 10 | 60", "value": "5"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Dichloroethyl ether | 111-44-4 | (C)15 | (C)90 | X |", "value": "(C)90"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "111444 | S | Dichloroethyl ether; bis(2-chloroethyl) ether | 5 | 30 | | 10 | 60", "value": "30"}]}], "id": "dichloroethyl-ether", "pel_mgm3": "(C)90", "pel_ppm": "(C)15", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Dichloroethyl ether | 111-44-4 | (C)15 | (C)90 | X |", "substance": "Dichloroethyl ether", "url": "https://referencesource.org/workplace-exposure-limits/dichloroethyl-ether/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0197.html", "source_quote": "NIOSH REL TWA 10 ppm (40 mg/m3)", "value": "TWA 10"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0197.html", "source_quote": "NIOSH REL TWA 10 ppm (40 mg/m3)", "value": "40"}], "cas_number": "75434", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75434 | | Dichlorofluoromethane; Fluorocarbon 21 | 10 | 42", "value": "10"}, {"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Dichloromonofluoromethane | 75-43-4 | 1000 | 4200 | - |", "value": "1000"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75434 | | Dichlorofluoromethane; Fluorocarbon 21 | 10 | 42", "value": "42"}, {"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Dichloromonofluoromethane | 75-43-4 | 1000 | 4200 | - |", "value": "4200"}]}], "id": "dichlorofluoromethane-fluorocarbon-21", "pel_mgm3": "42", "pel_ppm": "10", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75434 | | Dichlorofluoromethane; Fluorocarbon 21 | 10 | 42", "substance": "Dichlorofluoromethane; Fluorocarbon 21", "url": "https://referencesource.org/workplace-exposure-limits/dichlorofluoromethane-fluorocarbon-21/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Dichlorvos (DDVP) | 62-73-7 | - | 1 | X |", "value": "1"}, {"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "62737 | S | Dichlorvos (DDVP); 2,2-dichlorovinyl dimethyl phosphate | 0.1 | 1", "value": "0.1"}], "cas_number": "62-73-7", "disagreements": [], "id": "dichlorvos", "rel_mgm3": "TWA 1", "source": "https://www.cdc.gov/niosh/npg/npgd0202.html", "source_quote": "NIOSH REL TWA 1 mg/m3 [skin]", "substance": "Dichlorvos", "url": "https://referencesource.org/workplace-exposure-limits/dichlorvos/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0203.html", "source_quote": "NIOSH REL TWA 0.25 mg/m3 [skin]", "value": "TWA 0.25"}], "cas_number": "141662", "disagreements": [], "id": "dicrotophos", "pel_mgm3": "0.25", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "141662 | S | Dicrotophos | -- | 0.25", "substance": "Dicrotophos", "url": "https://referencesource.org/workplace-exposure-limits/dicrotophos/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0204.html", "source_quote": "NIOSH REL TWA 5 ppm (30 mg/m3)", "value": "TWA 5"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0204.html", "source_quote": "NIOSH REL TWA 5 ppm (30 mg/m3)", "value": "30"}], "cas_number": "77736", "disagreements": [], "id": "dicyclopentadiene", "pel_mgm3": "30", "pel_ppm": "5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "77736 | | Dicyclopentadiene | 5 | 30", "substance": "Dicyclopentadiene", "url": "https://referencesource.org/workplace-exposure-limits/dicyclopentadiene/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0205.html", "source_quote": "NIOSH REL TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)", "value": "TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)"}], "cas_number": "102-54-5", "disagreements": [], "id": "dicyclopentadienyl-iron", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Dicyclopentadienyl iron | 102-54-5 | - | - | - |", "substance": "Dicyclopentadienyl iron", "url": "https://referencesource.org/workplace-exposure-limits/dicyclopentadienyl-iron/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0206.html", "source_quote": "NIOSH REL Ca TWA 0.25 mg/m3 [skin]", "value": "TWA 0.25"}], "cas_number": "60-57-1", "disagreements": [], "id": "dieldrin", "pel_mgm3": "0.25", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Dieldrin | 60-57-1 | - | 0.25 | X |", "substance": "Dieldrin", "url": "https://referencesource.org/workplace-exposure-limits/dieldrin/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0208.html", "source_quote": "NIOSH REL TWA 3 ppm (15 mg/m3)", "value": "TWA 3"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0208.html", "source_quote": "NIOSH REL TWA 3 ppm (15 mg/m3)", "value": "15"}], "cas_number": "111422", "disagreements": [], "id": "diethanolamine", "pel_mgm3": "2", "pel_ppm": "0.46", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "111422 | S | Diethanolamine | 0.46 | 2", "substance": "Diethanolamine", "url": "https://referencesource.org/workplace-exposure-limits/diethanolamine/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0212.html", "source_quote": "NIOSH REL TWA 200 ppm (705 mg/m3)", "value": "TWA 200"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0212.html", "source_quote": "NIOSH REL TWA 200 ppm (705 mg/m3)", "value": "705"}], "cas_number": "96220", "disagreements": [], "id": "diethyl-ketone", "pel_mgm3": "705", "pel_ppm": "200", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "96220 | | Diethyl ketone | 200 | 705 | | 300 | 1057", "stel_mgm3": "1057", "stel_ppm": "300", "substance": "Diethyl ketone", "url": "https://referencesource.org/workplace-exposure-limits/diethyl-ketone/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "stel_mgm3", "stel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0213.html", "source_quote": "NIOSH REL TWA 5 mg/m3", "value": "TWA 5"}], "cas_number": "84662", "disagreements": [], "id": "diethyl-phthalate", "pel_mgm3": "5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "84662 | | Diethyl phthalate | -- | 5", "substance": "Diethyl phthalate", "url": "https://referencesource.org/workplace-exposure-limits/diethyl-phthalate/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "109897 | S | Diethylamine | 5 | 15 | C", "value": "the values given in the PEL columns are ceiling values"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0209.html", "source_quote": "NIOSH REL TWA 10 ppm (30 mg/m3) ST 25 ppm (75 mg/m3)", "value": "TWA 10"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0209.html", "source_quote": "NIOSH REL TWA 10 ppm (30 mg/m3) ST 25 ppm (75 mg/m3)", "value": "30"}], "cas_number": "109-89-7", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Diethylamine | 109-89-7 | 25 | 75 | - |", "value": "25"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "109897 | S | Diethylamine | 5 | 15 | C", "value": "5"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Diethylamine | 109-89-7 | 25 | 75 | - |", "value": "75"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "109897 | S | Diethylamine | 5 | 15 | C", "value": "15"}]}], "id": "diethylamine", "pel_mgm3": "75", "pel_ppm": "25", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Diethylamine | 109-89-7 | 25 | 75 | - |", "substance": "Diethylamine", "url": "https://referencesource.org/workplace-exposure-limits/diethylamine/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "112367", "id": "diethylene-glycol-diethyl-ether-ethyl-diglyme", "pel_mgm3": "33", "pel_ppm": "5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "112367 | S | Diethylene glycol diethyl ether, Ethyl diglyme | 5 | 33", "substance": "Diethylene glycol diethyl ether, Ethyl diglyme", "url": "https://referencesource.org/workplace-exposure-limits/diethylene-glycol-diethyl-ether-ethyl-diglyme/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "111966", "id": "diethylene-glycol-dimethyl-ether-diglyme", "pel_mgm3": "5.5", "pel_ppm": "1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "111966 | S | Diethylene glycol dimethyl ether, Diglyme | 1 | 5.5 | | 5 | 27", "stel_mgm3": "27", "stel_ppm": "5", "substance": "Diethylene glycol dimethyl ether, Diglyme", "url": "https://referencesource.org/workplace-exposure-limits/diethylene-glycol-dimethyl-ether-diglyme/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "stel_mgm3", "stel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-25", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "111400S | | Diethylenetriamine | 1 | 4", "value": "1"}, {"as_of": "2026-09-25", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "111400S | | Diethylenetriamine | 1 | 4", "value": "4"}], "cas_number": "111-40-0", "disagreements": [], "id": "diethylenetriamine", "rel_mgm3": "4", "rel_ppm": "TWA 1", "source": "https://www.cdc.gov/niosh/npg/npgd0211.html", "source_quote": "NIOSH REL TWA 1 ppm (4 mg/m3) [skin]", "substance": "Diethylenetriamine", "url": "https://referencesource.org/workplace-exposure-limits/diethylenetriamine/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0214.html", "source_quote": "NIOSH REL TWA 100 ppm (860 mg/m3)", "value": "TWA 100"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0214.html", "source_quote": "NIOSH REL TWA 100 ppm (860 mg/m3)", "value": "860"}], "cas_number": "75-61-6", "disagreements": [], "id": "difluorodibromomethane", "pel_mgm3": "860", "pel_ppm": "100", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Difluorodibromomethane | 75-61-6 | 100 | 860 | - |", "substance": "Difluorodibromomethane", "url": "https://referencesource.org/workplace-exposure-limits/difluorodibromomethane/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Diglycidyl ether (DGE) | 2238-07-5 | (C)0.5 | (C)2.8 | - |", "value": "(C)0.5"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Diglycidyl ether (DGE) | 2238-07-5 | (C)0.5 | (C)2.8 | - |", "value": "(C)2.8"}], "cas_number": "2238-07-5", "disagreements": [], "id": "diglycidyl-ether", "rel_mgm3": "0.5", "rel_ppm": "TWA 0.1", "source": "https://www.cdc.gov/niosh/npg/npgd0215.html", "source_quote": "NIOSH REL Ca TWA 0.1 ppm (0.5 mg/m3)", "substance": "Diglycidyl ether", "url": "https://referencesource.org/workplace-exposure-limits/diglycidyl-ether/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0216.html", "source_quote": "NIOSH REL TWA 25 ppm (150 mg/m3)", "value": "TWA 25"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0216.html", "source_quote": "NIOSH REL TWA 25 ppm (150 mg/m3)", "value": "150"}], "cas_number": "108-83-8", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Diisobutyl ketone | 108-83-8 | 50 | 290 | - |", "value": "50"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "108838 | | Diisobutyl ketone; 2,6-dimethyl-4-heptanone | 25 | 150", "value": "25"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Diisobutyl ketone | 108-83-8 | 50 | 290 | - |", "value": "290"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "108838 | | Diisobutyl ketone; 2,6-dimethyl-4-heptanone | 25 | 150", "value": "150"}]}], "id": "diisobutyl-ketone", "pel_mgm3": "290", "pel_ppm": "50", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Diisobutyl ketone | 108-83-8 | 50 | 290 | - |", "substance": "Diisobutyl ketone", "url": "https://referencesource.org/workplace-exposure-limits/diisobutyl-ketone/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0217.html", "source_quote": "NIOSH REL TWA 5 ppm (20 mg/m3) [skin]", "value": "TWA 5"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0217.html", "source_quote": "NIOSH REL TWA 5 ppm (20 mg/m3) [skin]", "value": "20"}], "cas_number": "108-18-9", "disagreements": [], "id": "diisopropylamine", "pel_mgm3": "20", "pel_ppm": "5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Diisopropylamine | 108-18-9 | 5 | 20 | X |", "substance": "Diisopropylamine", "url": "https://referencesource.org/workplace-exposure-limits/diisopropylamine/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Dimethyl-1,2-dibromo-2,2-dichloroethyl phosphate | 300-76-5 | - | 3 | - |", "value": "3"}], "cas_number": "300-76-5", "disagreements": [], "id": "dimethyl-1-2-dibromo-2-2-dichlorethyl-phosphate", "rel_mgm3": "TWA 3", "source": "https://www.cdc.gov/niosh/npg/npgd0225.html", "source_quote": "NIOSH REL TWA 3 mg/m3 [skin]", "substance": "Dimethyl-1,2-dibromo-2,2-dichlorethyl phosphate", "url": "https://referencesource.org/workplace-exposure-limits/dimethyl-1-2-dibromo-2-2-dichlorethyl-phosphate/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0218.html", "source_quote": "NIOSH REL TWA 10 ppm (35 mg/m3) [skin]", "value": "TWA 10"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0218.html", "source_quote": "NIOSH REL TWA 10 ppm (35 mg/m3) [skin]", "value": "35"}], "cas_number": "127-19-5", "disagreements": [], "id": "dimethyl-acetamide", "pel_mgm3": "35", "pel_ppm": "10", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Dimethyl acetamide | 127-19-5 | 10 | 35 | X |", "substance": "Dimethyl acetamide", "url": "https://referencesource.org/workplace-exposure-limits/dimethyl-acetamide/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "79-44-7", "id": "dimethyl-carbamoyl-chloride", "rel_statement": "Ca See Appendix A", "source": "https://www.cdc.gov/niosh/npg/npgd0224.html", "source_quote": "NIOSH REL Ca See Appendix A", "substance": "Dimethyl carbamoyl chloride", "url": "https://referencesource.org/workplace-exposure-limits/dimethyl-carbamoyl-chloride/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0228.html", "source_quote": "NIOSH REL TWA 5 mg/m3", "value": "TWA 5"}], "cas_number": "131113", "disagreements": [], "id": "dimethyl-phthalate", "pel_mgm3": "5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "131113 | | Dimethyl phthalate | -- | 5", "substance": "Dimethyl phthalate", "url": "https://referencesource.org/workplace-exposure-limits/dimethyl-phthalate/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0229.html", "source_quote": "NIOSH REL Ca TWA 0.1 ppm (0.5 mg/m3) [skin]", "value": "TWA 0.1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0229.html", "source_quote": "NIOSH REL Ca TWA 0.1 ppm (0.5 mg/m3) [skin]", "value": "0.5"}], "cas_number": "77-78-1", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Dimethyl sulfate | 77-78-1 | 1 | 5 | X |", "value": "1"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "77781 | S | Dimethyl sulfate; methyl sulfate | 0.1 | 0.5", "value": "0.1"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Dimethyl sulfate | 77-78-1 | 1 | 5 | X |", "value": "5"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "77781 | S | Dimethyl sulfate; methyl sulfate | 0.1 | 0.5", "value": "0.5"}]}], "id": "dimethyl-sulfate", "pel_mgm3": "5", "pel_ppm": "1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Dimethyl sulfate | 77-78-1 | 1 | 5 | X |", "substance": "Dimethyl sulfate", "url": "https://referencesource.org/workplace-exposure-limits/dimethyl-sulfate/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "124403 | | Dimethylamine | 5 | 9.2 | | 15 | 27.6", "value": "15"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "124403 | | Dimethylamine | 5 | 9.2 | | 15 | 27.6", "value": "27.6"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0219.html", "source_quote": "NIOSH REL TWA 10 ppm (18 mg/m3)", "value": "TWA 10"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0219.html", "source_quote": "NIOSH REL TWA 10 ppm (18 mg/m3)", "value": "18"}], "cas_number": "124-40-3", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Dimethylamine | 124-40-3 | 10 | 18 | - |", "value": "10"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "124403 | | Dimethylamine | 5 | 9.2 | | 15 | 27.6", "value": "5"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Dimethylamine | 124-40-3 | 10 | 18 | - |", "value": "18"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "124403 | | Dimethylamine | 5 | 9.2 | | 15 | 27.6", "value": "9.2"}]}], "id": "dimethylamine", "pel_mgm3": "18", "pel_ppm": "10", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Dimethylamine | 124-40-3 | 10 | 18 | - |", "substance": "Dimethylamine", "url": "https://referencesource.org/workplace-exposure-limits/dimethylamine/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "1738-25-6", "id": "dimethylaminopropionitrile", "rel_statement": "See Appendix C (NIAX® Catalyst ESN)", "source": "https://www.cdc.gov/niosh/npg/npgd0222.html", "source_quote": "NIOSH REL See Appendix C (NIAX® Catalyst ESN)", "substance": "Dimethylaminopropionitrile", "url": "https://referencesource.org/workplace-exposure-limits/dimethylaminopropionitrile/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0223.html", "source_quote": "NIOSH REL TWA 5 ppm (25 mg/m3) ST 10 ppm (50 mg/m3) [skin]", "value": "TWA 5"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0223.html", "source_quote": "NIOSH REL TWA 5 ppm (25 mg/m3) ST 10 ppm (50 mg/m3) [skin]", "value": "25"}, {"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "121697 | S | N,N-Dimethylaniline; dimethylphenylamine | 5 | 25 | | 10 | 50", "value": "10"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "121697 | S | N,N-Dimethylaniline; dimethylphenylamine | 5 | 25 | | 10 | 50", "value": "50"}], "cas_number": "121-69-7", "disagreements": [], "id": "dimethylaniline-n-n-dimethylaniline", "pel_mgm3": "25", "pel_ppm": "5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Dimethylaniline (N,N-Dimethylaniline) | 121-69-7 | 5 | 25 | X |", "substance": "Dimethylaniline (N,N-Dimethylaniline)", "url": "https://referencesource.org/workplace-exposure-limits/dimethylaniline-n-n-dimethylaniline/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "14857342", "id": "dimethylethoxysilane", "pel_mgm3": "2.1", "pel_ppm": "0.5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "14857342 | | Dimethylethoxysilane | 0.5 | 2.1 | | 1.5 | 6.4", "stel_mgm3": "6.4", "stel_ppm": "1.5", "substance": "Dimethylethoxysilane", "url": "https://referencesource.org/workplace-exposure-limits/dimethylethoxysilane/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "stel_mgm3", "stel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0226.html", "source_quote": "NIOSH REL TWA 10 ppm (30 mg/m3) [skin]", "value": "TWA 10"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0226.html", "source_quote": "NIOSH REL TWA 10 ppm (30 mg/m3) [skin]", "value": "30"}], "cas_number": "68-12-2", "disagreements": [], "id": "dimethylformamide", "pel_mgm3": "30", "pel_ppm": "10", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Dimethylformamide | 68-12-2 | 10 | 30 | X |", "substance": "Dimethylformamide", "url": "https://referencesource.org/workplace-exposure-limits/dimethylformamide/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "148016 | | Dinitolmide; 3,5-Dinitro-o-toluamide | -- | 5", "value": "5"}], "cas_number": "148-01-6", "disagreements": [], "id": "dinitolmide", "rel_mgm3": "TWA 5", "source": "https://www.cdc.gov/niosh/npg/npgd0230.html", "source_quote": "NIOSH REL TWA 5 mg/m3", "substance": "Dinitolmide", "url": "https://referencesource.org/workplace-exposure-limits/dinitolmide/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"cas_number": "528290, 99650, 100254", "id": "dinitrobenzene-all-isomers-ortho-meta-and-para-isomers", "pel_mgm3": "1", "pel_ppm": "0.15", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "528290, 99650, 100254 | S | Dinitrobenzene (all (isomers) ortho, meta and para isomers | 0.15 | 1", "substance": "Dinitrobenzene (all (isomers) ortho, meta and para isomers", "url": "https://referencesource.org/workplace-exposure-limits/dinitrobenzene-all-isomers-ortho-meta-and-para-isomers/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Dioxane (Diethylene dioxide) | 123-91-1 | 100 | 360 | X |", "value": "100"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Dioxane (Diethylene dioxide) | 123-91-1 | 100 | 360 | X |", "value": "360"}], "cas_number": "123-91-1", "disagreements": [], "id": "dioxane", "rel_mgm3": "3.6", "rel_ppm": "C 1", "source": "https://www.cdc.gov/niosh/npg/npgd0237.html", "source_quote": "NIOSH REL Ca C 1 ppm (3.6 mg/m3) [30-minute]", "substance": "Dioxane", "url": "https://referencesource.org/workplace-exposure-limits/dioxane/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0238.html", "source_quote": "NIOSH REL TWA 0.2 mg/m3 [skin]", "value": "TWA 0.2"}], "cas_number": "78342", "disagreements": [], "id": "dioxathion", "pel_mgm3": "0.2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "78342 | S | Dioxathion | -- | 0.2", "substance": "Dioxathion", "url": "https://referencesource.org/workplace-exposure-limits/dioxathion/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "122394 | | Diphenylamine; N-phenylaniline | -- | 10", "value": "10"}], "cas_number": "122-39-4", "disagreements": [], "id": "diphenylamine", "rel_mgm3": "TWA 10", "source": "https://www.cdc.gov/niosh/npg/npgd0240.html", "source_quote": "NIOSH REL TWA 10 mg/m3", "substance": "Diphenylamine", "url": "https://referencesource.org/workplace-exposure-limits/diphenylamine/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0242.html", "source_quote": "NIOSH REL TWA 50 ppm (235 mg/m3)", "value": "TWA 50"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0242.html", "source_quote": "NIOSH REL TWA 50 ppm (235 mg/m3)", "value": "235"}], "cas_number": "123193", "disagreements": [], "id": "dipropyl-ketone", "pel_mgm3": "235", "pel_ppm": "50", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "123193 | | Dipropyl ketone | 50 | 235", "substance": "Dipropyl ketone", "url": "https://referencesource.org/workplace-exposure-limits/dipropyl-ketone/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "34590948 | S | Dipropylene glycol methyl ether | 100 | 600 | | 150 | 900", "value": "150"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "34590948 | S | Dipropylene glycol methyl ether | 100 | 600 | | 150 | 900", "value": "900"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0241.html", "source_quote": "NIOSH REL TWA 100 ppm (600 mg/m3) ST 150 ppm (900 mg/m3) [skin]", "value": "TWA 100"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0241.html", "source_quote": "NIOSH REL TWA 100 ppm (600 mg/m3) ST 150 ppm (900 mg/m3) [skin]", "value": "600"}], "cas_number": "34590-94-8", "disagreements": [], "id": "dipropylene-glycol-methyl-ether", "pel_mgm3": "600", "pel_ppm": "100", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Dipropylene glycol methyl ether | 34590-94-8 | 100 | 600 | X |", "substance": "Dipropylene glycol methyl ether", "url": "https://referencesource.org/workplace-exposure-limits/dipropylene-glycol-methyl-ether/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0243.html", "source_quote": "NIOSH REL TWA 0.5 mg/m3", "value": "TWA 0.5"}], "cas_number": "85007", "disagreements": [], "id": "diquat-1-1-ethylene-2-2-dipyridinium-dibromide", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "85007 | | Diquat; 1,1'-ethylene-2,2'-dipyridinium dibromide | --", "substance": "Diquat; 1,1'-ethylene-2,2'-dipyridinium dibromide", "url": "https://referencesource.org/workplace-exposure-limits/diquat-1-1-ethylene-2-2-dipyridinium-dibromide/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0244.html", "source_quote": "NIOSH REL TWA 2 mg/m3 [Precautions should be taken to avoid concurrent exposure to ethylene dibromide.]", "value": "TWA 2"}], "cas_number": "97778", "disagreements": [], "id": "disulfiram", "pel_mgm3": "2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "97778 | | Disulfiram | -- | 2", "substance": "Disulfiram", "url": "https://referencesource.org/workplace-exposure-limits/disulfiram/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "298044 | S | Disulfoton; o,o-diethyl S-2-(ethylthio)ethyl phosphorodithioate | -- | 0.1", "value": "0.1"}], "cas_number": "298-04-4", "disagreements": [], "id": "disulfoton", "rel_mgm3": "TWA 0.1", "source": "https://www.cdc.gov/niosh/npg/npgd0245.html", "source_quote": "NIOSH REL TWA 0.1 mg/m3 [skin]", "substance": "Disulfoton", "url": "https://referencesource.org/workplace-exposure-limits/disulfoton/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0247.html", "source_quote": "NIOSH REL TWA 10 mg/m3", "value": "TWA 10"}], "cas_number": "330541", "disagreements": [], "id": "diuron", "pel_mgm3": "10", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "330541 | | Diuron | -- | 10", "substance": "Diuron", "url": "https://referencesource.org/workplace-exposure-limits/diuron/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0248.html", "source_quote": "NIOSH REL TWA 10 ppm (50 mg/m3)", "value": "TWA 10"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0248.html", "source_quote": "NIOSH REL TWA 10 ppm (50 mg/m3)", "value": "50"}], "cas_number": "1321740", "disagreements": [], "id": "divinyl-benzene", "pel_mgm3": "50", "pel_ppm": "10", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "1321740 | | Divinyl benzene | 10 | 50", "substance": "Divinyl benzene", "url": "https://referencesource.org/workplace-exposure-limits/divinyl-benzene/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "12415-34-8", "disagreements": [], "id": "emery", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Emery | 12415-34-8 | - | - | - |", "substance": "Emery", "url": "https://referencesource.org/workplace-exposure-limits/emery/", "verified_fields": ["cas_number", "substance"]}
{"cas_number": "1302-74-5 (corundum)", "id": "emery-2", "rel_statement": "See Appendix D", "source": "https://www.cdc.gov/niosh/npg/npgd0250.html", "source_quote": "NIOSH REL See Appendix D", "substance": "Emery", "url": "https://referencesource.org/workplace-exposure-limits/emery-2/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "115297 | S | Endosulfan; 6,7,8,9,10,10-hexachloro-1,5,5a,6,9,9a-hexahydro-6,9-methano-2,4, 3-benzodioxathiepin-3-oxide | -- | 0.1", "value": "0.1"}], "cas_number": "115-29-7", "disagreements": [], "id": "endosulfan", "rel_mgm3": "TWA 0.1", "source": "https://www.cdc.gov/niosh/npg/npgd0251.html", "source_quote": "NIOSH REL TWA 0.1 mg/m3 [skin]", "substance": "Endosulfan", "url": "https://referencesource.org/workplace-exposure-limits/endosulfan/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0252.html", "source_quote": "NIOSH REL TWA 0.1 mg/m3 [skin]", "value": "TWA 0.1"}], "cas_number": "72-20-8", "disagreements": [], "id": "endrin", "pel_mgm3": "0.1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Endrin | 72-20-8 | - | 0.1 | X |", "substance": "Endrin", "url": "https://referencesource.org/workplace-exposure-limits/endrin/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0253.html", "source_quote": "NIOSH REL C 2 ppm (15.1 mg/m3) [60-minute]", "value": "C 2"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0253.html", "source_quote": "NIOSH REL C 2 ppm (15.1 mg/m3) [60-minute]", "value": "15.1"}], "cas_number": "13838169", "disagreements": [], "id": "enflurane", "pel_mgm3": "15", "pel_ppm": "2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "13838169 | | Enflurane | 2 | 15", "substance": "Enflurane", "url": "https://referencesource.org/workplace-exposure-limits/enflurane/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0254.html", "source_quote": "NIOSH REL Ca See Appendix A", "value": "Ca See Appendix A"}], "cas_number": "106-89-8", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Epichlorohydrin | 106-89-8 | 5 | 19 | X |", "value": "5"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "106898 | S | Epichlorohydrin; 1-chloro-2, 3-epoxypropane | 0.05 | 0.19", "value": "0.05"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Epichlorohydrin | 106-89-8 | 5 | 19 | X |", "value": "19"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "106898 | S | Epichlorohydrin; 1-chloro-2, 3-epoxypropane | 0.05 | 0.19", "value": "0.19"}]}], "id": "epichlorohydrin", "pel_mgm3": "19", "pel_ppm": "5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Epichlorohydrin | 106-89-8 | 5 | 19 | X |", "substance": "Epichlorohydrin", "url": "https://referencesource.org/workplace-exposure-limits/epichlorohydrin/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0255.html", "source_quote": "NIOSH REL TWA 0.5 mg/m3 [skin]", "value": "TWA 0.5"}], "cas_number": "2104-64-5", "disagreements": [{"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "EPN | 2104-64-5 | - | 0.5 | X |", "value": "0.5"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "2104645 | S | EPN; o-ethyl o-(p-nitrophenyl) phenylphosphonothioate | -- | 0.1", "value": "0.1"}]}], "id": "epn", "pel_mgm3": "0.5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "EPN | 2104-64-5 | - | 0.5 | X |", "substance": "EPN", "url": "https://referencesource.org/workplace-exposure-limits/epn/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"cas_number": "74840", "id": "ethane", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "74840 | | Ethane | (h) | --", "substance": "Ethane", "url": "https://referencesource.org/workplace-exposure-limits/ethane/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0256.html", "source_quote": "NIOSH REL TWA 3 ppm (8 mg/m3) ST 6 ppm (15 mg/m3)", "value": "TWA 3"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0256.html", "source_quote": "NIOSH REL TWA 3 ppm (8 mg/m3) ST 6 ppm (15 mg/m3)", "value": "8"}, {"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "141435 | | Ethanolamine; 2-aminoethanol | 3 | 8 | | 6 | 15", "value": "6"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "141435 | | Ethanolamine; 2-aminoethanol | 3 | 8 | | 6 | 15", "value": "15"}], "cas_number": "141-43-5", "disagreements": [{"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ethanolamine | 141-43-5 | 3 | 6 | - |", "value": "6"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "141435 | | Ethanolamine; 2-aminoethanol | 3 | 8 | | 6 | 15", "value": "8"}]}], "id": "ethanolamine", "pel_mgm3": "6", "pel_ppm": "3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ethanolamine | 141-43-5 | 3 | 6 | - |", "substance": "Ethanolamine", "url": "https://referencesource.org/workplace-exposure-limits/ethanolamine/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0257.html", "source_quote": "NIOSH REL TWA 0.4 mg/m3 [skin]", "value": "TWA 0.4"}], "cas_number": "563122", "disagreements": [], "id": "ethion", "pel_mgm3": "0.4", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "563122 | S | Ethion | -- | 0.4", "substance": "Ethion", "url": "https://referencesource.org/workplace-exposure-limits/ethion/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0260.html", "source_quote": "NIOSH REL TWA 400 ppm (1400 mg/m3)", "value": "TWA 400"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0260.html", "source_quote": "NIOSH REL TWA 400 ppm (1400 mg/m3)", "value": "1400"}], "cas_number": "141-78-6", "disagreements": [], "id": "ethyl-acetate", "pel_mgm3": "1400", "pel_ppm": "400", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ethyl acetate | 141-78-6 | 400 | 1400 | - |", "substance": "Ethyl acetate", "url": "https://referencesource.org/workplace-exposure-limits/ethyl-acetate/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "140885 | S | Ethyl acrylate | 5 | 20 | | 25 | 100", "value": "25"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "140885 | S | Ethyl acrylate | 5 | 20 | | 25 | 100", "value": "100"}, {"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0261.html", "source_quote": "NIOSH REL Ca See Appendix A", "value": "Ca See Appendix A"}], "cas_number": "140-88-5", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ethyl acrylate | 140-88-5 | 25 | 100 | X |", "value": "25"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "140885 | S | Ethyl acrylate | 5 | 20 | | 25 | 100", "value": "5"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ethyl acrylate | 140-88-5 | 25 | 100 | X |", "value": "100"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "140885 | S | Ethyl acrylate | 5 | 20 | | 25 | 100", "value": "20"}]}], "id": "ethyl-acrylate", "pel_mgm3": "100", "pel_ppm": "25", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ethyl acrylate | 140-88-5 | 25 | 100 | X |", "substance": "Ethyl acrylate", "url": "https://referencesource.org/workplace-exposure-limits/ethyl-acrylate/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ethyl alcohol (Ethanol) | 64-17-5 | 1000 | 1900 | - |", "value": "1000"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ethyl alcohol (Ethanol) | 64-17-5 | 1000 | 1900 | - |", "value": "1900"}], "cas_number": "64-17-5", "disagreements": [], "id": "ethyl-alcohol", "rel_mgm3": "1900", "rel_ppm": "TWA 1000", "source": "https://www.cdc.gov/niosh/npg/npgd0262.html", "source_quote": "NIOSH REL TWA 1000 ppm (1900 mg/m3)", "substance": "Ethyl alcohol", "url": "https://referencesource.org/workplace-exposure-limits/ethyl-alcohol/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0264.html", "source_quote": "NIOSH REL TWA 100 ppm (435 mg/m3) ST 125 ppm (545 mg/m3)", "value": "TWA 100"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0264.html", "source_quote": "NIOSH REL TWA 100 ppm (435 mg/m3) ST 125 ppm (545 mg/m3)", "value": "435"}, {"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "100414 | | Ethylbenzene | 5 | 22 | | 30 | 130", "value": "30"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "100414 | | Ethylbenzene | 5 | 22 | | 30 | 130", "value": "130"}], "cas_number": "100-41-4", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ethyl benzene | 100-41-4 | 100 | 435 | - |", "value": "100"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "100414 | | Ethylbenzene | 5 | 22 | | 30 | 130", "value": "5"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ethyl benzene | 100-41-4 | 100 | 435 | - |", "value": "435"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "100414 | | Ethylbenzene | 5 | 22 | | 30 | 130", "value": "22"}]}], "id": "ethyl-benzene", "pel_mgm3": "435", "pel_ppm": "100", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ethyl benzene | 100-41-4 | 100 | 435 | - |", "substance": "Ethyl benzene", "url": "https://referencesource.org/workplace-exposure-limits/ethyl-benzene/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0265.html", "source_quote": "NIOSH REL See Appendix D", "value": "See Appendix D"}], "cas_number": "74-96-4", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ethyl bromide | 74-96-4 | 200 | 890 | - |", "value": "200"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "74964 | S | Ethyl bromide | 5 | 22", "value": "5"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ethyl bromide | 74-96-4 | 200 | 890 | - |", "value": "890"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "74964 | S | Ethyl bromide | 5 | 22", "value": "22"}]}], "id": "ethyl-bromide", "pel_mgm3": "890", "pel_ppm": "200", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ethyl bromide | 74-96-4 | 200 | 890 | - |", "substance": "Ethyl bromide", "url": "https://referencesource.org/workplace-exposure-limits/ethyl-bromide/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ethyl butyl ketone (3-Heptanone) | 106-35-4 | 50 | 230 | - |", "value": "50"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ethyl butyl ketone (3-Heptanone) | 106-35-4 | 50 | 230 | - |", "value": "230"}, {"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "106354 | | Ethyl butyl ketone; 3-heptanone | 50 | 230 | | 75 | 345", "value": "75"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "106354 | | Ethyl butyl ketone; 3-heptanone | 50 | 230 | | 75 | 345", "value": "345"}], "cas_number": "106-35-4", "disagreements": [], "id": "ethyl-butyl-ketone", "rel_mgm3": "230", "rel_ppm": "TWA 50", "source": "https://www.cdc.gov/niosh/npg/npgd0266.html", "source_quote": "NIOSH REL TWA 50 ppm (230 mg/m3)", "substance": "Ethyl butyl ketone", "url": "https://referencesource.org/workplace-exposure-limits/ethyl-butyl-ketone/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0267.html", "source_quote": "NIOSH REL Handle with caution in the workplace. See Appendix C (Chloroethanes)", "value": "Handle with caution in the workplace. See Appendix C (Chloroethanes)"}], "cas_number": "75-00-3", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ethyl chloride | 75-00-3 | 1000 | 2600 | - |", "value": "1000"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75003 | S | Ethyl chloride; chloroethane | 100 | 264", "value": "100"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ethyl chloride | 75-00-3 | 1000 | 2600 | - |", "value": "2600"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75003 | S | Ethyl chloride; chloroethane | 100 | 264", "value": "264"}]}], "id": "ethyl-chloride", "pel_mgm3": "2600", "pel_ppm": "1000", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ethyl chloride | 75-00-3 | 1000 | 2600 | - |", "substance": "Ethyl chloride", "url": "https://referencesource.org/workplace-exposure-limits/ethyl-chloride/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "7085850", "id": "ethyl-cyanoacrylate", "pel_mgm3": "1.02", "pel_ppm": "0.2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7085850 | | Ethyl cyanoacrylate | 0.2 | 1.02", "substance": "Ethyl cyanoacrylate", "url": "https://referencesource.org/workplace-exposure-limits/ethyl-cyanoacrylate/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "60297 | | Ethyl ether | 400 | 1,200 | | 500 | 1500", "value": "500"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "60297 | | Ethyl ether | 400 | 1,200 | | 500 | 1500", "value": "1500"}, {"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0277.html", "source_quote": "NIOSH REL See Appendix D", "value": "See Appendix D"}], "cas_number": "60-29-7", "disagreements": [], "id": "ethyl-ether", "pel_mgm3": "1200", "pel_ppm": "400", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ethyl ether | 60-29-7 | 400 | 1200 | - |", "substance": "Ethyl ether", "url": "https://referencesource.org/workplace-exposure-limits/ethyl-ether/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0278.html", "source_quote": "NIOSH REL TWA 100 ppm (300 mg/m3)", "value": "TWA 100"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0278.html", "source_quote": "NIOSH REL TWA 100 ppm (300 mg/m3)", "value": "300"}], "cas_number": "109-94-4", "disagreements": [], "id": "ethyl-formate", "pel_mgm3": "300", "pel_ppm": "100", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ethyl formate | 109-94-4 | 100 | 300 | - |", "substance": "Ethyl formate", "url": "https://referencesource.org/workplace-exposure-limits/ethyl-formate/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0280.html", "source_quote": "NIOSH REL C 0.5 ppm (1.3 mg/m3) [15-minute]", "value": "C 0.5"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0280.html", "source_quote": "NIOSH REL C 0.5 ppm (1.3 mg/m3) [15-minute]", "value": "1.3"}], "cas_number": "75-08-1", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ethyl mercaptan | 75-08-1 | (C)10 | (C)25 | - |", "value": "(C)10"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75081 | | Ethyl mercaptan; ethanethiol | 0.5 | 1", "value": "0.5"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ethyl mercaptan | 75-08-1 | (C)10 | (C)25 | - |", "value": "(C)25"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75081 | | Ethyl mercaptan; ethanethiol | 0.5 | 1", "value": "1"}]}], "id": "ethyl-mercaptan", "pel_mgm3": "(C)25", "pel_ppm": "(C)10", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ethyl mercaptan | 75-08-1 | (C)10 | (C)25 | - |", "substance": "Ethyl mercaptan", "url": "https://referencesource.org/workplace-exposure-limits/ethyl-mercaptan/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0282.html", "source_quote": "NIOSH REL TWA 10 ppm (85 mg/m3)", "value": "TWA 10"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0282.html", "source_quote": "NIOSH REL TWA 10 ppm (85 mg/m3)", "value": "85"}], "cas_number": "78-10-4", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ethyl silicate | 78-10-4 | 100 | 850 | - |", "value": "100"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "78104 | | Ethyl silicate; tetraethyl silicate | 10 | 85", "value": "10"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ethyl silicate | 78-10-4 | 100 | 850 | - |", "value": "850"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "78104 | | Ethyl silicate; tetraethyl silicate | 10 | 85", "value": "85"}]}], "id": "ethyl-silicate", "pel_mgm3": "850", "pel_ppm": "100", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ethyl silicate | 78-10-4 | 100 | 850 | - |", "substance": "Ethyl silicate", "url": "https://referencesource.org/workplace-exposure-limits/ethyl-silicate/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "637923", "id": "ethyl-tert-butyl-ether", "pel_mgm3": "21", "pel_ppm": "5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "637923 | | Ethyl tert-butyl ether | 5 | 21", "substance": "Ethyl tert-butyl ether", "url": "https://referencesource.org/workplace-exposure-limits/ethyl-tert-butyl-ether/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75047 | S | Ethylamine | 5 | 9.2 | C", "value": "the values given in the PEL columns are ceiling values"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0263.html", "source_quote": "NIOSH REL TWA 10 ppm (18 mg/m3)", "value": "TWA 10"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0263.html", "source_quote": "NIOSH