US
OSHA Exposure Limit Lookup (PEL)
Showing 584 matching row(s) across Tables Z-1, Z-2, and Z-3
Table Z-1 — Limits for Air Contaminants
| Substance | CAS | ppm | mg/m³ | Skin | Z-2 / Z-3 detail |
|---|---|---|---|---|---|
| Acetaldehyde | 75-07-0 | 200 | 360 | ||
| Acetic acid | 64-19-7 | 10 | 25 | ||
| Acetic anhydride | 108-24-7 | 5 | 20 | ||
| Acetone | 67-64-1 | 1000 | 2400 | ||
| Acetonitrile | 75-05-8 | 40 | 70 | ||
| 2-Acetylaminofluorine; see 1910.1014 | 53-96-3 | — | — | ||
| Acetylene dichloride; see 1,2-Dichloroethylene | — | — | — | ||
| Acetylene tetrabromide | 79-27-6 | 1 | 14 | ||
| Acrolein | 107-02-8 | 0.1 | 0.25 | ||
| Acrylamide | 79-06-1 | — | 0.3 | X | |
| Acrylonitrile; see 1910.1045 | 107-13-1 | — | — | ||
| Aldrin | 309-00-2 | — | 0.25 | X | |
| Allyl alcohol | 107-18-6 | 2 | 5 | X | |
| Allyl chloride | 107-05-1 | 1 | 3 | ||
| Allyl glycidyl ether (AGE) | 106-92-3 | (C)10 | (C)45 | ||
| Allyl propyl disulfide | 2179-59-1 | 2 | 12 | ||
| alpha-Alumina — Total dust | 1344-28-1 | — | 15 | ||
| alpha-Alumina — Respirable fraction | 1344-28-1 | — | 5 | ||
| Aluminum, metal (as Al) — Total dust | 7429-90-5 | — | 15 | ||
| Aluminum, metal (as Al) — Respirable fraction | 7429-90-5 | — | 5 | ||
| 4-Aminodiphenyl; see 1910.1011 | 92-67-1 | — | — | ||
| 2-Aminoethanol; see Ethanolamine | — | — | — | ||
| 2-Aminopyridine | 504-29-0 | 0.5 | 2 | ||
| Ammonia | 7664-41-7 | 50 | 35 | ||
| Ammonium sulfamate — Total dust | 7773-06-0 | — | 15 | ||
| Ammonium sulfamate — Respirable fraction | 7773-06-0 | — | 5 | ||
| n-Amyl acetate | 628-63-7 | 100 | 525 | ||
| sec-Amyl acetate | 626-38-0 | 125 | 650 | ||
| Aniline and homologs | 62-53-3 | 5 | 19 | X | |
| Anisidine (o-, p-isomers) | 29191-52-4 | — | 0.5 | X | |
| Antimony and compounds (as Sb) | 7440-36-0 | — | 0.5 | ||
| ANTU (alpha Naphthylthiourea) | 86-88-4 | — | 0.3 | ||
| Arsenic, inorganic compounds (as As); see 1910.1018 | 7440-38-2 | — | — | ||
| Arsenic, organic compounds (as As) | 7440-38-2 | — | 0.5 | ||
| Arsine | 7784-42-1 | 0.05 | 0.2 | ||
| Asbestos; see 1910.1001 | (4) | — | — | ||
| Azinphos-methyl | 86-50-0 | — | 0.2 | X | |
| Barium, soluble compounds (as Ba) | 7440-39-3 | — | 0.5 | ||
| Barium sulfate — Total dust | 7727-43-7 | — | 15 | ||
| Barium sulfate — Respirable fraction | 7727-43-7 | — | 5 | ||
| Benomyl — Total dust | 17804-35-2 | — | 15 | ||
| Benomyl — Respirable fraction | 17804-35-2 | — | 5 | ||
| Benzene; see 1910.1028 (Z-2 limits apply in excluded operations/sectors, fn d) | 71-43-2 | — | — | ||
| Benzidine; see 1910.1010 | 92-87-5 | — | — | ||
| p-Benzoquinone; see Quinone | — | — | — | ||
| Benzo(a)pyrene; see Coal tar pitch volatiles | — | — | — | ||
| Benzoyl peroxide | 94-36-0 | — | 5 | ||