REL TWA 10 ppm (18 mg/m3)", "value": "18"}], "cas_number": "75-04-7", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ethylamine | 75-04-7 | 10 | 18 | - |", "value": "10"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75047 | S | Ethylamine | 5 | 9.2 | C", "value": "5"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ethylamine | 75-04-7 | 10 | 18 | - |", "value": "18"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75047 | S | Ethylamine | 5 | 9.2 | C", "value": "9.2"}]}], "id": "ethylamine", "pel_mgm3": "18", "pel_ppm": "10", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ethylamine | 75-04-7 | 10 | 18 | - |", "substance": "Ethylamine", "url": "https://referencesource.org/workplace-exposure-limits/ethylamine/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "74851", "id": "ethylene", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "74851 | | Ethylene | (h) | --", "substance": "Ethylene", "url": "https://referencesource.org/workplace-exposure-limits/ethylene/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0268.html", "source_quote": "NIOSH REL C 1 ppm (3 mg/m3) [skin]", "value": "C 1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0268.html", "source_quote": "NIOSH REL C 1 ppm (3 mg/m3) [skin]", "value": "3"}, {"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "107073 | S | Ethylene chlorohydrin; 2-chloroethanol | 1 | 3 | C", "value": "the values given in the PEL columns are ceiling values"}], "cas_number": "107-07-3", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ethylene chlorohydrin | 107-07-3 | 5 | 16 | X |", "value": "5"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "107073 | S | Ethylene chlorohydrin; 2-chloroethanol | 1 | 3 | C", "value": "1"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ethylene chlorohydrin | 107-07-3 | 5 | 16 | X |", "value": "16"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "107073 | S | Ethylene chlorohydrin; 2-chloroethanol | 1 | 3 | C", "value": "3"}]}], "id": "ethylene-chlorohydrin", "pel_mgm3": "16", "pel_ppm": "5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ethylene chlorohydrin | 107-07-3 | 5 | 16 | X |", "substance": "Ethylene chlorohydrin", "url": "https://referencesource.org/workplace-exposure-limits/ethylene-chlorohydrin/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-28", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "106934 | S | Ethylene dibromide; 1,2-dibromoethane, see Section 5219 | 0.13 | 1 | C", "value": "0.13"}, {"as_of": "2026-09-28", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "106934 | S | Ethylene dibromide; 1,2-dibromoethane, see Section 5219 | 0.13 | 1 | C", "value": "1"}, {"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "106934 | S | Ethylene dibromide; 1,2-dibromoethane, see Section 5219 | 0.13 | 1 | C", "value": "the values given in the PEL columns are ceiling values"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0270.html", "source_quote": "NIOSH REL Ca TWA 0.045 ppm C 0.13 ppm [15-minute]", "value": "TWA 0.045"}], "cas_number": "106-93-4", "disagreements": [], "id": "ethylene-dibromide", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ethylene dibromide | 106-93-4 | - | (2) | - |", "substance": "Ethylene dibromide", "url": "https://referencesource.org/workplace-exposure-limits/ethylene-dibromide/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-09-28", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "107062 | | Ethylene dichloride; 1,2-dichloroethane | 1 | 4 | 200 ppm | 2 | 8", "value": "1"}, {"as_of": "2026-09-28", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "107062 | | Ethylene dichloride; 1,2-dichloroethane | 1 | 4 | 200 ppm | 2 | 8", "value": "4"}, {"as_of": "2026-09-28", "field": "ceiling", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "107062 | | Ethylene dichloride; 1,2-dichloroethane | 1 | 4 | 200 ppm | 2 | 8", "value": "200 ppm"}, {"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "107062 | | Ethylene dichloride; 1,2-dichloroethane | 1 | 4 | 200 ppm | 2 | 8", "value": "a ceiling value in addition to the TWA values"}, {"as_of": "2026-09-28", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "107062 | | Ethylene dichloride; 1,2-dichloroethane | 1 | 4 | 200 ppm | 2 | 8", "value": "2"}, {"as_of": "2026-09-28", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "107062 | | Ethylene dichloride; 1,2-dichloroethane | 1 | 4 | 200 ppm | 2 | 8", "value": "8"}], "cas_number": "107-06-2", "disagreements": [], "id": "ethylene-dichloride", "rel_mgm3": "4", "rel_ppm": "TWA 1", "source": "https://www.cdc.gov/niosh/npg/npgd0271.html", "source_quote": "NIOSH REL Ca TWA 1 ppm (4 mg/m3) ST 2 ppm (8 mg/m3)", "substance": "Ethylene dichloride", "url": "https://referencesource.org/workplace-exposure-limits/ethylene-dichloride/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-28", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "107211 | | Ethylene glycol (vapor) | 40 | 100 | C", "value": "40"}, {"as_of": "2026-09-28", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "107211 | | Ethylene glycol (vapor) | 40 | 100 | C", "value": "100"}, {"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "107211 | | Ethylene glycol (vapor) | 40 | 100 | C", "value": "the values given in the PEL columns are ceiling values"}], "cas_number": "107-21-1", "disagreements": [], "id": "ethylene-glycol", "rel_statement": "See Appendix D", "source": "https://www.cdc.gov/niosh/npg/npgd0272.html", "source_quote": "NIOSH REL See Appendix D", "substance": "Ethylene glycol", "url": "https://referencesource.org/workplace-exposure-limits/ethylene-glycol/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"cas_number": "629141", "id": "ethylene-glycol-diethyl-ether-1-2-diethoxyethane", "pel_mgm3": "24", "pel_ppm": "5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "629141 | S | Ethylene glycol diethyl ether, 1,2-diethoxyethane | 5 | 24", "substance": "Ethylene glycol diethyl ether, 1,2-diethoxyethane", "url": "https://referencesource.org/workplace-exposure-limits/ethylene-glycol-diethyl-ether-1-2-diethoxyethane/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "110714", "id": "ethylene-glycol-dimethyl-ether-1-2-dimethoxyethane-glyme", "pel_mgm3": "3.7", "pel_ppm": "1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "110714 | S | Ethylene glycol dimethyl ether, 1,2-dimethoxyethane, Glyme | 1 | 3.7 | | 5 | 18", "stel_mgm3": "18", "stel_ppm": "5", "substance": "Ethylene glycol dimethyl ether, 1,2-dimethoxyethane, Glyme", "url": "https://referencesource.org/workplace-exposure-limits/ethylene-glycol-dimethyl-ether-1-2-dimethoxyethane-glyme/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "stel_mgm3", "stel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "628966 | S | Ethylene glycol dinitrate | | (k) | | -- | 0.1", "value": "0.1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0273.html", "source_quote": "NIOSH REL ST 0.1 mg/m3 [skin]", "value": "ST 0.1"}], "cas_number": "628-96-6", "disagreements": [], "id": "ethylene-glycol-dinitrate", "pel_mgm3": "(C)1", "pel_ppm": "(C)0.2", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ethylene glycol dinitrate | 628-96-6 | (C)0.2 | (C)1 | X |", "substance": "Ethylene glycol dinitrate", "url": "https://referencesource.org/workplace-exposure-limits/ethylene-glycol-dinitrate/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75218 | | Ethylene oxide; see Section 5220 | 1 | 2 | | 5", "value": "1"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75218 | | Ethylene oxide; see Section 5220 | 1 | 2 | | 5", "value": "2"}, {"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75218 | | Ethylene oxide; see Section 5220 | 1 | 2 | | 5", "value": "5"}], "cas_number": "75-21-8", "disagreements": [], "id": "ethylene-oxide", "rel_mgm3": "9", "rel_ppm": "C 5", "source": "https://www.cdc.gov/niosh/npg/npgd0275.html", "source_quote": "NIOSH REL Ca TWA <0.1 ppm (0.18 mg/m3) C 5 ppm (9 mg/m3) [10-min/day]", "substance": "Ethylene oxide", "url": "https://referencesource.org/workplace-exposure-limits/ethylene-oxide/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"cas_number": "96-45-7", "id": "ethylene-thiourea", "rel_statement": "Ca Use encapsulated form. See Appendix A", "source": "https://www.cdc.gov/niosh/npg/npgd0276.html", "source_quote": "NIOSH REL Ca Use encapsulated form. See Appendix A", "substance": "Ethylene thiourea", "url": "https://referencesource.org/workplace-exposure-limits/ethylene-thiourea/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0269.html", "source_quote": "NIOSH REL TWA 10 ppm (25 mg/m3)", "value": "TWA 10"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0269.html", "source_quote": "NIOSH REL TWA 10 ppm (25 mg/m3)", "value": "25"}], "cas_number": "107-15-3", "disagreements": [], "id": "ethylenediamine", "pel_mgm3": "25", "pel_ppm": "10", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ethylenediamine | 107-15-3 | 10 | 25 | - |", "substance": "Ethylenediamine", "url": "https://referencesource.org/workplace-exposure-limits/ethylenediamine/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "151564 | S | Ethyleneimine; see also Section 5209 | 0.5 | 1", "value": "0.5"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "151564 | S | Ethyleneimine; see also Section 5209 | 0.5 | 1", "value": "1"}], "cas_number": "151-56-4", "disagreements": [], "id": "ethyleneimine", "rel_statement": "Ca See Appendix A", "source": "https://www.cdc.gov/niosh/npg/npgd0274.html", "source_quote": "NIOSH REL Ca See Appendix A", "substance": "Ethyleneimine", "url": "https://referencesource.org/workplace-exposure-limits/ethyleneimine/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0279.html", "source_quote": "NIOSH REL C 5 ppm (25 mg/m3)", "value": "C 5"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0279.html", "source_quote": "NIOSH REL C 5 ppm (25 mg/m3)", "value": "25"}], "cas_number": "16219753", "ceiling_notation": "the values given in the PEL columns are ceiling values", "disagreements": [], "id": "ethylidene-norbornene", "pel_mgm3": "25", "pel_ppm": "5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "16219753 | | Ethylidene norbornene | 5 | 25 | C", "substance": "Ethylidene norbornene", "url": "https://referencesource.org/workplace-exposure-limits/ethylidene-norbornene/", "verified_fields": ["cas_number", "ceiling_notation", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0283.html", "source_quote": "NIOSH REL TWA 0.1 mg/m3 [skin]", "value": "TWA 0.1"}], "cas_number": "22224926", "disagreements": [], "id": "fenamiphos", "pel_mgm3": "0.1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "22224926 | S | Fenamiphos | | 0.1", "substance": "Fenamiphos", "url": "https://referencesource.org/workplace-exposure-limits/fenamiphos/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0284.html", "source_quote": "NIOSH REL TWA 0.1 mg/m3", "value": "TWA 0.1"}], "cas_number": "115902", "disagreements": [], "id": "fensulfothion", "pel_mgm3": "0.1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "115902 | | Fensulfothion | -- | 0.1", "substance": "Fensulfothion", "url": "https://referencesource.org/workplace-exposure-limits/fensulfothion/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0285.html", "source_quote": "NIOSH REL See Appendix D", "value": "See Appendix D"}], "cas_number": "55389", "disagreements": [], "id": "fenthion", "pel_mgm3": "0.2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "55389 | S | Fenthion | -- | 0.2", "substance": "Fenthion", "url": "https://referencesource.org/workplace-exposure-limits/fenthion/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0286.html", "source_quote": "NIOSH REL TWA 10 mg/m3", "value": "TWA 10"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "14484641 | | Ferbam; ferric N,N-dimethylthiocarbamate | -- | 10", "value": "10"}], "cas_number": "14484-64-1", "disagreements": [], "id": "ferbam", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ferbam | 14484-64-1 | - | - | - |", "substance": "Ferbam", "url": "https://referencesource.org/workplace-exposure-limits/ferbam/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "12604589 | | Ferrovanadium dust | -- | 1 | | -- | 3", "value": "3"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0287.html", "source_quote": "NIOSH REL TWA 1 mg/m3 ST 3 mg/m3", "value": "TWA 1"}], "cas_number": "12604-58-9", "disagreements": [], "id": "ferrovanadium-dust", "pel_mgm3": "1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ferrovanadium dust | 12604-58-9 | - | 1 | - |", "substance": "Ferrovanadium dust", "url": "https://referencesource.org/workplace-exposure-limits/ferrovanadium-dust/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"id": "flour-dust", "pel_mgm3": "0.5(s)", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Flour dust | | 0.5(s)", "substance": "Flour dust", "url": "https://referencesource.org/workplace-exposure-limits/flour-dust/", "verified_fields": ["pel_mgm3", "substance"]}
{"id": "fluorides-as-f", "pel_mgm3": "2.5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Fluorides, as F | -- | 2.5", "substance": "Fluorides, as F", "url": "https://referencesource.org/workplace-exposure-limits/fluorides-as-f/", "verified_fields": ["pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0289.html", "source_quote": "NIOSH REL TWA 0.1 ppm (0.2 mg/m3)", "value": "TWA 0.1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0289.html", "source_quote": "NIOSH REL TWA 0.1 ppm (0.2 mg/m3)", "value": "0.2"}], "cas_number": "7782-41-4", "disagreements": [], "id": "fluorine", "pel_mgm3": "0.2", "pel_ppm": "0.1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Fluorine | 7782-41-4 | 0.1 | 0.2 | - |", "substance": "Fluorine", "url": "https://referencesource.org/workplace-exposure-limits/fluorine/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Fluorotrichloromethane (Trichlorofluoromethane) | 75-69-4 | 1000 | 5600 | - |", "value": "1000"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Fluorotrichloromethane (Trichlorofluoromethane) | 75-69-4 | 1000 | 5600 | - |", "value": "5600"}, {"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75694 | | Trichlorofluoromethane; Fluorocarbon 11 | 1,000 | 5,600 | C", "value": "the values given in the PEL columns are ceiling values"}], "cas_number": "75-69-4", "disagreements": [], "id": "fluorotrichloromethane", "rel_mgm3": "5600", "rel_ppm": "C 1000", "source": "https://www.cdc.gov/niosh/npg/npgd0290.html", "source_quote": "NIOSH REL C 1000 ppm (5600 mg/m3)", "substance": "Fluorotrichloromethane", "url": "https://referencesource.org/workplace-exposure-limits/fluorotrichloromethane/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"cas_number": "406-90-6", "id": "fluoroxene", "rel_mgm3": "10.3", "rel_ppm": "C 2", "source": "https://www.cdc.gov/niosh/npg/npgd0291.html", "source_quote": "NIOSH REL C 2 ppm (10.3 mg/m3) [60-minute]", "substance": "Fluoroxene", "url": "https://referencesource.org/workplace-exposure-limits/fluoroxene/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0292.html", "source_quote": "NIOSH REL TWA 0.1 mg/m3 [skin]", "value": "TWA 0.1"}], "cas_number": "944229", "disagreements": [], "id": "fonofos", "pel_mgm3": "0.1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "944229 | S | Fonofos | -- | 0.1", "substance": "Fonofos", "url": "https://referencesource.org/workplace-exposure-limits/fonofos/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "50000 | | Formaldehyde, see Section 5217 | 0.75 | -- | | 2 | --", "value": "0.75"}, {"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "50000 | | Formaldehyde, see Section 5217 | 0.75 | -- | | 2 | --", "value": "2"}], "cas_number": "50-00-0", "disagreements": [], "id": "formaldehyde", "rel_ppm": "TWA 0.016", "source": "https://www.cdc.gov/niosh/npg/npgd0293.html", "source_quote": "NIOSH REL Ca TWA 0.016 ppm C 0.1 ppm [15-minute]", "substance": "Formaldehyde", "url": "https://referencesource.org/workplace-exposure-limits/formaldehyde/", "verified_fields": ["cas_number", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0295.html", "source_quote": "NIOSH REL TWA 10 ppm (15 mg/m3) [skin]", "value": "TWA 10"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0295.html", "source_quote": "NIOSH REL TWA 10 ppm (15 mg/m3) [skin]", "value": "15"}], "cas_number": "75127", "disagreements": [], "id": "formamide", "pel_mgm3": "18", "pel_ppm": "10", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75127 | S | Formamide | 10 | 18", "substance": "Formamide", "url": "https://referencesource.org/workplace-exposure-limits/formamide/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "64186 | | Formic acid | 5 | 9 | | 10 | 19", "value": "10"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "64186 | | Formic acid | 5 | 9 | | 10 | 19", "value": "19"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0296.html", "source_quote": "NIOSH REL TWA 5 ppm (9 mg/m3)", "value": "TWA 5"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0296.html", "source_quote": "NIOSH REL TWA 5 ppm (9 mg/m3)", "value": "9"}], "cas_number": "64-18-6", "disagreements": [], "id": "formic-acid", "pel_mgm3": "9", "pel_ppm": "5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Formic acid | 64-18-6 | 5 | 9 | - |", "substance": "Formic acid", "url": "https://referencesource.org/workplace-exposure-limits/formic-acid/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0297.html", "source_quote": "NIOSH REL See Appendix D", "value": "See Appendix D"}], "cas_number": "98-01-1", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Furfural | 98-01-1 | 5 | 20 | X |", "value": "5"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "98011 | S | Furfural | 2 | 8", "value": "2"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Furfural | 98-01-1 | 5 | 20 | X |", "value": "20"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "98011 | S | Furfural | 2 | 8", "value": "8"}]}], "id": "furfural", "pel_mgm3": "20", "pel_ppm": "5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Furfural | 98-01-1 | 5 | 20 | X |", "substance": "Furfural", "url": "https://referencesource.org/workplace-exposure-limits/furfural/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "98000 | S | Furfuryl alcohol | 10 | 40 | | 15 | 60", "value": "15"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "98000 | S | Furfuryl alcohol | 10 | 40 | | 15 | 60", "value": "60"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0298.html", "source_quote": "NIOSH REL TWA 10 ppm (40 mg/m3) ST 15 ppm (60 mg/m3) [skin]", "value": "TWA 10"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0298.html", "source_quote": "NIOSH REL TWA 10 ppm (40 mg/m3) ST 15 ppm (60 mg/m3) [skin]", "value": "40"}], "cas_number": "98-00-0", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Furfuryl alcohol | 98-00-0 | 50 | 200 | - |", "value": "50"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "98000 | S | Furfuryl alcohol | 10 | 40 | | 15 | 60", "value": "10"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Furfuryl alcohol | 98-00-0 | 50 | 200 | - |", "value": "200"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "98000 | S | Furfuryl alcohol | 10 | 40 | | 15 | 60", "value": "40"}]}], "id": "furfuryl-alcohol", "pel_mgm3": "200", "pel_ppm": "50", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Furfuryl alcohol | 98-00-0 | 50 | 200 | - |", "substance": "Furfuryl alcohol", "url": "https://referencesource.org/workplace-exposure-limits/furfuryl-alcohol/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0299.html", "source_quote": "NIOSH REL Ca See Appendix A", "value": "Ca See Appendix A"}], "cas_number": "8006619", "disagreements": [], "id": "gasoline", "pel_mgm3": "900", "pel_ppm": "300", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "8006619 | | Gasoline | 300 | 900 | | 500 | 1500", "stel_mgm3": "1500", "stel_ppm": "500", "substance": "Gasoline", "url": "https://referencesource.org/workplace-exposure-limits/gasoline/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "stel_mgm3", "stel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0300.html", "source_quote": "NIOSH REL TWA 0.2 ppm (0.6 mg/m3)", "value": "TWA 0.2"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0300.html", "source_quote": "NIOSH REL TWA 0.2 ppm (0.6 mg/m3)", "value": "0.6"}], "cas_number": "7782652", "disagreements": [], "id": "germanium-tetrahydride", "pel_mgm3": "0.6", "pel_ppm": "0.2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7782652 | | Germanium tetrahydride | 0.2 | 0.6", "substance": "Germanium tetrahydride", "url": "https://referencesource.org/workplace-exposure-limits/germanium-tetrahydride/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"id": "glass-fibrous", "pel_ppm": "1.0 f/cc(q)", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Glass, fibrous | 1.0 f/cc(q)", "substance": "Glass, fibrous", "url": "https://referencesource.org/workplace-exposure-limits/glass-fibrous/", "verified_fields": ["pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-28", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "111308 | | Glutaraldehyde(t) | 0.05 | 0.2 | C", "value": "0.05"}, {"as_of": "2026-09-28", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "111308 | | Glutaraldehyde(t) | 0.05 | 0.2 | C", "value": "0.2"}, {"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "111308 | | Glutaraldehyde(t) | 0.05 | 0.2 | C", "value": "the values given in the PEL columns are ceiling values"}], "cas_number": "111-30-8", "disagreements": [], "id": "glutaraldehyde", "rel_mgm3": "0.8", "rel_ppm": "C 0.2", "source": "https://www.cdc.gov/niosh/npg/npgd0301.html", "source_quote": "NIOSH REL C 0.2 ppm (0.8 mg/m3)", "substance": "Glutaraldehyde", "url": "https://referencesource.org/workplace-exposure-limits/glutaraldehyde/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0302.html", "source_quote": "NIOSH REL See Appendix D", "value": "See Appendix D"}], "cas_number": "56-81-5", "disagreements": [], "id": "glycerin-mist", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Glycerin (mist) | 56-81-5 | - | - | - |", "substance": "Glycerin (mist)", "url": "https://referencesource.org/workplace-exposure-limits/glycerin-mist/", "verified_fields": ["cas_number", "substance"]}
{"cas_number": "123944", "id": "glyceryl-stearate", "pel_mgm3": "10", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "123944 | | Glyceryl stearate | -- | 10", "substance": "Glyceryl stearate", "url": "https://referencesource.org/workplace-exposure-limits/glyceryl-stearate/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0303.html", "source_quote": "NIOSH REL TWA 25 ppm (75 mg/m3)", "value": "TWA 25"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0303.html", "source_quote": "NIOSH REL TWA 25 ppm (75 mg/m3)", "value": "75"}], "cas_number": "556-52-5", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Glycidol | 556-52-5 | 50 | 150 | - |", "value": "50"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "556525 | | Glycidol; 2,3-epoxy-1-propanol | 2 | 6.1", "value": "2"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Glycidol | 556-52-5 | 50 | 150 | - |", "value": "150"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "556525 | | Glycidol; 2,3-epoxy-1-propanol | 2 | 6.1", "value": "6.1"}]}], "id": "glycidol", "pel_mgm3": "150", "pel_ppm": "50", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Glycidol | 556-52-5 | 50 | 150 | - |", "substance": "Glycidol", "url": "https://referencesource.org/workplace-exposure-limits/glycidol/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "107-16-4", "id": "glycolonitrile", "rel_mgm3": "5", "rel_ppm": "C 2", "source": "https://www.cdc.gov/niosh/npg/npgd0304.html", "source_quote": "NIOSH REL C 2 ppm (5 mg/m3) [15-minute]", "substance": "Glycolonitrile", "url": "https://referencesource.org/workplace-exposure-limits/glycolonitrile/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"cas_number": "107222", "id": "glyoxal-1-2-ethanedione", "pel_mgm3": "0.1(s), (u)", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "107222 | | Glyoxal, 1,2-ethanedione | -- | 0.1(s), (u)", "substance": "Glyoxal, 1,2-ethanedione", "url": "https://referencesource.org/workplace-exposure-limits/glyoxal-1-2-ethanedione/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"id": "grain-dust-oat-wheat-barley", "pel_mgm3": "10", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Grain dust (oat, wheat, barley) | -- | 10", "substance": "Grain dust (oat, wheat, barley)", "url": "https://referencesource.org/workplace-exposure-limits/grain-dust-oat-wheat-barley/", "verified_fields": ["pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7782425 | | Graphite, natural respirable dust | | 2.5", "value": "2.5"}], "cas_number": "7782-42-5", "disagreements": [], "id": "graphite-natural", "rel_statement": "TWA 2.5 mg/m3 (resp)", "source": "https://www.cdc.gov/niosh/npg/npgd0306.html", "source_quote": "NIOSH REL TWA 2.5 mg/m3 (resp)", "substance": "Graphite (natural)", "url": "https://referencesource.org/workplace-exposure-limits/graphite-natural/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"cas_number": "7440-44-0 (synthetic)", "id": "graphite-synthetic", "rel_statement": "See Appendix D", "source": "https://www.cdc.gov/niosh/npg/npgd0307.html", "source_quote": "NIOSH REL See Appendix D", "substance": "Graphite (synthetic)", "url": "https://referencesource.org/workplace-exposure-limits/graphite-synthetic/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0308.html", "source_quote": "NIOSH REL TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)", "value": "TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)"}], "cas_number": "13397-24-5", "disagreements": [], "id": "gypsum", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Gypsum | 13397-24-5 | - | - | - |", "substance": "Gypsum", "url": "https://referencesource.org/workplace-exposure-limits/gypsum/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0309.html", "source_quote": "NIOSH REL TWA 0.5 mg/m3", "value": "TWA 0.5"}], "cas_number": "7440-58-6", "disagreements": [], "id": "hafnium", "pel_mgm3": "0.5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Hafnium | 7440-58-6 | - | 0.5 | - |", "substance": "Hafnium", "url": "https://referencesource.org/workplace-exposure-limits/hafnium/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0310.html", "source_quote": "NIOSH REL C 2 ppm (16.2 mg/m3) [60-minute]", "value": "C 2"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0310.html", "source_quote": "NIOSH REL C 2 ppm (16.2 mg/m3) [60-minute]", "value": "16.2"}], "cas_number": "151677", "disagreements": [], "id": "halothane", "pel_mgm3": "16", "pel_ppm": "2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "151677 | | Halothane | 2 | 16", "substance": "Halothane", "url": "https://referencesource.org/workplace-exposure-limits/halothane/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "7440597", "id": "helium", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7440597 | | Helium | (h) | --", "substance": "Helium", "url": "https://referencesource.org/workplace-exposure-limits/helium/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0311.html", "source_quote": "NIOSH REL Ca TWA 0.5 mg/m3 [skin]", "value": "TWA 0.5"}], "cas_number": "76-44-8", "disagreements": [{"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Heptachlor | 76-44-8 | - | 0.5 | X |", "value": "0.5"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "76448 | S | Heptachlor; 1,4,5,6,7,8,8-hepta-chloro-3a,4,7,7a-tetrahydro-4,7-methanoindene | -- | 0.05", "value": "0.05"}]}], "id": "heptachlor", "pel_mgm3": "0.5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Heptachlor | 76-44-8 | - | 0.5 | X |", "substance": "Heptachlor", "url": "https://referencesource.org/workplace-exposure-limits/heptachlor/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "142825 | | n-Heptane | 400 | 1,600 | | 500 | 2000", "value": "500"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "142825 | | n-Heptane | 400 | 1,600 | | 500 | 2000", "value": "2000"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0312.html", "source_quote": "NIOSH REL TWA 85 ppm (350 mg/m3) C 440 ppm (1800 mg/m3) [15-minute]", "value": "TWA 85"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0312.html", "source_quote": "NIOSH REL TWA 85 ppm (350 mg/m3) C 440 ppm (1800 mg/m3) [15-minute]", "value": "350"}], "cas_number": "142-82-5", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Heptane (n-Heptane) | 142-82-5 | 500 | 2000 | - |", "value": "500"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "142825 | | n-Heptane | 400 | 1,600 | | 500 | 2000", "value": "400"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Heptane (n-Heptane) | 142-82-5 | 500 | 2000 | - |", "value": "2000"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "142825 | | n-Heptane | 400 | 1,600 | | 500 | 2000", "value": "1,600"}]}], "id": "heptane-n-heptane", "pel_mgm3": "2000", "pel_ppm": "500", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Heptane (n-Heptane) | 142-82-5 | 500 | 2000 | - |", "substance": "Heptane (n-Heptane)", "url": "https://referencesource.org/workplace-exposure-limits/heptane-n-heptane/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "118741", "id": "hexachlorobenzene", "pel_mgm3": "0.002", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "118741 | S | Hexachlorobenzene | -- | 0.002", "substance": "Hexachlorobenzene", "url": "https://referencesource.org/workplace-exposure-limits/hexachlorobenzene/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0314.html", "source_quote": "NIOSH REL Ca TWA 0.02 ppm (0.24 mg/m3) [skin]", "value": "TWA 0.02"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0314.html", "source_quote": "NIOSH REL Ca TWA 0.02 ppm (0.24 mg/m3) [skin]", "value": "0.24"}], "cas_number": "87683", "disagreements": [], "id": "hexachlorobutadiene", "pel_mgm3": "0.24", "pel_ppm": "0.02", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "87683 | S | Hexachlorobutadiene | 0.02 | 0.24", "substance": "Hexachlorobutadiene", "url": "https://referencesource.org/workplace-exposure-limits/hexachlorobutadiene/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0315.html", "source_quote": "NIOSH REL TWA 0.01 ppm (0.1 mg/m3)", "value": "TWA 0.01"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0315.html", "source_quote": "NIOSH REL TWA 0.01 ppm (0.1 mg/m3)", "value": "0.1"}], "cas_number": "77474", "disagreements": [], "id": "hexachlorocyclopentadiene", "pel_mgm3": "0.11", "pel_ppm": "0.01", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "77474 | | Hexachlorocyclopentadiene | 0.01 | 0.11", "substance": "Hexachlorocyclopentadiene", "url": "https://referencesource.org/workplace-exposure-limits/hexachlorocyclopentadiene/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0316.html", "source_quote": "NIOSH REL Ca TWA 1 ppm (10 mg/m3) [skin]", "value": "TWA 1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0316.html", "source_quote": "NIOSH REL Ca TWA 1 ppm (10 mg/m3) [skin]", "value": "10"}], "cas_number": "67-72-1", "disagreements": [], "id": "hexachloroethane", "pel_mgm3": "10", "pel_ppm": "1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Hexachloroethane | 67-72-1 | 1 | 10 | X |", "substance": "Hexachloroethane", "url": "https://referencesource.org/workplace-exposure-limits/hexachloroethane/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0317.html", "source_quote": "NIOSH REL TWA 0.2 mg/m3 [skin]", "value": "TWA 0.2"}], "cas_number": "1335-87-1", "disagreements": [], "id": "hexachloronaphthalene", "pel_mgm3": "0.2", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Hexachloronaphthalene | 1335-87-1 | - | 0.2 | X |", "substance": "Hexachloronaphthalene", "url": "https://referencesource.org/workplace-exposure-limits/hexachloronaphthalene/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "684162 | S | Hexafluoroacetone; 1,1,1,3,3,3-hexafluoro-2-propanone | 0.1 | 0.7", "value": "0.1"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "684162 | S | Hexafluoroacetone; 1,1,1,3,3,3-hexafluoro-2-propanone | 0.1 | 0.7", "value": "0.7"}], "cas_number": "684-16-2", "disagreements": [], "id": "hexafluoroacetone", "rel_mgm3": "0.7", "rel_ppm": "TWA 0.1", "source": "https://www.cdc.gov/niosh/npg/npgd0319.html", "source_quote": "NIOSH REL TWA 0.1 ppm (0.7 mg/m³) [skin]", "substance": "Hexafluoroacetone", "url": "https://referencesource.org/workplace-exposure-limits/hexafluoroacetone/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"cas_number": "680-31-9", "id": "hexamethyl-phosphoramide", "rel_statement": "Ca See Appendix A", "source": "https://www.cdc.gov/niosh/npg/npgd0321.html", "source_quote": "NIOSH REL Ca See Appendix A", "substance": "Hexamethyl phosphoramide", "url": "https://referencesource.org/workplace-exposure-limits/hexamethyl-phosphoramide/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "822060 | | Hexamethylene diisocyanate; HDI | 0.005 | 0.034", "value": "0.005"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "822060 | | Hexamethylene diisocyanate; HDI | 0.005 | 0.034", "value": "0.034"}], "cas_number": "822-06-0", "disagreements": [], "id": "hexamethylene-diisocyanate", "rel_mgm3": "0.035", "rel_ppm": "TWA 0.005", "source": "https://www.cdc.gov/niosh/npg/npgd0320.html", "source_quote": "NIOSH REL TWA 0.005 ppm (0.035 mg/m3) C 0.020 ppm (0.140 mg/m3) [10-minute]", "substance": "Hexamethylene diisocyanate", "url": "https://referencesource.org/workplace-exposure-limits/hexamethylene-diisocyanate/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"id": "hexane-other-isomers", "pel_mgm3": "1800", "pel_ppm": "500", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Hexane, other isomers | 500 | 1800 | | 1000 | 3600", "stel_mgm3": "3600", "stel_ppm": "1000", "substance": "Hexane, other isomers", "url": "https://referencesource.org/workplace-exposure-limits/hexane-other-isomers/", "verified_fields": ["pel_mgm3", "pel_ppm", "stel_mgm3", "stel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Hexone (Methyl isobutyl ketone) | 108-10-1 | 100 | 410 | - |", "value": "100"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Hexone (Methyl isobutyl ketone) | 108-10-1 | 100 | 410 | - |", "value": "410"}, {"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "108101 | | Methyl isobutyl ketone; Hexone | 50 | 205 | | 75 | 300", "value": "75"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "108101 | | Methyl isobutyl ketone; Hexone | 50 | 205 | | 75 | 300", "value": "300"}], "cas_number": "108-10-1", "disagreements": [], "id": "hexone", "rel_mgm3": "205", "rel_ppm": "TWA 50", "source": "https://www.cdc.gov/niosh/npg/npgd0326.html", "source_quote": "NIOSH REL TWA 50 ppm (205 mg/m3) ST 75 ppm (300 mg/m3)", "substance": "Hexone", "url": "https://referencesource.org/workplace-exposure-limits/hexone/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0328.html", "source_quote": "NIOSH REL C 25 ppm (125 mg/m3)", "value": "C 25"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0328.html", "source_quote": "NIOSH REL C 25 ppm (125 mg/m3)", "value": "125"}], "cas_number": "107415", "ceiling_notation": "the values given in the PEL columns are ceiling values", "disagreements": [], "id": "hexylene-glycol", "pel_mgm3": "125", "pel_ppm": "25", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "107415 | | Hexylene glycol | 25 | 125 | C", "substance": "Hexylene glycol", "url": "https://referencesource.org/workplace-exposure-limits/hexylene-glycol/", "verified_fields": ["cas_number", "ceiling_notation", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0329.html", "source_quote": "NIOSH REL Ca C 0.03 ppm (0.04 mg/m3) [2-hour]", "value": "C 0.03"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0329.html", "source_quote": "NIOSH REL Ca C 0.03 ppm (0.04 mg/m3) [2-hour]", "value": "0.04"}], "cas_number": "302-01-2", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Hydrazine | 302-01-2 | 1 | 1.3 | X |", "value": "1"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "302012 | S | Hydrazine | 0.01 | 0.013", "value": "0.01"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Hydrazine | 302-01-2 | 1 | 1.3 | X |", "value": "1.3"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "302012 | S | Hydrazine | 0.01 | 0.013", "value": "0.013"}]}], "id": "hydrazine", "pel_mgm3": "1.3", "pel_ppm": "1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Hydrazine | 302-01-2 | 1 | 1.3 | X |", "substance": "Hydrazine", "url": "https://referencesource.org/workplace-exposure-limits/hydrazine/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "1333740", "id": "hydrogen", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "1333740 | | Hydrogen | (h) | --", "substance": "Hydrogen", "url": "https://referencesource.org/workplace-exposure-limits/hydrogen/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "10035106 | | Hydrogen bromide | 3 | 10 | C", "value": "the values given in the PEL columns are ceiling values"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0331.html", "source_quote": "NIOSH REL C 3 ppm (10 mg/m3)", "value": "C 3"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0331.html", "source_quote": "NIOSH REL C 3 ppm (10 mg/m3)", "value": "10"}], "cas_number": "10035-10-6", "disagreements": [], "id": "hydrogen-bromide", "pel_mgm3": "10", "pel_ppm": "3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Hydrogen bromide | 10035-10-6 | 3 | 10 | - |", "substance": "Hydrogen bromide", "url": "https://referencesource.org/workplace-exposure-limits/hydrogen-bromide/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-28", "field": "ceiling", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7647010 | | Hydrogen chloride | 0.3 | 0.45 | 2 ppm", "value": "2 ppm"}, {"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7647010 | | Hydrogen chloride | 0.3 | 0.45 | 2 ppm", "value": "a ceiling value in addition to the TWA values"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0332.html", "source_quote": "NIOSH REL C 5 ppm (7 mg/m3)", "value": "C 5"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0332.html", "source_quote": "NIOSH REL C 5 ppm (7 mg/m3)", "value": "7"}], "cas_number": "7647-01-0", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Hydrogen chloride | 7647-01-0 | (C)5 | (C)7 | - |", "value": "(C)5"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7647010 | | Hydrogen chloride | 0.3 | 0.45 | 2 ppm", "value": "0.3"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Hydrogen chloride | 7647-01-0 | (C)5 | (C)7 | - |", "value": "(C)7"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7647010 | | Hydrogen chloride | 0.3 | 0.45 | 2 ppm", "value": "0.45"}]}], "id": "hydrogen-chloride", "pel_mgm3": "(C)7", "pel_ppm": "(C)5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Hydrogen chloride | 7647-01-0 | (C)5 | (C)7 | - |", "substance": "Hydrogen chloride", "url": "https://referencesource.org/workplace-exposure-limits/hydrogen-chloride/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "74908 | S | Hydrogen cyanide | 4.7 | 5 | C", "value": "the values given in the PEL columns are ceiling values"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0333.html", "source_quote": "NIOSH REL ST 4.7 ppm (5 mg/m3) [skin]", "value": "ST 4.7"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0333.html", "source_quote": "NIOSH REL ST 4.7 ppm (5 mg/m3) [skin]", "value": "5"}], "cas_number": "74-90-8", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Hydrogen cyanide | 74-90-8 | 10 | 11 | X |", "value": "10"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "74908 | S | Hydrogen cyanide | 4.7 | 5 | C", "value": "4.7"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Hydrogen cyanide | 74-90-8 | 10 | 11 | X |", "value": "11"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "74908 | S | Hydrogen cyanide | 4.7 | 5 | C", "value": "5"}]}], "id": "hydrogen-cyanide", "pel_mgm3": "11", "pel_ppm": "10", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Hydrogen cyanide | 74-90-8 | 10 | 11 | X |", "substance": "Hydrogen cyanide", "url": "https://referencesource.org/workplace-exposure-limits/hydrogen-cyanide/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7664393 | S | Hydrogen fluoride, as F | 0.4 | 0.33 | | 1 | 0.83", "value": "0.4"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7664393 | S | Hydrogen fluoride, as F | 0.4 | 0.33 | | 1 | 0.83", "value": "0.33"}, {"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7664393 | S | Hydrogen fluoride, as F | 0.4 | 0.33 | | 1 | 0.83", "value": "1"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7664393 | S | Hydrogen fluoride, as F | 0.4 | 0.33 | | 1 | 0.83", "value": "0.83"}], "cas_number": "7664-39-3", "disagreements": [], "id": "hydrogen-fluoride", "rel_mgm3": "2.5", "rel_ppm": "TWA 3", "source": "https://www.cdc.gov/niosh/npg/npgd0334.html", "source_quote": "NIOSH REL TWA 3 ppm (2.5 mg/m3) C 6 ppm (5 mg/m3) [15-minute]", "substance": "Hydrogen fluoride", "url": "https://referencesource.org/workplace-exposure-limits/hydrogen-fluoride/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0335.html", "source_quote": "NIOSH REL TWA 1 ppm (1.4 mg/m3)", "value": "TWA 1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0335.html", "source_quote": "NIOSH REL TWA 1 ppm (1.4 mg/m3)", "value": "1.4"}], "cas_number": "7722-84-1", "disagreements": [], "id": "hydrogen-peroxide", "pel_mgm3": "1.4", "pel_ppm": "1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Hydrogen peroxide | 7722-84-1 | 1 | 1.4 | - |", "substance": "Hydrogen peroxide", "url": "https://referencesource.org/workplace-exposure-limits/hydrogen-peroxide/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Hydrogen selenide (as Se) | 7783-07-5 | 0.05 | 0.2 | - |", "value": "0.05"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Hydrogen selenide (as Se) | 7783-07-5 | 0.05 | 0.2 | - |", "value": "0.2"}], "cas_number": "7783-07-5", "disagreements": [], "id": "hydrogen-selenide", "rel_mgm3": "0.2", "rel_ppm": "TWA 0.05", "source": "https://www.cdc.gov/niosh/npg/npgd0336.html", "source_quote": "NIOSH REL TWA 0.05 ppm (0.2 mg/m3)", "substance": "Hydrogen selenide", "url": "https://referencesource.org/workplace-exposure-limits/hydrogen-selenide/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-28", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7783064 | | Hydrogen sulfide | 10 | 14 | 50 ppm | 15 | 21", "value": "10"}, {"as_of": "2026-09-28", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7783064 | | Hydrogen sulfide | 10 | 14 | 50 ppm | 15 | 21", "value": "14"}, {"as_of": "2026-09-28", "field": "ceiling", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7783064 | | Hydrogen sulfide | 10 | 14 | 50 ppm | 15 | 21", "value": "50 ppm"}, {"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7783064 | | Hydrogen sulfide | 10 | 14 | 50 ppm | 15 | 21", "value": "a ceiling value in addition to the TWA values"}, {"as_of": "2026-09-28", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7783064 | | Hydrogen sulfide | 10 | 14 | 50 ppm | 15 | 21", "value": "15"}, {"as_of": "2026-09-28", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7783064 | | Hydrogen sulfide | 10 | 14 | 50 ppm | 15 | 21", "value": "21"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0337.html", "source_quote": "NIOSH REL C 10 ppm (15 mg/m3) [10-minute]", "value": "C 10"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0337.html", "source_quote": "NIOSH REL C 10 ppm (15 mg/m3) [10-minute]", "value": "15"}], "cas_number": "7783-06-4", "disagreements": [], "id": "hydrogen-sulfide", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Hydrogen sulfide | 7783-06-4 | - | (2) | - |", "substance": "Hydrogen sulfide", "url": "https://referencesource.org/workplace-exposure-limits/hydrogen-sulfide/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0330.html", "source_quote": "NIOSH REL TWA 0.5 ppm (5 mg/m3)", "value": "TWA 0.5"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0330.html", "source_quote": "NIOSH REL TWA 0.5 ppm (5 mg/m3)", "value": "5"}], "cas_number": "61788327", "disagreements": [], "id": "hydrogenated-terphenyls", "pel_mgm3": "5", "pel_ppm": "0.5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "61788327 | | Hydrogenated terphenyls | 0.5 | 5", "substance": "Hydrogenated terphenyls", "url": "https://referencesource.org/workplace-exposure-limits/hydrogenated-terphenyls/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0338.html", "source_quote": "NIOSH REL C 2 mg/m3 [15-minute]", "value": "C 2"}], "cas_number": "123-31-9", "disagreements": [], "id": "hydroquinone", "pel_mgm3": "2", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Hydroquinone | 123-31-9 | - | 2 | - |", "substance": "Hydroquinone", "url": "https://referencesource.org/workplace-exposure-limits/hydroquinone/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0340.html", "source_quote": "NIOSH REL TWA 10 ppm (45 mg/m3)", "value": "TWA 10"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0340.html", "source_quote": "NIOSH REL TWA 10 ppm (45 mg/m3)", "value": "45"}], "cas_number": "95136", "disagreements": [], "id": "indene", "pel_mgm3": "48", "pel_ppm": "10", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "95136 | | Indene | 10 | 48", "substance": "Indene", "url": "https://referencesource.org/workplace-exposure-limits/indene/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0341.html", "source_quote": "NIOSH REL TWA 0.1 mg/m3", "value": "TWA 0.1"}], "cas_number": "7440746", "disagreements": [], "id": "indium", "pel_mgm3": "0.1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7440746 | | Indium | -- | 0.1", "substance": "Indium", "url": "https://referencesource.org/workplace-exposure-limits/indium/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"id": "indium-compounds", "pel_mgm3": "0.1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Indium compounds | -- | 0.1", "substance": "Indium compounds", "url": "https://referencesource.org/workplace-exposure-limits/indium-compounds/", "verified_fields": ["pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7553562 | | Iodine | 0.1 | 1 | C", "value": "the values given in the PEL columns are ceiling values"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0342.html", "source_quote": "NIOSH REL C 0.1 ppm (1 mg/m3)", "value": "C 0.1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0342.html", "source_quote": "NIOSH REL C 0.1 ppm (1 mg/m3)", "value": "1"}], "cas_number": "7553-56-2", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Iodine | 7553-56-2 | (C)0.1 | (C)1 | - |", "value": "(C)0.1"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7553562 | | Iodine | 0.1 | 1 | C", "value": "0.1"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Iodine | 7553-56-2 | (C)0.1 | (C)1 | - |", "value": "(C)1"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7553562 | | Iodine | 0.1 | 1 | C", "value": "1"}]}], "id": "iodine", "pel_mgm3": "(C)1", "pel_ppm": "(C)0.1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Iodine | 7553-56-2 | (C)0.1 | (C)1 | - |", "substance": "Iodine", "url": "https://referencesource.org/workplace-exposure-limits/iodine/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0343.html", "source_quote": "NIOSH REL TWA 0.6 ppm (10 mg/m3)", "value": "TWA 0.6"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0343.html", "source_quote": "NIOSH REL TWA 0.6 ppm (10 mg/m3)", "value": "10"}], "cas_number": "75478", "disagreements": [], "id": "iodoform", "pel_mgm3": "10", "pel_ppm": "0.6", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75478 | | Iodoform | 0.6 | 10", "substance": "Iodoform", "url": "https://referencesource.org/workplace-exposure-limits/iodoform/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Iron oxide fume | 1309-37-1 | - | 10 | - |", "value": "10"}, {"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0549.html", "source_quote": "NIOSH REL See Appendix D", "value": "See Appendix D"}], "cas_number": "1309-37-1", "disagreements": [], "id": "iron-oxide-dust-and-fume-as-fe", "rel_mgm3": "TWA 5", "source": "https://www.cdc.gov/niosh/npg/npgd0344.html", "source_quote": "NIOSH REL TWA 5 mg/m3", "substance": "Iron oxide dust and fume (as Fe)", "url": "https://referencesource.org/workplace-exposure-limits/iron-oxide-dust-and-fume-as-fe/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0345.html", "source_quote": "NIOSH REL TWA 0.1 ppm (0.23 mg/m³) ST 0.2 ppm (0.45 mg/m³)", "value": "TWA 0.1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0345.html", "source_quote": "NIOSH REL TWA 0.1 ppm (0.23 mg/m³) ST 0.2 ppm (0.45 mg/m³)", "value": "0.23"}], "cas_number": "13463406", "disagreements": [], "id": "iron-pentacarbonyl-as-fe", "pel_mgm3": "0.8", "pel_ppm": "0.1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "13463406 | | Iron pentacarbonyl, as Fe | 0.1 | 0.8 | | 0.2 | 1.6", "stel_mgm3": "1.6", "stel_ppm": "0.2", "substance": "Iron pentacarbonyl, as Fe", "url": "https://referencesource.org/workplace-exposure-limits/iron-pentacarbonyl-as-fe/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "stel_mgm3", "stel_ppm", "substance"]}
{"id": "iron-salts-soluble-as-fe", "pel_mgm3": "1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Iron salts, soluble, as Fe | -- | 1", "substance": "Iron salts, soluble, as Fe", "url": "https://referencesource.org/workplace-exposure-limits/iron-salts-soluble-as-fe/", "verified_fields": ["pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0347.html", "source_quote": "NIOSH REL TWA 100 ppm (525 mg/m3)", "value": "TWA 100"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0347.html", "source_quote": "NIOSH REL TWA 100 ppm (525 mg/m3)", "value": "525"}], "cas_number": "123-92-2", "disagreements": [], "id": "isoamyl-acetate", "pel_mgm3": "525", "pel_ppm": "100", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Isoamyl acetate | 123-92-2 | 100 | 525 | - |", "substance": "Isoamyl acetate", "url": "https://referencesource.org/workplace-exposure-limits/isoamyl-acetate/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0348.html", "source_quote": "NIOSH REL TWA 100 ppm (360 mg/m3) ST 125 ppm (450 mg/m3)", "value": "TWA 100"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0348.html", "source_quote": "NIOSH REL TWA 100 ppm (360 mg/m3) ST 125 ppm (450 mg/m3)", "value": "360"}], "cas_number": "123513", "disagreements": [], "id": "isoamyl-alcohol-3-methylbutanol", "pel_mgm3": "360", "pel_ppm": "100", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "123513 | | Isoamyl alcohol; 3-methylbutanol | 100 | 360 | | 125 | 450", "stel_mgm3": "450", "stel_ppm": "125", "substance": "Isoamyl alcohol; 3-methylbutanol", "url": "https://referencesource.org/workplace-exposure-limits/isoamyl-alcohol-3-methylbutanol/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "stel_mgm3", "stel_ppm", "substance"]}
{"cas_number": "6032-29-7", "id": "isoamyl-alcohol-secondary", "rel_mgm3": "360", "rel_ppm": "TWA 100", "source": "https://www.cdc.gov/niosh/npg/npgd0349.html", "source_quote": "NIOSH REL TWA 100 ppm (360 mg/m3) ST 125 ppm (450 mg/m3)", "substance": "Isoamyl alcohol (secondary)", "url": "https://referencesource.org/workplace-exposure-limits/isoamyl-alcohol-secondary/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"cas_number": "75-28-5", "id": "isobutane", "rel_mgm3": "1900", "rel_ppm": "TWA 800", "source": "https://www.cdc.gov/niosh/npg/npgd0350.html", "source_quote": "NIOSH REL TWA 800 ppm (1900 mg/m3)", "substance": "Isobutane", "url": "https://referencesource.org/workplace-exposure-limits/isobutane/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0351.html", "source_quote": "NIOSH REL TWA 150 ppm (700 mg/m3)", "value": "TWA 150"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0351.html", "source_quote": "NIOSH REL TWA 150 ppm (700 mg/m3)", "value": "700"}], "cas_number": "110-19-0", "disagreements": [], "id": "isobutyl-acetate", "pel_mgm3": "700", "pel_ppm": "150", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Isobutyl acetate | 110-19-0 | 150 | 700 | - |", "substance": "Isobutyl acetate", "url": "https://referencesource.org/workplace-exposure-limits/isobutyl-acetate/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0352.html", "source_quote": "NIOSH REL TWA 50 ppm (150 mg/m3)", "value": "TWA 50"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0352.html", "source_quote": "NIOSH REL TWA 50 ppm (150 mg/m3)", "value": "150"}], "cas_number": "78-83-1", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Isobutyl alcohol | 78-83-1 | 100 | 300 | - |", "value": "100"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "78831 | | Isobutyl alcohol; 2-methylpropanol | 50 | 150", "value": "50"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Isobutyl alcohol | 78-83-1 | 100 | 300 | - |", "value": "300"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "78831 | | Isobutyl alcohol; 2-methylpropanol | 50 | 150", "value": "150"}]}], "id": "isobutyl-alcohol", "pel_mgm3": "300", "pel_ppm": "100", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Isobutyl alcohol | 78-83-1 | 100 | 300 | - |", "substance": "Isobutyl alcohol", "url": "https://referencesource.org/workplace-exposure-limits/isobutyl-alcohol/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "78-82-0", "id": "isobutyronitrile", "rel_mgm3": "22", "rel_ppm": "TWA 8", "source": "https://www.cdc.gov/niosh/npg/npgd0353.html", "source_quote": "NIOSH REL TWA 8 ppm (22 mg/m3)", "substance": "Isobutyronitrile", "url": "https://referencesource.org/workplace-exposure-limits/isobutyronitrile/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"cas_number": "26675467", "id": "isoflurane", "pel_mgm3": "15", "pel_ppm": "2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "26675467 | | Isoflurane | 2 | 15", "substance": "Isoflurane", "url": "https://referencesource.org/workplace-exposure-limits/isoflurane/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0354.html", "source_quote": "NIOSH REL TWA 50 ppm (270 mg/m3) [skin]", "value": "TWA 50"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0354.html", "source_quote": "NIOSH REL TWA 50 ppm (270 mg/m3) [skin]", "value": "270"}], "cas_number": "26952216", "disagreements": [], "id": "isooctyl-alcohol", "pel_mgm3": "270", "pel_ppm": "50", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "26952216 | S | Isooctyl alcohol | 50 | 270", "substance": "Isooctyl alcohol", "url": "https://referencesource.org/workplace-exposure-limits/isooctyl-alcohol/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0355.html", "source_quote": "NIOSH REL TWA 4 ppm (23 mg/m3)", "value": "TWA 4"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0355.html", "source_quote": "NIOSH REL TWA 4 ppm (23 mg/m3)", "value": "23"}], "cas_number": "78-59-1", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Isophorone | 78-59-1 | 25 | 140 | - |", "value": "25"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "78591 | | Isophorone; 3,5,5-trimethyl-2-cyclohexene-1-one | 4 | 23", "value": "4"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Isophorone | 78-59-1 | 25 | 140 | - |", "value": "140"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "78591 | | Isophorone; 3,5,5-trimethyl-2-cyclohexene-1-one | 4 | 23", "value": "23"}]}], "id": "isophorone", "pel_mgm3": "140", "pel_ppm": "25", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Isophorone | 78-59-1 | 25 | 140 | - |", "substance": "Isophorone", "url": "https://referencesource.org/workplace-exposure-limits/isophorone/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "4098719 | S | Isophorone diisocyanate; IPDI | 0.005 | 0.045 | | 0.02 | --", "value": "0.005"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "4098719 | S | Isophorone diisocyanate; IPDI | 0.005 | 0.045 | | 0.02 | --", "value": "0.045"}, {"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "4098719 | S | Isophorone diisocyanate; IPDI | 0.005 | 0.045 | | 0.02 | --", "value": "0.02"}], "cas_number": "4098-71-9", "disagreements": [], "id": "isophorone-diisocyanate", "rel_mgm3": "0.045", "rel_ppm": "TWA 0.005", "source": "https://www.cdc.gov/niosh/npg/npgd0356.html", "source_quote": "NIOSH REL TWA 0.005 ppm (0.045 mg/m3) ST 0.02 ppm (0.180 mg/m3) [skin]", "substance": "Isophorone diisocyanate", "url": "https://referencesource.org/workplace-exposure-limits/isophorone-diisocyanate/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "108214 | | Isopropyl acetate | 250 | 950 | | 310 | 1185", "value": "310"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "108214 | | Isopropyl acetate | 250 | 950 | | 310 | 1185", "value": "1185"}, {"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0358.html", "source_quote": "NIOSH REL See Appendix D", "value": "See Appendix D"}], "cas_number": "108-21-4", "disagreements": [], "id": "isopropyl-acetate", "pel_mgm3": "950", "pel_ppm": "250", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Isopropyl acetate | 108-21-4 | 250 | 950 | - |", "substance": "Isopropyl acetate", "url": "https://referencesource.org/workplace-exposure-limits/isopropyl-acetate/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "67630 | | Isopropyl alcohol | 400 | 980 | | 500 | 1225", "value": "500"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "67630 | | Isopropyl alcohol | 400 | 980 | | 500 | 1225", "value": "1225"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0359.html", "source_quote": "NIOSH REL TWA 400 ppm (980 mg/m3) ST 500 ppm (1225 mg/m3)", "value": "TWA 400"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0359.html", "source_quote": "NIOSH REL TWA 400 ppm (980 mg/m3) ST 500 ppm (1225 mg/m3)", "value": "980"}], "cas_number": "67-63-0", "disagreements": [], "id": "isopropyl-alcohol", "pel_mgm3": "980", "pel_ppm": "400", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Isopropyl alcohol | 67-63-0 | 400 | 980 | - |", "substance": "Isopropyl alcohol", "url": "https://referencesource.org/workplace-exposure-limits/isopropyl-alcohol/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0362.html", "source_quote": "NIOSH REL TWA 500 ppm (2100 mg/m3)", "value": "TWA 500"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0362.html", "source_quote": "NIOSH REL TWA 500 ppm (2100 mg/m3)", "value": "2100"}], "cas_number": "108-20-3", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Isopropyl ether | 108-20-3 | 500 | 2100 | - |", "value": "500"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "108203 | | Isopropyl ether; diisopropyl ether | 250 | 1,050", "value": "250"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Isopropyl ether | 108-20-3 | 500 | 2100 | - |", "value": "2100"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "108203 | | Isopropyl ether; diisopropyl ether | 250 | 1,050", "value": "1,050"}]}], "id": "isopropyl-ether", "pel_mgm3": "2100", "pel_ppm": "500", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Isopropyl ether | 108-20-3 | 500 | 2100 | - |", "substance": "Isopropyl ether", "url": "https://referencesource.org/workplace-exposure-limits/isopropyl-ether/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Isopropyl glycidyl ether (IGE) | 4016-14-2 | 50 | 240 | - |", "value": "50"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Isopropyl glycidyl ether (IGE) | 4016-14-2 | 50 | 240 | - |", "value": "240"}, {"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "4016142 | | Isopropyl glycidyl ether; IGE; 1,2-epoxy-3-isopropoxypropane | 50 | 240 | | 75 | 360", "value": "75"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "4016142 | | Isopropyl glycidyl ether; IGE; 1,2-epoxy-3-isopropoxypropane | 50 | 240 | | 75 | 360", "value": "360"}], "cas_number": "4016-14-2", "disagreements": [], "id": "isopropyl-glycidyl-ether", "rel_mgm3": "240", "rel_ppm": "C 50", "source": "https://www.cdc.gov/niosh/npg/npgd0363.html", "source_quote": "NIOSH REL C 50 ppm (240 mg/m3) [15-minute]", "substance": "Isopropyl glycidyl ether", "url": "https://referencesource.org/workplace-exposure-limits/isopropyl-glycidyl-ether/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75310 | | Isopropylamine | 5 | 12 | | 10 | 24", "value": "10"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75310 | | Isopropylamine | 5 | 12 | | 10 | 24", "value": "24"}, {"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0360.html", "source_quote": "NIOSH REL See Appendix D", "value": "See Appendix D"}], "cas_number": "75-31-0", "disagreements": [], "id": "isopropylamine", "pel_mgm3": "12", "pel_ppm": "5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Isopropylamine | 75-31-0 | 5 | 12 | - |", "substance": "Isopropylamine", "url": "https://referencesource.org/workplace-exposure-limits/isopropylamine/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0364.html", "source_quote": "NIOSH REL TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)", "value": "TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "1332587 | | Kaolin; (respirable dust containing no asbestos and <1% crystaline silica) | -- | 2", "value": "2"}], "cas_number": "1332-58-7", "disagreements": [], "id": "kaolin", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Kaolin | 1332-58-7 | - | - | - |", "substance": "Kaolin", "url": "https://referencesource.org/workplace-exposure-limits/kaolin/", "verified_fields": ["cas_number", "substance"]}
{"cas_number": "143-50-0", "id": "kepone", "rel_mgm3": "TWA 0.001", "source": "https://www.cdc.gov/niosh/npg/npgd0365.html", "source_quote": "NIOSH REL Ca TWA 0.001 mg/m3", "substance": "Kepone", "url": "https://referencesource.org/workplace-exposure-limits/kepone/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"cas_number": "8008-20-6", "id": "kerosene", "rel_mgm3": "TWA 100", "source": "https://www.cdc.gov/niosh/npg/npgd0366.html", "source_quote": "NIOSH REL TWA 100 mg/m3", "substance": "Kerosene", "url": "https://referencesource.org/workplace-exposure-limits/kerosene/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0367.html", "source_quote": "NIOSH REL TWA 0.5 ppm (0.9 mg/m3) ST 1.5 ppm (3 mg/m3)", "value": "TWA 0.5"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0367.html", "source_quote": "NIOSH REL TWA 0.5 ppm (0.9 mg/m3) ST 1.5 ppm (3 mg/m3)", "value": "0.9"}, {"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "463514 | | Ketene; ethenone | 0.5 | 0.9 | | 1.5 | 3", "value": "1.5"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "463514 | | Ketene; ethenone | 0.5 | 0.9 | | 1.5 | 3", "value": "3"}], "cas_number": "463-51-4", "disagreements": [], "id": "ketene", "pel_mgm3": "0.9", "pel_ppm": "0.5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ketene | 463-51-4 | 0.5 | 0.9 | - |", "substance": "Ketene", "url": "https://referencesource.org/workplace-exposure-limits/ketene/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "L.P.G. (Liquefied petroleum gas) | 68476-85-7 | 1000 | 1800 | - |", "value": "1000"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "L.P.G. (Liquefied petroleum gas) | 68476-85-7 | 1000 | 1800 | - |", "value": "1800"}], "cas_number": "68476-85-7", "disagreements": [], "id": "l-p-g", "rel_mgm3": "1800", "rel_ppm": "TWA 1000", "source": "https://www.cdc.gov/niosh/npg/npgd0679.html", "source_quote": "NIOSH REL TWA 1000 ppm (1800 mg/m3)", "substance": "L.P.G.", "url": "https://referencesource.org/workplace-exposure-limits/l-p-g/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7439921 | | Lead (metallic) and inorganic compounds, dust and fume, as Pb | -- | 0.01", "value": "0.01"}], "cas_number": "7439-92-1", "disagreements": [], "id": "lead", "rel_statement": "TWA (8-hour) 0.050 mg/m3 See Appendix C", "source": "https://www.cdc.gov/niosh/npg/npgd0368.html", "source_quote": "NIOSH REL TWA (8-hour) 0.050 mg/m3 See Appendix C", "substance": "Lead", "url": "https://referencesource.org/workplace-exposure-limits/lead/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"cas_number": "7758976", "id": "lead-chromate-as-pb", "pel_mgm3": "0.01", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7758976 | | Lead chromate, as Pb | -- | 0.01", "substance": "Lead chromate, as Pb", "url": "https://referencesource.org/workplace-exposure-limits/lead-chromate-as-pb/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0369.html", "source_quote": "NIOSH REL TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)", "value": "TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)"}], "cas_number": "1317-65-3", "disagreements": [], "id": "limestone", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Limestone | 1317-65-3 | - | - | - |", "substance": "Limestone", "url": "https://referencesource.org/workplace-exposure-limits/limestone/", "verified_fields": ["cas_number", "substance"]}
{"cas_number": "1317653", "id": "limestone-calcium-carbonate-see-particulates-not-otherwise-regulated", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "1317653 | | Limestone; calcium carbonate; see Particulates not otherwise regulated", "substance": "Limestone; calcium carbonate; see Particulates not otherwise regulated", "url": "https://referencesource.org/workplace-exposure-limits/limestone-calcium-carbonate-see-particulates-not-otherwise-regulated/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0370.html", "source_quote": "NIOSH REL TWA 0.5 mg/m3 [skin]", "value": "TWA 0.5"}], "cas_number": "58-89-9", "disagreements": [], "id": "lindane", "pel_mgm3": "0.5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Lindane | 58-89-9 | - | 0.5 | X |", "substance": "Lindane", "url": "https://referencesource.org/workplace-exposure-limits/lindane/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0371.html", "source_quote": "NIOSH REL TWA 0.025 mg/m3", "value": "TWA 0.025"}], "cas_number": "7580-67-8", "disagreements": [], "id": "lithium-hydride", "pel_mgm3": "0.025", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Lithium hydride | 7580-67-8 | - | 0.025 | - |", "substance": "Lithium hydride", "url": "https://referencesource.org/workplace-exposure-limits/lithium-hydride/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"cas_number": "4485125", "id": "lithium-stearate", "pel_mgm3": "10", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "4485125 | | Lithium stearate | -- | 10", "substance": "Lithium stearate", "url": "https://referencesource.org/workplace-exposure-limits/lithium-stearate/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"cas_number": "108-39-4", "id": "m-cresol", "rel_mgm3": "10", "rel_ppm": "TWA 2.3", "source": "https://www.cdc.gov/niosh/npg/npgd0155.html", "source_quote": "NIOSH REL TWA 2.3 ppm (10 mg/m3)", "substance": "m-Cresol", "url": "https://referencesource.org/workplace-exposure-limits/m-cresol/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"cas_number": "99-65-0", "disagreements": [], "id": "m-dinitrobenzene", "rel_mgm3": "TWA 1", "source": "https://www.cdc.gov/niosh/npg/npgd0232.html", "source_quote": "NIOSH REL TWA 1 mg/m3 [skin]", "substance": "m-Dinitrobenzene", "url": "https://referencesource.org/workplace-exposure-limits/m-dinitrobenzene/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0463.html", "source_quote": "NIOSH REL TWA 2 ppm (11 mg/m3) [skin]", "value": "TWA 2"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0463.html", "source_quote": "NIOSH REL TWA 2 ppm (11 mg/m3) [skin]", "value": "11"}], "cas_number": "99-08-1", "disagreements": [], "id": "m-isomer", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "m-isomer | 99-08-1 | - | - | - |", "substance": "m-isomer", "url": "https://referencesource.org/workplace-exposure-limits/m-isomer/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0513.html", "source_quote": "NIOSH REL TWA 5 mg/m3", "value": "TWA 5"}], "cas_number": "626175", "disagreements": [], "id": "m-phthalodinitrile", "pel_mgm3": "5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "626175 | | m-Phthalodinitrile | -- | 5", "substance": "m-Phthalodinitrile", "url": "https://referencesource.org/workplace-exposure-limits/m-phthalodinitrile/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"cas_number": "92-06-8", "id": "m-terphenyl", "rel_mgm3": "C 5", "rel_ppm": "0.5", "source": "https://www.cdc.gov/niosh/npg/npgd0592.html", "source_quote": "NIOSH REL C 5 mg/m3 (0.5 ppm)", "substance": "m-Terphenyl", "url": "https://referencesource.org/workplace-exposure-limits/m-terphenyl/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0623.html", "source_quote": "NIOSH REL See Appendix D", "value": "See Appendix D"}], "cas_number": "108441", "disagreements": [], "id": "m-toluidine", "pel_mgm3": "9", "pel_ppm": "2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "108441 | S | m-Toluidine | 2 | 9", "substance": "m-Toluidine", "url": "https://referencesource.org/workplace-exposure-limits/m-toluidine/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "108-38-3", "id": "m-xylene", "rel_mgm3": "435", "rel_ppm": "TWA 100", "source": "https://www.cdc.gov/niosh/npg/npgd0669.html", "source_quote": "NIOSH REL TWA 100 ppm (435 mg/m3) ST 150 ppm (655 mg/m3)", "substance": "m-Xylene", "url": "https://referencesource.org/workplace-exposure-limits/m-xylene/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0671.html", "source_quote": "NIOSH REL C 0.1 mg/m3 [skin]", "value": "C 0.1"}], "cas_number": "1477550", "ceiling_notation": "the values given in the PEL columns are ceiling values", "disagreements": [], "id": "m-xylene-a-a-diamine", "pel_mgm3": "0.1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "1477550 | S | m-Xylene-a,a′-diamine | -- | 0.1 | C", "substance": "m-Xylene-a,a′-diamine", "url": "https://referencesource.org/workplace-exposure-limits/m-xylene-a-a-diamine/", "verified_fields": ["cas_number", "ceiling_notation", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0373.html", "source_quote": "NIOSH REL TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)", "value": "TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)"}], "cas_number": "546-93-0", "disagreements": [], "id": "magnesite", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Magnesite | 546-93-0 | - | - | - |", "substance": "Magnesite", "url": "https://referencesource.org/workplace-exposure-limits/magnesite/", "verified_fields": ["cas_number", "substance"]}
{"cas_number": "13717005", "id": "magnesite-magnesium-carbonate-see-particulates-not-otherwise-regulated", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "13717005 | | Magnesite; magnesium carbonate; see Particulates not otherwise regulated", "substance": "Magnesite; magnesium carbonate; see Particulates not otherwise regulated", "url": "https://referencesource.org/workplace-exposure-limits/magnesite-magnesium-carbonate-see-particulates-not-otherwise-regulated/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0374.html", "source_quote": "NIOSH REL See Appendix D", "value": "See Appendix D"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "1309484 | | Magnesium oxide fume, as Mg | -- | 10", "value": "10"}], "cas_number": "1309-48-4", "disagreements": [], "id": "magnesium-oxide-fume", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Magnesium oxide fume | 1309-48-4 | - | - | - |", "substance": "Magnesium oxide fume", "url": "https://referencesource.org/workplace-exposure-limits/magnesium-oxide-fume/", "verified_fields": ["cas_number", "substance"]}
{"cas_number": "557040", "id": "magnesium-stearate", "pel_mgm3": "10", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "557040 | | Magnesium stearate | -- | 10", "substance": "Magnesium stearate", "url": "https://referencesource.org/workplace-exposure-limits/magnesium-stearate/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0375.html", "source_quote": "NIOSH REL TWA 10 mg/m3 [skin]", "value": "TWA 10"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "121755 | S | Malathion; o,o-dimethyl S-1(1,2-dicarboethyoxyethyl) phosphorodithioate | -- | 10", "value": "10"}], "cas_number": "121-75-5", "disagreements": [], "id": "malathion", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Malathion | 121-75-5 | - | - | - |", "substance": "Malathion", "url": "https://referencesource.org/workplace-exposure-limits/malathion/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0376.html", "source_quote": "NIOSH REL TWA 1 mg/m3 (0.25 ppm)", "value": "0.25"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0376.html", "source_quote": "NIOSH REL TWA 1 mg/m3 (0.25 ppm)", "value": "TWA 1"}], "cas_number": "108-31-6", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Maleic anhydride | 108-31-6 | 0.25 | 1 | - |", "value": "0.25"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "108316 | | Maleic anhydride; cis-butenedioic anhydride | 0.1 | 0.4", "value": "0.1"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Maleic anhydride | 108-31-6 | 0.25 | 1 | - |", "value": "1"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "108316 | | Maleic anhydride; cis-butenedioic anhydride | 0.1 | 0.4", "value": "0.4"}]}], "id": "maleic-anhydride", "pel_mgm3": "1", "pel_ppm": "0.25", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Maleic anhydride | 108-31-6 | 0.25 | 1 | - |", "substance": "Maleic anhydride", "url": "https://referencesource.org/workplace-exposure-limits/maleic-anhydride/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "542-78-9", "id": "malonaldehyde", "rel_statement": "Ca See Appendix A See Appendix C (Aldehydes)", "source": "https://www.cdc.gov/niosh/npg/npgd0377.html", "source_quote": "NIOSH REL Ca See Appendix A See Appendix C (Aldehydes)", "substance": "Malonaldehyde", "url": "https://referencesource.org/workplace-exposure-limits/malonaldehyde/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"cas_number": "109-77-3", "id": "malononitrile", "rel_mgm3": "8", "rel_ppm": "TWA 3", "source": "https://www.cdc.gov/niosh/npg/npgd0378.html", "source_quote": "NIOSH REL TWA 3 ppm (8 mg/m3)", "substance": "Malononitrile", "url": "https://referencesource.org/workplace-exposure-limits/malononitrile/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"id": "manganese-and-compounds-as-mn", "pel_mgm3": "0.2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Manganese and compounds, as Mn | -- | 0.2", "substance": "Manganese and compounds, as Mn", "url": "https://referencesource.org/workplace-exposure-limits/manganese-and-compounds-as-mn/", "verified_fields": ["pel_mgm3", "substance"]}
{"cas_number": "7439-96-5 (metal)", "id": "manganese-compounds-and-fume-as-mn", "rel_mgm3": "TWA 1", "source": "https://www.cdc.gov/niosh/npg/npgd0379.html", "source_quote": "NIOSH REL TWA 1 mg/m3 ST 3 mg/m3", "substance": "Manganese compounds and fume (as Mn)", "url": "https://referencesource.org/workplace-exposure-limits/manganese-compounds-and-fume-as-mn/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"cas_number": "7439-96-5", "id": "manganese-compounds-as-mn", "pel_mgm3": "(C)5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Manganese compounds (as Mn) | 7439-96-5 | - | (C)5 | - |", "substance": "Manganese compounds (as Mn)", "url": "https://referencesource.org/workplace-exposure-limits/manganese-compounds-as-mn/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0380.html", "source_quote": "NIOSH REL TWA 0.1 mg/m3 [skin]", "value": "TWA 0.1"}], "cas_number": "12079651", "disagreements": [], "id": "manganese-cyclopentadienyl-tricarbonyl-as-mn", "pel_mgm3": "0.1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "12079651 | S | Manganese, cyclopentadienyl-tricarbonyl, as Mn | -- | 0.1", "substance": "Manganese, cyclopentadienyl-tricarbonyl, as Mn", "url": "https://referencesource.org/workplace-exposure-limits/manganese-cyclopentadienyl-tricarbonyl-as-mn/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7439965 | | Manganese fume, as Mn | -- | 0.2 | | -- | 3", "value": "3"}], "cas_number": "7439-96-5", "disagreements": [{"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Manganese fume (as Mn) | 7439-96-5 | - | (C)5 | - |", "value": "(C)5"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7439965 | | Manganese fume, as Mn | -- | 0.2 | | -- | 3", "value": "0.2"}]}], "id": "manganese-fume-as-mn", "pel_mgm3": "(C)5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Manganese fume (as Mn) | 7439-96-5 | - | (C)5 | - |", "substance": "Manganese fume (as Mn)", "url": "https://referencesource.org/workplace-exposure-limits/manganese-fume-as-mn/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"id": "manganese-tetroxide", "pel_mgm3": "0.2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Manganese tetroxide | -- | 0.2", "substance": "Manganese tetroxide", "url": "https://referencesource.org/workplace-exposure-limits/manganese-tetroxide/", "verified_fields": ["pel_mgm3", "substance"]}
{"cas_number": "1317-35-7", "id": "manganese-tetroxide-as-mn", "rel_statement": "See Appendix D", "source": "https://www.cdc.gov/niosh/npg/npgd0381.html", "source_quote": "NIOSH REL See Appendix D", "substance": "Manganese tetroxide (as Mn)", "url": "https://referencesource.org/workplace-exposure-limits/manganese-tetroxide-as-mn/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0382.html", "source_quote": "NIOSH REL TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)", "value": "TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)"}], "cas_number": "1317-65-3", "disagreements": [], "id": "marble", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Marble | 1317-65-3 | - | - | - |", "substance": "Marble", "url": "https://referencesource.org/workplace-exposure-limits/marble/", "verified_fields": ["cas_number", "substance"]}
{"cas_number": "7439976", "ceiling": "0.04 mg/M3", "ceiling_notation": "a ceiling value in addition to the TWA values", "id": "mercury-alkyls-as-hg", "pel_mgm3": "0.01", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7439976 | S | Mercury alkyls, as Hg | -- | 0.01 | 0.04 mg/M3 | -- | 0.03", "stel_mgm3": "0.03", "substance": "Mercury alkyls, as Hg", "url": "https://referencesource.org/workplace-exposure-limits/mercury-alkyls-as-hg/", "verified_fields": ["cas_number", "ceiling", "ceiling_notation", "pel_mgm3", "stel_mgm3", "substance"]}
{"cas_number": "7439-97-6", "id": "mercury-aryl-and-inorganic-as-hg", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Mercury (aryl and inorganic) (as Hg) | 7439-97-6 | - | (2) | - |", "substance": "Mercury (aryl and inorganic) (as Hg)", "url": "https://referencesource.org/workplace-exposure-limits/mercury-aryl-and-inorganic-as-hg/", "verified_fields": ["cas_number", "substance"]}
{"cas_number": "7439976", "ceiling_notation": "the values given in the PEL columns are ceiling values", "id": "mercury-aryl-compounds-as-hg", "pel_mgm3": "0.1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7439976 | S | Mercury aryl compounds as Hg | | 0.1 | C", "substance": "Mercury aryl compounds as Hg", "url": "https://referencesource.org/workplace-exposure-limits/mercury-aryl-compounds-as-hg/", "verified_fields": ["cas_number", "ceiling_notation", "pel_mgm3", "substance"]}
{"cas_number": "7439-97-6 (metal)", "id": "mercury-compounds-except-organo-alkyls-as-hg", "rel_mgm3": "TWA 0.05", "source": "https://www.cdc.gov/niosh/npg/npgd0383.html", "source_quote": "NIOSH REL NIOSH REL: Hg Vapor: TWA 0.05 mg/m3 [skin] Other: C 0.1 mg/m3 [skin]", "substance": "Mercury compounds [except (organo) alkyls] (as Hg)", "url": "https://referencesource.org/workplace-exposure-limits/mercury-compounds-except-organo-alkyls-as-hg/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"cas_number": "7439976", "ceiling": "0.1 mg/M3", "ceiling_notation": "a ceiling value in addition to the TWA values", "id": "mercury-metallic-and-inorganic-compounds-as-hg", "pel_mgm3": "0.025", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7439976 | S | Mercury, metallic and inorganic compounds as Hg | -- | 0.025 | 0.1 mg/M3", "substance": "Mercury, metallic and inorganic compounds as Hg", "url": "https://referencesource.org/workplace-exposure-limits/mercury-metallic-and-inorganic-compounds-as-hg/", "verified_fields": ["cas_number", "ceiling", "ceiling_notation", "pel_mgm3", "substance"]}
{"cas_number": "7439-97-6", "id": "mercury-organo-alkyl-compounds-as-hg", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Mercury (organo) alkyl compounds (as Hg) | 7439-97-6 | - | (2) | - |", "substance": "Mercury (organo) alkyl compounds (as Hg)", "url": "https://referencesource.org/workplace-exposure-limits/mercury-organo-alkyl-compounds-as-hg/", "verified_fields": ["cas_number", "substance"]}