| Benzyl chloride | 100-44-7 | 1 | 5 | ||
| Beryllium and beryllium compounds (as Be); see 1926.1124 (fn 8) | 7440-41-7 | — | — | ||
| Biphenyl; see Diphenyl | — | — | — | ||
| Bismuth telluride, Undoped — Total dust | 1304-82-1 | — | 15 | ||
| Bismuth telluride, Undoped — Respirable fraction | 1304-82-1 | — | 5 | ||
| Boron oxide — Total dust | 1303-86-2 | — | 15 | ||
| Boron trifluoride | 7637-07-2 | (C)1 | (C)3 | ||
| Bromine | 7726-95-6 | 0.1 | 0.7 | ||
| Bromoform | 75-25-2 | 0.5 | 5 | X | |
| Butadiene (1,3-Butadiene); see 1910.1051, 1910.19(l) | 106-99-0 | 1 ppm / 5 ppm STEL | — | ||
| Butanethiol; see Butyl mercaptan | — | — | — | ||
| 2-Butanone (Methyl ethyl ketone) | 78-93-3 | 200 | 590 | ||
| 2-Butoxyethanol | 111-76-2 | 50 | 240 | X | |
| n-Butyl-acetate | 123-86-4 | 150 | 710 | ||
| sec-Butyl acetate | 105-46-4 | 200 | 950 | ||
| tert-Butyl acetate | 540-88-5 | 200 | 950 | ||
| n-Butyl alcohol | 71-36-3 | 100 | 300 | ||
| sec-Butyl alcohol | 78-92-2 | 150 | 450 | ||
| tert-Butyl alcohol | 75-65-0 | 100 | 300 | ||
| Butylamine | 109-73-9 | (C)5 | (C)15 | X | |
| tert-Butyl chromate (as CrO3); see 1910.1026 (fn 6) | 1189-85-1 | — | — | ||
| n-Butyl glycidyl ether (BGE) | 2426-08-6 | 50 | 270 | ||
| Butyl mercaptan | 109-79-5 | 10 | 35 | ||
| p-tert-Butyltoluene | 98-51-1 | 10 | 60 | ||
| Cadmium (as Cd); see 1910.1027 | 7440-43-9 | — | — | ||
| Calcium carbonate — Total dust | 1317-65-3 | — | 15 | ||
| Calcium carbonate — Respirable fraction | 1317-65-3 | — | 5 | ||
| Calcium hydroxide — Total dust | 1305-62-0 | — | 15 | ||
| Calcium hydroxide — Respirable fraction | 1305-62-0 | — | 5 | ||
| Calcium oxide | 1305-78-8 | — | 5 | ||
| Calcium silicate — Total dust | 1344-95-2 | — | 15 | ||
| Calcium silicate — Respirable fraction | 1344-95-2 | — | 5 | ||
| Calcium sulfate — Total dust | 7778-18-9 | — | 15 | ||
| Calcium sulfate — Respirable fraction | 7778-18-9 | — | 5 | ||
| Camphor, synthetic | 76-22-2 | — | 2 | ||
| Carbaryl (Sevin) | 63-25-2 | — | 5 | ||
| Carbon black | 1333-86-4 | — | 3.5 | ||
| Carbon dioxide | 124-38-9 | 5000 | 9000 | ||
| Carbon disulfide | 75-15-0 | — | (2) | Z-2 (Carbon disulfide (Z37.3-1968)): TWA 20 ppm · Ceiling 30 ppm · Peak 100 ppm (30 minutes) | |
| Carbon monoxide | 630-08-0 | 50 | 55 | ||
| Carbon tetrachloride | 56-23-5 | — | (2) | Z-2 (Carbon tetrachloride (Z37.17-1967)): TWA 10 ppm · Ceiling 25 ppm · Peak 200 ppm (5 min in any 4 hrs) | |
| Cellulose — Total dust | 9004-34-6 | — | 15 | ||
| Cellulose — Respirable fraction | 9004-34-6 | — | 5 | ||
| Chlordane | 57-74-9 | — | 0.5 | X | |
| Chlorinated camphene | 8001-35-2 | — | 0.5 | X | |
| Chlorinated diphenyl oxide | 55720-99-5 | — | 0.5 | ||
| Chlorine | 7782-50-5 | (C)1 | (C)3 | ||
| Chlorine dioxide | 10049-04-4 | 0.1 | 0.3 | ||
| Chlorine trifluoride | 7790-91-2 | (C)0.1 | (C)0.4 | ||
| Chloroacetaldehyde | 107-20-0 | (C)1 | (C)3 | ||
| a-Chloroacetophenone (Phenacyl chloride) | 532-27-4 | 0.05 | 0.3 | ||
| Chlorobenzene | 108-90-7 | 75 | 350 | ||
| o-Chlorobenzylidene malononitrile | 2698-41-1 | 0.05 | 0.4 | ||
| Chlorobromomethane | 74-97-5 | 200 | 1050 | ||
| 2-Chloro-1,3-butadiene; see beta-Chloroprene | — | — | — | ||
| Chlorodiphenyl (42% Chlorine) (PCB) | 53469-21-9 | — | 1 | X | |
| Chlorodiphenyl (54% Chlorine) (PCB) | 11097-69-1 | — | 0.5 | X | |
| 1-Chloro-2,3-epoxypropane; see Epichlorohydrin | — | — | — | ||
| 2-Chloroethanol; see Ethylene chlorohydrin | — | — | — | ||
| Chloroethylene; see Vinyl chloride | — | — | — | ||
| Chloroform (Trichloromethane) | 67-66-3 | (C)50 | (C)240 | ||
| bis(Chloromethyl) ether; see 1910.1008 | 542-88-1 | — | — | ||
| Chloromethyl methyl ether; see 1910.1006 | 107-30-2 | — | — | ||
| 1-Chloro-1-nitropropane | 600-25-9 | 20 | 100 | ||
| Chloropicrin | 76-06-2 | 0.1 | 0.7 | ||
| beta-Chloroprene | 126-99-8 | 25 | 90 | X | |
| 2-Chloro-6-(trichloromethyl) pyridine — Total dust | 1929-82-4 | — | 15 | ||
| 2-Chloro-6-(trichloromethyl) pyridine — Respirable fraction | 1929-82-4 | — | 5 | ||
| Chromium (II) compounds (as Cr) | 7440-47-3 | — | 0.5 | ||
| Chromium (III) compounds (as Cr) | 7440-47-3 | — | 0.5 | ||
| Chromium (VI) compounds; see 1910.1026 (fn 5) | — | — | — | ||
| Chromium metal and insol. salts (as Cr) | 7440-47-3 | — | 1 | ||
| Chrysene; see Coal tar pitch volatiles | — | — | — | ||
| Clopidol — Total dust | 2971-90-6 | — | 15 | ||
| Clopidol — Respirable fraction | 2971-90-6 | — | 5 | ||
| Coal dust (<5% SiO2), respirable fraction | — | — | (3) | Z-3 (Coal dust: Respirable fraction <5% SiO2): — mppcf · 2.4 mg/m3 (fn e; MRE instrument; 4.5 mg/m3 equivalent noted) — formula/count text, not computed | |
| Coal dust (>=5% SiO2), respirable fraction | — | — | (3) | Z-3 (Coal dust: Respirable fraction >=5% SiO2): — mppcf · 10 mg/m3 / (%SiO2 + 2) (fn e) — formula/count text, not computed | |
| Coal tar pitch volatiles (benzene soluble fraction: anthracene, BaP, phenanthrene, acridine, chrysene, pyrene) | 65996-93-2 | — | 0.2 | ||
| Cobalt metal, dust, and fume (as Co) | 7440-48-4 | — | 0.1 | ||
| Coke oven emissions; see 1910.1029 | — | — | — | ||
| Copper — Fume (as Cu) | 7440-50-8 | — | 0.1 | ||
| Copper — Dusts and mists (as Cu) | 7440-50-8 | — | 1 | ||
| Cotton dust (fn e); see 1910.1043 | — | — | 1 | ||
| Crag herbicide (Sesone) — Total dust | 136-78-7 | — | 15 | ||
| Crag herbicide (Sesone) — Respirable fraction | 136-78-7 | — | 5 | ||
| Cresol, all isomers | 1319-77-3 | 5 | 22 | X | |
| Crotonaldehyde | 123-73-9; 4170-30-3 | 2 | 6 | ||
| Cumene | 98-82-8 | 50 | 245 | X | |