{"cas_number": "7439-97-6", "id": "mercury-vapor-as-hg", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Mercury (vapor) (as Hg) | 7439-97-6 | - | (2) | - |", "substance": "Mercury (vapor) (as Hg)", "url": "https://referencesource.org/workplace-exposure-limits/mercury-vapor-as-hg/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0385.html", "source_quote": "NIOSH REL TWA 10 ppm (40 mg/m3)", "value": "TWA 10"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0385.html", "source_quote": "NIOSH REL TWA 10 ppm (40 mg/m3)", "value": "40"}, {"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "141797 | | Mesityl oxide; 4-methyl-3-pentene-2-one | 15 | 60 | | 25 | 100", "value": "25"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "141797 | | Mesityl oxide; 4-methyl-3-pentene-2-one | 15 | 60 | | 25 | 100", "value": "100"}], "cas_number": "141-79-7", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Mesityl oxide | 141-79-7 | 25 | 100 | - |", "value": "25"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "141797 | | Mesityl oxide; 4-methyl-3-pentene-2-one | 15 | 60 | | 25 | 100", "value": "15"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Mesityl oxide | 141-79-7 | 25 | 100 | - |", "value": "100"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "141797 | | Mesityl oxide; 4-methyl-3-pentene-2-one | 15 | 60 | | 25 | 100", "value": "60"}]}], "id": "mesityl-oxide", "pel_mgm3": "100", "pel_ppm": "25", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Mesityl oxide | 141-79-7 | 25 | 100 | - |", "substance": "Mesityl oxide", "url": "https://referencesource.org/workplace-exposure-limits/mesityl-oxide/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0386.html", "source_quote": "NIOSH REL TWA 20 ppm (70 mg/m3) [skin]", "value": "TWA 20"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0386.html", "source_quote": "NIOSH REL TWA 20 ppm (70 mg/m3) [skin]", "value": "70"}], "cas_number": "79414", "disagreements": [], "id": "methacrylic-acid", "pel_mgm3": "70", "pel_ppm": "20", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "79414 | S | Methacrylic acid | 20 | 70", "substance": "Methacrylic acid", "url": "https://referencesource.org/workplace-exposure-limits/methacrylic-acid/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "74828", "id": "methane", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "74828 | | Methane | (h) | --", "substance": "Methane", "url": "https://referencesource.org/workplace-exposure-limits/methane/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0387.html", "source_quote": "NIOSH REL TWA 2.5 mg/m3", "value": "TWA 2.5"}], "cas_number": "16752775", "disagreements": [], "id": "methomyl", "pel_mgm3": "2.5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "16752775 | S | Methomyl | -- | 2.5", "substance": "Methomyl", "url": "https://referencesource.org/workplace-exposure-limits/methomyl/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "72435 | | Methoxychlor; 1,1,1-trichloro-2, 2-bis(p-methoxyphenyl)ethane | -- | 10", "value": "10"}, {"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0388.html", "source_quote": "NIOSH REL Ca See Appendix A", "value": "Ca See Appendix A"}], "cas_number": "72-43-5", "disagreements": [], "id": "methoxychlor", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methoxychlor | 72-43-5 | - | - | - |", "substance": "Methoxychlor", "url": "https://referencesource.org/workplace-exposure-limits/methoxychlor/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0389.html", "source_quote": "NIOSH REL C 2 ppm (13.5 mg/m3) [60-minute]", "value": "C 2"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0389.html", "source_quote": "NIOSH REL C 2 ppm (13.5 mg/m3) [60-minute]", "value": "13.5"}], "cas_number": "76380", "disagreements": [], "id": "methoxyflurane", "pel_mgm3": "13", "pel_ppm": "2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "76380 | | Methoxyflurane | 2 | 13", "substance": "Methoxyflurane", "url": "https://referencesource.org/workplace-exposure-limits/methoxyflurane/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0405.html", "source_quote": "NIOSH REL TWA 2 ppm (8 mg/m3) ST 4 ppm (16 mg/m3)", "value": "TWA 2"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0405.html", "source_quote": "NIOSH REL TWA 2 ppm (8 mg/m3) ST 4 ppm (16 mg/m3)", "value": "8"}], "cas_number": "137053", "disagreements": [], "id": "methyl-2-cyanoacrylate", "pel_mgm3": "0.908", "pel_ppm": "0.2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "137053 | | Methyl 2-cyanoacrylate | 0.2 | 0.908", "substance": "Methyl 2-cyanoacrylate", "url": "https://referencesource.org/workplace-exposure-limits/methyl-2-cyanoacrylate/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "79209 | | Methyl acetate | 200 | 610 | | 250 | 760", "value": "250"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "79209 | | Methyl acetate | 200 | 610 | | 250 | 760", "value": "760"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0391.html", "source_quote": "NIOSH REL TWA 200 ppm (610 mg/m3) ST 250 ppm (760 mg/m3)", "value": "TWA 200"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0391.html", "source_quote": "NIOSH REL TWA 200 ppm (610 mg/m3) ST 250 ppm (760 mg/m3)", "value": "610"}], "cas_number": "79-20-9", "disagreements": [], "id": "methyl-acetate", "pel_mgm3": "610", "pel_ppm": "200", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methyl acetate | 79-20-9 | 200 | 610 | - |", "substance": "Methyl acetate", "url": "https://referencesource.org/workplace-exposure-limits/methyl-acetate/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methyl acetylene (Propyne) | 74-99-7 | 1000 | 1650 | - |", "value": "1000"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methyl acetylene (Propyne) | 74-99-7 | 1000 | 1650 | - |", "value": "1650"}], "cas_number": "74-99-7", "disagreements": [], "id": "methyl-acetylene", "rel_mgm3": "1650", "rel_ppm": "TWA 1000", "source": "https://www.cdc.gov/niosh/npg/npgd0392.html", "source_quote": "NIOSH REL TWA 1000 ppm (1650 mg/m3)", "substance": "Methyl acetylene", "url": "https://referencesource.org/workplace-exposure-limits/methyl-acetylene/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"cas_number": "59355-75-8", "id": "methyl-acetylene-propadiene-mixture", "rel_mgm3": "1800", "rel_ppm": "TWA 1000", "source": "https://www.cdc.gov/niosh/npg/npgd0393.html", "source_quote": "NIOSH REL TWA 1000 ppm (1800 mg/m3) ST 1250 ppm (2250 mg/m3)", "substance": "Methyl acetylene-propadiene mixture", "url": "https://referencesource.org/workplace-exposure-limits/methyl-acetylene-propadiene-mixture/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"id": "methyl-acetylene-propadiene-mixture-mapp", "pel_mgm3": "1,800", "pel_ppm": "1,000", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Methyl acetylene-propadiene mixture; MAPP | 1,000 | 1,800 | | 1250 | 2250", "stel_mgm3": "2250", "stel_ppm": "1250", "substance": "Methyl acetylene-propadiene mixture; MAPP", "url": "https://referencesource.org/workplace-exposure-limits/methyl-acetylene-propadiene-mixture-mapp/", "verified_fields": ["pel_mgm3", "pel_ppm", "stel_mgm3", "stel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0394.html", "source_quote": "NIOSH REL TWA 10 ppm (35 mg/m3) [skin]", "value": "TWA 10"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0394.html", "source_quote": "NIOSH REL TWA 10 ppm (35 mg/m3) [skin]", "value": "35"}], "cas_number": "96-33-3", "disagreements": [], "id": "methyl-acrylate", "pel_mgm3": "35", "pel_ppm": "10", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methyl acrylate | 96-33-3 | 10 | 35 | X |", "substance": "Methyl acrylate", "url": "https://referencesource.org/workplace-exposure-limits/methyl-acrylate/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0397.html", "source_quote": "NIOSH REL TWA 200 ppm (260 mg/m3) ST 250 ppm (325 mg/m3) [skin]", "value": "TWA 200"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0397.html", "source_quote": "NIOSH REL TWA 200 ppm (260 mg/m3) ST 250 ppm (325 mg/m3) [skin]", "value": "260"}, {"as_of": "2026-09-28", "field": "ceiling", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "67561 | S | Methyl alcohol; methanol | 200 | 260 | 1000 ppm | 250 | 325", "value": "1000 ppm"}, {"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "67561 | S | Methyl alcohol; methanol | 200 | 260 | 1000 ppm | 250 | 325", "value": "a ceiling value in addition to the TWA values"}, {"as_of": "2026-09-28", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "67561 | S | Methyl alcohol; methanol | 200 | 260 | 1000 ppm | 250 | 325", "value": "250"}, {"as_of": "2026-09-28", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "67561 | S | Methyl alcohol; methanol | 200 | 260 | 1000 ppm | 250 | 325", "value": "325"}], "cas_number": "67-56-1", "disagreements": [], "id": "methyl-alcohol", "pel_mgm3": "260", "pel_ppm": "200", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methyl alcohol | 67-56-1 | 200 | 260 | - |", "substance": "Methyl alcohol", "url": "https://referencesource.org/workplace-exposure-limits/methyl-alcohol/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-28", "field": "ceiling", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "74839 | S | Methyl bromide | 1 | 3.88 | 20 ppm", "value": "20 ppm"}, {"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "74839 | S | Methyl bromide | 1 | 3.88 | 20 ppm", "value": "a ceiling value in addition to the TWA values"}, {"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0400.html", "source_quote": "NIOSH REL Ca See Appendix A", "value": "Ca See Appendix A"}], "cas_number": "74-83-9", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methyl bromide | 74-83-9 | (C)20 | (C)80 | X |", "value": "(C)20"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "74839 | S | Methyl bromide | 1 | 3.88 | 20 ppm", "value": "1"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methyl bromide | 74-83-9 | (C)20 | (C)80 | X |", "value": "(C)80"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "74839 | S | Methyl bromide | 1 | 3.88 | 20 ppm", "value": "3.88"}]}], "id": "methyl-bromide", "pel_mgm3": "(C)80", "pel_ppm": "(C)20", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methyl bromide | 74-83-9 | (C)20 | (C)80 | X |", "substance": "Methyl bromide", "url": "https://referencesource.org/workplace-exposure-limits/methyl-bromide/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-28", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "74873 | | Methyl chloride | 50 | 105 | 300 ppm | 100 | 210", "value": "50"}, {"as_of": "2026-09-28", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "74873 | | Methyl chloride | 50 | 105 | 300 ppm | 100 | 210", "value": "105"}, {"as_of": "2026-09-28", "field": "ceiling", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "74873 | | Methyl chloride | 50 | 105 | 300 ppm | 100 | 210", "value": "300 ppm"}, {"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "74873 | | Methyl chloride | 50 | 105 | 300 ppm | 100 | 210", "value": "a ceiling value in addition to the TWA values"}, {"as_of": "2026-09-28", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "74873 | | Methyl chloride | 50 | 105 | 300 ppm | 100 | 210", "value": "100"}, {"as_of": "2026-09-28", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "74873 | | Methyl chloride | 50 | 105 | 300 ppm | 100 | 210", "value": "210"}, {"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0403.html", "source_quote": "NIOSH REL Ca See Appendix A", "value": "Ca See Appendix A"}], "cas_number": "74-87-3", "disagreements": [], "id": "methyl-chloride", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methyl chloride | 74-87-3 | - | (2) | - |", "substance": "Methyl chloride", "url": "https://referencesource.org/workplace-exposure-limits/methyl-chloride/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methyl chloroform (1,1,1-Trichloroethane) | 71-55-6 | 350 | 1900 | - |", "value": "350"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methyl chloroform (1,1,1-Trichloroethane) | 71-55-6 | 350 | 1900 | - |", "value": "1900"}, {"as_of": "2026-09-28", "field": "ceiling", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "71556 | | Methyl chloroform; 1,1,1-trichloroethane | 350 | 1900 | 800 ppm | 450 | 2450", "value": "800 ppm"}, {"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "71556 | | Methyl chloroform; 1,1,1-trichloroethane | 350 | 1900 | 800 ppm | 450 | 2450", "value": "a ceiling value in addition to the TWA values"}, {"as_of": "2026-09-28", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "71556 | | Methyl chloroform; 1,1,1-trichloroethane | 350 | 1900 | 800 ppm | 450 | 2450", "value": "450"}, {"as_of": "2026-09-28", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "71556 | | Methyl chloroform; 1,1,1-trichloroethane | 350 | 1900 | 800 ppm | 450 | 2450", "value": "2450"}], "cas_number": "71-55-6", "disagreements": [], "id": "methyl-chloroform", "rel_mgm3": "1900", "rel_ppm": "C 350", "source": "https://www.cdc.gov/niosh/npg/npgd0404.html", "source_quote": "NIOSH REL C 350 ppm (1900 mg/m3) [15-minute]", "substance": "Methyl chloroform", "url": "https://referencesource.org/workplace-exposure-limits/methyl-chloroform/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "8022002 | S | Methyl demeton; a mixture of o,o-dimethyl o-(2-(ethylthio)ethyl) phosphorothioate and o,o-dimethyl S-(2-(ethylthio)-ethyl) phosphorothioate | -- | 0.5", "value": "0.5"}], "cas_number": "8022-00-2", "disagreements": [], "id": "methyl-demeton", "rel_mgm3": "TWA 0.5", "source": "https://www.cdc.gov/niosh/npg/npgd0410.html", "source_quote": "NIOSH REL TWA 0.5 mg/m3 [skin]", "substance": "Methyl demeton", "url": "https://referencesource.org/workplace-exposure-limits/methyl-demeton/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0416.html", "source_quote": "NIOSH REL C 0.2 ppm (1.5 mg/m3)", "value": "C 0.2"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0416.html", "source_quote": "NIOSH REL C 0.2 ppm (1.5 mg/m3)", "value": "1.5"}], "cas_number": "1338234", "ceiling_notation": "the values given in the PEL columns are ceiling values", "disagreements": [], "id": "methyl-ethyl-ketone-peroxide", "pel_mgm3": "1.5", "pel_ppm": "0.2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "1338234 | | Methyl ethyl ketone peroxide | 0.2 | 1.5 | C", "substance": "Methyl ethyl ketone peroxide", "url": "https://referencesource.org/workplace-exposure-limits/methyl-ethyl-ketone-peroxide/", "verified_fields": ["cas_number", "ceiling_notation", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "107313 | | Methyl formate | 100 | 250 | | 150 | 375", "value": "150"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "107313 | | Methyl formate | 100 | 250 | | 150 | 375", "value": "375"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0417.html", "source_quote": "NIOSH REL TWA 100 ppm (250 mg/m3) ST 150 ppm (375 mg/m3)", "value": "TWA 100"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0417.html", "source_quote": "NIOSH REL TWA 100 ppm (250 mg/m3) ST 150 ppm (375 mg/m3)", "value": "250"}], "cas_number": "107-31-3", "disagreements": [], "id": "methyl-formate", "pel_mgm3": "250", "pel_ppm": "100", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methyl formate | 107-31-3 | 100 | 250 | - |", "substance": "Methyl formate", "url": "https://referencesource.org/workplace-exposure-limits/methyl-formate/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methyl hydrazine (Monomethyl hydrazine) | 60-34-4 | (C)0.2 | (C)0.35 | X |", "value": "(C)0.2"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methyl hydrazine (Monomethyl hydrazine) | 60-34-4 | (C)0.2 | (C)0.35 | X |", "value": "(C)0.35"}], "cas_number": "60-34-4", "disagreements": [], "id": "methyl-hydrazine", "rel_mgm3": "0.08", "rel_ppm": "C 0.04", "source": "https://www.cdc.gov/niosh/npg/npgd0419.html", "source_quote": "NIOSH REL Ca C 0.04 ppm (0.08 mg/m3) [2-hr]", "substance": "Methyl hydrazine", "url": "https://referencesource.org/workplace-exposure-limits/methyl-hydrazine/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0420.html", "source_quote": "NIOSH REL Ca TWA 2 ppm (10 mg/m3) [skin]", "value": "TWA 2"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0420.html", "source_quote": "NIOSH REL Ca TWA 2 ppm (10 mg/m3) [skin]", "value": "10"}], "cas_number": "74-88-4", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methyl iodide | 74-88-4 | 5 | 28 | X |", "value": "5"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "74884 | S | Methyl iodide | 2 | 10", "value": "2"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methyl iodide | 74-88-4 | 5 | 28 | X |", "value": "28"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "74884 | S | Methyl iodide | 2 | 10", "value": "10"}]}], "id": "methyl-iodide", "pel_mgm3": "28", "pel_ppm": "5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methyl iodide | 74-88-4 | 5 | 28 | X |", "substance": "Methyl iodide", "url": "https://referencesource.org/workplace-exposure-limits/methyl-iodide/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0421.html", "source_quote": "NIOSH REL TWA 50 ppm (240 mg/m3)", "value": "TWA 50"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0421.html", "source_quote": "NIOSH REL TWA 50 ppm (240 mg/m3)", "value": "240"}], "cas_number": "110-12-3", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methyl isoamyl ketone | 110-12-3 | 100 | 475 | - |", "value": "100"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "110123 | | Methyl isoamyl ketone | 50 | 234", "value": "50"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methyl isoamyl ketone | 110-12-3 | 100 | 475 | - |", "value": "475"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "110123 | | Methyl isoamyl ketone | 50 | 234", "value": "234"}]}], "id": "methyl-isoamyl-ketone", "pel_mgm3": "475", "pel_ppm": "100", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methyl isoamyl ketone | 110-12-3 | 100 | 475 | - |", "substance": "Methyl isoamyl ketone", "url": "https://referencesource.org/workplace-exposure-limits/methyl-isoamyl-ketone/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0422.html", "source_quote": "NIOSH REL TWA 25 ppm (100 mg/m3) ST 40 ppm (165 mg/m3) [skin]", "value": "TWA 25"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0422.html", "source_quote": "NIOSH REL TWA 25 ppm (100 mg/m3) ST 40 ppm (165 mg/m3) [skin]", "value": "100"}, {"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "108112 | S | Methyl isobutyl carbinol; 4-methyl-2-pentanol; methyl amyl alcohol | 25 | 100 | | 40 | 165", "value": "40"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "108112 | S | Methyl isobutyl carbinol; 4-methyl-2-pentanol; methyl amyl alcohol | 25 | 100 | | 40 | 165", "value": "165"}], "cas_number": "108-11-2", "disagreements": [], "id": "methyl-isobutyl-carbinol", "pel_mgm3": "100", "pel_ppm": "25", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methyl isobutyl carbinol | 108-11-2 | 25 | 100 | X |", "substance": "Methyl isobutyl carbinol", "url": "https://referencesource.org/workplace-exposure-limits/methyl-isobutyl-carbinol/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0423.html", "source_quote": "NIOSH REL TWA 0.02 ppm (0.05 mg/m³) [skin]", "value": "TWA 0.02"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0423.html", "source_quote": "NIOSH REL TWA 0.02 ppm (0.05 mg/m³) [skin]", "value": "0.05"}], "cas_number": "624-83-9", "disagreements": [], "id": "methyl-isocyanate", "pel_mgm3": "0.05", "pel_ppm": "0.02", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methyl isocyanate | 624-83-9 | 0.02 | 0.05 | X |", "substance": "Methyl isocyanate", "url": "https://referencesource.org/workplace-exposure-limits/methyl-isocyanate/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0424.html", "source_quote": "NIOSH REL TWA 200 ppm (705 mg/m3)", "value": "TWA 200"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0424.html", "source_quote": "NIOSH REL TWA 200 ppm (705 mg/m3)", "value": "705"}], "cas_number": "563804", "disagreements": [], "id": "methyl-isopropyl-ketone", "pel_mgm3": "705", "pel_ppm": "200", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "563804 | | Methyl isopropyl ketone | 200 | 705", "substance": "Methyl isopropyl ketone", "url": "https://referencesource.org/workplace-exposure-limits/methyl-isopropyl-ketone/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0425.html", "source_quote": "NIOSH REL C 0.5 ppm (1 mg/m3) [15-minute]", "value": "C 0.5"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0425.html", "source_quote": "NIOSH REL C 0.5 ppm (1 mg/m3) [15-minute]", "value": "1"}], "cas_number": "74-93-1", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methyl mercaptan | 74-93-1 | (C)10 | (C)20 | - |", "value": "(C)10"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "74931 | | Methyl mercaptan | 0.5 | 1", "value": "0.5"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methyl mercaptan | 74-93-1 | (C)10 | (C)20 | - |", "value": "(C)20"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "74931 | | Methyl mercaptan | 0.5 | 1", "value": "1"}]}], "id": "methyl-mercaptan", "pel_mgm3": "(C)20", "pel_ppm": "(C)10", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methyl mercaptan | 74-93-1 | (C)10 | (C)20 | - |", "substance": "Methyl mercaptan", "url": "https://referencesource.org/workplace-exposure-limits/methyl-mercaptan/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0426.html", "source_quote": "NIOSH REL TWA 100 ppm (410 mg/m3)", "value": "TWA 100"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0426.html", "source_quote": "NIOSH REL TWA 100 ppm (410 mg/m3)", "value": "410"}, {"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "80626 | | Methyl methacrylate; methyl 2-methyl-2-propenoate | 50 | 205 | | 100 | 410", "value": "100"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "80626 | | Methyl methacrylate; methyl 2-methyl-2-propenoate | 50 | 205 | | 100 | 410", "value": "410"}], "cas_number": "80-62-6", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methyl methacrylate | 80-62-6 | 100 | 410 | - |", "value": "100"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "80626 | | Methyl methacrylate; methyl 2-methyl-2-propenoate | 50 | 205 | | 100 | 410", "value": "50"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methyl methacrylate | 80-62-6 | 100 | 410 | - |", "value": "410"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "80626 | | Methyl methacrylate; methyl 2-methyl-2-propenoate | 50 | 205 | | 100 | 410", "value": "205"}]}], "id": "methyl-methacrylate", "pel_mgm3": "410", "pel_ppm": "100", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methyl methacrylate | 80-62-6 | 100 | 410 | - |", "substance": "Methyl methacrylate", "url": "https://referencesource.org/workplace-exposure-limits/methyl-methacrylate/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0399.html", "source_quote": "NIOSH REL TWA 100 ppm (465 mg/m3)", "value": "TWA 100"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0399.html", "source_quote": "NIOSH REL TWA 100 ppm (465 mg/m3)", "value": "465"}], "cas_number": "110-43-0", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methyl n-amyl ketone | 110-43-0 | 100 | 465 | - |", "value": "100"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "110430 | | Methyl n-amyl ketone; 2-heptanone | 50 | 235", "value": "50"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methyl n-amyl ketone | 110-43-0 | 100 | 465 | - |", "value": "465"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "110430 | | Methyl n-amyl ketone; 2-heptanone | 50 | 235", "value": "235"}]}], "id": "methyl-n-amyl-ketone", "pel_mgm3": "465", "pel_ppm": "100", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methyl n-amyl ketone | 110-43-0 | 100 | 465 | - |", "substance": "Methyl n-amyl ketone", "url": "https://referencesource.org/workplace-exposure-limits/methyl-n-amyl-ketone/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "298000 | S | Methyl parathion; o,o-dimethyl o-(p-nitrophenyl) phosphorothioate | -- | 0.2", "value": "0.2"}], "cas_number": "298-00-0", "disagreements": [], "id": "methyl-parathion", "rel_mgm3": "TWA 0.2", "source": "https://www.cdc.gov/niosh/npg/npgd0427.html", "source_quote": "NIOSH REL TWA 0.2 mg/m3 [skin]", "substance": "Methyl parathion", "url": "https://referencesource.org/workplace-exposure-limits/methyl-parathion/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "681845 | | Methyl silicate; tetramethyl silicate | 1 | 6", "value": "1"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "681845 | | Methyl silicate; tetramethyl silicate | 1 | 6", "value": "6"}], "cas_number": "681-84-5", "disagreements": [], "id": "methyl-silicate", "rel_mgm3": "6", "rel_ppm": "TWA 1", "source": "https://www.cdc.gov/niosh/npg/npgd0428.html", "source_quote": "NIOSH REL TWA 1 ppm (6 mg/m3)", "substance": "Methyl silicate", "url": "https://referencesource.org/workplace-exposure-limits/methyl-silicate/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"cas_number": "1634044", "id": "methyl-tert-butyl-ether-mtbe", "pel_mgm3": "144", "pel_ppm": "40", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "1634044 | | Methyl tert-butyl ether; MTBE | 40 | 144", "substance": "Methyl tert-butyl ether; MTBE", "url": "https://referencesource.org/workplace-exposure-limits/methyl-tert-butyl-ether-mtbe/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "78944", "ceiling_notation": "the values given in the PEL columns are ceiling values", "id": "methyl-vinyl-ketone", "pel_mgm3": "0.14", "pel_ppm": "0.05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "78944 | S | Methyl vinyl ketone | 0.05 | 0.14 | C", "substance": "Methyl vinyl ketone", "url": "https://referencesource.org/workplace-exposure-limits/methyl-vinyl-ketone/", "verified_fields": ["cas_number", "ceiling_notation", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methylal (Dimethoxy-methane) | 109-87-5 | 1000 | 3100 | - |", "value": "1000"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methylal (Dimethoxy-methane) | 109-87-5 | 1000 | 3100 | - |", "value": "3100"}], "cas_number": "109-87-5", "disagreements": [], "id": "methylal", "rel_mgm3": "3100", "rel_ppm": "TWA 1000", "source": "https://www.cdc.gov/niosh/npg/npgd0396.html", "source_quote": "NIOSH REL TWA 1000 ppm (3100 mg/m3)", "substance": "Methylal", "url": "https://referencesource.org/workplace-exposure-limits/methylal/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "74895 | | Methylamine | 5 | 6.4 | | 15 | 19", "value": "15"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "74895 | | Methylamine | 5 | 6.4 | | 15 | 19", "value": "19"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0398.html", "source_quote": "NIOSH REL TWA 10 ppm (12 mg/m3)", "value": "TWA 10"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0398.html", "source_quote": "NIOSH REL TWA 10 ppm (12 mg/m3)", "value": "12"}], "cas_number": "74-89-5", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methylamine | 74-89-5 | 10 | 12 | - |", "value": "10"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "74895 | | Methylamine | 5 | 6.4 | | 15 | 19", "value": "5"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methylamine | 74-89-5 | 10 | 12 | - |", "value": "12"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "74895 | | Methylamine | 5 | 6.4 | | 15 | 19", "value": "6.4"}]}], "id": "methylamine", "pel_mgm3": "12", "pel_ppm": "10", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methylamine | 74-89-5 | 10 | 12 | - |", "substance": "Methylamine", "url": "https://referencesource.org/workplace-exposure-limits/methylamine/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0406.html", "source_quote": "NIOSH REL TWA 400 ppm (1600 mg/m3)", "value": "TWA 400"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0406.html", "source_quote": "NIOSH REL TWA 400 ppm (1600 mg/m3)", "value": "1600"}], "cas_number": "108-87-2", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methylcyclohexane | 108-87-2 | 500 | 2000 | - |", "value": "500"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "108872 | | Methylcyclohexane | 400 | 1,600", "value": "400"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methylcyclohexane | 108-87-2 | 500 | 2000 | - |", "value": "2000"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "108872 | | Methylcyclohexane | 400 | 1,600", "value": "1,600"}]}], "id": "methylcyclohexane", "pel_mgm3": "2000", "pel_ppm": "500", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methylcyclohexane | 108-87-2 | 500 | 2000 | - |", "substance": "Methylcyclohexane", "url": "https://referencesource.org/workplace-exposure-limits/methylcyclohexane/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0407.html", "source_quote": "NIOSH REL TWA 50 ppm (235 mg/m3)", "value": "TWA 50"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0407.html", "source_quote": "NIOSH REL TWA 50 ppm (235 mg/m3)", "value": "235"}], "cas_number": "25639-42-3", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methylcyclohexanol | 25639-42-3 | 100 | 470 | - |", "value": "100"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "25639423 | | Methylcyclohexanol (meta- and para-isomer mixture) | 50 | 235", "value": "50"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methylcyclohexanol | 25639-42-3 | 100 | 470 | - |", "value": "470"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "25639423 | | Methylcyclohexanol (meta- and para-isomer mixture) | 50 | 235", "value": "235"}]}], "id": "methylcyclohexanol", "pel_mgm3": "470", "pel_ppm": "100", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methylcyclohexanol | 25639-42-3 | 100 | 470 | - |", "substance": "Methylcyclohexanol", "url": "https://referencesource.org/workplace-exposure-limits/methylcyclohexanol/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "5124301 | | Methylene bis(4-cyclohexylisocyanate); hydrogenated MDI | 0.005 | 0.054", "value": "0.005"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "5124301 | | Methylene bis(4-cyclohexylisocyanate); hydrogenated MDI | 0.005 | 0.054", "value": "0.054"}], "cas_number": "5124-30-1", "disagreements": [], "id": "methylene-bis-4-cyclohexylisocyanate", "rel_mgm3": "0.11", "rel_ppm": "C 0.01", "source": "https://www.cdc.gov/niosh/npg/npgd0412.html", "source_quote": "NIOSH REL C 0.01 ppm (0.11 mg/m3)", "substance": "Methylene bis(4-cyclohexylisocyanate)", "url": "https://referencesource.org/workplace-exposure-limits/methylene-bis-4-cyclohexylisocyanate/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0413.html", "source_quote": "NIOSH REL TWA 0.05 mg/m3 (0.005 ppm) C 0.2 mg/m3 (0.020 ppm) [10-minute]", "value": "0.005"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0413.html", "source_quote": "NIOSH REL TWA 0.05 mg/m3 (0.005 ppm) C 0.2 mg/m3 (0.020 ppm) [10-minute]", "value": "TWA 0.05"}], "cas_number": "101688", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "101688 | | Methylene bis(phenylisocyanate); MDI; diphenylmethane diisocyanate | 0.005 | 0.051", "value": "0.005"}, {"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methylene bisphenyl isocyanate (MDI) | 101-68-8 | (C)0.02 | (C)0.2 | - |", "value": "(C)0.02"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "101688 | | Methylene bis(phenylisocyanate); MDI; diphenylmethane diisocyanate | 0.005 | 0.051", "value": "0.051"}, {"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methylene bisphenyl isocyanate (MDI) | 101-68-8 | (C)0.02 | (C)0.2 | - |", "value": "(C)0.2"}]}], "id": "methylene-bis-phenylisocyanate-mdi-diphenylmethane-diisocyanate", "pel_mgm3": "0.051", "pel_ppm": "0.005", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "101688 | | Methylene bis(phenylisocyanate); MDI; diphenylmethane diisocyanate | 0.005 | 0.051", "substance": "Methylene bis(phenylisocyanate); MDI; diphenylmethane diisocyanate", "url": "https://referencesource.org/workplace-exposure-limits/methylene-bis-phenylisocyanate-mdi-diphenylmethane-diisocyanate/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0414.html", "source_quote": "NIOSH REL Ca See Appendix A", "value": "Ca See Appendix A"}, {"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75092 | | Methylene chloride; dichloromethane (see also section 5202) | 25 | 87 | | 125 | 435", "value": "25"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75092 | | Methylene chloride; dichloromethane (see also section 5202) | 25 | 87 | | 125 | 435", "value": "87"}, {"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75092 | | Methylene chloride; dichloromethane (see also section 5202) | 25 | 87 | | 125 | 435", "value": "125"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75092 | | Methylene chloride; dichloromethane (see also section 5202) | 25 | 87 | | 125 | 435", "value": "435"}], "cas_number": "75-09-2", "disagreements": [], "id": "methylene-chloride", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Methylene chloride | 75-09-2 | - | (2) | - |", "substance": "Methylene chloride", "url": "https://referencesource.org/workplace-exposure-limits/methylene-chloride/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0430.html", "source_quote": "NIOSH REL TWA 5 mg/m3", "value": "TWA 5"}], "cas_number": "21087649", "disagreements": [], "id": "metribuzin", "pel_mgm3": "5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "21087649 | | Metribuzin | -- | 5", "substance": "Metribuzin", "url": "https://referencesource.org/workplace-exposure-limits/metribuzin/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0503.html", "source_quote": "NIOSH REL TWA 0.01 ppm (0.1 mg/m3) ST 0.03 ppm (0.3 mg/m3) [skin]", "value": "TWA 0.01"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0503.html", "source_quote": "NIOSH REL TWA 0.01 ppm (0.1 mg/m3) ST 0.03 ppm (0.3 mg/m3) [skin]", "value": "0.1"}], "cas_number": "7786347", "disagreements": [], "id": "mevinphos-2-carbomethoxyl-1-propen-2-yl-dimethyl-phosphate", "pel_mgm3": "0.1", "pel_ppm": "0.01", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7786347 | S | Mevinphos; 2-carbomethoxyl-1-propen-2-yl dimethyl phosphate | 0.01 | 0.1 | | 0.03 | 0.3", "stel_mgm3": "0.3", "stel_ppm": "0.03", "substance": "Mevinphos; 2-carbomethoxyl-1-propen-2-yl dimethyl phosphate", "url": "https://referencesource.org/workplace-exposure-limits/mevinphos-2-carbomethoxyl-1-propen-2-yl-dimethyl-phosphate/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "stel_mgm3", "stel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "12001262 | | Mica (respirable dust) | -- | 3", "value": "3"}], "cas_number": "12001-26-2", "disagreements": [], "id": "mica-containing-less-than-1-quartz", "rel_statement": "TWA 3 mg/m3 (resp)", "source": "https://www.cdc.gov/niosh/npg/npgd0431.html", "source_quote": "NIOSH REL TWA 3 mg/m3 (resp)", "substance": "Mica (containing less than 1% quartz)", "url": "https://referencesource.org/workplace-exposure-limits/mica-containing-less-than-1-quartz/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7439987 | | Molybdenum, insoluble compounds, as Mo | -- | 0.5(n)", "value": "0.5(n)"}], "cas_number": "7439-98-7", "disagreements": [], "id": "molybdenum", "rel_statement": "See Appendix D", "source": "https://www.cdc.gov/niosh/npg/npgd0433.html", "source_quote": "NIOSH REL See Appendix D", "substance": "Molybdenum", "url": "https://referencesource.org/workplace-exposure-limits/molybdenum/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"id": "molybdenum-soluble-compounds-as-mo", "pel_mgm3": "0.5(n)", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Molybdenum, soluble compounds, as Mo | -- | 0.5(n)", "substance": "Molybdenum, soluble compounds, as Mo", "url": "https://referencesource.org/workplace-exposure-limits/molybdenum-soluble-compounds-as-mo/", "verified_fields": ["pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0435.html", "source_quote": "NIOSH REL TWA 0.25 mg/m3", "value": "TWA 0.25"}], "cas_number": "6923224", "disagreements": [], "id": "monocrotophos", "pel_mgm3": "0.25", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "6923224 | | Monocrotophos | -- | 0.25", "substance": "Monocrotophos", "url": "https://referencesource.org/workplace-exposure-limits/monocrotophos/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0436.html", "source_quote": "NIOSH REL TWA 0.5 ppm (2 mg/m3) [skin]", "value": "TWA 0.5"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0436.html", "source_quote": "NIOSH REL TWA 0.5 ppm (2 mg/m3) [skin]", "value": "2"}], "cas_number": "100-61-8", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Monomethyl aniline | 100-61-8 | 2 | 9 | X |", "value": "2"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "100618 | S | N-Methylaniline; monomethylaniline | 0.5 | 2", "value": "0.5"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Monomethyl aniline | 100-61-8 | 2 | 9 | X |", "value": "9"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "100618 | S | N-Methylaniline; monomethylaniline | 0.5 | 2", "value": "2"}]}], "id": "monomethyl-aniline", "pel_mgm3": "9", "pel_ppm": "2", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Monomethyl aniline | 100-61-8 | 2 | 9 | X |", "substance": "Monomethyl aniline", "url": "https://referencesource.org/workplace-exposure-limits/monomethyl-aniline/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0437.html", "source_quote": "NIOSH REL TWA 20 ppm (70 mg/m3) ST 30 ppm (105 mg/m3) [skin]", "value": "TWA 20"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0437.html", "source_quote": "NIOSH REL TWA 20 ppm (70 mg/m3) ST 30 ppm (105 mg/m3) [skin]", "value": "70"}, {"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "110918 | S | Morpholine; tetrahydro-4H-1, 4-oxazine | 20 | 70 | | 30 | 105", "value": "30"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "110918 | S | Morpholine; tetrahydro-4H-1, 4-oxazine | 20 | 70 | | 30 | 105", "value": "105"}], "cas_number": "110-91-8", "disagreements": [], "id": "morpholine", "pel_mgm3": "70", "pel_ppm": "20", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Morpholine | 110-91-8 | 20 | 70 | X |", "substance": "Morpholine", "url": "https://referencesource.org/workplace-exposure-limits/morpholine/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0031.html", "source_quote": "NIOSH REL TWA 100 ppm (525 mg/m3)", "value": "TWA 100"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0031.html", "source_quote": "NIOSH REL TWA 100 ppm (525 mg/m3)", "value": "525"}], "cas_number": "628-63-7", "disagreements": [], "id": "n-amyl-acetate", "pel_mgm3": "525", "pel_ppm": "100", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "n-Amyl acetate | 628-63-7 | 100 | 525 | - |", "substance": "n-Amyl acetate", "url": "https://referencesource.org/workplace-exposure-limits/n-amyl-acetate/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "123864 | | n-Butyl acetate | 150 | 710 | | 200 | 950", "value": "200"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "123864 | | n-Butyl acetate | 150 | 710 | | 200 | 950", "value": "950"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0072.html", "source_quote": "NIOSH REL TWA 150 ppm (710 mg/m3) ST 200 ppm (950 mg/m3)", "value": "TWA 150"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0072.html", "source_quote": "NIOSH REL TWA 150 ppm (710 mg/m3) ST 200 ppm (950 mg/m3)", "value": "710"}], "cas_number": "123-86-4", "disagreements": [], "id": "n-butyl-acetate", "pel_mgm3": "710", "pel_ppm": "150", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "n-Butyl-acetate | 123-86-4 | 150 | 710 | - |", "substance": "n-Butyl-acetate", "url": "https://referencesource.org/workplace-exposure-limits/n-butyl-acetate/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "71363 | S | n-Butyl alcohol; 1-butanol | 50 | 150 | C", "value": "the values given in the PEL columns are ceiling values"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0076.html", "source_quote": "NIOSH REL C 50 ppm (150 mg/m3) [skin]", "value": "C 50"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0076.html", "source_quote": "NIOSH REL C 50 ppm (150 mg/m3) [skin]", "value": "150"}], "cas_number": "71-36-3", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "n-Butyl alcohol | 71-36-3 | 100 | 300 | - |", "value": "100"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "71363 | S | n-Butyl alcohol; 1-butanol | 50 | 150 | C", "value": "50"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "n-Butyl alcohol | 71-36-3 | 100 | 300 | - |", "value": "300"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "71363 | S | n-Butyl alcohol; 1-butanol | 50 | 150 | C", "value": "150"}]}], "id": "n-butyl-alcohol", "pel_mgm3": "300", "pel_ppm": "100", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "n-Butyl alcohol | 71-36-3 | 100 | 300 | - |", "substance": "n-Butyl alcohol", "url": "https://referencesource.org/workplace-exposure-limits/n-butyl-alcohol/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "n-Butyl glycidyl ether (BGE) | 2426-08-6 | 50 | 270 | - |", "value": "50"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "n-Butyl glycidyl ether (BGE) | 2426-08-6 | 50 | 270 | - |", "value": "270"}], "cas_number": "2426-08-6", "disagreements": [], "id": "n-butyl-glycidyl-ether", "rel_mgm3": "30", "rel_ppm": "C 5.6", "source": "https://www.cdc.gov/niosh/npg/npgd0081.html", "source_quote": "NIOSH REL C 5.6 ppm (30 mg/m3) [15-minute]", "substance": "n-Butyl glycidyl ether", "url": "https://referencesource.org/workplace-exposure-limits/n-butyl-glycidyl-ether/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0082.html", "source_quote": "NIOSH REL TWA 5 ppm (25 mg/m3)", "value": "TWA 5"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0082.html", "source_quote": "NIOSH REL TWA 5 ppm (25 mg/m3)", "value": "25"}], "cas_number": "138227", "disagreements": [], "id": "n-butyl-lactate", "pel_mgm3": "25", "pel_ppm": "5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "138227 | | n-Butyl lactate | 5 | 25", "substance": "n-Butyl lactate", "url": "https://referencesource.org/workplace-exposure-limits/n-butyl-lactate/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "109-74-0", "id": "n-butyronitrile", "rel_mgm3": "22", "rel_ppm": "TWA 8", "source": "https://www.cdc.gov/niosh/npg/npgd0086.html", "source_quote": "NIOSH REL TWA 8 ppm (22 mg/m3)", "substance": "n-Butyronitrile", "url": "https://referencesource.org/workplace-exposure-limits/n-butyronitrile/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0281.html", "source_quote": "NIOSH