| Cyanides (as CN) | (4) | — | 5 | X | |
| Cyclohexane | 110-82-7 | 300 | 1050 | ||
| Cyclohexanol | 108-93-0 | 50 | 200 | ||
| Cyclohexanone | 108-94-1 | 50 | 200 | ||
| Cyclohexene | 110-83-8 | 300 | 1015 | ||
| Cyclopentadiene | 542-92-7 | 75 | 200 | ||
| 2,4-D (Dichlorophenoxyacetic acid) | 94-75-7 | — | 10 | ||
| Decaborane | 17702-41-9 | 0.05 | 0.3 | X | |
| Demeton (Systox) | 8065-48-3 | — | 0.1 | X | |
| Diacetone alcohol (4-Hydroxy-4-methyl-2-pentanone) | 123-42-2 | 50 | 240 | ||
| 1,2-Diaminoethane; see Ethylenediamine | — | — | — | ||
| Diazomethane | 334-88-3 | 0.2 | 0.4 | ||
| Diborane | 19287-45-7 | 0.1 | 0.1 | ||
| 1,2-Dibromo-3-chloropropane (DBCP); see 1910.1044 | 96-12-8 | — | — | ||
| 1,2-Dibromoethane; see Ethylene dibromide | — | — | — | ||
| Dibutyl phosphate | 107-66-4 | 1 | 5 | ||
| Dibutyl phthalate | 84-74-2 | — | 5 | ||
| o-Dichlorobenzene | 95-50-1 | (C)50 | (C)300 | ||
| p-Dichlorobenzene | 106-46-7 | 75 | 450 | ||
| 3,'-Dichlorobenzidine; see 1910.1007 | 91-94-1 | — | — | ||
| Dichlorodifluoromethane | 75-71-8 | 1000 | 4950 | ||
| 1,3-Dichloro-5,5-dimethyl hydantoin | 118-52-5 | — | 0.2 | ||
| Dichlorodiphenyltrichloroethane (DDT) | 50-29-3 | — | 1 | X | |
| 1,1-Dichloroethane | 75-34-3 | 100 | 400 | ||
| 1,2-Dichloroethane; see Ethylene dichloride | — | — | — | ||
| 1,2-Dichloroethylene | 540-59-0 | 200 | 790 | ||
| Dichloroethyl ether | 111-44-4 | (C)15 | (C)90 | X | |
| Dichloromethane; see Methylene chloride | — | — | — | ||
| Dichloromonofluoromethane | 75-43-4 | 1000 | 4200 | ||
| 1,1-Dichloro-1-nitroethane | 594-72-9 | (C)10 | (C)60 | ||
| 1,2-Dichloropropane; see Propylene dichloride | — | — | — | ||
| Dichlorotetrafluoroethane | 76-14-2 | 1000 | 7000 | ||
| Dichlorvos (DDVP) | 62-73-7 | — | 1 | X | |
| Dicyclopentadienyl iron — Total dust | 102-54-5 | — | 15 | ||
| Dicyclopentadienyl iron — Respirable fraction | 102-54-5 | — | 5 | ||
| Dieldrin | 60-57-1 | — | 0.25 | X | |
| Diethylamine | 109-89-7 | 25 | 75 | ||
| 2-Diethylaminoethanol | 100-37-8 | 10 | 50 | X | |
| Diethyl ether; see Ethyl ether | — | — | — | ||
| Difluorodibromomethane | 75-61-6 | 100 | 860 | ||
| Diglycidyl ether (DGE) | 2238-07-5 | (C)0.5 | (C)2.8 | ||
| Dihydroxybenzene; see Hydroquinone | — | — | — | ||
| Diisobutyl ketone | 108-83-8 | 50 | 290 | ||
| Diisopropylamine | 108-18-9 | 5 | 20 | X | |
| 4-Dimethylaminoazobenzene; see 1910.1015 | 60-11-7 | — | — | ||
| Dimethoxymethane; see Methylal | — | — | — | ||
| Dimethyl acetamide | 127-19-5 | 10 | 35 | X | |
| Dimethylamine | 124-40-3 | 10 | 18 | ||
| Dimethylaminobenzene; see Xylidine | — | — | — | ||
| Dimethylaniline (N,N-Dimethylaniline) | 121-69-7 | 5 | 25 | X | |
| Dimethylbenzene; see Xylene | — | — | — | ||