REL TWA 5 ppm (23 mg/m3) [skin]", "value": "TWA 5"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0281.html", "source_quote": "NIOSH REL TWA 5 ppm (23 mg/m3) [skin]", "value": "23"}], "cas_number": "100-74-3", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "N-Ethylmorpholine | 100-74-3 | 20 | 94 | X |", "value": "20"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "100743 | S | N-Ethylmorpholine; 4-ethyl-1, 4-tetrahydrooxazine | 5 | 23", "value": "5"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "N-Ethylmorpholine | 100-74-3 | 20 | 94 | X |", "value": "94"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "100743 | S | N-Ethylmorpholine; 4-ethyl-1, 4-tetrahydrooxazine | 5 | 23", "value": "23"}]}], "id": "n-ethylmorpholine", "pel_mgm3": "94", "pel_ppm": "20", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "N-Ethylmorpholine | 100-74-3 | 20 | 94 | X |", "substance": "N-Ethylmorpholine", "url": "https://referencesource.org/workplace-exposure-limits/n-ethylmorpholine/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0322.html", "source_quote": "NIOSH REL TWA 50 ppm (180 mg/m3)", "value": "TWA 50"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0322.html", "source_quote": "NIOSH REL TWA 50 ppm (180 mg/m3)", "value": "180"}], "cas_number": "110-54-3", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "n-Hexane | 110-54-3 | 500 | 1800 | - |", "value": "500"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "110543 | S | n-Hexane | 50 | 180", "value": "50"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "n-Hexane | 110-54-3 | 500 | 1800 | - |", "value": "1800"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "110543 | S | n-Hexane | 50 | 180", "value": "180"}]}], "id": "n-hexane", "pel_mgm3": "1800", "pel_ppm": "500", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "n-Hexane | 110-54-3 | 500 | 1800 | - |", "substance": "n-Hexane", "url": "https://referencesource.org/workplace-exposure-limits/n-hexane/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "111-31-9", "id": "n-hexanethiol", "rel_mgm3": "2.7", "rel_ppm": "C 0.5", "source": "https://www.cdc.gov/niosh/npg/npgd0324.html", "source_quote": "NIOSH REL C 0.5 ppm (2.7 mg/m3) [15-minute]", "substance": "n-Hexanethiol", "url": "https://referencesource.org/workplace-exposure-limits/n-hexanethiol/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0361.html", "source_quote": "NIOSH REL TWA 2 ppm (10 mg/m3) [skin]", "value": "TWA 2"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0361.html", "source_quote": "NIOSH REL TWA 2 ppm (10 mg/m3) [skin]", "value": "10"}], "cas_number": "768525", "disagreements": [], "id": "n-isopropylaniline", "pel_mgm3": "10", "pel_ppm": "2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "768525 | S | N-isopropylaniline | 2 | 10", "substance": "N-isopropylaniline", "url": "https://referencesource.org/workplace-exposure-limits/n-isopropylaniline/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "872504", "id": "n-methylpyrrolidone-nmp", "pel_mgm3": "4", "pel_ppm": "1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "872504 | S | N-Methylpyrrolidone (NMP) | 1 | 4", "substance": "N-Methylpyrrolidone (NMP)", "url": "https://referencesource.org/workplace-exposure-limits/n-methylpyrrolidone-nmp/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "62-75-9", "disagreements": [], "id": "n-nitrosodimethylamine", "rel_statement": "Ca See Appendix A", "source": "https://www.cdc.gov/niosh/npg/npgd0461.html", "source_quote": "NIOSH REL Ca See Appendix A", "substance": "N-Nitrosodimethylamine", "url": "https://referencesource.org/workplace-exposure-limits/n-nitrosodimethylamine/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Pentane | 109-66-0 | 1000 | 2950 | - |", "value": "1000"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Pentane | 109-66-0 | 1000 | 2950 | - |", "value": "2950"}], "cas_number": "109-66-0", "disagreements": [], "id": "n-pentane", "rel_mgm3": "350", "rel_ppm": "TWA 120", "source": "https://www.cdc.gov/niosh/npg/npgd0486.html", "source_quote": "NIOSH REL TWA 120 ppm (350 mg/m3) C 610 ppm (1800 mg/m3) [15-minute]", "substance": "n-Pentane", "url": "https://referencesource.org/workplace-exposure-limits/n-pentane/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"cas_number": "135-88-6", "id": "n-phenyl-naphthylamine", "rel_statement": "Ca* See Appendix A", "source": "https://www.cdc.gov/niosh/npg/npgd0500.html", "source_quote": "NIOSH REL Ca* See Appendix A", "substance": "N-Phenyl-β-naphthylamine", "url": "https://referencesource.org/workplace-exposure-limits/n-phenyl-naphthylamine/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "109604 | | n-Propyl acetate | 200 | 840 | | 250 | 1050", "value": "250"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "109604 | | n-Propyl acetate | 200 | 840 | | 250 | 1050", "value": "1050"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0532.html", "source_quote": "NIOSH REL TWA 200 ppm (840 mg/m3) ST 250 ppm (1050 mg/m3)", "value": "TWA 200"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0532.html", "source_quote": "NIOSH REL TWA 200 ppm (840 mg/m3) ST 250 ppm (1050 mg/m3)", "value": "840"}], "cas_number": "109-60-4", "disagreements": [], "id": "n-propyl-acetate", "pel_mgm3": "840", "pel_ppm": "200", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "n-Propyl acetate | 109-60-4 | 200 | 840 | - |", "substance": "n-Propyl acetate", "url": "https://referencesource.org/workplace-exposure-limits/n-propyl-acetate/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "71238 | S | n-Propyl alcohol | 200 | 500 | | 250 | 625", "value": "250"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "71238 | S | n-Propyl alcohol | 200 | 500 | | 250 | 625", "value": "625"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0533.html", "source_quote": "NIOSH REL TWA 200 ppm (500 mg/m3) ST 250 ppm (625 mg/m3) [skin]", "value": "TWA 200"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0533.html", "source_quote": "NIOSH REL TWA 200 ppm (500 mg/m3) ST 250 ppm (625 mg/m3) [skin]", "value": "500"}], "cas_number": "71-23-8", "disagreements": [], "id": "n-propyl-alcohol", "pel_mgm3": "500", "pel_ppm": "200", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "n-Propyl alcohol | 71-23-8 | 200 | 500 | - |", "substance": "n-Propyl alcohol", "url": "https://referencesource.org/workplace-exposure-limits/n-propyl-alcohol/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "627134 | | n-Propyl nitrate | 25 | 107 | | 40 | 170", "value": "40"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "627134 | | n-Propyl nitrate | 25 | 107 | | 40 | 170", "value": "170"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0539.html", "source_quote": "NIOSH REL TWA 25 ppm (105 mg/m3) ST 40 ppm (170 mg/m3)", "value": "TWA 25"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0539.html", "source_quote": "NIOSH REL TWA 25 ppm (105 mg/m3) ST 40 ppm (170 mg/m3)", "value": "105"}], "cas_number": "627-13-4", "disagreements": [{"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "n-Propyl nitrate | 627-13-4 | 25 | 110 | - |", "value": "110"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "627134 | | n-Propyl nitrate | 25 | 107 | | 40 | 170", "value": "107"}]}], "id": "n-propyl-nitrate", "pel_mgm3": "110", "pel_ppm": "25", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "n-Propyl nitrate | 627-13-4 | 25 | 110 | - |", "substance": "n-Propyl nitrate", "url": "https://referencesource.org/workplace-exposure-limits/n-propyl-nitrate/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "110623 | | Valeraldehyde | 50 | 175", "value": "50"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "110623 | | Valeraldehyde | 50 | 175", "value": "175"}], "cas_number": "110-62-3", "disagreements": [], "id": "n-valeraldehyde", "rel_mgm3": "175", "rel_ppm": "TWA 50", "source": "https://www.cdc.gov/niosh/npg/npgd0652.html", "source_quote": "NIOSH REL TWA 50 ppm (175 mg/m3)", "substance": "n-Valeraldehyde", "url": "https://referencesource.org/workplace-exposure-limits/n-valeraldehyde/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0438.html", "source_quote": "NIOSH REL TWA 100 ppm (400 mg/m3)", "value": "TWA 100"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0438.html", "source_quote": "NIOSH REL TWA 100 ppm (400 mg/m3)", "value": "400"}, {"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "8030306 | | VM & P (Varnish Makers and Painters) Naphtha | 300 | 1,350 | | 400 | 1800", "value": "400"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "8030306 | | VM & P (Varnish Makers and Painters) Naphtha | 300 | 1,350 | | 400 | 1800", "value": "1800"}], "cas_number": "8030-30-6", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Naphtha (Coal tar) | 8030-30-6 | 100 | 400 | - |", "value": "100"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "8030306 | | VM & P (Varnish Makers and Painters) Naphtha | 300 | 1,350 | | 400 | 1800", "value": "300"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Naphtha (Coal tar) | 8030-30-6 | 100 | 400 | - |", "value": "400"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "8030306 | | VM & P (Varnish Makers and Painters) Naphtha | 300 | 1,350 | | 400 | 1800", "value": "1,350"}]}], "id": "naphtha-coal-tar", "pel_mgm3": "400", "pel_ppm": "100", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Naphtha (Coal tar) | 8030-30-6 | 100 | 400 | - |", "substance": "Naphtha (Coal tar)", "url": "https://referencesource.org/workplace-exposure-limits/naphtha-coal-tar/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "8030317", "id": "naphtha-coal-tar-2", "pel_mgm3": "400", "pel_ppm": "100", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "8030317 | | Naphtha, coal tar | 100 | 400", "substance": "Naphtha, coal tar", "url": "https://referencesource.org/workplace-exposure-limits/naphtha-coal-tar-2/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0439.html", "source_quote": "NIOSH REL TWA 10 ppm (50 mg/m3) ST 15 ppm (75 mg/m3)", "value": "TWA 10"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0439.html", "source_quote": "NIOSH REL TWA 10 ppm (50 mg/m3) ST 15 ppm (75 mg/m3)", "value": "50"}], "cas_number": "91-20-3", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Naphthalene | 91-20-3 | 10 | 50 | - |", "value": "10"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "91203 | S | Naphthalene | 0.1 | 0.5", "value": "0.1"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Naphthalene | 91-20-3 | 10 | 50 | - |", "value": "50"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "91203 | S | Naphthalene | 0.1 | 0.5", "value": "0.5"}]}], "id": "naphthalene", "pel_mgm3": "50", "pel_ppm": "10", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Naphthalene | 91-20-3 | 10 | 50 | - |", "substance": "Naphthalene", "url": "https://referencesource.org/workplace-exposure-limits/naphthalene/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "3173-72-6", "id": "naphthalene-diisocyanate", "rel_mgm3": "TWA 0.040", "rel_ppm": "0.005", "source": "https://www.cdc.gov/niosh/npg/npgd0440.html", "source_quote": "NIOSH REL TWA 0.040 mg/m3 (0.005 ppm) C 0.170 mg/m3 (0.020 ppm) [10-minute]", "substance": "Naphthalene diisocyanate", "url": "https://referencesource.org/workplace-exposure-limits/naphthalene-diisocyanate/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"cas_number": "25551284", "ceiling_notation": "the values given in the PEL columns are ceiling values", "id": "naphthalene-diisocyanate-ndi", "pel_mgm3": "0.085", "pel_ppm": "0.01", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "25551284 | | Naphthalene diisocyanate; NDI | 0.01 | 0.085 | C", "substance": "Naphthalene diisocyanate; NDI", "url": "https://referencesource.org/workplace-exposure-limits/naphthalene-diisocyanate-ndi/", "verified_fields": ["cas_number", "ceiling_notation", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "7440019", "id": "neon", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7440019 | | Neon | (h)", "substance": "Neon", "url": "https://referencesource.org/workplace-exposure-limits/neon/", "verified_fields": ["cas_number", "substance"]}
{"cas_number": "62765-93-9", "id": "niax-catalyst-esn", "rel_statement": "See Appendix C", "source": "https://www.cdc.gov/niosh/npg/npgd0443.html", "source_quote": "NIOSH REL See Appendix C", "substance": "Niax® Catalyst ESN", "url": "https://referencesource.org/workplace-exposure-limits/niax-catalyst-esn/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Nickel carbonyl (as Ni) | 13463-39-3 | 0.001 | 0.007 | - |", "value": "0.001"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Nickel carbonyl (as Ni) | 13463-39-3 | 0.001 | 0.007 | - |", "value": "0.007"}], "cas_number": "13463-39-3", "disagreements": [], "id": "nickel-carbonyl", "rel_mgm3": "0.007", "rel_ppm": "TWA 0.001", "source": "https://www.cdc.gov/niosh/npg/npgd0444.html", "source_quote": "NIOSH REL Ca TWA 0.001 ppm (0.007 mg/m3)", "substance": "Nickel carbonyl", "url": "https://referencesource.org/workplace-exposure-limits/nickel-carbonyl/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"id": "nickel-insoluble-compounds-as-ni", "pel_mgm3": "0.1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Nickel, insoluble compounds, as Ni | -- | 0.1", "substance": "Nickel, insoluble compounds, as Ni", "url": "https://referencesource.org/workplace-exposure-limits/nickel-insoluble-compounds-as-ni/", "verified_fields": ["pel_mgm3", "substance"]}
{"cas_number": "7440-02-0", "id": "nickel-metal-and-insoluble-compounds-as-ni", "pel_mgm3": "1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Nickel, metal and insoluble compounds (as Ni) | 7440-02-0 | - | 1 | - |", "substance": "Nickel, metal and insoluble compounds (as Ni)", "url": "https://referencesource.org/workplace-exposure-limits/nickel-metal-and-insoluble-compounds-as-ni/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"cas_number": "7440-02-0 (Metal)", "id": "nickel-metal-and-other-compounds-as-ni", "rel_mgm3": "TWA 0.015", "source": "https://www.cdc.gov/niosh/npg/npgd0445.html", "source_quote": "NIOSH REL Ca TWA 0.015 mg/m3", "substance": "Nickel metal and other compounds (as Ni)", "url": "https://referencesource.org/workplace-exposure-limits/nickel-metal-and-other-compounds-as-ni/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"cas_number": "7440020", "id": "nickel-metal-as-ni", "pel_mgm3": "0.5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7440020 | | Nickel metal, as Ni | -- | 0.5", "substance": "Nickel metal, as Ni", "url": "https://referencesource.org/workplace-exposure-limits/nickel-metal-as-ni/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"cas_number": "7440-02-0", "disagreements": [{"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Nickel, soluble compounds (as Ni) | 7440-02-0 | - | 1 | - |", "value": "1"}, {"as_of": "2026-09-25", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Nickel, soluble compounds, as Ni | -- | 0.05", "value": "0.05"}]}], "id": "nickel-soluble-compounds-as-ni", "pel_mgm3": "1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Nickel, soluble compounds (as Ni) | 7440-02-0 | - | 1 | - |", "substance": "Nickel, soluble compounds (as Ni)", "url": "https://referencesource.org/workplace-exposure-limits/nickel-soluble-compounds-as-ni/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"cas_number": "12035722", "id": "nickel-subsulfide", "pel_mgm3": ".05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "12035722 | | Nickel subsulfide | -- | .05", "substance": "Nickel subsulfide", "url": "https://referencesource.org/workplace-exposure-limits/nickel-subsulfide/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "54115 | S | Nicotine; 1-methyl-2-(3-pyridyl)-pyrrolidine | 0.075 | 0.5", "value": "0.075"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0446.html", "source_quote": "NIOSH REL TWA 0.5 mg/m3 [skin]", "value": "TWA 0.5"}], "cas_number": "54-11-5", "disagreements": [], "id": "nicotine", "pel_mgm3": "0.5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Nicotine | 54-11-5 | - | 0.5 | X |", "substance": "Nicotine", "url": "https://referencesource.org/workplace-exposure-limits/nicotine/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7697372 | | Nitric acid | 2 | 5 | | 4 | 10", "value": "4"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7697372 | | Nitric acid | 2 | 5 | | 4 | 10", "value": "10"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0447.html", "source_quote": "NIOSH REL TWA 2 ppm (5 mg/m3) ST 4 ppm (10 mg/m3)", "value": "TWA 2"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0447.html", "source_quote": "NIOSH REL TWA 2 ppm (5 mg/m3) ST 4 ppm (10 mg/m3)", "value": "5"}], "cas_number": "7697-37-2", "disagreements": [], "id": "nitric-acid", "pel_mgm3": "5", "pel_ppm": "2", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Nitric acid | 7697-37-2 | 2 | 5 | - |", "substance": "Nitric acid", "url": "https://referencesource.org/workplace-exposure-limits/nitric-acid/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0448.html", "source_quote": "NIOSH REL TWA 25 ppm (30 mg/m3)", "value": "TWA 25"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0448.html", "source_quote": "NIOSH REL TWA 25 ppm (30 mg/m3)", "value": "30"}], "cas_number": "10102-43-9", "disagreements": [], "id": "nitric-oxide", "pel_mgm3": "30", "pel_ppm": "25", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Nitric oxide | 10102-43-9 | 25 | 30 | - |", "substance": "Nitric oxide", "url": "https://referencesource.org/workplace-exposure-limits/nitric-oxide/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0450.html", "source_quote": "NIOSH REL TWA 1 ppm (5 mg/m3) [skin]", "value": "TWA 1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0450.html", "source_quote": "NIOSH REL TWA 1 ppm (5 mg/m3) [skin]", "value": "5"}], "cas_number": "98-95-3", "disagreements": [], "id": "nitrobenzene", "pel_mgm3": "5", "pel_ppm": "1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Nitrobenzene | 98-95-3 | 1 | 5 | X |", "substance": "Nitrobenzene", "url": "https://referencesource.org/workplace-exposure-limits/nitrobenzene/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0453.html", "source_quote": "NIOSH REL TWA 100 ppm (310 mg/m3)", "value": "TWA 100"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0453.html", "source_quote": "NIOSH REL TWA 100 ppm (310 mg/m3)", "value": "310"}], "cas_number": "79-24-3", "disagreements": [], "id": "nitroethane", "pel_mgm3": "310", "pel_ppm": "100", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Nitroethane | 79-24-3 | 100 | 310 | - |", "substance": "Nitroethane", "url": "https://referencesource.org/workplace-exposure-limits/nitroethane/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "7727379", "id": "nitrogen", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7727379 | | Nitrogen | (h) | --", "substance": "Nitrogen", "url": "https://referencesource.org/workplace-exposure-limits/nitrogen/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "10102440 | | Nitrogen dioxide | | | | 1 | 1.8", "value": "1"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "10102440 | | Nitrogen dioxide | | | | 1 | 1.8", "value": "1.8"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0454.html", "source_quote": "NIOSH REL ST 1 ppm (1.8 mg/m³)", "value": "ST 1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0454.html", "source_quote": "NIOSH REL ST 1 ppm (1.8 mg/m³)", "value": "1.8"}], "cas_number": "10102-44-0", "disagreements": [], "id": "nitrogen-dioxide", "pel_mgm3": "(C)9", "pel_ppm": "(C)5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Nitrogen dioxide | 10102-44-0 | (C)5 | (C)9 | - |", "substance": "Nitrogen dioxide", "url": "https://referencesource.org/workplace-exposure-limits/nitrogen-dioxide/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0455.html", "source_quote": "NIOSH REL TWA 10 ppm (29 mg/m3)", "value": "TWA 10"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0455.html", "source_quote": "NIOSH REL TWA 10 ppm (29 mg/m3)", "value": "29"}], "cas_number": "7783-54-2", "disagreements": [], "id": "nitrogen-trifluoride", "pel_mgm3": "29", "pel_ppm": "10", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Nitrogen trifluoride | 7783-54-2 | 10 | 29 | - |", "substance": "Nitrogen trifluoride", "url": "https://referencesource.org/workplace-exposure-limits/nitrogen-trifluoride/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "55630 | S | Nitroglycerin | | (k) | | -- | 0.1", "value": "0.1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0456.html", "source_quote": "NIOSH REL ST 0.1 mg/m3 [skin]", "value": "ST 0.1"}], "cas_number": "55-63-0", "disagreements": [], "id": "nitroglycerin", "pel_mgm3": "(C)2", "pel_ppm": "(C)0.2", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Nitroglycerin | 55-63-0 | (C)0.2 | (C)2 | X |", "substance": "Nitroglycerin", "url": "https://referencesource.org/workplace-exposure-limits/nitroglycerin/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0457.html", "source_quote": "NIOSH REL See Appendix D", "value": "See Appendix D"}], "cas_number": "75-52-5", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Nitromethane | 75-52-5 | 100 | 250 | - |", "value": "100"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75525 | | Nitromethane | 2 | 5", "value": "2"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Nitromethane | 75-52-5 | 100 | 250 | - |", "value": "250"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75525 | | Nitromethane | 2 | 5", "value": "5"}]}], "id": "nitromethane", "pel_mgm3": "250", "pel_ppm": "100", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Nitromethane | 75-52-5 | 100 | 250 | - |", "substance": "Nitromethane", "url": "https://referencesource.org/workplace-exposure-limits/nitromethane/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "1321126, 99081, 88722, 99990", "id": "nitrotoluene", "pel_mgm3": "11", "pel_ppm": "2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "1321126, 99081, 88722, 99990 | S | Nitrotoluene | 2 | 11", "substance": "Nitrotoluene", "url": "https://referencesource.org/workplace-exposure-limits/nitrotoluene/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "0024972", "id": "nitrous-oxide", "pel_mgm3": "90", "pel_ppm": "50", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "0024972 | | Nitrous oxide | 50 | 90", "substance": "Nitrous oxide", "url": "https://referencesource.org/workplace-exposure-limits/nitrous-oxide/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "10024-97-2", "id": "nitrous-oxide-2", "rel_mgm3": "46", "rel_ppm": "TWA 25", "source": "https://www.cdc.gov/niosh/npg/npgd0465.html", "source_quote": "NIOSH REL TWA 25 ppm (46 mg/m3) (TWA over the time exposed)", "substance": "Nitrous oxide", "url": "https://referencesource.org/workplace-exposure-limits/nitrous-oxide-2/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0466.html", "source_quote": "NIOSH REL TWA 200 ppm (1050 mg/m3)", "value": "TWA 200"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0466.html", "source_quote": "NIOSH REL TWA 200 ppm (1050 mg/m3)", "value": "1050"}], "cas_number": "111842", "disagreements": [], "id": "nonane", "pel_mgm3": "1,050", "pel_ppm": "200", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "111842 | | Nonane | 200 | 1,050", "substance": "Nonane", "url": "https://referencesource.org/workplace-exposure-limits/nonane/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"id": "nuisance-particulates-see-particulates-not-otherwise-regulated-total-dust", "pel_mgm3": "10", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Nuisance particulates, see Particulates not otherwise regulated Total dust | -- | 10", "substance": "Nuisance particulates, see Particulates not otherwise regulated Total dust", "url": "https://referencesource.org/workplace-exposure-limits/nuisance-particulates-see-particulates-not-otherwise-regulated-total-dust/", "verified_fields": ["pel_mgm3", "substance"]}
{"cas_number": "90-04-0", "id": "o-anisidine", "rel_mgm3": "TWA 0.5", "source": "https://www.cdc.gov/niosh/npg/npgd0034.html", "source_quote": "NIOSH REL Ca TWA 0.5 mg/m3 [skin]", "substance": "o-Anisidine", "url": "https://referencesource.org/workplace-exposure-limits/o-anisidine/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0122.html", "source_quote": "NIOSH REL C 0.05 ppm (0.4 mg/m3) [skin]", "value": "C 0.05"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0122.html", "source_quote": "NIOSH REL C 0.05 ppm (0.4 mg/m3) [skin]", "value": "0.4"}, {"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "2698411 | S | o-Chlorobenzylidene malononitrile; OCBM | 0.05 | 0.4 | C", "value": "the values given in the PEL columns are ceiling values"}], "cas_number": "2698-41-1", "disagreements": [], "id": "o-chlorobenzylidene-malononitrile", "pel_mgm3": "0.4", "pel_ppm": "0.05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "o-Chlorobenzylidene malononitrile | 2698-41-1 | 0.05 | 0.4 | - |", "substance": "o-Chlorobenzylidene malononitrile", "url": "https://referencesource.org/workplace-exposure-limits/o-chlorobenzylidene-malononitrile/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0134.html", "source_quote": "NIOSH REL TWA 50 ppm (285 mg/m3) ST 75 ppm (428 mg/m3)", "value": "TWA 50"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0134.html", "source_quote": "NIOSH REL TWA 50 ppm (285 mg/m3) ST 75 ppm (428 mg/m3)", "value": "285"}], "cas_number": "2039874", "disagreements": [], "id": "o-chlorostyrene", "pel_mgm3": "285", "pel_ppm": "50", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "2039874 | | o-Chlorostyrene | 50 | 285 | | 75 | 428", "stel_mgm3": "428", "stel_ppm": "75", "substance": "o-Chlorostyrene", "url": "https://referencesource.org/workplace-exposure-limits/o-chlorostyrene/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "stel_mgm3", "stel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0135.html", "source_quote": "NIOSH REL TWA 50 ppm (250 mg/m3) ST 75 ppm (375 mg/m3)", "value": "TWA 50"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0135.html", "source_quote": "NIOSH REL TWA 50 ppm (250 mg/m3) ST 75 ppm (375 mg/m3)", "value": "250"}], "cas_number": "95498", "disagreements": [], "id": "o-chlorotoluene", "pel_mgm3": "250", "pel_ppm": "50", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "95498 | S | o-Chlorotoluene | 50 | 250", "substance": "o-Chlorotoluene", "url": "https://referencesource.org/workplace-exposure-limits/o-chlorotoluene/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "95-48-7", "id": "o-cresol", "rel_mgm3": "10", "rel_ppm": "TWA 2.3", "source": "https://www.cdc.gov/niosh/npg/npgd0154.html", "source_quote": "NIOSH REL TWA 2.3 ppm (10 mg/m3)", "substance": "o-Cresol", "url": "https://referencesource.org/workplace-exposure-limits/o-cresol/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"cas_number": "119-90-4", "id": "o-dianisidine", "rel_statement": "Ca See Appendix A See Appendix C", "source": "https://www.cdc.gov/niosh/npg/npgd0180.html", "source_quote": "NIOSH REL Ca See Appendix A See Appendix C", "substance": "o-Dianisidine", "url": "https://referencesource.org/workplace-exposure-limits/o-dianisidine/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"also_reported": [{"as_of": "2026-09-28", "field": "ceiling", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "95501 | S | o-Dichlorobenzene | 25 | 150 | 50 ppm", "value": "50 ppm"}, {"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "95501 | S | o-Dichlorobenzene | 25 | 150 | 50 ppm", "value": "a ceiling value in addition to the TWA values"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0189.html", "source_quote": "NIOSH REL C 50 ppm (300 mg/m3)", "value": "C 50"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0189.html", "source_quote": "NIOSH REL C 50 ppm (300 mg/m3)", "value": "300"}], "cas_number": "95-50-1", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "o-Dichlorobenzene | 95-50-1 | (C)50 | (C)300 | - |", "value": "(C)50"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "95501 | S | o-Dichlorobenzene | 25 | 150 | 50 ppm", "value": "25"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "o-Dichlorobenzene | 95-50-1 | (C)50 | (C)300 | - |", "value": "(C)300"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "95501 | S | o-Dichlorobenzene | 25 | 150 | 50 ppm", "value": "150"}]}], "id": "o-dichlorobenzene", "pel_mgm3": "(C)300", "pel_ppm": "(C)50", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "o-Dichlorobenzene | 95-50-1 | (C)50 | (C)300 | - |", "substance": "o-Dichlorobenzene", "url": "https://referencesource.org/workplace-exposure-limits/o-dichlorobenzene/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "528-29-0", "disagreements": [], "id": "o-dinitrobenzene", "rel_mgm3": "TWA 1", "source": "https://www.cdc.gov/niosh/npg/npgd0231.html", "source_quote": "NIOSH REL TWA 1 mg/m3 [skin]", "substance": "o-Dinitrobenzene", "url": "https://referencesource.org/workplace-exposure-limits/o-dinitrobenzene/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0462.html", "source_quote": "NIOSH REL TWA 2 ppm (11 mg/m3) [skin]", "value": "TWA 2"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0462.html", "source_quote": "NIOSH REL TWA 2 ppm (11 mg/m3) [skin]", "value": "11"}], "cas_number": "88-72-2", "disagreements": [], "id": "o-isomer", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "o-isomer | 88-72-2 | - | - | - |", "substance": "o-isomer", "url": "https://referencesource.org/workplace-exposure-limits/o-isomer/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "583608 | S | o-Methylcyclohexanone | 50 | 230 | | 75 | 345", "value": "75"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "583608 | S | o-Methylcyclohexanone | 50 | 230 | | 75 | 345", "value": "345"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0408.html", "source_quote": "NIOSH REL TWA 50 ppm (230 mg/m3) ST 75 ppm (345 mg/m3) [skin]", "value": "TWA 50"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0408.html", "source_quote": "NIOSH REL TWA 50 ppm (230 mg/m3) ST 75 ppm (345 mg/m3) [skin]", "value": "230"}], "cas_number": "583-60-8", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "o-Methylcyclohexanone | 583-60-8 | 100 | 460 | X |", "value": "100"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "583608 | S | o-Methylcyclohexanone | 50 | 230 | | 75 | 345", "value": "50"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "o-Methylcyclohexanone | 583-60-8 | 100 | 460 | X |", "value": "460"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "583608 | S | o-Methylcyclohexanone | 50 | 230 | | 75 | 345", "value": "230"}]}], "id": "o-methylcyclohexanone", "pel_mgm3": "460", "pel_ppm": "100", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "o-Methylcyclohexanone | 583-60-8 | 100 | 460 | X |", "substance": "o-Methylcyclohexanone", "url": "https://referencesource.org/workplace-exposure-limits/o-methylcyclohexanone/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0084.html", "source_quote": "NIOSH REL TWA 5 ppm (30 mg/m3) [skin]", "value": "TWA 5"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0084.html", "source_quote": "NIOSH REL TWA 5 ppm (30 mg/m3) [skin]", "value": "30"}], "cas_number": "89725", "disagreements": [], "id": "o-sec-butylphenol", "pel_mgm3": "30", "pel_ppm": "5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "89725 | S | o-sec-Butylphenol | 5 | 30", "substance": "o-sec-Butylphenol", "url": "https://referencesource.org/workplace-exposure-limits/o-sec-butylphenol/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "84-15-1", "id": "o-terphenyl", "rel_mgm3": "C 5", "rel_ppm": "0.5", "source": "https://www.cdc.gov/niosh/npg/npgd0591.html", "source_quote": "NIOSH REL C 5 mg/m3 (0.5 ppm)", "substance": "o-Terphenyl", "url": "https://referencesource.org/workplace-exposure-limits/o-terphenyl/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"cas_number": "119-93-7", "id": "o-tolidine", "rel_mgm3": "C 0.02", "source": "https://www.cdc.gov/niosh/npg/npgd0618.html", "source_quote": "NIOSH REL Ca C 0.02 mg/m3 [60-minute] [skin]", "substance": "o-Tolidine", "url": "https://referencesource.org/workplace-exposure-limits/o-tolidine/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0622.html", "source_quote": "NIOSH REL Ca [skin] See Appendix A", "value": "Ca [skin] See Appendix A"}], "cas_number": "95-53-4", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "o-Toluidine | 95-53-4 | 5 | 22 | X |", "value": "5"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "95534 | S | o-Toluidine; o-methylaniline | 2 | 9", "value": "2"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "o-Toluidine | 95-53-4 | 5 | 22 | X |", "value": "22"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "95534 | S | o-Toluidine; o-methylaniline | 2 | 9", "value": "9"}]}], "id": "o-toluidine", "pel_mgm3": "22", "pel_ppm": "5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "o-Toluidine | 95-53-4 | 5 | 22 | X |", "substance": "o-Toluidine", "url": "https://referencesource.org/workplace-exposure-limits/o-toluidine/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "95-47-6", "id": "o-xylene", "rel_mgm3": "435", "rel_ppm": "TWA 100", "source": "https://www.cdc.gov/niosh/npg/npgd0668.html", "source_quote": "NIOSH REL TWA 100 ppm (435 mg/m3) ST 150 ppm (655 mg/m3)", "substance": "o-Xylene", "url": "https://referencesource.org/workplace-exposure-limits/o-xylene/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "2234131 | S | Octachloronaphthalene | -- | 0.1 | | -- | 0.3", "value": "0.3"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0468.html", "source_quote": "NIOSH REL TWA 0.1 mg/m3 ST 0.3 mg/m3 [skin]", "value": "TWA 0.1"}], "cas_number": "2234-13-1", "disagreements": [], "id": "octachloronaphthalene", "pel_mgm3": "0.1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Octachloronaphthalene | 2234-13-1 | - | 0.1 | X |", "substance": "Octachloronaphthalene", "url": "https://referencesource.org/workplace-exposure-limits/octachloronaphthalene/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "111659 | | Octane | 300 | 1,450 | | 375 | 1800", "value": "375"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "111659 | | Octane | 300 | 1,450 | | 375 | 1800", "value": "1800"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0470.html", "source_quote": "NIOSH REL TWA 75 ppm (350 mg/m3) C 385 ppm (1800 mg/m3) [15-minute]", "value": "TWA 75"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0470.html", "source_quote": "NIOSH REL TWA 75 ppm (350 mg/m3) C 385 ppm (1800 mg/m3) [15-minute]", "value": "350"}], "cas_number": "111-65-9", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Octane | 111-65-9 | 500 | 2350 | - |", "value": "500"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "111659 | | Octane | 300 | 1,450 | | 375 | 1800", "value": "300"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Octane | 111-65-9 | 500 | 2350 | - |", "value": "2350"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "111659 | | Octane | 300 | 1,450 | | 375 | 1800", "value": "1,450"}]}], "id": "octane", "pel_mgm3": "2350", "pel_ppm": "500", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Octane | 111-65-9 | 500 | 2350 | - |", "substance": "Octane", "url": "https://referencesource.org/workplace-exposure-limits/octane/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0472.html", "source_quote": "NIOSH REL TWA 5 mg/m3 ST 10 mg/m3", "value": "TWA 5"}], "cas_number": "8012951", "disagreements": [{"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "8012951 | | Oil (mineral) mist, particulate | -- | (5)(l)", "value": "(5)(l)"}, {"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Oil mist, mineral | 8012-95-1 | - | 5 | - |", "value": "5"}]}], "id": "oil-mineral-mist-particulate", "pel_mgm3": "(5)(l)", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "8012951 | | Oil (mineral) mist, particulate | -- | (5)(l)", "substance": "Oil (mineral) mist, particulate", "url": "https://referencesource.org/workplace-exposure-limits/oil-mineral-mist-particulate/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Osmium tetroxide (as Os) | 20816-12-0 | - | 0.002 | - |", "value": "0.002"}, {"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "20816120 | | Osmium tetroxide, as Os | 0.0002 | 0.002 | | 0.0006 | 0.006", "value": "0.0002"}, {"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "20816120 | | Osmium tetroxide, as Os | 0.0002 | 0.002 | | 0.0006 | 0.006", "value": "0.0006"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "20816120 | | Osmium tetroxide, as Os | 0.0002 | 0.002 | | 0.0006 | 0.006", "value": "0.006"}], "cas_number": "20816-12-0", "disagreements": [], "id": "osmium-tetroxide", "rel_mgm3": "TWA 0.002", "rel_ppm": "0.0002", "source": "https://www.cdc.gov/niosh/npg/npgd0473.html", "source_quote": "NIOSH REL TWA 0.002 mg/m3 (0.0002 ppm) ST 0.006 mg/m3 (0.0006 ppm)", "substance": "Osmium tetroxide", "url": "https://referencesource.org/workplace-exposure-limits/osmium-tetroxide/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "144627 | | Oxalic acid | -- | 1 | | -- | 2", "value": "2"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0474.html", "source_quote": "NIOSH REL TWA 1 mg/m3 ST 2 mg/m3", "value": "TWA 1"}], "cas_number": "144-62-7", "disagreements": [], "id": "oxalic-acid", "pel_mgm3": "1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Oxalic acid | 144-62-7 | - | 1 | - |", "substance": "Oxalic acid", "url": "https://referencesource.org/workplace-exposure-limits/oxalic-acid/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7783417 | | Oxygen difluoride | 0.05 | 0.1 | C", "value": "the values given in the PEL columns are ceiling values"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0475.html", "source_quote": "NIOSH REL C 0.05 ppm (0.1 mg/m3)", "value": "C 0.05"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0475.html", "source_quote": "NIOSH REL C 0.05 ppm (0.1 mg/m3)", "value": "0.1"}], "cas_number": "7783-41-7", "disagreements": [], "id": "oxygen-difluoride", "pel_mgm3": "0.1", "pel_ppm": "0.05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Oxygen difluoride | 7783-41-7 | 0.05 | 0.1 | - |", "substance": "Oxygen difluoride", "url": "https://referencesource.org/workplace-exposure-limits/oxygen-difluoride/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "10028156 | | Ozone | 0.1 | 0.2 | | 0.3 | 0.6", "value": "0.3"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "10028156 | | Ozone | 0.1 | 0.2 | | 0.3 | 0.6", "value": "0.6"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0476.html", "source_quote": "NIOSH REL C 0.1 ppm (0.2 mg/m3)", "value": "C 0.1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0476.html", "source_quote": "NIOSH REL C 0.1 ppm (0.2 mg/m3)", "value": "0.2"}], "cas_number": "10028-15-6", "disagreements": [], "id": "ozone", "pel_mgm3": "0.2", "pel_ppm": "0.1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ozone | 10028-15-6 | 0.1 | 0.2 | - |", "substance": "Ozone", "url": "https://referencesource.org/workplace-exposure-limits/ozone/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "104-94-9", "id": "p-anisidine", "rel_mgm3": "TWA 0.5", "source": "https://www.cdc.gov/niosh/npg/npgd0035.html", "source_quote": "NIOSH REL TWA 0.5 mg/m3 [skin]", "substance": "p-Anisidine", "url": "https://referencesource.org/workplace-exposure-limits/p-anisidine/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"cas_number": "106-44-5", "id": "p-cresol", "rel_mgm3": "10", "rel_ppm": "TWA 2.3", "source": "https://www.cdc.gov/niosh/npg/npgd0156.html", "source_quote": "NIOSH REL TWA 2.3 ppm (10 mg/m3)", "substance": "p-Cresol", "url": "https://referencesource.org/workplace-exposure-limits/p-cresol/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-28", "field": "ceiling", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "106467 | | p-Dichlorobenzene; 1,4-dichlorobenzene | 10 | 60 | 200 ppm | 110 | 675", "value": "200 ppm"}, {"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "106467 | | p-Dichlorobenzene; 1,4-dichlorobenzene | 10 | 60 | 200 ppm | 110 | 675", "value": "a ceiling value in addition to the TWA values"}, {"as_of": "2026-09-28", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "106467 | | p-Dichlorobenzene; 1,4-dichlorobenzene | 10 | 60 | 200 ppm | 110 | 675", "value": "110"}, {"as_of": "2026-09-28", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "106467 | | p-Dichlorobenzene; 1,4-dichlorobenzene | 10 | 60 | 200 ppm | 110 | 675", "value": "675"}, {"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0190.html", "source_quote": "NIOSH REL Ca See Appendix A", "value": "Ca See Appendix A"}], "cas_number": "106-46-7", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "p-Dichlorobenzene | 106-46-7 | 75 | 450 | - |", "value": "75"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "106467 | | p-Dichlorobenzene; 1,4-dichlorobenzene | 10 | 60 | 200 ppm | 110 | 675", "value": "10"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "p-Dichlorobenzene | 106-46-7 | 75 | 450 | - |", "value": "450"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "106467 | | p-Dichlorobenzene; 1,4-dichlorobenzene | 10 | 60 | 200 ppm | 110 | 675", "value": "60"}]}], "id": "p-dichlorobenzene", "pel_mgm3": "450", "pel_ppm": "75", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "p-Dichlorobenzene | 106-46-7 | 75 | 450 | - |", "substance": "p-Dichlorobenzene", "url": "https://referencesource.org/workplace-exposure-limits/p-dichlorobenzene/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "100-25-4", "disagreements": [], "id": "p-dinitrobenzene", "rel_mgm3": "TWA 1", "source": "https://www.cdc.gov/niosh/npg/npgd0233.html", "source_quote": "NIOSH REL TWA 1 mg/m3 [skin]", "substance": "p-Dinitrobenzene", "url": "https://referencesource.org/workplace-exposure-limits/p-dinitrobenzene/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0464.html", "source_quote": "NIOSH REL TWA 2 ppm (11 mg/m3) [skin]", "value": "TWA 2"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0464.html", "source_quote": "NIOSH REL TWA 2 ppm (11 mg/m3) [skin]", "value": "11"}], "cas_number": "99-99-0", "disagreements": [], "id": "p-isomer", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "p-isomer | 99-99-0 | - | - | - |", "substance": "p-isomer", "url": "https://referencesource.org/workplace-exposure-limits/p-isomer/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0449.html", "source_quote": "NIOSH REL TWA 3 mg/m3 [skin]", "value": "TWA 3"}], "cas_number": "100-01-6", "disagreements": [{"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "p-Nitroaniline | 100-01-6 | 1 | 6 | X |", "value": "6"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "100016 | S | p-Nitroaniline | -- | 3", "value": "3"}]}], "id": "p-nitroaniline", "pel_mgm3": "6", "pel_ppm": "1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "p-Nitroaniline | 100-01-6 | 1 | 6 | X |", "substance": "p-Nitroaniline", "url": "https://referencesource.org/workplace-exposure-limits/p-nitroaniline/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "100005 | S | p-Nitrochlorobenzene; 1-chloro-4-nitrobenzene | 0.1 | 0.64", "value": "0.1"}, {"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0452.html", "source_quote": "NIOSH REL Ca See Appendix A [skin]", "value": "Ca See Appendix A [skin]"}], "cas_number": "100-00-5", "disagreements": [{"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "p-Nitrochlorobenzene | 100-00-5 | - | 1 | X |", "value": "1"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "100005 | S | p-Nitrochlorobenzene; 1-chloro-4-nitrobenzene | 0.1 | 0.64", "value": "0.64"}]}], "id": "p-nitrochlorobenzene", "pel_mgm3": "1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "p-Nitrochlorobenzene | 100-00-5 | - | 1 | X |", "substance": "p-Nitrochlorobenzene", "url": "https://referencesource.org/workplace-exposure-limits/p-nitrochlorobenzene/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0495.html", "source_quote": "NIOSH REL TWA 0.1 mg/m3 [skin]", "value": "TWA 0.1"}], "cas_number": "106-50-3", "disagreements": [], "id": "p-phenylene-diamine", "pel_mgm3": "0.1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "p-Phenylene diamine | 106-50-3 | - | 0.1 | X |", "substance": "p-Phenylene diamine", "url": "https://referencesource.org/workplace-exposure-limits/p-phenylene-diamine/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"cas_number": "92-94-4", "id": "p-terphenyl", "rel_mgm3": "C 5", "rel_ppm": "0.5", "source": "https://www.cdc.gov/niosh/npg/npgd0593.html", "source_quote": "NIOSH REL C 5 mg/m3 (0.5 ppm)", "substance": "p-Terphenyl", "url": "https://referencesource.org/workplace-exposure-limits/p-terphenyl/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "98511 | | p-tert-Butyltoluene | 1 | 6.1 | | 20 | 120", "value": "20"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "98511 | | p-tert-Butyltoluene | 1 | 6.1 | | 20 | 120", "value": "120"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0085.html", "source_quote": "NIOSH REL TWA 10 ppm (60 mg/m3) ST 20 ppm (120 mg/m3)", "value": "TWA 10"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0085.html", "source_quote": "NIOSH REL TWA 10 ppm (60 mg/m3) ST 20 ppm (120 mg/m3)", "value": "60"}], "cas_number": "98-51-1", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "p-tert-Butyltoluene | 98-51-1 | 10 | 60 | - |", "value": "10"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "98511 | | p-tert-Butyltoluene | 1 | 6.1 | | 20 | 120", "value": "1"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "p-tert-Butyltoluene | 98-51-1 | 10 | 60 | - |", "value": "60"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "98511 | | p-tert-Butyltoluene | 1 | 6.1 | | 20 | 120", "value": "6.1"}]}], "id": "p-tert-butyltoluene", "pel_mgm3": "60", "pel_ppm": "10", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "p-tert-Butyltoluene | 98-51-1 | 10 | 60 | - |", "substance": "p-tert-Butyltoluene", "url": "https://referencesource.org/workplace-exposure-limits/p-tert-butyltoluene/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0624.html", "source_quote": "NIOSH REL Ca See Appendix A", "value": "Ca See Appendix A"}], "cas_number": "106490", "disagreements": [], "id": "p-toluidine", "pel_mgm3": "9", "pel_ppm": "2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "106490 | S | p-Toluidine | 2 | 9", "substance": "p-Toluidine", "url": "https://referencesource.org/workplace-exposure-limits/p-toluidine/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "106-42-3", "id": "p-xylene", "rel_mgm3": "435", "rel_ppm": "TWA 100", "source": "https://www.cdc.gov/niosh/npg/npgd0670.html", "source_quote": "NIOSH REL TWA 100 ppm (435 mg/m3) ST 150 ppm (655 mg/m3)", "substance": "p-Xylene", "url": "https://referencesource.org/workplace-exposure-limits/p-xylene/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0477.html", "source_quote": "NIOSH REL TWA 2 mg/m3", "value": "TWA 2"}], "cas_number": "8002742", "disagreements": [], "id": "paraffin-wax-fume", "pel_mgm3": "2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "8002742 | | Paraffin wax fume | -- | 2", "substance": "Paraffin wax fume", "url": "https://referencesource.org/workplace-exposure-limits/paraffin-wax-fume/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"cas_number": "1910-42-5", "id": "paraquat-paraquat-dichloride", "rel_statement": "TWA 0.1 mg/m3 (resp) [skin]", "source": "https://www.cdc.gov/niosh/npg/npgd0478.html", "source_quote": "NIOSH REL TWA 0.1 mg/m3 (resp) [skin]", "substance": "Paraquat (Paraquat dichloride)", "url": "https://referencesource.org/workplace-exposure-limits/paraquat-paraquat-dichloride/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"cas_number": "1910425", "id": "paraquat-respirable-sizes", "pel_mgm3": "0.1(n)", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "1910425, | S | Paraquat, respirable sizes | -- | 0.1(n)", "substance": "Paraquat, respirable sizes", "url": "https://referencesource.org/workplace-exposure-limits/paraquat-respirable-sizes/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"cas_number": "1910425", "id": "paraquat-total-particulates", "pel_mgm3": "0.5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "1910425, | S | Paraquat, total particulates | -- | 0.5", "substance": "Paraquat, total particulates", "url": "https://referencesource.org/workplace-exposure-limits/paraquat-total-particulates/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0479.html", "source_quote": "NIOSH REL TWA 0.05 mg/m3 [skin]", "value": "TWA 0.05"}], "cas_number": "56-38-2", "disagreements": [], "id": "parathion", "pel_mgm3": "0.1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Parathion | 56-38-2 | - | 0.1 | X |", "substance": "Parathion", "url": "https://referencesource.org/workplace-exposure-limits/parathion/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"id": "particulates-not-otherwise-regulated-total-dust", "pel_mgm3": "10", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Particulates not otherwise regulated Total dust | -- | 10", "substance": "Particulates not otherwise regulated Total dust", "url": "https://referencesource.org/workplace-exposure-limits/particulates-not-otherwise-regulated-total-dust/", "verified_fields": ["pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "19624227 | | Pentaborane | 0.005 | 0.01 | | 0.015 | 0.03", "value": "0.015"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "19624227 | | Pentaborane | 0.005 | 0.01 | | 0.015 | 0.03", "value": "0.03"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0481.html", "source_quote": "NIOSH REL TWA 0.005 ppm (0.01 mg/m3) ST 0.015 ppm (0.03 mg/m3)", "value": "TWA 0.005"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0481.html", "source_quote": "NIOSH REL TWA 0.005 ppm (0.01 mg/m3) ST 0.015 ppm (0.03 mg/m3)", "value": "0.01"}], "cas_number": "19624-22-7", "disagreements": [], "id": "pentaborane", "pel_mgm3": "0.01", "pel_ppm": "0.005", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Pentaborane | 19624-22-7 | 0.005 | 0.01 | - |", "substance": "Pentaborane", "url": "https://referencesource.org/workplace-exposure-limits/pentaborane/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "76-01-7", "id": "pentachloroethane", "rel_statement": "Handle with care in the workplace. See Appendix C (Chloroethanes)", "source": "https://www.cdc.gov/niosh/npg/npgd0482.html", "source_quote": "NIOSH REL Handle with care in the workplace. See Appendix C (Chloroethanes)", "substance": "Pentachloroethane", "url": "https://referencesource.org/workplace-exposure-limits/pentachloroethane/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0483.html", "source_quote": "NIOSH REL TWA 0.5 mg/m3 [skin]", "value": "TWA 0.5"}], "cas_number": "1321-64-8", "disagreements": [], "id": "pentachloronaphthalene", "pel_mgm3": "0.5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Pentachloronaphthalene | 1321-64-8 | - | 0.5 | X |", "substance": "Pentachloronaphthalene", "url": "https://referencesource.org/workplace-exposure-limits/pentachloronaphthalene/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0484.html", "source_quote": "NIOSH REL TWA 0.5 mg/m3 [skin]", "value": "TWA 0.5"}], "cas_number": "87-86-5", "disagreements": [], "id": "pentachlorophenol", "pel_mgm3": "0.5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Pentachlorophenol | 87-86-5 | - | 0.5 | X |", "substance": "Pentachlorophenol", "url": "https://referencesource.org/workplace-exposure-limits/pentachlorophenol/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0485.html", "source_quote": "NIOSH REL TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)", "value": "TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)"}], "cas_number": "115-77-5", "disagreements": [], "id": "pentaerythritol", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Pentaerythritol | 115-77-5 | - | - | - |", "substance": "Pentaerythritol", "url": "https://referencesource.org/workplace-exposure-limits/pentaerythritol/", "verified_fields": ["cas_number", "substance"]}
{"cas_number": "628637; 626380; 123922; 625161; 620111; 624419", "id": "pentyl-acetate", "pel_mgm3": "266", "pel_ppm": "50", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "628637; 626380; 123922; 625161; 620111; 624419 | | Pentyl acetate | 50 | 266 | | 100 | 532", "stel_mgm3": "532", "stel_ppm": "100", "substance": "Pentyl acetate", "url": "https://referencesource.org/workplace-exposure-limits/pentyl-acetate/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "stel_mgm3", "stel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0599.html", "source_quote": "NIOSH REL Ca Minimize workplace exposure concentrations. See Appendix A", "value": "Ca Minimize workplace exposure concentrations. See Appendix A"}], "cas_number": "127184", "ceiling": "300 ppm", "ceiling_notation": "a ceiling value in addition to the TWA values", "disagreements": [], "id": "perchloroethylene", "pel_mgm3": "170", "pel_ppm": "25", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "127184 | | Perchloroethylene | 25 | 170 | 300 ppm | 100 | 685", "stel_mgm3": "685", "stel_ppm": "100", "substance": "Perchloroethylene", "url": "https://referencesource.org/workplace-exposure-limits/perchloroethylene/", "verified_fields": ["cas_number", "ceiling", "ceiling_notation", "pel_mgm3", "pel_ppm", "stel_mgm3", "stel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0489.html", "source_quote": "NIOSH REL TWA 0.1 ppm (0.8 mg/m3)", "value": "TWA 0.1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0489.html", "source_quote": "NIOSH REL TWA 0.1 ppm (0.8 mg/m3)", "value": "0.8"}], "cas_number": "594-42-3", "disagreements": [], "id": "perchloromethyl-mercaptan", "pel_mgm3": "0.8", "pel_ppm": "0.1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Perchloromethyl mercaptan | 594-42-3 | 0.1 | 0.8 | - |", "substance": "Perchloromethyl mercaptan", "url": "https://referencesource.org/workplace-exposure-limits/perchloromethyl-mercaptan/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0490.html", "source_quote": "NIOSH REL TWA 3 ppm (14 mg/m3) ST 6 ppm (28 mg/m3)", "value": "TWA 3"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0490.html", "source_quote": "NIOSH REL TWA 3 ppm (14 mg/m3) ST 6 ppm (28 mg/m3)", "value": "14"}, {"as_of": "2026-09-25", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7616946 | | Perchloryl fluoride; C10$3F | 3 | 14 | | 6 | 28", "value": "6"}, {"as_of": "2026-09-25", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7616946 | | Perchloryl fluoride; C10$3F | 3 | 14 | | 6 | 28", "value": "28"}], "cas_number": "7616-94-6", "disagreements": [{"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Perchloryl fluoride | 7616-94-6 | 3 | 13.5 | - |", "value": "13.5"}, {"as_of": "2026-09-25", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7616946 | | Perchloryl fluoride; C10$3F | 3 | 14 | | 6 | 28", "value": "14"}]}], "id": "perchloryl-fluoride", "pel_mgm3": "13.5", "pel_ppm": "3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Perchloryl fluoride | 7616-94-6 | 3 | 13.5 | - |", "substance": "Perchloryl fluoride", "url": "https://referencesource.org/workplace-exposure-limits/perchloryl-fluoride/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "382218", "ceiling_notation": "the values given in the PEL columns are ceiling values", "id": "perfluoroisobutylene", "pel_mgm3": "0.082", "pel_ppm": "0.01", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "382218 | | Perfluoroisobutylene | 0.01 | 0.082 | C", "substance": "Perfluoroisobutylene", "url": "https://referencesource.org/workplace-exposure-limits/perfluoroisobutylene/", "verified_fields": ["cas_number", "ceiling_notation", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "93763-70-3", "id": "perlite", "rel_statement": "TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)", "source": "https://www.cdc.gov/niosh/npg/npgd0491.html", "source_quote": "NIOSH REL TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)", "substance": "Perlite", "url": "https://referencesource.org/workplace-exposure-limits/perlite/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"cas_number": "8002-05-9", "id": "petroleum-distillates-naphtha", "rel_mgm3": "TWA 350", "source": "https://www.cdc.gov/niosh/npg/npgd0492.html", "source_quote": "NIOSH REL TWA 350 mg/m3 C 1800 mg/m3 [15-minute]", "substance": "Petroleum distillates (naphtha)", "url": "https://referencesource.org/workplace-exposure-limits/petroleum-distillates-naphtha/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0493.html", "source_quote": "NIOSH REL TWA 5 ppm (19 mg/m3) C 15.6 ppm (60 mg/m3) [15-minute] [skin]", "value": "TWA 5"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0493.html", "source_quote": "NIOSH REL TWA 5 ppm (19 mg/m3) C 15.6 ppm (60 mg/m3) [15-minute] [skin]", "value": "19"}], "cas_number": "108-95-2", "disagreements": [], "id": "phenol", "pel_mgm3": "19", "pel_ppm": "5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Phenol | 108-95-2 | 5 | 19 | X |", "substance": "Phenol", "url": "https://referencesource.org/workplace-exposure-limits/phenol/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "92842 | S | Phenothiazine; dibenzothiazine | -- | 5", "value": "5"}], "cas_number": "92-84-2", "disagreements": [], "id": "phenothiazine", "rel_mgm3": "TWA 5", "source": "https://www.cdc.gov/niosh/npg/npgd0494.html", "source_quote": "NIOSH REL TWA 5 mg/m3 [skin]", "substance": "Phenothiazine", "url": "https://referencesource.org/workplace-exposure-limits/phenothiazine/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"cas_number": "8004-13-5", "id": "phenyl-ether-biphenyl-mixture-vapor", "rel_mgm3": "7", "rel_ppm": "TWA 1", "source": "https://www.cdc.gov/niosh/npg/npgd0683.html", "source_quote": "NIOSH REL TWA 1 ppm (7 mg/m3)", "substance": "Phenyl ether-biphenyl mixture (vapor)", "url": "https://referencesource.org/workplace-exposure-limits/phenyl-ether-biphenyl-mixture-vapor/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0496.html", "source_quote": "NIOSH REL TWA 1 ppm (7 mg/m3)", "value": "TWA 1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0496.html", "source_quote": "NIOSH REL TWA 1 ppm (7 mg/m3)", "value": "7"}], "cas_number": "101-84-8", "disagreements": [], "id": "phenyl-ether-vapor", "pel_mgm3": "7", "pel_ppm": "1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Phenyl ether, vapor | 101-84-8 | 1 | 7 | - |", "substance": "Phenyl ether, vapor", "url": "https://referencesource.org/workplace-exposure-limits/phenyl-ether-vapor/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Phenyl glycidyl ether (PGE) | 122-60-1 | 10 | 60 | - |", "value": "10"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Phenyl glycidyl ether (PGE) | 122-60-1 | 10 | 60 | - |", "value": "60"}], "cas_number": "122-60-1", "disagreements": [], "id": "phenyl-glycidyl-ether", "rel_mgm3": "6", "rel_ppm": "C 1", "source": "https://www.cdc.gov/niosh/npg/npgd0498.html", "source_quote": "NIOSH REL Ca C 1 ppm (6 mg/m3) [15-minute]", "substance": "Phenyl glycidyl ether", "url": "https://referencesource.org/workplace-exposure-limits/phenyl-glycidyl-ether/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "100630 | S | Phenylhydrazine | 5 | 20 | | 10 | 45", "value": "10"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "100630 | S | Phenylhydrazine | 5 | 20 | | 10 | 45", "value": "45"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0499.html", "source_quote": "NIOSH REL Ca C 0.14 ppm (0.6 mg/m3) [2-hr] [skin]", "value": "C 0.14"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0499.html", "source_quote": "NIOSH REL Ca C 0.14 ppm (0.6 mg/m3) [2-hr] [skin]", "value": "0.6"}], "cas_number": "100-63-0", "disagreements": [{"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Phenylhydrazine | 100-63-0 | 5 | 22 | X |", "value": "22"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "100630 | S | Phenylhydrazine | 5 | 20 | | 10 | 45", "value": "20"}]}], "id": "phenylhydrazine", "pel_mgm3": "22", "pel_ppm": "5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Phenylhydrazine | 100-63-0 | 5 | 22 | X |", "substance": "Phenylhydrazine", "url": "https://referencesource.org/workplace-exposure-limits/phenylhydrazine/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0501.html", "source_quote": "NIOSH REL C 0.05 ppm (0.25 mg/m3)", "value": "C 0.05"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0501.html", "source_quote": "NIOSH REL C 0.05 ppm (0.25 mg/m3)", "value": "0.25"}], "cas_number": "638211", "ceiling_notation": "the values given in the PEL columns are ceiling values", "disagreements": [], "id": "phenylphosphine", "pel_mgm3": "0.25", "pel_ppm": "0.05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "638211 | | Phenylphosphine | 0.05 | 0.25 | C", "substance": "Phenylphosphine", "url": "https://referencesource.org/workplace-exposure-limits/phenylphosphine/", "verified_fields": ["cas_number", "ceiling_notation", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "298022 | S | Phorate; o,o-diethyl S-(ethylthio)methyl phosphorodithioate | -- | 0.05 | | -- | 0.2", "value": "0.05"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "298022 | S | Phorate; o,o-diethyl S-(ethylthio)methyl phosphorodithioate | -- | 0.05 | | -- | 0.2", "value": "0.2"}], "cas_number": "298-02-2", "disagreements": [], "id": "phorate", "rel_mgm3": "TWA 0.05", "source": "https://www.cdc.gov/niosh/npg/npgd0502.html", "source_quote": "NIOSH REL TWA 0.05 mg/m3 ST 0.2 mg/m3 [skin]", "substance": "Phorate", "url": "https://referencesource.org/workplace-exposure-limits/phorate/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Phosgene (Carbonyl chloride) | 75-44-5 | 0.1 | 0.4 | - |", "value": "0.1"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Phosgene (Carbonyl chloride) | 75-44-5 | 0.1 | 0.4 | - |", "value": "0.4"}], "cas_number": "75-44-5", "disagreements": [], "id": "phosgene", "rel_mgm3": "0.4", "rel_ppm": "TWA 0.1", "source": "https://www.cdc.gov/niosh/npg/npgd0504.html", "source_quote": "NIOSH REL TWA 0.1 ppm (0.4 mg/m3) C 0.2 ppm (0.8 mg/m3) [15-minute]", "substance": "Phosgene", "url": "https://referencesource.org/workplace-exposure-limits/phosgene/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0505.html", "source_quote": "NIOSH REL TWA 0.3 ppm (0.4 mg/m3) ST 1 ppm (1 mg/m3)", "value": "TWA 0.3"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0505.html", "source_quote": "NIOSH REL TWA 0.3 ppm (0.4 mg/m3) ST 1 ppm (1 mg/m3)", "value": "0.4"}, {"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7803512 | | Phosphine; PH$3 | 0.3 | 0.4 | | 1 | 1", "value": "1"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7803512 | | Phosphine; PH$3 | 0.3 | 0.4 | | 1 | 1", "value": "1"}], "cas_number": "7803-51-2", "disagreements": [], "id": "phosphine", "pel_mgm3": "0.4", "pel_ppm": "0.3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Phosphine | 7803-51-2 | 0.3 | 0.4 | - |", "substance": "Phosphine", "url": "https://referencesource.org/workplace-exposure-limits/phosphine/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7664382 | | Phosphoric acid | -- | 1 | | -- | 3", "value": "3"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0506.html", "source_quote": "NIOSH REL TWA 1 mg/m3 ST 3 mg/m3", "value": "TWA 1"}], "cas_number": "7664-38-2", "disagreements": [], "id": "phosphoric-acid", "pel_mgm3": "1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Phosphoric acid | 7664-38-2 | - | 1 | - |", "substance": "Phosphoric acid", "url": "https://referencesource.org/workplace-exposure-limits/phosphoric-acid/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0508.html", "source_quote": "NIOSH REL TWA 0.1 ppm (0.6 mg/m3) ST 0.5 ppm (3 mg/m3)", "value": "TWA 0.1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0508.html", "source_quote": "NIOSH REL TWA 0.1 ppm (0.6 mg/m3) ST 0.5 ppm (3 mg/m3)", "value": "0.6"}], "cas_number": "10025873", "disagreements": [], "id": "phosphorus-oxychloride", "pel_mgm3": "0.6", "pel_ppm": "0.1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "10025873 | | Phosphorus oxychloride | 0.1 | 0.6", "substance": "Phosphorus oxychloride", "url": "https://referencesource.org/workplace-exposure-limits/phosphorus-oxychloride/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "10026138 | | Phosphorus pentachloride | 0.1 | 1", "value": "0.1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0509.html", "source_quote": "NIOSH REL TWA 1 mg/m3", "value": "TWA 1"}], "cas_number": "10026-13-8", "disagreements": [], "id": "phosphorus-pentachloride", "pel_mgm3": "1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Phosphorus pentachloride | 10026-13-8 | - | 1 | - |", "substance": "Phosphorus pentachloride", "url": "https://referencesource.org/workplace-exposure-limits/phosphorus-pentachloride/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0510.html", "source_quote": "NIOSH REL TWA 1 mg/m3 ST 3 mg/m3", "value": "TWA 1"}, {"as_of": "2026-09-25", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "1314803 | | Phosphorus pentasulfide; P$2S$5 | -- | 1 | | -- | 3", "value": "3"}], "cas_number": "1314-80-3", "disagreements": [], "id": "phosphorus-pentasulfide", "pel_mgm3": "1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Phosphorus pentasulfide | 1314-80-3 | - | 1 | - |", "substance": "Phosphorus pentasulfide", "url": "https://referencesource.org/workplace-exposure-limits/phosphorus-pentasulfide/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7719122 | | Phosphorus trichloride | 0.2 | 1.5 | | 0.5 | 3", "value": "0.5"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7719122 | | Phosphorus trichloride | 0.2 | 1.5 | | 0.5 | 3", "value": "3"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0511.html", "source_quote": "NIOSH REL TWA 0.2 ppm (1.5 mg/m3) ST 0.5 ppm (3 mg/m3)", "value": "TWA 0.2"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0511.html", "source_quote": "NIOSH REL TWA 0.2 ppm (1.5 mg/m3) ST 0.5 ppm (3 mg/m3)", "value": "1.5"}], "cas_number": "7719-12-2", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Phosphorus trichloride | 7719-12-2 | 0.5 | 3 | - |", "value": "0.5"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7719122 | | Phosphorus trichloride | 0.2 | 1.5 | | 0.5 | 3", "value": "0.2"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Phosphorus trichloride | 7719-12-2 | 0.5 | 3 | - |", "value": "3"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7719122 | | Phosphorus trichloride | 0.2 | 1.5 | | 0.5 | 3", "value": "1.5"}]}], "id": "phosphorus-trichloride", "pel_mgm3": "3", "pel_ppm": "0.5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Phosphorus trichloride | 7719-12-2 | 0.5 | 3 | - |", "substance": "Phosphorus trichloride", "url": "https://referencesource.org/workplace-exposure-limits/phosphorus-trichloride/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0507.html", "source_quote": "NIOSH REL TWA 0.1 mg/m3", "value": "TWA 0.1"}], "cas_number": "7723-14-0", "disagreements": [], "id": "phosphorus-yellow", "pel_mgm3": "0.1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Phosphorus (yellow) | 7723-14-0 | - | 0.1 | - |", "substance": "Phosphorus (yellow)", "url": "https://referencesource.org/workplace-exposure-limits/phosphorus-yellow/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0512.html", "source_quote": "NIOSH REL TWA 6 mg/m3 (1 ppm)", "value": "1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0512.html", "source_quote": "NIOSH REL TWA 6 mg/m3 (1 ppm)", "value": "TWA 6"}], "cas_number": "85-44-9", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Phthalic anhydride | 85-44-9 | 2 | 12 | - |", "value": "2"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "85449 | | Phthalic anhydride | 1 | 6", "value": "1"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Phthalic anhydride | 85-44-9 | 2 | 12 | - |", "value": "12"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "85449 | | Phthalic anhydride | 1 | 6", "value": "6"}]}], "id": "phthalic-anhydride", "pel_mgm3": "12", "pel_ppm": "2", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Phthalic anhydride | 85-44-9 | 2 | 12 | - |", "substance": "Phthalic anhydride", "url": "https://referencesource.org/workplace-exposure-limits/phthalic-anhydride/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0514.html", "source_quote": "NIOSH REL See Appendix D", "value": "See Appendix D"}], "cas_number": "1918-02-1", "disagreements": [], "id": "picloram", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Picloram | 1918-02-1 | - | - | - |", "substance": "Picloram", "url": "https://referencesource.org/workplace-exposure-limits/picloram/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0515.html", "source_quote": "NIOSH REL TWA 0.1 mg/m3 ST 0.3 mg/m3 [skin]", "value": "TWA 0.1"}], "cas_number": "88-89-1", "disagreements": [], "id": "picric-acid", "pel_mgm3": "0.1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Picric acid | 88-89-1 | - | 0.1 | X |", "substance": "Picric acid", "url": "https://referencesource.org/workplace-exposure-limits/picric-acid/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Pindone (2-Pivalyl-1,3-indandione) | 83-26-1 | - | 0.1 | - |", "value": "0.1"}], "cas_number": "83-26-1", "disagreements": [], "id": "pindone", "rel_mgm3": "TWA 0.1", "source": "https://www.cdc.gov/niosh/npg/npgd0516.html", "source_quote": "NIOSH REL TWA 0.1 mg/m3", "substance": "Pindone", "url": "https://referencesource.org/workplace-exposure-limits/pindone/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0517.html", "source_quote": "NIOSH REL TWA 5 mg/m3", "value": "TWA 5"}], "cas_number": "142643", "disagreements": [], "id": "piperazine-dihydrochloride", "pel_mgm3": "5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "142643 | | Piperazine dihydrochloride | -- | 5", "substance": "Piperazine dihydrochloride", "url": "https://referencesource.org/workplace-exposure-limits/piperazine-dihydrochloride/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0518.html", "source_quote": "NIOSH REL TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)", "value": "TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)"}], "cas_number": "26499-65-0", "disagreements": [], "id": "plaster-of-paris", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Plaster of Paris | 26499-65-0 | - | - | - |", "substance": "Plaster of Paris", "url": "https://referencesource.org/workplace-exposure-limits/plaster-of-paris/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7440064 | | Platinum, metal | -- | 1", "value": "1"}], "cas_number": "7440-06-4", "disagreements": [], "id": "platinum", "rel_mgm3": "TWA 1", "source": "https://www.cdc.gov/niosh/npg/npgd0519.html", "source_quote": "NIOSH REL TWA 1 mg/m3", "substance": "Platinum", "url": "https://referencesource.org/workplace-exposure-limits/platinum/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"id": "platinum-soluble-salts-as-pt", "pel_mgm3": "0.002", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Platinum, soluble salts, as Pt | -- | 0.002", "substance": "Platinum, soluble salts, as Pt", "url": "https://referencesource.org/workplace-exposure-limits/platinum-soluble-salts-as-pt/", "verified_fields": ["pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0521.html", "source_quote": "NIOSH REL TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)", "value": "TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)"}], "cas_number": "65997-15-1", "disagreements": [], "id": "portland-cement", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Portland cement | 65997-15-1 | - | - | - |", "substance": "Portland cement", "url": "https://referencesource.org/workplace-exposure-limits/portland-cement/", "verified_fields": ["cas_number", "substance"]}
{"cas_number": "151-50-8", "id": "potassium-cyanide-as-cn", "rel_mgm3": "C 5", "rel_ppm": "4.7", "source": "https://www.cdc.gov/niosh/npg/npgd0522.html", "source_quote": "NIOSH REL C 5 mg/m3 (4.7 ppm) [10-minute]", "substance": "Potassium cyanide (as CN)", "url": "https://referencesource.org/workplace-exposure-limits/potassium-cyanide-as-cn/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-28", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "1310583 | | Potassium hydroxide; caustic potash | -- | 2 | C", "value": "2"}, {"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "1310583 | | Potassium hydroxide; caustic potash | -- | 2 | C", "value": "the values given in the PEL columns are ceiling values"}], "cas_number": "1310-58-3", "disagreements": [], "id": "potassium-hydroxide", "rel_mgm3": "C 2", "source": "https://www.cdc.gov/niosh/npg/npgd0523.html", "source_quote": "NIOSH REL C 2 mg/m3", "substance": "Potassium hydroxide", "url": "https://referencesource.org/workplace-exposure-limits/potassium-hydroxide/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"cas_number": "593293", "id": "potassium-stearate", "pel_mgm3": "10", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "593293 | | Potassium stearate | -- | 10", "substance": "Potassium stearate", "url": "https://referencesource.org/workplace-exposure-limits/potassium-stearate/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0524.html", "source_quote": "NIOSH REL TWA 1000 ppm (1800 mg/m3)", "value": "TWA 1000"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0524.html", "source_quote": "NIOSH REL TWA 1000 ppm (1800 mg/m3)", "value": "1800"}], "cas_number": "74-98-6", "disagreements": [{"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Propane | 74-98-6 | 1000 | 1800 | - |", "value": "1800"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "74986 | | Propane | 1000 | 1800(h)", "value": "1800(h)"}]}], "id": "propane", "pel_mgm3": "1800", "pel_ppm": "1000", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Propane | 74-98-6 | 1000 | 1800 | - |", "substance": "Propane", "url": "https://referencesource.org/workplace-exposure-limits/propane/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "1120-71-4", "id": "propane-sultone", "rel_statement": "Ca See Appendix A", "source": "https://www.cdc.gov/niosh/npg/npgd0525.html", "source_quote": "NIOSH REL Ca See Appendix A", "substance": "Propane sultone", "url": "https://referencesource.org/workplace-exposure-limits/propane-sultone/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "107197 | S | Propargyl alcohol; 2-propyn-1-o1 | 1 | 2", "value": "1"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "107197 | S | Propargyl alcohol; 2-propyn-1-o1 | 1 | 2", "value": "2"}], "cas_number": "107-19-7", "disagreements": [], "id": "propargyl-alcohol", "rel_mgm3": "2", "rel_ppm": "TWA 1", "source": "https://www.cdc.gov/niosh/npg/npgd0527.html", "source_quote": "NIOSH REL TWA 1 ppm (2 mg/m3) [skin]", "substance": "Propargyl alcohol", "url": "https://referencesource.org/workplace-exposure-limits/propargyl-alcohol/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0529.html", "source_quote": "NIOSH REL TWA 10 ppm (30 mg/m3) ST 15 ppm (45 mg/m3)", "value": "TWA 10"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0529.html", "source_quote": "NIOSH REL TWA 10 ppm (30 mg/m3) ST 15 ppm (45 mg/m3)", "value": "30"}], "cas_number": "79094", "disagreements": [], "id": "propionic-acid", "pel_mgm3": "30", "pel_ppm": "10", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "79094 | | Propionic acid | 10 | 30", "substance": "Propionic acid", "url": "https://referencesource.org/workplace-exposure-limits/propionic-acid/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "107-12-0", "id": "propionitrile", "rel_mgm3": "14", "rel_ppm": "TWA 6", "source": "https://www.cdc.gov/niosh/npg/npgd0530.html", "source_quote": "NIOSH REL TWA 6 ppm (14 mg/m3)", "substance": "Propionitrile", "url": "https://referencesource.org/workplace-exposure-limits/propionitrile/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "114261 | | Propoxur; 2-isopropoxyphenyl N-methyl carbamate | | 0.5", "value": "0.5"}], "cas_number": "114-26-1", "disagreements": [], "id": "propoxur", "rel_mgm3": "TWA 0.5", "source": "https://www.cdc.gov/niosh/npg/npgd0531.html", "source_quote": "NIOSH REL TWA 0.5 mg/m3", "substance": "Propoxur", "url": "https://referencesource.org/workplace-exposure-limits/propoxur/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"cas_number": "115071", "id": "propylene", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "115071 | | Propylene | (h) | --", "substance": "Propylene", "url": "https://referencesource.org/workplace-exposure-limits/propylene/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "78875 | | Propylene dichloride; 1,2-dichloropropane | 75 | 350 | | 110 | 510", "value": "110"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "78875 | | Propylene dichloride; 1,2-dichloropropane | 75 | 350 | | 110 | 510", "value": "510"}, {"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0534.html", "source_quote": "NIOSH REL Ca See Appendix A", "value": "Ca See Appendix A"}], "cas_number": "78-87-5", "disagreements": [], "id": "propylene-dichloride", "pel_mgm3": "350", "pel_ppm": "75", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Propylene dichloride | 78-87-5 | 75 | 350 | - |", "substance": "Propylene dichloride", "url": "https://referencesource.org/workplace-exposure-limits/propylene-dichloride/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "6423434 | S | Propylene glycol dinitrate; PGDN | 0.05 | 0.3", "value": "0.05"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "6423434 | S | Propylene glycol dinitrate; PGDN | 0.05 | 0.3", "value": "0.3"}], "cas_number": "6423-43-4", "disagreements": [], "id": "propylene-glycol-dinitrate", "rel_mgm3": "0.3", "rel_ppm": "TWA 0.05", "source": "https://www.cdc.gov/niosh/npg/npgd0535.html", "source_quote": "NIOSH REL TWA 0.05 ppm (0.3 mg/m3) [skin]", "substance": "Propylene glycol dinitrate", "url": "https://referencesource.org/workplace-exposure-limits/propylene-glycol-dinitrate/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0536.html", "source_quote": "NIOSH REL TWA 100 ppm (360 mg/m3) ST 150 ppm (540 mg/m3)", "value": "TWA 100"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0536.html", "source_quote": "NIOSH REL TWA 100 ppm (360 mg/m3) ST 150 ppm (540 mg/m3)", "value": "360"}], "cas_number": "107982", "disagreements": [], "id": "propylene-glycol-monomethyl-ether", "pel_mgm3": "360", "pel_ppm": "100", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "107982 | S | Propylene glycol monomethyl ether | 100 | 360 | | 150 | 540", "stel_mgm3": "540", "stel_ppm": "150", "substance": "Propylene glycol monomethyl ether", "url": "https://referencesource.org/workplace-exposure-limits/propylene-glycol-monomethyl-ether/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "stel_mgm3", "stel_ppm", "substance"]}
{"cas_number": "108656", "id": "propylene-glycol-monomethyl-ether-acetate", "pel_mgm3": "541", "pel_ppm": "100", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "108656 | S | Propylene glycol monomethyl ether acetate | 100 | 541 | | 150 | 811", "stel_mgm3": "811", "stel_ppm": "150", "substance": "Propylene glycol monomethyl ether acetate", "url": "https://referencesource.org/workplace-exposure-limits/propylene-glycol-monomethyl-ether-acetate/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "stel_mgm3", "stel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0537.html", "source_quote": "NIOSH REL Ca TWA 2 ppm (5 mg/m3) [skin]", "value": "TWA 2"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0537.html", "source_quote": "NIOSH REL Ca TWA 2 ppm (5 mg/m3) [skin]", "value": "5"}], "cas_number": "75-55-8", "disagreements": [], "id": "propylene-imine", "pel_mgm3": "5", "pel_ppm": "2", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Propylene imine | 75-55-8 | 2 | 5 | X |", "substance": "Propylene imine", "url": "https://referencesource.org/workplace-exposure-limits/propylene-imine/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0538.html", "source_quote": "NIOSH REL Ca See Appendix A", "value": "Ca See Appendix A"}], "cas_number": "75-56-9", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Propylene oxide | 75-56-9 | 100 | 240 | - |", "value": "100"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75569 | | Propylene oxide; 1,2-epoxy-propane | 2 | 4.75", "value": "2"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Propylene oxide | 75-56-9 | 100 | 240 | - |", "value": "240"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75569 | | Propylene oxide; 1,2-epoxy-propane | 2 | 4.75", "value": "4.75"}]}], "id": "propylene-oxide", "pel_mgm3": "240", "pel_ppm": "100", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Propylene oxide | 75-56-9 | 100 | 240 | - |", "substance": "Propylene oxide", "url": "https://referencesource.org/workplace-exposure-limits/propylene-oxide/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0685.html", "source_quote": "NIOSH REL TWA 5 mg/m3", "value": "TWA 5"}], "cas_number": "8003-34-7", "disagreements": [], "id": "pyrethrum", "pel_mgm3": "5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Pyrethrum | 8003-34-7 | - | 5 | - |", "substance": "Pyrethrum", "url": "https://referencesource.org/workplace-exposure-limits/pyrethrum/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0541.html", "source_quote": "NIOSH REL TWA 5 ppm (15 mg/m3)", "value": "TWA 5"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0541.html", "source_quote": "NIOSH REL TWA 5 ppm (15 mg/m3)", "value": "15"}], "cas_number": "110-86-1", "disagreements": [], "id": "pyridine", "pel_mgm3": "15", "pel_ppm": "5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Pyridine | 110-86-1 | 5 | 15 | - |", "substance": "Pyridine", "url": "https://referencesource.org/workplace-exposure-limits/pyridine/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0684.html", "source_quote": "NIOSH REL Ca TWA 0.05 mg/m³", "value": "TWA 0.05"}], "cas_number": "14808607", "disagreements": [], "id": "quartz", "pel_mgm3": "0.05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "14808607 | | Quartz, | -- | 0.05", "substance": "Quartz,", "url": "https://referencesource.org/workplace-exposure-limits/quartz/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0542.html", "source_quote": "NIOSH REL TWA 0.4 mg/m3 (0.1 ppm)", "value": "0.1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0542.html", "source_quote": "NIOSH REL TWA 0.4 mg/m3 (0.1 ppm)", "value": "TWA 0.4"}], "cas_number": "106-51-4", "disagreements": [], "id": "quinone", "pel_mgm3": "0.4", "pel_ppm": "0.1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Quinone | 106-51-4 | 0.1 | 0.4 | - |", "substance": "Quinone", "url": "https://referencesource.org/workplace-exposure-limits/quinone/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"id": "refractory-ceramic-fiber", "pel_mgm3": "0.2 f/cc(q)", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Refractory ceramic fiber | | 0.2 f/cc(q)", "substance": "Refractory ceramic fiber", "url": "https://referencesource.org/workplace-exposure-limits/refractory-ceramic-fiber/", "verified_fields": ["pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0543.html", "source_quote": "NIOSH REL TWA 10 ppm (45 mg/m3) ST 20 ppm (90 mg/m3)", "value": "TWA 10"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0543.html", "source_quote": "NIOSH REL TWA 10 ppm (45 mg/m3) ST 20 ppm (90 mg/m3)", "value": "45"}], "cas_number": "108463", "disagreements": [], "id": "resorcinol", "pel_mgm3": "45", "pel_ppm": "10", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "108463 | | Resorcinol | 10 | 45 | | 20 | 90", "stel_mgm3": "90", "stel_ppm": "20", "substance": "Resorcinol", "url": "https://referencesource.org/workplace-exposure-limits/resorcinol/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "stel_mgm3", "stel_ppm", "substance"]}
{"cas_number": "7440-16-6", "id": "rhodium-as-rh-metal-fume-and-insoluble-compounds", "pel_mgm3": "0.1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Rhodium (as Rh), metal fume and insoluble compounds | 7440-16-6 | - | 0.1 | - |", "substance": "Rhodium (as Rh), metal fume and insoluble compounds", "url": "https://referencesource.org/workplace-exposure-limits/rhodium-as-rh-metal-fume-and-insoluble-compounds/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"cas_number": "7440-16-6", "id": "rhodium-as-rh-soluble-compounds", "pel_mgm3": "0.001", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Rhodium (as Rh), soluble compounds | 7440-16-6 | - | 0.001 | - |", "substance": "Rhodium (as Rh), soluble compounds", "url": "https://referencesource.org/workplace-exposure-limits/rhodium-as-rh-soluble-compounds/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"cas_number": "7440166", "id": "rhodium-metal", "pel_mgm3": "0.1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7440166 | | Rhodium, metal | -- | 0.1", "substance": "Rhodium, metal", "url": "https://referencesource.org/workplace-exposure-limits/rhodium-metal/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"cas_number": "7440-16-6 (metal)", "id": "rhodium-metal-fume-and-insoluble-compounds-as-rh", "rel_mgm3": "TWA 0.1", "source": "https://www.cdc.gov/niosh/npg/npgd0544.html", "source_quote": "NIOSH REL TWA 0.1 mg/m3", "substance": "Rhodium (metal fume and insoluble compounds, as Rh)", "url": "https://referencesource.org/workplace-exposure-limits/rhodium-metal-fume-and-insoluble-compounds-as-rh/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0546.html", "source_quote": "NIOSH REL TWA 10 mg/m3", "value": "TWA 10"}], "cas_number": "299-84-3", "disagreements": [{"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ronnel | 299-84-3 | - | 15 | - |", "value": "15"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "299843 | | Ronnel; o,o-dimethyl o-(2,4,5-trichlorophenyl) phosphorothioite | -- | 10", "value": "10"}]}], "id": "ronnel", "pel_mgm3": "15", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Ronnel | 299-84-3 | - | 15 | - |", "substance": "Ronnel", "url": "https://referencesource.org/workplace-exposure-limits/ronnel/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"id": "rosin-core-solder-pyrolysis-products-as-formaldehyde", "pel_mgm3": "0.1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Rosin core solder, pyrolysis products, as formaldehyde | -- | 0.1", "substance": "Rosin core solder, pyrolysis products, as formaldehyde", "url": "https://referencesource.org/workplace-exposure-limits/rosin-core-solder-pyrolysis-products-as-formaldehyde/", "verified_fields": ["pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0548.html", "source_quote": "NIOSH REL TWA 5 mg/m3", "value": "TWA 5"}], "cas_number": "83-79-4", "disagreements": [], "id": "rotenone", "pel_mgm3": "5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Rotenone | 83-79-4 | - | 5 | - |", "substance": "Rotenone", "url": "https://referencesource.org/workplace-exposure-limits/rotenone/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"id": "rubber-solvent-naphtha", "pel_mgm3": "1,600", "pel_ppm": "400", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Rubber solvent (Naphtha) | 400 | 1,600", "substance": "Rubber solvent (Naphtha)", "url": "https://referencesource.org/workplace-exposure-limits/rubber-solvent-naphtha/", "verified_fields": ["pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0032.html", "source_quote": "NIOSH REL TWA 125 ppm (650 mg/m3)", "value": "TWA 125"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0032.html", "source_quote": "NIOSH REL TWA 125 ppm (650 mg/m3)", "value": "650"}], "cas_number": "626-38-0", "disagreements": [], "id": "sec-amyl-acetate", "pel_mgm3": "650", "pel_ppm": "125", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "sec-Amyl acetate | 626-38-0 | 125 | 650 | - |", "substance": "sec-Amyl acetate", "url": "https://referencesource.org/workplace-exposure-limits/sec-amyl-acetate/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0073.html", "source_quote": "NIOSH REL TWA 200 ppm (950 mg/m3)", "value": "TWA 200"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0073.html", "source_quote": "NIOSH REL TWA 200 ppm (950 mg/m3)", "value": "950"}], "cas_number": "105-46-4", "disagreements": [], "id": "sec-butyl-acetate", "pel_mgm3": "950", "pel_ppm": "200", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "sec-Butyl acetate | 105-46-4 | 200 | 950 | - |", "substance": "sec-Butyl acetate", "url": "https://referencesource.org/workplace-exposure-limits/sec-butyl-acetate/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0077.html", "source_quote": "NIOSH REL TWA 100 ppm (305 mg/m3) ST 150 ppm (455 mg/m3)", "value": "TWA 100"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0077.html", "source_quote": "NIOSH REL TWA 100 ppm (305 mg/m3) ST 150 ppm (455 mg/m3)", "value": "305"}], "cas_number": "78-92-2", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "sec-Butyl alcohol | 78-92-2 | 150 | 450 | - |", "value": "150"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "78922 | | sec-Butyl alcohol | 100 | 305", "value": "100"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "sec-Butyl alcohol | 78-92-2 | 150 | 450 | - |", "value": "450"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "78922 | | sec-Butyl alcohol | 100 | 305", "value": "305"}]}], "id": "sec-butyl-alcohol", "pel_mgm3": "450", "pel_ppm": "150", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "sec-Butyl alcohol | 78-92-2 | 150 | 450 | - |", "substance": "sec-Butyl alcohol", "url": "https://referencesource.org/workplace-exposure-limits/sec-butyl-alcohol/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0327.html", "source_quote": "NIOSH REL TWA 50 ppm (300 mg/m3)", "value": "TWA 50"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0327.html", "source_quote": "NIOSH REL TWA 50 ppm (300 mg/m3)", "value": "300"}], "cas_number": "108-84-9", "disagreements": [], "id": "sec-hexyl-acetate", "pel_mgm3": "300", "pel_ppm": "50", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "sec-Hexyl acetate | 108-84-9 | 50 | 300 | - |", "substance": "sec-Hexyl acetate", "url": "https://referencesource.org/workplace-exposure-limits/sec-hexyl-acetate/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Selenium compounds (as Se) | 7782-49-2 | - | 0.2 | - |", "value": "0.2"}], "cas_number": "7782-49-2", "disagreements": [], "id": "selenium", "rel_mgm3": "TWA 0.2", "source": "https://www.cdc.gov/niosh/npg/npgd0550.html", "source_quote": "NIOSH REL TWA 0.2 mg/m3", "substance": "Selenium", "url": "https://referencesource.org/workplace-exposure-limits/selenium/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0551.html", "source_quote": "NIOSH REL TWA 0.05 ppm", "value": "TWA 0.05"}], "cas_number": "7783791", "disagreements": [], "id": "selenium-hexafluoride", "pel_mgm3": "0.4", "pel_ppm": "0.05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7783791 | | Selenium hexafluoride | 0.05 | 0.4", "substance": "Selenium hexafluoride", "url": "https://referencesource.org/workplace-exposure-limits/selenium-hexafluoride/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "7631-86-9", "id": "silica-amorphous", "rel_mgm3": "TWA 6", "source": "https://www.cdc.gov/niosh/npg/npgd0552.html", "source_quote": "NIOSH REL TWA 6 mg/m3", "substance": "Silica, amorphous", "url": "https://referencesource.org/workplace-exposure-limits/silica-amorphous/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"cas_number": "61790532", "disagreements": [], "id": "silica-amorphous-diatomaceous-earth", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "61790532 | | Silica, amorphous Diatomaceous earth", "substance": "Silica, amorphous Diatomaceous earth", "url": "https://referencesource.org/workplace-exposure-limits/silica-amorphous-diatomaceous-earth/", "verified_fields": ["cas_number", "substance"]}
{"cas_number": "112926-00-8", "id": "silica-amorphous-precipitated-and-gel", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Silica, amorphous, precipitated and gel | 112926-00-8 | - | (3) | - |", "substance": "Silica, amorphous, precipitated and gel", "url": "https://referencesource.org/workplace-exposure-limits/silica-amorphous-precipitated-and-gel/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "60676860 | | Silica, fused, respirable dust | -- | 0.1", "value": "0.1"}], "cas_number": "60676-86-0", "disagreements": [], "id": "silica-fused-respirable-dust", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Silica, fused, respirable dust | 60676-86-0 | - | (3) | - |", "substance": "Silica, fused, respirable dust", "url": "https://referencesource.org/workplace-exposure-limits/silica-fused-respirable-dust/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0554.html", "source_quote": "NIOSH REL TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)", "value": "TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)"}], "cas_number": "7440-21-3", "disagreements": [], "id": "silicon", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Silicon | 7440-21-3 | - | - | - |", "substance": "Silicon", "url": "https://referencesource.org/workplace-exposure-limits/silicon/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0555.html", "source_quote": "NIOSH REL TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)", "value": "TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)"}], "cas_number": "409-21-2", "disagreements": [], "id": "silicon-carbide", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Silicon carbide | 409-21-2 | - | - | - |", "substance": "Silicon carbide", "url": "https://referencesource.org/workplace-exposure-limits/silicon-carbide/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7803625 | | Silicon tetrahydride; silane | 5 | 7", "value": "5"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7803625 | | Silicon tetrahydride; silane | 5 | 7", "value": "7"}], "cas_number": "7803-62-5", "disagreements": [], "id": "silicon-tetrahydride", "rel_mgm3": "7", "rel_ppm": "TWA 5", "source": "https://www.cdc.gov/niosh/npg/npgd0556.html", "source_quote": "NIOSH REL TWA 5 ppm (7 mg/m3)", "substance": "Silicon tetrahydride", "url": "https://referencesource.org/workplace-exposure-limits/silicon-tetrahydride/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0557.html", "source_quote": "NIOSH REL TWA 0.01 mg/m3", "value": "TWA 0.01"}], "cas_number": "7440-22-4", "disagreements": [], "id": "silver-metal-and-soluble-compounds-as-ag", "pel_mgm3": "0.01", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Silver, metal and soluble compounds (as Ag) | 7440-22-4 | - | 0.01 | - |", "substance": "Silver, metal and soluble compounds (as Ag)", "url": "https://referencesource.org/workplace-exposure-limits/silver-metal-and-soluble-compounds-as-ag/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"id": "silver-soluble-compounds-as-ag", "pel_mgm3": "0.01", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Silver, soluble compounds, as Ag | -- | 0.01", "substance": "Silver, soluble compounds, as Ag", "url": "https://referencesource.org/workplace-exposure-limits/silver-soluble-compounds-as-ag/", "verified_fields": ["pel_mgm3", "substance"]}
{"id": "soapstone-respirable-dust", "pel_mgm3": "3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Soapstone, respirable dust | -- | 3", "substance": "Soapstone, respirable dust", "url": "https://referencesource.org/workplace-exposure-limits/soapstone-respirable-dust/", "verified_fields": ["pel_mgm3", "substance"]}
{"id": "soapstone-total-dust", "pel_mgm3": "6", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Soapstone, total dust | -- | 6", "substance": "Soapstone, total dust", "url": "https://referencesource.org/workplace-exposure-limits/soapstone-total-dust/", "verified_fields": ["pel_mgm3", "substance"]}
{"cas_number": "15096-52-3", "id": "sodium-aluminum-fluoride-as-f", "rel_mgm3": "TWA 2.5", "source": "https://www.cdc.gov/niosh/npg/npgd0559.html", "source_quote": "NIOSH REL TWA 2.5 mg/m3", "substance": "Sodium aluminum fluoride (as F)", "url": "https://referencesource.org/workplace-exposure-limits/sodium-aluminum-fluoride-as-f/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0560.html", "source_quote": "NIOSH REL C 0.1 ppm (as HN3) [skin] C 0.3 mg/m3 (as NaN3) [skin]", "value": "C 0.1 ppm (as HN3) [skin] C 0.3 mg/m3 (as NaN3) [skin]"}], "cas_number": "26628228", "ceiling_notation": "the values given in the PEL columns are ceiling values", "disagreements": [], "id": "sodium-azide", "pel_mgm3": "0.3", "pel_ppm": "0.1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "26628228 | S | Sodium azide | 0.1 | 0.3 | C", "substance": "Sodium azide", "url": "https://referencesource.org/workplace-exposure-limits/sodium-azide/", "verified_fields": ["cas_number", "ceiling_notation", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0561.html", "source_quote": "NIOSH REL TWA 5 mg/m3", "value": "TWA 5"}], "cas_number": "7631905", "disagreements": [], "id": "sodium-bisulfite", "pel_mgm3": "5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7631905 | | Sodium bisulfite | -- | 5", "substance": "Sodium bisulfite", "url": "https://referencesource.org/workplace-exposure-limits/sodium-bisulfite/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"cas_number": "143-33-9", "id": "sodium-cyanide-as-cn", "rel_mgm3": "C 5", "rel_ppm": "4.7", "source": "https://www.cdc.gov/niosh/npg/npgd0562.html", "source_quote": "NIOSH REL C 5 mg/m3 (4.7 ppm) [10-minute]", "substance": "Sodium cyanide (as CN)", "url": "https://referencesource.org/workplace-exposure-limits/sodium-cyanide-as-cn/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"cas_number": "7681-49-4", "id": "sodium-fluoride-as-f", "rel_mgm3": "TWA 2.5", "source": "https://www.cdc.gov/niosh/npg/npgd0563.html", "source_quote": "NIOSH REL TWA 2.5 mg/m3", "substance": "Sodium fluoride (as F)", "url": "https://referencesource.org/workplace-exposure-limits/sodium-fluoride-as-f/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "62748 | S | Sodium fluoroacetate | -- | 0.05 | | -- | 0.15", "value": "0.15"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0564.html", "source_quote": "NIOSH REL TWA 0.05 mg/m3 ST 0.15 mg/m3 [skin]", "value": "TWA 0.05"}], "cas_number": "62-74-8", "disagreements": [], "id": "sodium-fluoroacetate", "pel_mgm3": "0.05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Sodium fluoroacetate | 62-74-8 | - | 0.05 | X |", "substance": "Sodium fluoroacetate", "url": "https://referencesource.org/workplace-exposure-limits/sodium-fluoroacetate/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0565.html", "source_quote": "NIOSH REL C 2 mg/m3", "value": "C 2"}, {"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "1310732 | | Sodium hydroxide; caustic soda | -- | 2 | C", "value": "the values given in the PEL columns are ceiling values"}], "cas_number": "1310-73-2", "disagreements": [], "id": "sodium-hydroxide", "pel_mgm3": "2", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Sodium hydroxide | 1310-73-2 | - | 2 | - |", "substance": "Sodium hydroxide", "url": "https://referencesource.org/workplace-exposure-limits/sodium-hydroxide/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0566.html", "source_quote": "NIOSH REL TWA 5 mg/m3", "value": "TWA 5"}], "cas_number": "7681574", "disagreements": [], "id": "sodium-metabisulfite", "pel_mgm3": "5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7681574 | | Sodium metabisulfite | -- | 5", "substance": "Sodium metabisulfite", "url": "https://referencesource.org/workplace-exposure-limits/sodium-metabisulfite/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"cas_number": "822162", "id": "sodium-stearate", "pel_mgm3": "10", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "822162 | | Sodium stearate | -- | 10", "substance": "Sodium stearate", "url": "https://referencesource.org/workplace-exposure-limits/sodium-stearate/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0567.html", "source_quote": "NIOSH REL TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)", "value": "TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)"}], "cas_number": "9005-25-8", "disagreements": [], "id": "starch", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Starch | 9005-25-8 | - | - | - |", "substance": "Starch", "url": "https://referencesource.org/workplace-exposure-limits/starch/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0568.html", "source_quote": "NIOSH REL TWA 0.1 ppm (0.5 mg/m3)", "value": "TWA 0.1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0568.html", "source_quote": "NIOSH REL TWA 0.1 ppm (0.5 mg/m3)", "value": "0.5"}], "cas_number": "7803-52-3", "disagreements": [], "id": "stibine", "pel_mgm3": "0.5", "pel_ppm": "0.1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Stibine | 7803-52-3 | 0.1 | 0.5 | - |", "substance": "Stibine", "url": "https://referencesource.org/workplace-exposure-limits/stibine/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0569.html", "source_quote": "NIOSH REL TWA 350 mg/m3 C 1800 mg/m3 [15-minute]", "value": "TWA 350"}], "cas_number": "8052-41-3", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Stoddard solvent | 8052-41-3 | 500 | 2900 | - |", "value": "500"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "8052413 | | Stoddard solvent | 100 | 525", "value": "100"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Stoddard solvent | 8052-41-3 | 500 | 2900 | - |", "value": "2900"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "8052413 | | Stoddard solvent | 100 | 525", "value": "525"}]}], "id": "stoddard-solvent", "pel_mgm3": "2900", "pel_ppm": "500", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Stoddard solvent | 8052-41-3 | 500 | 2900 | - |", "substance": "Stoddard solvent", "url": "https://referencesource.org/workplace-exposure-limits/stoddard-solvent/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "7789062", "id": "strontium-chromate-as-cr-see-also-sections-1532-2-5206-8359-stearates-see-specif", "pel_mgm3": "0.0005", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7789062 | | Strontium chromate, as Cr (see also Sections 1532.2, 5206 & 8359) Stearates; see specific compound | -- | 0.0005", "substance": "Strontium chromate, as Cr (see also Sections 1532.2, 5206 & 8359) Stearates; see specific compound", "url": "https://referencesource.org/workplace-exposure-limits/strontium-chromate-as-cr-see-also-sections-1532-2-5206-8359-stearates-see-specif/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0570.html", "source_quote": "NIOSH REL TWA 0.15 mg/m3", "value": "TWA 0.15"}], "cas_number": "57-24-9", "disagreements": [], "id": "strychnine", "pel_mgm3": "0.15", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Strychnine | 57-24-9 | - | 0.15 | - |", "substance": "Strychnine", "url": "https://referencesource.org/workplace-exposure-limits/strychnine/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0571.html", "source_quote": "NIOSH REL TWA 50 ppm (215 mg/m3) ST 100 ppm (425 mg/m3)", "value": "TWA 50"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0571.html", "source_quote": "NIOSH REL TWA 50 ppm (215 mg/m3) ST 100 ppm (425 mg/m3)", "value": "215"}, {"as_of": "2026-09-28", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "100425 | S | Styrene (monomer); phenylethylene | 50 | 215 | 500 ppm | 100 | 425", "value": "50"}, {"as_of": "2026-09-28", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "100425 | S | Styrene (monomer); phenylethylene | 50 | 215 | 500 ppm | 100 | 425", "value": "215"}, {"as_of": "2026-09-28", "field": "ceiling", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "100425 | S | Styrene (monomer); phenylethylene | 50 | 215 | 500 ppm | 100 | 425", "value": "500 ppm"}, {"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "100425 | S | Styrene (monomer); phenylethylene | 50 | 215 | 500 ppm | 100 | 425", "value": "a ceiling value in addition to the TWA values"}, {"as_of": "2026-09-28", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "100425 | S | Styrene (monomer); phenylethylene | 50 | 215 | 500 ppm | 100 | 425", "value": "100"}, {"as_of": "2026-09-28", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "100425 | S | Styrene (monomer); phenylethylene | 50 | 215 | 500 ppm | 100 | 425", "value": "425"}], "cas_number": "100-42-5", "disagreements": [], "id": "styrene", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Styrene | 100-42-5 | - | (2) | - |", "substance": "Styrene", "url": "https://referencesource.org/workplace-exposure-limits/styrene/", "verified_fields": ["cas_number", "substance"]}
{"cas_number": "1395-21-7 (BPN) 9014-01-1 (Carlsburg)", "id": "subtilisins", "rel_mgm3": "ST 0.00006", "source": "https://www.cdc.gov/niosh/npg/npgd0572.html", "source_quote": "NIOSH REL ST 0.00006 mg/m3 [60-minute]", "substance": "Subtilisins", "url": "https://referencesource.org/workplace-exposure-limits/subtilisins/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"cas_number": "9014011", "id": "subtilisins-as-pure-crystalline-proteolytic-enzymes", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "9014011 | | Subtilisins (as pure crystalline proteolytic enzymes) | -- | | | | 0.00006(r)", "stel_mgm3": "0.00006(r)", "substance": "Subtilisins (as pure crystalline proteolytic enzymes)", "url": "https://referencesource.org/workplace-exposure-limits/subtilisins-as-pure-crystalline-proteolytic-enzymes/", "verified_fields": ["cas_number", "stel_mgm3", "substance"]}
{"cas_number": "110-61-2", "id": "succinonitrile", "rel_mgm3": "20", "rel_ppm": "TWA 6", "source": "https://www.cdc.gov/niosh/npg/npgd0573.html", "source_quote": "NIOSH REL TWA 6 ppm (20 mg/m3)", "substance": "Succinonitrile", "url": "https://referencesource.org/workplace-exposure-limits/succinonitrile/", "verified_fields": ["cas_number", "rel_mgm3", "rel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0574.html", "source_quote": "NIOSH REL TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)", "value": "TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)"}], "cas_number": "57-50-1", "disagreements": [], "id": "sucrose", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Sucrose | 57-50-1 | - | - | - |", "substance": "Sucrose", "url": "https://referencesource.org/workplace-exposure-limits/sucrose/", "verified_fields": ["cas_number", "substance"]}
{"cas_number": "74222972", "id": "sulfometuron-methyl", "pel_mgm3": "3.5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "74222972 | | Sulfometuron methyl | -- | 3.5", "substance": "Sulfometuron methyl", "url": "https://referencesource.org/workplace-exposure-limits/sulfometuron-methyl/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0586.html", "source_quote": "NIOSH REL TWA 0.2 mg/m3 [skin]", "value": "TWA 0.2"}], "cas_number": "3689245", "disagreements": [], "id": "sulfotep-tetraethyl-dithionopyrophosphate", "pel_mgm3": "0.2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "3689245 | S | Sulfotep; tetraethyl dithionopyrophosphate | | 0.2", "substance": "Sulfotep; tetraethyl dithionopyrophosphate", "url": "https://referencesource.org/workplace-exposure-limits/sulfotep-tetraethyl-dithionopyrophosphate/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7446095 | | Sulfur dioxide | 2 | 5 | | 5 | 10", "value": "5"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7446095 | | Sulfur dioxide | 2 | 5 | | 5 | 10", "value": "10"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0575.html", "source_quote": "NIOSH REL TWA 2 ppm (5 mg/m3) ST 5 ppm (13 mg/m3)", "value": "TWA 2"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0575.html", "source_quote": "NIOSH REL TWA 2 ppm (5 mg/m3) ST 5 ppm (13 mg/m3)", "value": "5"}], "cas_number": "7446-09-5", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Sulfur dioxide | 7446-09-5 | 5 | 13 | - |", "value": "5"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7446095 | | Sulfur dioxide | 2 | 5 | | 5 | 10", "value": "2"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Sulfur dioxide | 7446-09-5 | 5 | 13 | - |", "value": "13"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7446095 | | Sulfur dioxide | 2 | 5 | | 5 | 10", "value": "5"}]}], "id": "sulfur-dioxide", "pel_mgm3": "13", "pel_ppm": "5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Sulfur dioxide | 7446-09-5 | 5 | 13 | - |", "substance": "Sulfur dioxide", "url": "https://referencesource.org/workplace-exposure-limits/sulfur-dioxide/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0576.html", "source_quote": "NIOSH REL TWA 1000 ppm (6000 mg/m3)", "value": "TWA 1000"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0576.html", "source_quote": "NIOSH REL TWA 1000 ppm (6000 mg/m3)", "value": "6000"}], "cas_number": "2551-62-4", "disagreements": [], "id": "sulfur-hexafluoride", "pel_mgm3": "6000", "pel_ppm": "1000", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Sulfur hexafluoride | 2551-62-4 | 1000 | 6000 | - |", "substance": "Sulfur hexafluoride", "url": "https://referencesource.org/workplace-exposure-limits/sulfur-hexafluoride/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0578.html", "source_quote": "NIOSH REL C 1 ppm (6 mg/m3)", "value": "C 1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0578.html", "source_quote": "NIOSH REL C 1 ppm (6 mg/m3)", "value": "6"}, {"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "10025679 | | Sulfur monochloride; S$2Cl$2 | 1 | 6 | C", "value": "the values given in the PEL columns are ceiling values"}], "cas_number": "10025-67-9", "disagreements": [], "id": "sulfur-monochloride", "pel_mgm3": "6", "pel_ppm": "1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Sulfur monochloride | 10025-67-9 | 1 | 6 | - |", "substance": "Sulfur monochloride", "url": "https://referencesource.org/workplace-exposure-limits/sulfur-monochloride/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0579.html", "source_quote": "NIOSH REL C 0.01 ppm (0.1 mg/m3)", "value": "C 0.01"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0579.html", "source_quote": "NIOSH REL C 0.01 ppm (0.1 mg/m3)", "value": "0.1"}, {"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "5714227 | | Sulfur pentafluoride; S$2F$10 | 0.01 | 0.1 | C", "value": "the values given in the PEL columns are ceiling values"}], "cas_number": "5714-22-7", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Sulfur pentafluoride | 5714-22-7 | 0.025 | 0.25 | - |", "value": "0.025"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "5714227 | | Sulfur pentafluoride; S$2F$10 | 0.01 | 0.1 | C", "value": "0.01"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Sulfur pentafluoride | 5714-22-7 | 0.025 | 0.25 | - |", "value": "0.25"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "5714227 | | Sulfur pentafluoride; S$2F$10 | 0.01 | 0.1 | C", "value": "0.1"}]}], "id": "sulfur-pentafluoride", "pel_mgm3": "0.25", "pel_ppm": "0.025", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Sulfur pentafluoride | 5714-22-7 | 0.025 | 0.25 | - |", "substance": "Sulfur pentafluoride", "url": "https://referencesource.org/workplace-exposure-limits/sulfur-pentafluoride/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0580.html", "source_quote": "NIOSH REL C 0.1 ppm (0.4 mg/m3)", "value": "C 0.1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0580.html", "source_quote": "NIOSH REL C 0.1 ppm (0.4 mg/m3)", "value": "0.4"}], "cas_number": "7783600", "ceiling_notation": "the values given in the PEL columns are ceiling values", "disagreements": [], "id": "sulfur-tetrafluoride", "pel_mgm3": "0.4", "pel_ppm": "0.1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7783600 | | Sulfur tetrafluoride | 0.1 | 0.4 | C", "substance": "Sulfur tetrafluoride", "url": "https://referencesource.org/workplace-exposure-limits/sulfur-tetrafluoride/", "verified_fields": ["cas_number", "ceiling_notation", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7664939 | | Sulfuric acid | -- | 0.1 | | -- | 3", "value": "3"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0577.html", "source_quote": "NIOSH REL TWA 1 mg/m3", "value": "TWA 1"}], "cas_number": "7664-93-9", "disagreements": [{"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Sulfuric acid | 7664-93-9 | - | 1 | - |", "value": "1"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7664939 | | Sulfuric acid | -- | 0.1 | | -- | 3", "value": "0.1"}]}], "id": "sulfuric-acid", "pel_mgm3": "1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Sulfuric acid | 7664-93-9 | - | 1 | - |", "substance": "Sulfuric acid", "url": "https://referencesource.org/workplace-exposure-limits/sulfuric-acid/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0581.html", "source_quote": "NIOSH REL TWA 5 ppm (20 mg/m3) ST 10 ppm (40 mg/m3)", "value": "TWA 5"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0581.html", "source_quote": "NIOSH REL TWA 5 ppm (20 mg/m3) ST 10 ppm (40 mg/m3)", "value": "20"}, {"as_of": "2026-09-25", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "2699798 | | Sulfuryl fluoride; SO$2F$2 | 5 | 20 | | 10 | 40", "value": "10"}, {"as_of": "2026-09-25", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "2699798 | | Sulfuryl fluoride; SO$2F$2 | 5 | 20 | | 10 | 40", "value": "40"}], "cas_number": "2699-79-8", "disagreements": [], "id": "sulfuryl-fluoride", "pel_mgm3": "20", "pel_ppm": "5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Sulfuryl fluoride | 2699-79-8 | 5 | 20 | - |", "substance": "Sulfuryl fluoride", "url": "https://referencesource.org/workplace-exposure-limits/sulfuryl-fluoride/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0582.html", "source_quote": "NIOSH REL TWA 1 mg/m3", "value": "TWA 1"}], "cas_number": "35400432", "disagreements": [], "id": "sulprofos", "pel_mgm3": "1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "35400432 | | Sulprofos | | 1", "substance": "Sulprofos", "url": "https://referencesource.org/workplace-exposure-limits/sulprofos/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "14807966 | | Talc (containing no asbestos fibers), respirable dust | -- | 2", "value": "2"}], "cas_number": "14807-96-6", "disagreements": [], "id": "talc-containing-no-asbestos-and-less-than-1-quartz", "rel_statement": "TWA 2 mg/m3 (resp)", "source": "https://www.cdc.gov/niosh/npg/npgd0584.html", "source_quote": "NIOSH REL TWA 2 mg/m3 (resp)", "substance": "Talc (containing no asbestos and less than 1% quartz)", "url": "https://referencesource.org/workplace-exposure-limits/talc-containing-no-asbestos-and-less-than-1-quartz/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0585.html", "source_quote": "NIOSH REL TWA 5 mg/m3 ST 10 mg/m3", "value": "TWA 5"}], "cas_number": "7440-25-7", "disagreements": [], "id": "tantalum-metal-and-oxide-dust", "pel_mgm3": "5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Tantalum, metal and oxide dust | 7440-25-7 | - | 5 | - |", "substance": "Tantalum, metal and oxide dust", "url": "https://referencesource.org/workplace-exposure-limits/tantalum-metal-and-oxide-dust/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"cas_number": "1314610", "id": "tantalum-oxide-dust-as-ta", "pel_mgm3": "5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "1314610 | | Tantalum oxide dust, as Ta | -- | 5", "substance": "Tantalum oxide dust, as Ta", "url": "https://referencesource.org/workplace-exposure-limits/tantalum-oxide-dust-as-ta/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Tellurium and compounds (as Te) | 13494-80-9 | - | 0.1 | - |", "value": "0.1"}], "cas_number": "13494-80-9", "disagreements": [], "id": "tellurium", "rel_mgm3": "TWA 0.1", "source": "https://www.cdc.gov/niosh/npg/npgd0587.html", "source_quote": "NIOSH REL TWA 0.1 mg/m3", "substance": "Tellurium", "url": "https://referencesource.org/workplace-exposure-limits/tellurium/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0588.html", "source_quote": "NIOSH REL TWA 0.02 ppm (0.2 mg/m3)", "value": "TWA 0.02"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0588.html", "source_quote": "NIOSH REL TWA 0.02 ppm (0.2 mg/m3)", "value": "0.2"}], "cas_number": "7783804", "disagreements": [], "id": "tellurium-hexafluoride", "pel_mgm3": "0.2", "pel_ppm": "0.02", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7783804 | | Tellurium hexafluoride | 0.02 | 0.2", "substance": "Tellurium hexafluoride", "url": "https://referencesource.org/workplace-exposure-limits/tellurium-hexafluoride/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0589.html", "source_quote": "NIOSH REL TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)", "value": "TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "3383968 | | Temephos; o,o,o′ ,o′-tetramethyl o,o′-thiodi-p-phenylene phosphorothioate Total dust | -- | 10", "value": "10"}], "cas_number": "3383-96-8", "disagreements": [], "id": "temephos", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Temephos | 3383-96-8 | - | - | - |", "substance": "Temephos", "url": "https://referencesource.org/workplace-exposure-limits/temephos/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "TEPP (Tetraethyl pyrophosphate) | 107-49-3 | - | 0.05 | X |", "value": "0.05"}, {"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "107493 | S | TEPP; tetraethyl pyrophosphate; | 0.004 | 0.05", "value": "0.004"}], "cas_number": "107-49-3", "disagreements": [], "id": "tepp", "rel_mgm3": "TWA 0.05", "source": "https://www.cdc.gov/niosh/npg/npgd0590.html", "source_quote": "NIOSH REL TWA 0.05 mg/m3 [skin]", "substance": "TEPP", "url": "https://referencesource.org/workplace-exposure-limits/tepp/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"cas_number": "100210", "id": "terephthalic-acid", "pel_mgm3": "10", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "100210 | | Terephthalic acid | -- | 10", "substance": "Terephthalic acid", "url": "https://referencesource.org/workplace-exposure-limits/terephthalic-acid/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Terphenyls | 0.5 | 5 | C", "value": "the values given in the PEL columns are ceiling values"}], "cas_number": "26140-60-3", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Terphenyls | 26140-60-3 | (C)1 | (C)9 | - |", "value": "(C)1"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Terphenyls | 0.5 | 5 | C", "value": "0.5"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Terphenyls | 26140-60-3 | (C)1 | (C)9 | - |", "value": "(C)9"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Terphenyls | 0.5 | 5 | C", "value": "5"}]}], "id": "terphenyls", "pel_mgm3": "(C)9", "pel_ppm": "(C)1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Terphenyls | 26140-60-3 | (C)1 | (C)9 | - |", "substance": "Terphenyls", "url": "https://referencesource.org/workplace-exposure-limits/terphenyls/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "625161", "id": "tert-amyl-acetate-see-pentyl-acetate", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "625161 | | tert-Amyl acetate; see Pentyl acetate", "substance": "tert-Amyl acetate; see Pentyl acetate", "url": "https://referencesource.org/workplace-exposure-limits/tert-amyl-acetate-see-pentyl-acetate/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0074.html", "source_quote": "NIOSH REL TWA 200 ppm (950 mg/m3)", "value": "TWA 200"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0074.html", "source_quote": "NIOSH REL TWA 200 ppm (950 mg/m3)", "value": "950"}], "cas_number": "540-88-5", "disagreements": [{"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "tert-Butyl acetate | 540-88-5 | 200 | 950 | - |", "value": "950"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "540885 | | tert-Butyl acetate | 200 | 955", "value": "955"}]}], "id": "tert-butyl-acetate", "pel_mgm3": "950", "pel_ppm": "200", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "tert-Butyl acetate | 540-88-5 | 200 | 950 | - |", "substance": "tert-Butyl acetate", "url": "https://referencesource.org/workplace-exposure-limits/tert-butyl-acetate/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75650 | | tert-Butyl alcohol | 100 | 300 | | 150 | 450", "value": "150"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75650 | | tert-Butyl alcohol | 100 | 300 | | 150 | 450", "value": "450"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0078.html", "source_quote": "NIOSH REL TWA 100 ppm (300 mg/m3) ST 150 ppm (450 mg/m3)", "value": "TWA 100"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0078.html", "source_quote": "NIOSH REL TWA 100 ppm (300 mg/m3) ST 150 ppm (450 mg/m3)", "value": "300"}], "cas_number": "75-65-0", "disagreements": [], "id": "tert-butyl-alcohol", "pel_mgm3": "300", "pel_ppm": "100", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "tert-Butyl alcohol | 75-65-0 | 100 | 300 | - |", "substance": "tert-Butyl alcohol", "url": "https://referencesource.org/workplace-exposure-limits/tert-butyl-alcohol/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-28", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "1189851 | S | tert-Butyl chromate; di-tert-butyl Chromate, as CrO$3 | -- | 0.1 | C", "value": "0.1"}, {"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "1189851 | S | tert-Butyl chromate; di-tert-butyl Chromate, as CrO$3 | -- | 0.1 | C", "value": "the values given in the PEL columns are ceiling values"}], "cas_number": "1189-85-1", "disagreements": [], "id": "tert-butyl-chromate", "rel_statement": "Ca TWA 0.001 mg Cr(VI)/m3 See Appendix A See Appendix C", "source": "https://www.cdc.gov/niosh/npg/npgd0080.html", "source_quote": "NIOSH REL Ca TWA 0.001 mg Cr(VI)/m3 See Appendix A See Appendix C", "substance": "tert-Butyl chromate", "url": "https://referencesource.org/workplace-exposure-limits/tert-butyl-chromate/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0600.html", "source_quote": "NIOSH REL TWA 2 mg/m3 [skin]", "value": "TWA 2"}], "cas_number": "1335-88-2", "disagreements": [], "id": "tetrachloronaphthalene", "pel_mgm3": "2", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Tetrachloronaphthalene | 1335-88-2 | - | 2 | X |", "substance": "Tetrachloronaphthalene", "url": "https://referencesource.org/workplace-exposure-limits/tetrachloronaphthalene/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0601.html", "source_quote": "NIOSH REL TWA 0.075 mg/m3 [skin]", "value": "TWA 0.075"}], "cas_number": "78-00-2", "disagreements": [], "id": "tetraethyl-lead-as-pb", "pel_mgm3": "0.075", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Tetraethyl lead (as Pb) | 78-00-2 | - | 0.075 | X |", "substance": "Tetraethyl lead (as Pb)", "url": "https://referencesource.org/workplace-exposure-limits/tetraethyl-lead-as-pb/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "109999 | | Tetrahydrofuran | 200 | 590 | | 250 | 735", "value": "250"}, {"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "109999 | | Tetrahydrofuran | 200 | 590 | | 250 | 735", "value": "735"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0602.html", "source_quote": "NIOSH REL TWA 200 ppm (590 mg/m3) ST 250 ppm (735 mg/m3)", "value": "TWA 200"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0602.html", "source_quote": "NIOSH REL TWA 200 ppm (590 mg/m3) ST 250 ppm (735 mg/m3)", "value": "590"}], "cas_number": "109-99-9", "disagreements": [], "id": "tetrahydrofuran", "pel_mgm3": "590", "pel_ppm": "200", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Tetrahydrofuran | 109-99-9 | 200 | 590 | - |", "substance": "Tetrahydrofuran", "url": "https://referencesource.org/workplace-exposure-limits/tetrahydrofuran/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0603.html", "source_quote": "NIOSH REL TWA 0.075 mg/m3 [skin]", "value": "TWA 0.075"}], "cas_number": "75-74-1", "disagreements": [], "id": "tetramethyl-lead-as-pb", "pel_mgm3": "0.075", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Tetramethyl lead (as Pb) | 75-74-1 | - | 0.075 | X |", "substance": "Tetramethyl lead (as Pb)", "url": "https://referencesource.org/workplace-exposure-limits/tetramethyl-lead-as-pb/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0604.html", "source_quote": "NIOSH REL TWA 3 mg/m3 (0.5 ppm) [skin]", "value": "0.5"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0604.html", "source_quote": "NIOSH REL TWA 3 mg/m3 (0.5 ppm) [skin]", "value": "TWA 3"}], "cas_number": "3333-52-6", "disagreements": [], "id": "tetramethyl-succinonitrile", "pel_mgm3": "3", "pel_ppm": "0.5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Tetramethyl succinonitrile | 3333-52-6 | 0.5 | 3 | X |", "substance": "Tetramethyl succinonitrile", "url": "https://referencesource.org/workplace-exposure-limits/tetramethyl-succinonitrile/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0605.html", "source_quote": "NIOSH REL TWA 1 ppm (8 mg/m3)", "value": "TWA 1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0605.html", "source_quote": "NIOSH REL TWA 1 ppm (8 mg/m3)", "value": "8"}], "cas_number": "509-14-8", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Tetranitromethane | 509-14-8 | 1 | 8 | - |", "value": "1"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "509148 | | Tetranitromethane | 0.005 | 0.04", "value": "0.005"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Tetranitromethane | 509-14-8 | 1 | 8 | - |", "value": "8"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "509148 | | Tetranitromethane | 0.005 | 0.04", "value": "0.04"}]}], "id": "tetranitromethane", "pel_mgm3": "8", "pel_ppm": "1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Tetranitromethane | 509-14-8 | 1 | 8 | - |", "substance": "Tetranitromethane", "url": "https://referencesource.org/workplace-exposure-limits/tetranitromethane/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0606.html", "source_quote": "NIOSH REL TWA 5 mg/m3", "value": "TWA 5"}], "cas_number": "7722885", "disagreements": [], "id": "tetrasodium-pyrophosphate", "pel_mgm3": "5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7722885 | | Tetrasodium pyrophosphate | -- | 5", "substance": "Tetrasodium pyrophosphate", "url": "https://referencesource.org/workplace-exposure-limits/tetrasodium-pyrophosphate/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Tetryl (2,4,6-Trinitrophenylmethylnitramine) | 479-45-8 | - | 1.5 | X |", "value": "1.5"}], "cas_number": "479-45-8", "disagreements": [], "id": "tetryl", "rel_mgm3": "TWA 1.5", "source": "https://www.cdc.gov/niosh/npg/npgd0607.html", "source_quote": "NIOSH REL TWA 1.5 mg/m3 [skin]", "substance": "Tetryl", "url": "https://referencesource.org/workplace-exposure-limits/tetryl/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"cas_number": "7440-28-0", "disagreements": [], "id": "thallium-soluble-compounds-as-tl", "pel_mgm3": "0.1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Thallium, soluble compounds (as Tl) | 7440-28-0 | - | 0.1 | X |", "substance": "Thallium, soluble compounds (as Tl)", "url": "https://referencesource.org/workplace-exposure-limits/thallium-soluble-compounds-as-tl/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0610.html", "source_quote": "NIOSH REL TWA 1 ppm (4 mg/m3) [skin]", "value": "TWA 1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0610.html", "source_quote": "NIOSH REL TWA 1 ppm (4 mg/m3) [skin]", "value": "4"}], "cas_number": "68111", "disagreements": [], "id": "thioglycolic-acid", "pel_mgm3": "3.8", "pel_ppm": "1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "68111 | S | Thioglycolic acid | 1 | 3.8", "substance": "Thioglycolic acid", "url": "https://referencesource.org/workplace-exposure-limits/thioglycolic-acid/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0611.html", "source_quote": "NIOSH REL C 1 ppm (5 mg/m3)", "value": "C 1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0611.html", "source_quote": "NIOSH REL C 1 ppm (5 mg/m3)", "value": "5"}], "cas_number": "7719097", "ceiling_notation": "the values given in the PEL columns are ceiling values", "disagreements": [], "id": "thionyl-chloride", "pel_mgm3": "5", "pel_ppm": "1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7719097 | | Thionyl chloride | 1 | 5 | C", "substance": "Thionyl chloride", "url": "https://referencesource.org/workplace-exposure-limits/thionyl-chloride/", "verified_fields": ["cas_number", "ceiling_notation", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0612.html", "source_quote": "NIOSH REL TWA 5 mg/m3", "value": "TWA 5"}], "cas_number": "137-26-8", "disagreements": [], "id": "thiram", "pel_mgm3": "5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Thiram | 137-26-8 | - | 5 | - |", "substance": "Thiram", "url": "https://referencesource.org/workplace-exposure-limits/thiram/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"cas_number": "7440-31-5", "id": "tin", "rel_mgm3": "TWA 2", "source": "https://www.cdc.gov/niosh/npg/npgd0613.html", "source_quote": "NIOSH REL TWA 2 mg/m3", "substance": "Tin", "url": "https://referencesource.org/workplace-exposure-limits/tin/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "21651194 | | Tin, tin oxide and inorganic compounds, except SnH $4, as Sn | -- | 2", "value": "2"}], "cas_number": "21651-19-4", "disagreements": [], "id": "tin-ii-oxide-as-sn", "rel_mgm3": "TWA 2", "source": "https://www.cdc.gov/niosh/npg/npgd0615.html", "source_quote": "NIOSH REL TWA 2 mg/m3", "substance": "Tin(II) oxide (as Sn)", "url": "https://referencesource.org/workplace-exposure-limits/tin-ii-oxide-as-sn/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"cas_number": "7440-31-5", "id": "tin-inorganic-compounds-except-oxides-as-sn", "pel_mgm3": "2", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Tin, inorganic compounds (except oxides) (as Sn) | 7440-31-5 | - | 2 | - |", "substance": "Tin, inorganic compounds (except oxides) (as Sn)", "url": "https://referencesource.org/workplace-exposure-limits/tin-inorganic-compounds-except-oxides-as-sn/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"cas_number": "18282-10-5", "id": "tin-iv-oxide-as-sn", "rel_mgm3": "TWA 2", "source": "https://www.cdc.gov/niosh/npg/npgd0616.html", "source_quote": "NIOSH REL TWA 2 mg/m3", "substance": "Tin(IV) oxide (as Sn)", "url": "https://referencesource.org/workplace-exposure-limits/tin-iv-oxide-as-sn/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-25", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "S | Tin, organic compounds, as Sn | -- | 0.1 | | -- | 0.2", "value": "0.2"}], "cas_number": "7440-31-5", "disagreements": [], "id": "tin-organic-compounds-as-sn", "pel_mgm3": "0.1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Tin, organic compounds (as Sn) | 7440-31-5 | - | 0.1 | - |", "substance": "Tin, organic compounds (as Sn)", "url": "https://referencesource.org/workplace-exposure-limits/tin-organic-compounds-as-sn/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0617.html", "source_quote": "NIOSH REL Ca See Appendix A", "value": "Ca See Appendix A"}], "cas_number": "13463-67-7", "disagreements": [], "id": "titanium-dioxide", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Titanium dioxide | 13463-67-7 | - | - | - |", "substance": "Titanium dioxide", "url": "https://referencesource.org/workplace-exposure-limits/titanium-dioxide/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0619.html", "source_quote": "NIOSH REL TWA 100 ppm (375 mg/m3) ST 150 ppm (560 mg/m3)", "value": "TWA 100"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0619.html", "source_quote": "NIOSH REL TWA 100 ppm (375 mg/m3) ST 150 ppm (560 mg/m3)", "value": "375"}, {"as_of": "2026-09-28", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "108883 | S | Toluene; toluol | 10 | 37 | 500 ppm | 150 | 560", "value": "10"}, {"as_of": "2026-09-28", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "108883 | S | Toluene; toluol | 10 | 37 | 500 ppm | 150 | 560", "value": "37"}, {"as_of": "2026-09-28", "field": "ceiling", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "108883 | S | Toluene; toluol | 10 | 37 | 500 ppm | 150 | 560", "value": "500 ppm"}, {"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "108883 | S | Toluene; toluol | 10 | 37 | 500 ppm | 150 | 560", "value": "a ceiling value in addition to the TWA values"}, {"as_of": "2026-09-28", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "108883 | S | Toluene; toluol | 10 | 37 | 500 ppm | 150 | 560", "value": "150"}, {"as_of": "2026-09-28", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "108883 | S | Toluene; toluol | 10 | 37 | 500 ppm | 150 | 560", "value": "560"}], "cas_number": "108-88-3", "disagreements": [], "id": "toluene", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Toluene | 108-88-3 | - | (2) | - |", "substance": "Toluene", "url": "https://referencesource.org/workplace-exposure-limits/toluene/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Toluene-2,4-diisocyanate (TDI) | 584-84-9 | (C)0.02 | (C)0.14 | - |", "value": "(C)0.02"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Toluene-2,4-diisocyanate (TDI) | 584-84-9 | (C)0.02 | (C)0.14 | - |", "value": "(C)0.14"}, {"as_of": "2026-09-28", "field": "ceiling", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "584849 | | Toluene-2,4-diisocyanate; TDI | 0.005 | 0.04 | 0.02 ppm | 0.02 | 0.15", "value": "0.02 ppm"}, {"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "584849 | | Toluene-2,4-diisocyanate; TDI | 0.005 | 0.04 | 0.02 ppm | 0.02 | 0.15", "value": "a ceiling value in addition to the TWA values"}, {"as_of": "2026-09-28", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "584849 | | Toluene-2,4-diisocyanate; TDI | 0.005 | 0.04 | 0.02 ppm | 0.02 | 0.15", "value": "0.02"}, {"as_of": "2026-09-28", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "584849 | | Toluene-2,4-diisocyanate; TDI | 0.005 | 0.04 | 0.02 ppm | 0.02 | 0.15", "value": "0.15"}], "cas_number": "584-84-9", "disagreements": [], "id": "toluene-2-4-diisocyanate", "rel_statement": "Ca See Appendix A", "source": "https://www.cdc.gov/niosh/npg/npgd0621.html", "source_quote": "NIOSH REL Ca See Appendix A", "substance": "Toluene-2,4-diisocyanate", "url": "https://referencesource.org/workplace-exposure-limits/toluene-2-4-diisocyanate/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"cas_number": "25376-45-8 95-80-7 (2,4-TDA)", "id": "toluenediamine", "rel_statement": "Ca (all isomers) See Appendix A", "source": "https://www.cdc.gov/niosh/npg/npgd0620.html", "source_quote": "NIOSH REL Ca (all isomers) See Appendix A", "substance": "Toluenediamine", "url": "https://referencesource.org/workplace-exposure-limits/toluenediamine/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"id": "tremolite-containing-no-asbestos-fibers-respirable-dust", "pel_mgm3": "2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Tremolite (containing no asbestos fibers), respirable dust | -- | 2", "substance": "Tremolite (containing no asbestos fibers), respirable dust", "url": "https://referencesource.org/workplace-exposure-limits/tremolite-containing-no-asbestos-fibers-respirable-dust/", "verified_fields": ["pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "126738 | | Tributyl phosphate | 0.2 | 2.5", "value": "0.2"}, {"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0625.html", "source_quote": "NIOSH REL TWA 0.2 ppm (2.5 mg/m3)", "value": "TWA 0.2"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0625.html", "source_quote": "NIOSH REL TWA 0.2 ppm (2.5 mg/m3)", "value": "2.5"}], "cas_number": "126-73-8", "disagreements": [{"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Tributyl phosphate | 126-73-8 | - | 5 | - |", "value": "5"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "126738 | | Tributyl phosphate | 0.2 | 2.5", "value": "2.5"}]}], "id": "tributyl-phosphate", "pel_mgm3": "5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Tributyl phosphate | 126-73-8 | - | 5 | - |", "substance": "Tributyl phosphate", "url": "https://referencesource.org/workplace-exposure-limits/tributyl-phosphate/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0626.html", "source_quote": "NIOSH REL TWA 1 ppm (7 mg/m3)", "value": "TWA 1"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0626.html", "source_quote": "NIOSH REL TWA 1 ppm (7 mg/m3)", "value": "7"}], "cas_number": "76039", "disagreements": [], "id": "trichloroacetic-acid", "pel_mgm3": "5", "pel_ppm": "1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "76039 | | Trichloroacetic acid | 1 | 5", "substance": "Trichloroacetic acid", "url": "https://referencesource.org/workplace-exposure-limits/trichloroacetic-acid/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0629.html", "source_quote": "NIOSH REL Ca See Appendix A See Appendix C", "value": "Ca See Appendix A See Appendix C"}, {"as_of": "2026-09-28", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "79016 | | Trichloroethylene; trichloro-ethene | 25 | 135 | 300 ppm | 100 | 537", "value": "25"}, {"as_of": "2026-09-28", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "79016 | | Trichloroethylene; trichloro-ethene | 25 | 135 | 300 ppm | 100 | 537", "value": "135"}, {"as_of": "2026-09-28", "field": "ceiling", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "79016 | | Trichloroethylene; trichloro-ethene | 25 | 135 | 300 ppm | 100 | 537", "value": "300 ppm"}, {"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "79016 | | Trichloroethylene; trichloro-ethene | 25 | 135 | 300 ppm | 100 | 537", "value": "a ceiling value in addition to the TWA values"}, {"as_of": "2026-09-28", "field": "stel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "79016 | | Trichloroethylene; trichloro-ethene | 25 | 135 | 300 ppm | 100 | 537", "value": "100"}, {"as_of": "2026-09-28", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "79016 | | Trichloroethylene; trichloro-ethene | 25 | 135 | 300 ppm | 100 | 537", "value": "537"}], "cas_number": "79-01-6", "disagreements": [], "id": "trichloroethylene", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Trichloroethylene | 79-01-6 | - | (2) | - |", "substance": "Trichloroethylene", "url": "https://referencesource.org/workplace-exposure-limits/trichloroethylene/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0630.html", "source_quote": "NIOSH REL TWA 5 mg/m3 [skin]", "value": "TWA 5"}], "cas_number": "1321-65-9", "disagreements": [], "id": "trichloronaphthalene", "pel_mgm3": "5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Trichloronaphthalene | 1321-65-9 | - | 5 | X |", "substance": "Trichloronaphthalene", "url": "https://referencesource.org/workplace-exposure-limits/trichloronaphthalene/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"cas_number": "15468323", "disagreements": [], "id": "tridymite", "pel_mgm3": "0.05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "15468323 | | Tridymite, | -- | 0.05", "substance": "Tridymite,", "url": "https://referencesource.org/workplace-exposure-limits/tridymite/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"cas_number": "102716", "id": "triethanolamine", "pel_mgm3": "5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "102716 | | Triethanolamine | -- | 5", "substance": "Triethanolamine", "url": "https://referencesource.org/workplace-exposure-limits/triethanolamine/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-28", "field": "ceiling_notation", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "121448 | S | Triethylamine | 1 | 4.1 | C", "value": "the values given in the PEL columns are ceiling values"}, {"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0633.html", "source_quote": "NIOSH REL See Appendix D", "value": "See Appendix D"}], "cas_number": "121-44-8", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Triethylamine | 121-44-8 | 25 | 100 | - |", "value": "25"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "121448 | S | Triethylamine | 1 | 4.1 | C", "value": "1"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Triethylamine | 121-44-8 | 25 | 100 | - |", "value": "100"}, {"as_of": "2026-09-28", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "121448 | S | Triethylamine | 1 | 4.1 | C", "value": "4.1"}]}], "id": "triethylamine", "pel_mgm3": "100", "pel_ppm": "25", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Triethylamine | 121-44-8 | 25 | 100 | - |", "substance": "Triethylamine", "url": "https://referencesource.org/workplace-exposure-limits/triethylamine/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "112492", "id": "triethylene-glycol-dimethyl-ether-triglyme", "pel_mgm3": "36", "pel_ppm": "5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "112492 | S | Triethylene glycol dimethyl ether, Triglyme | 5 | 36", "substance": "Triethylene glycol dimethyl ether, Triglyme", "url": "https://referencesource.org/workplace-exposure-limits/triethylene-glycol-dimethyl-ether-triglyme/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0634.html", "source_quote": "NIOSH REL TWA 1000 ppm (6100 mg/m3)", "value": "TWA 1000"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0634.html", "source_quote": "NIOSH REL TWA 1000 ppm (6100 mg/m3)", "value": "6100"}], "cas_number": "75-63-8", "disagreements": [], "id": "trifluorobromomethane", "pel_mgm3": "6100", "pel_ppm": "1000", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Trifluorobromomethane | 75-63-8 | 1000 | 6100 | - |", "substance": "Trifluorobromomethane", "url": "https://referencesource.org/workplace-exposure-limits/trifluorobromomethane/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0635.html", "source_quote": "NIOSH REL TWA 0.005 ppm (0.04 mg/m3) Should be handled in the workplace as an extremely toxic substance", "value": "TWA 0.005"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0635.html", "source_quote": "NIOSH REL TWA 0.005 ppm (0.04 mg/m3) Should be handled in the workplace as an extremely toxic substance", "value": "0.04"}], "cas_number": "552307", "ceiling_notation": "the values given in the PEL columns are ceiling values", "disagreements": [], "id": "trimellitic-anhydride", "pel_mgm3": "0.04", "pel_ppm": "0.005", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "552307 | | Trimellitic anhydride | 0.005 | 0.04 | C", "substance": "Trimellitic anhydride", "url": "https://referencesource.org/workplace-exposure-limits/trimellitic-anhydride/", "verified_fields": ["cas_number", "ceiling_notation", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0640.html", "source_quote": "NIOSH REL TWA 2 ppm (10 mg/m3)", "value": "TWA 2"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0640.html", "source_quote": "NIOSH REL TWA 2 ppm (10 mg/m3)", "value": "10"}], "cas_number": "121459", "disagreements": [], "id": "trimethyl-phosphite", "pel_mgm3": "10", "pel_ppm": "2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "121459 | | Trimethyl phosphite | 2 | 10", "substance": "Trimethyl phosphite", "url": "https://referencesource.org/workplace-exposure-limits/trimethyl-phosphite/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0636.html", "source_quote": "NIOSH REL TWA 10 ppm (24 mg/m3) ST 15 ppm (36 mg/m3)", "value": "TWA 10"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0636.html", "source_quote": "NIOSH REL TWA 10 ppm (24 mg/m3) ST 15 ppm (36 mg/m3)", "value": "24"}], "cas_number": "75503", "disagreements": [], "id": "trimethylamine", "pel_mgm3": "12", "pel_ppm": "5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75503 | | Trimethylamine | 5 | 12 | | 15 | 36", "stel_mgm3": "36", "stel_ppm": "15", "substance": "Trimethylamine", "url": "https://referencesource.org/workplace-exposure-limits/trimethylamine/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "stel_mgm3", "stel_ppm", "substance"]}
{"id": "trimethylbenzene-all-isomers", "pel_mgm3": "125", "pel_ppm": "25", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Trimethylbenzene, all isomers | 25 | 125", "substance": "Trimethylbenzene, all isomers", "url": "https://referencesource.org/workplace-exposure-limits/trimethylbenzene-all-isomers/", "verified_fields": ["pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0642.html", "source_quote": "NIOSH REL TWA 0.1 mg/m3 [skin]", "value": "TWA 0.1"}], "cas_number": "78-30-8", "disagreements": [], "id": "triorthocresyl-phosphate", "pel_mgm3": "0.1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Triorthocresyl phosphate | 78-30-8 | - | 0.1 | - |", "substance": "Triorthocresyl phosphate", "url": "https://referencesource.org/workplace-exposure-limits/triorthocresyl-phosphate/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0644.html", "source_quote": "NIOSH REL TWA 3 mg/m3", "value": "TWA 3"}], "cas_number": "115-86-6", "disagreements": [], "id": "triphenyl-phosphate", "pel_mgm3": "3", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Triphenyl phosphate | 115-86-6 | - | 3 | - |", "substance": "Triphenyl phosphate", "url": "https://referencesource.org/workplace-exposure-limits/triphenyl-phosphate/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0643.html", "source_quote": "NIOSH REL TWA 5 mg/m3", "value": "TWA 5"}], "cas_number": "603349", "disagreements": [], "id": "triphenylamine", "pel_mgm3": "5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "603349 | | Triphenylamine | -- | 5", "substance": "Triphenylamine", "url": "https://referencesource.org/workplace-exposure-limits/triphenylamine/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"cas_number": "1317959", "disagreements": [], "id": "tripoli-as-quartz", "pel_mgm3": "0.05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "1317959 | | Tripoli, (as quartz) | -- | 0.05", "substance": "Tripoli, (as quartz)", "url": "https://referencesource.org/workplace-exposure-limits/tripoli-as-quartz/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7440337 | | Tungsten metal, as W | -- | 5", "value": "5"}], "cas_number": "7440-33-7", "disagreements": [], "id": "tungsten", "rel_mgm3": "TWA 5", "source": "https://www.cdc.gov/niosh/npg/npgd0645.html", "source_quote": "NIOSH REL TWA 5 mg/m3 ST 10 mg/m3", "substance": "Tungsten", "url": "https://referencesource.org/workplace-exposure-limits/tungsten/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"cas_number": "1: 11107-01-0 2: 12718-69-3 3: 37329-49-0", "id": "tungsten-carbide-cemented", "rel_statement": "See Appendix C", "source": "https://www.cdc.gov/niosh/npg/npgd0647.html", "source_quote": "NIOSH REL See Appendix C", "substance": "Tungsten carbide (cemented)", "url": "https://referencesource.org/workplace-exposure-limits/tungsten-carbide-cemented/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"id": "tungsten-insoluble-compounds-as-w", "pel_mgm3": "5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Tungsten, insoluble compounds, as W | -- | 5 | | -- | 10", "stel_mgm3": "10", "substance": "Tungsten, insoluble compounds, as W", "url": "https://referencesource.org/workplace-exposure-limits/tungsten-insoluble-compounds-as-w/", "verified_fields": ["pel_mgm3", "stel_mgm3", "substance"]}
{"id": "tungsten-soluble-compounds-as-w", "pel_mgm3": "1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Tungsten, soluble compounds, as W | -- | 1 | | -- | 3", "stel_mgm3": "3", "substance": "Tungsten, soluble compounds, as W", "url": "https://referencesource.org/workplace-exposure-limits/tungsten-soluble-compounds-as-w/", "verified_fields": ["pel_mgm3", "stel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0648.html", "source_quote": "NIOSH REL TWA 100 ppm (560 mg/m3)", "value": "TWA 100"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0648.html", "source_quote": "NIOSH REL TWA 100 ppm (560 mg/m3)", "value": "560"}], "cas_number": "8006-64-2", "disagreements": [], "id": "turpentine", "pel_mgm3": "560", "pel_ppm": "100", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Turpentine | 8006-64-2 | 100 | 560 | - |", "substance": "Turpentine", "url": "https://referencesource.org/workplace-exposure-limits/turpentine/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0650.html", "source_quote": "NIOSH REL Ca TWA 0.2 mg/m3 ST 0.6 mg/m3", "value": "TWA 0.2"}], "cas_number": "7440-61-1", "disagreements": [], "id": "uranium-as-u", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Uranium (as U) | 7440-61-1 | - | - | - |", "substance": "Uranium (as U)", "url": "https://referencesource.org/workplace-exposure-limits/uranium-as-u/", "verified_fields": ["cas_number", "substance"]}
{"id": "uranium-natural-insoluble-compounds-as-u", "pel_mgm3": "0.2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Uranium (natural), insoluble compounds, as U | -- | 0.2 | | -- | 0.6", "stel_mgm3": "0.6", "substance": "Uranium (natural), insoluble compounds, as U", "url": "https://referencesource.org/workplace-exposure-limits/uranium-natural-insoluble-compounds-as-u/", "verified_fields": ["pel_mgm3", "stel_mgm3", "substance"]}
{"id": "uranium-natural-soluble-compounds-as-u", "pel_mgm3": "0.05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Uranium (natural), soluble compounds, as U | -- | 0.05", "substance": "Uranium (natural), soluble compounds, as U", "url": "https://referencesource.org/workplace-exposure-limits/uranium-natural-soluble-compounds-as-u/", "verified_fields": ["pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0653.html", "source_quote": "NIOSH REL C 0.05 mg V/m3 [15-minute]", "value": "C 0.05 mg V/m3 [15-minute]"}, {"as_of": "2026-09-25", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "1314621 | | Vanadium pentoxide (V$2O$5), respirable dust and fume | -- | 0.05", "value": "0.05"}], "cas_number": "1314-62-1", "disagreements": [], "id": "vanadium", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Vanadium | 1314-62-1 | - | - | - |", "substance": "Vanadium", "url": "https://referencesource.org/workplace-exposure-limits/vanadium/", "verified_fields": ["cas_number", "substance"]}
{"cas_number": "68956-68-3", "id": "vegetable-oil-mist", "rel_statement": "TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)", "source": "https://www.cdc.gov/niosh/npg/npgd0655.html", "source_quote": "NIOSH REL TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)", "substance": "Vegetable oil mist", "url": "https://referencesource.org/workplace-exposure-limits/vegetable-oil-mist/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0656.html", "source_quote": "NIOSH REL C 4 ppm (15 mg/m3) [15-minute]", "value": "C 4"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0656.html", "source_quote": "NIOSH REL C 4 ppm (15 mg/m3) [15-minute]", "value": "15"}], "cas_number": "108054", "disagreements": [], "id": "vinyl-acetate", "pel_mgm3": "30", "pel_ppm": "10", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "108054 | | Vinyl acetate | 10 | 30 | | 15 | 45", "stel_mgm3": "45", "stel_ppm": "15", "substance": "Vinyl acetate", "url": "https://referencesource.org/workplace-exposure-limits/vinyl-acetate/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "stel_mgm3", "stel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "593602 | | Vinyl bromide; bromoethylene | 0.1 | 0.44", "value": "0.1"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "593602 | | Vinyl bromide; bromoethylene | 0.1 | 0.44", "value": "0.44"}], "cas_number": "593-60-2", "disagreements": [], "id": "vinyl-bromide", "rel_statement": "Ca See Appendix A", "source": "https://www.cdc.gov/niosh/npg/npgd0657.html", "source_quote": "NIOSH REL Ca See Appendix A", "substance": "Vinyl bromide", "url": "https://referencesource.org/workplace-exposure-limits/vinyl-bromide/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75014 | S | Vinyl chloride, see Section 5210 | 1", "value": "1"}], "cas_number": "75-01-4", "disagreements": [], "id": "vinyl-chloride", "rel_statement": "Ca See Appendix A", "source": "https://www.cdc.gov/niosh/npg/npgd0658.html", "source_quote": "NIOSH REL Ca See Appendix A", "substance": "Vinyl chloride", "url": "https://referencesource.org/workplace-exposure-limits/vinyl-chloride/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0659.html", "source_quote": "NIOSH REL Ca TWA 10 ppm (60 mg/m3) [skin]", "value": "TWA 10"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0659.html", "source_quote": "NIOSH REL Ca TWA 10 ppm (60 mg/m3) [skin]", "value": "60"}], "cas_number": "106876", "disagreements": [], "id": "vinyl-cyclohexene-dioxide", "pel_mgm3": "0.57", "pel_ppm": "0.1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "106876 | S | Vinyl cyclohexene dioxide | 0.1 | 0.57", "substance": "Vinyl cyclohexene dioxide", "url": "https://referencesource.org/workplace-exposure-limits/vinyl-cyclohexene-dioxide/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0660.html", "source_quote": "NIOSH REL TWA 1 ppm C 5 ppm [use 1910.1017]", "value": "TWA 1"}], "cas_number": "75025", "disagreements": [], "id": "vinyl-fluoride", "pel_mgm3": "0.38", "pel_ppm": "0.2", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75025 | | Vinyl fluoride | 0.2 | 0.38", "substance": "Vinyl fluoride", "url": "https://referencesource.org/workplace-exposure-limits/vinyl-fluoride/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0663.html", "source_quote": "NIOSH REL TWA 100 ppm (480 mg/m3)", "value": "TWA 100"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0663.html", "source_quote": "NIOSH REL TWA 100 ppm (480 mg/m3)", "value": "480"}], "cas_number": "25013-15-4", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Vinyl toluene | 25013-15-4 | 100 | 480 | - |", "value": "100"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "25013154 | | Vinyltoluene | 50 | 240", "value": "50"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Vinyl toluene | 25013-15-4 | 100 | 480 | - |", "value": "480"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "25013154 | | Vinyltoluene | 50 | 240", "value": "240"}]}], "id": "vinyl-toluene", "pel_mgm3": "480", "pel_ppm": "100", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Vinyl toluene | 25013-15-4 | 100 | 480 | - |", "substance": "Vinyl toluene", "url": "https://referencesource.org/workplace-exposure-limits/vinyl-toluene/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_ppm", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75354 | | Vinylidene chloride; 1,1-dichloroethylene | 1 | 4", "value": "1"}, {"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75354 | | Vinylidene chloride; 1,1-dichloroethylene | 1 | 4", "value": "4"}], "cas_number": "75-35-4", "disagreements": [], "id": "vinylidene-chloride", "rel_statement": "Ca See Appendix A", "source": "https://www.cdc.gov/niosh/npg/npgd0661.html", "source_quote": "NIOSH REL Ca See Appendix A", "substance": "Vinylidene chloride", "url": "https://referencesource.org/workplace-exposure-limits/vinylidene-chloride/", "verified_fields": ["cas_number", "rel_statement", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0662.html", "source_quote": "NIOSH REL TWA 1 ppm C 5 ppm [use 1910.1017]", "value": "TWA 1"}], "cas_number": "75387", "disagreements": [], "id": "vinylidene-fluoride", "pel_mgm3": "262", "pel_ppm": "100", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "75387 | | Vinylidene fluoride | 100 | 262", "substance": "Vinylidene fluoride", "url": "https://referencesource.org/workplace-exposure-limits/vinylidene-fluoride/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"cas_number": "8032-32-4", "id": "vm-p-naphtha", "rel_mgm3": "TWA 350", "source": "https://www.cdc.gov/niosh/npg/npgd0664.html", "source_quote": "NIOSH REL TWA 350 mg/m3 C 1800 mg/m3 [15-minute]", "substance": "VM & P Naphtha", "url": "https://referencesource.org/workplace-exposure-limits/vm-p-naphtha/", "verified_fields": ["cas_number", "rel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0665.html", "source_quote": "NIOSH REL TWA 0.1 mg/m3", "value": "TWA 0.1"}], "cas_number": "81-81-2", "disagreements": [], "id": "warfarin", "pel_mgm3": "0.1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Warfarin | 81-81-2 | - | 0.1 | - |", "substance": "Warfarin", "url": "https://referencesource.org/workplace-exposure-limits/warfarin/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"id": "welding-fumes-total-particulates-see-also-individual-constituents", "pel_mgm3": "5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Welding fumes; total particulates (see also individual constituents) | -- | 5", "substance": "Welding fumes; total particulates (see also individual constituents)", "url": "https://referencesource.org/workplace-exposure-limits/welding-fumes-total-particulates-see-also-individual-constituents/", "verified_fields": ["pel_mgm3", "substance"]}
{"id": "wood-dust-western-red-cedar", "pel_mgm3": "0.5", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Wood dust, Western red cedar | -- | 0.5", "substance": "Wood dust, Western red cedar", "url": "https://referencesource.org/workplace-exposure-limits/wood-dust-western-red-cedar/", "verified_fields": ["pel_mgm3", "substance"]}
{"cas_number": "1330207", "ceiling": "300 ppm", "ceiling_notation": "a ceiling value in addition to the TWA values", "disagreements": [], "id": "xylene-xylol-dimethylbenzene", "pel_mgm3": "435", "pel_ppm": "100", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "1330207 | | Xylene; xylol; dimethylbenzene | 100 | 435 | 300 ppm | 150 | 655", "stel_mgm3": "655", "stel_ppm": "150", "substance": "Xylene; xylol; dimethylbenzene", "url": "https://referencesource.org/workplace-exposure-limits/xylene-xylol-dimethylbenzene/", "verified_fields": ["cas_number", "ceiling", "ceiling_notation", "pel_mgm3", "pel_ppm", "stel_mgm3", "stel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_ppm", "source": "https://www.cdc.gov/niosh/npg/npgd0672.html", "source_quote": "NIOSH REL TWA 2 ppm (10 mg/m3) [skin]", "value": "TWA 2"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0672.html", "source_quote": "NIOSH REL TWA 2 ppm (10 mg/m3) [skin]", "value": "10"}], "cas_number": "1300-73-8", "disagreements": [{"field": "pel_ppm", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Xylidine | 1300-73-8 | 5 | 25 | X |", "value": "5"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "1300738 | S | Xylidine; aminodimethylbenzene | 0.5 | 2.5", "value": "0.5"}]}, {"field": "pel_mgm3", "versions": [{"as_of": "2026-08-05", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Xylidine | 1300-73-8 | 5 | 25 | X |", "value": "25"}, {"as_of": "2026-08-05", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "1300738 | S | Xylidine; aminodimethylbenzene | 0.5 | 2.5", "value": "2.5"}]}], "id": "xylidine", "pel_mgm3": "25", "pel_ppm": "5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Xylidine | 1300-73-8 | 5 | 25 | X |", "substance": "Xylidine", "url": "https://referencesource.org/workplace-exposure-limits/xylidine/", "verified_fields": ["cas_number", "pel_mgm3", "pel_ppm", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0673.html", "source_quote": "NIOSH REL TWA 1 mg/m3", "value": "TWA 1"}], "cas_number": "7440-65-5", "disagreements": [], "id": "yttrium", "pel_mgm3": "1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Yttrium | 7440-65-5 | - | 1 | - |", "substance": "Yttrium", "url": "https://referencesource.org/workplace-exposure-limits/yttrium/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"id": "yttrium-compounds-as-y", "pel_mgm3": "1", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Yttrium compounds, as Y | -- | 1", "substance": "Yttrium compounds, as Y", "url": "https://referencesource.org/workplace-exposure-limits/yttrium-compounds-as-y/", "verified_fields": ["pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "7646857 | | Zinc chloride fume | -- | 1 | | -- | 2", "value": "2"}, {"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0674.html", "source_quote": "NIOSH REL TWA 1 mg/m3 ST 2 mg/m3", "value": "TWA 1"}], "cas_number": "7646-85-7", "disagreements": [], "id": "zinc-chloride-fume", "pel_mgm3": "1", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Zinc chloride fume | 7646-85-7 | - | 1 | - |", "substance": "Zinc chloride fume", "url": "https://referencesource.org/workplace-exposure-limits/zinc-chloride-fume/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"cas_number": "13530659", "id": "zinc-chromate-as-cr", "pel_mgm3": "0.005", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "13530659 | | Zinc chromate, as Cr | -- | 0.005", "substance": "Zinc chromate, as Cr", "url": "https://referencesource.org/workplace-exposure-limits/zinc-chromate-as-cr/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"cas_number": "15930946", "id": "zinc-chromate-hydroxide-as-cr", "pel_mgm3": "0.005", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "15930946 | | Zinc chromate hydroxide, as Cr | -- | 0.005", "substance": "Zinc chromate hydroxide, as Cr", "url": "https://referencesource.org/workplace-exposure-limits/zinc-chromate-hydroxide-as-cr/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0675.html", "source_quote": "NIOSH REL Dust: TWA 5 mg/m3 C 15 mg/m3 Fume: TWA 5 mg/m3 ST 10 mg/m3", "value": "Dust: TWA 5 mg/m3 C 15 mg/m3 Fume: TWA 5 mg/m3 ST 10 mg/m3"}], "cas_number": "1314-13-2", "disagreements": [], "id": "zinc-oxide", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Zinc oxide | 1314-13-2 | - | - | - |", "substance": "Zinc oxide", "url": "https://referencesource.org/workplace-exposure-limits/zinc-oxide/", "verified_fields": ["cas_number", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "1314132 | | Zinc oxide fume | -- | 5 | | -- | 10", "value": "10"}], "cas_number": "1314-13-2", "disagreements": [], "id": "zinc-oxide-fume", "pel_mgm3": "5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Zinc oxide fume | 1314-13-2 | - | 5 | - |", "substance": "Zinc oxide fume", "url": "https://referencesource.org/workplace-exposure-limits/zinc-oxide-fume/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"cas_number": "11103869", "id": "zinc-potassium-chromate-as-cr", "pel_mgm3": "0.005", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "11103869 | | Zinc potassium chromate, as Cr | -- | 0.005", "substance": "Zinc potassium chromate, as Cr", "url": "https://referencesource.org/workplace-exposure-limits/zinc-potassium-chromate-as-cr/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-08-05", "field": "pel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "557051 | | Zinc stearate | -- | 10", "value": "10"}, {"as_of": "2026-09-08", "field": "rel_statement", "source": "https://www.cdc.gov/niosh/npg/npgd0676.html", "source_quote": "NIOSH REL TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)", "value": "TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)"}], "cas_number": "557-05-1", "disagreements": [], "id": "zinc-stearate", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Zinc stearate | 557-05-1 | - | - | - |", "substance": "Zinc stearate", "url": "https://referencesource.org/workplace-exposure-limits/zinc-stearate/", "verified_fields": ["cas_number", "substance"]}
{"cas_number": "37300235", "id": "zinc-yellow-as-cr", "pel_mgm3": "0.005", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "37300235 | | Zinc yellow, as Cr | -- | 0.005", "substance": "Zinc yellow, as Cr", "url": "https://referencesource.org/workplace-exposure-limits/zinc-yellow-as-cr/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}
{"also_reported": [{"as_of": "2026-09-08", "field": "rel_mgm3", "source": "https://www.cdc.gov/niosh/npg/npgd0677.html", "source_quote": "NIOSH REL TWA 5 mg/m3 ST 10 mg/m3", "value": "TWA 5"}, {"as_of": "2026-09-25", "field": "stel_mgm3", "source": "https://www.dir.ca.gov/title8/5155.html", "source_quote": "Zirconium compounds, as Zr | -- | 5 | | -- | 10", "value": "10"}], "cas_number": "7440-67-7", "disagreements": [], "id": "zirconium-compounds-as-zr", "pel_mgm3": "5", "source": "https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000TableZ1", "source_quote": "Zirconium compounds (as Zr) | 7440-67-7 | - | 5 | - |", "substance": "Zirconium compounds (as Zr)", "url": "https://referencesource.org/workplace-exposure-limits/zirconium-compounds-as-zr/", "verified_fields": ["cas_number", "pel_mgm3", "substance"]}