| Dimethyl-1,2-dibromo-2,2-dichloroethyl phosphate | 300-76-5 | — | 3 | ||
| Dimethylformamide | 68-12-2 | 10 | 30 | X | |
| 2,6-Dimethyl-4-heptanone; see Diisobutyl ketone | — | — | — | ||
| 1,1-Dimethylhydrazine | 57-14-7 | 0.5 | 1 | X | |
| Dimethylphthalate | 131-11-3 | — | 5 | ||
| Dimethyl sulfate | 77-78-1 | 1 | 5 | X | |
| Dinitrobenzene (all isomers) [ortho 528-29-0, meta 99-65-0, para 100-25-4] | — | — | 1 | X | |
| Dinitro-o-cresol | 534-52-1 | — | 0.2 | X | |
| Dinitrotoluene | 25321-14-6 | — | 1.5 | X | |
| Dioxane (Diethylene dioxide) | 123-91-1 | 100 | 360 | X | |
| Diphenyl (Biphenyl) | 92-52-4 | 0.2 | 1 | ||
| Diphenylmethane diisocyanate; see Methylene bisphenyl isocyanate | — | — | — | ||
| Dipropylene glycol methyl ether | 34590-94-8 | 100 | 600 | X | |
| Di-sec octyl phthalate (Di-(2-ethylhexyl) phthalate) | 117-81-7 | — | 5 | ||
| Emery — Total dust | 12415-34-8 | — | 15 | ||
| Emery — Respirable fraction | 12415-34-8 | — | 5 | ||
| Endrin | 72-20-8 | — | 0.1 | X | |
| Epichlorohydrin | 106-89-8 | 5 | 19 | X | |
| EPN | 2104-64-5 | — | 0.5 | X | |
| 1,2-Epoxypropane; see Propylene oxide | — | — | — | ||
| 2,3-Epoxy-1-propanol; see Glycidol | — | — | — | ||
| Ethanethiol; see Ethyl mercaptan | — | — | — | ||
| Ethanolamine | 141-43-5 | 3 | 6 | ||
| 2-Ethoxyethanol (Cellosolve) | 110-80-5 | 200 | 740 | X | |
| 2-Ethoxyethyl acetate (Cellosolve acetate) | 111-15-9 | 100 | 540 | X | |
| Ethyl acetate | 141-78-6 | 400 | 1400 | ||
| Ethyl acrylate | 140-88-5 | 25 | 100 | X | |
| Ethyl alcohol (Ethanol) | 64-17-5 | 1000 | 1900 | ||
| Ethylamine | 75-04-7 | 10 | 18 | ||
| Ethyl amyl ketone (5-Methyl-3-heptanone) | 541-85-5 | 25 | 130 | ||
| Ethyl benzene | 100-41-4 | 100 | 435 | ||
| Ethyl bromide | 74-96-4 | 200 | 890 | ||
| Ethyl butyl ketone (3-Heptanone) | 106-35-4 | 50 | 230 | ||
| Ethyl chloride | 75-00-3 | 1000 | 2600 | ||
| Ethyl ether | 60-29-7 | 400 | 1200 | ||
| Ethyl formate | 109-94-4 | 100 | 300 | ||
| Ethyl mercaptan | 75-08-1 | (C)10 | (C)25 | ||
| Ethyl silicate | 78-10-4 | 100 | 850 | ||
| Ethylene chlorohydrin | 107-07-3 | 5 | 16 | X | |
| Ethylenediamine | 107-15-3 | 10 | 25 | ||
| Ethylene dibromide | 106-93-4 | — | (2) | Z-2 (Ethylene dibromide (Z37.31-1970)): TWA 20 ppm · Ceiling 30 ppm · Peak 50 ppm (5 minutes) | |
| Ethylene dichloride (1,2-Dichloroethane) | 107-06-2 | — | (2) | Z-2 (Ethylene dichloride (Z37.21-1969)): TWA 50 ppm · Ceiling 100 ppm · Peak 200 ppm (5 min in any 3 hrs) | |
| Ethylene glycol dinitrate | 628-96-6 | (C)0.2 | (C)1 | X | |
| Ethylene glycol methyl acetate; see Methyl cellosolve acetate | — | — | — | ||
| Ethyleneimine; see 1910.1012 | 151-56-4 | — | — | ||
| Ethylene oxide; see 1910.1047 | 75-21-8 | — | — | ||
| Ethylidene chloride; see 1,1-Dichloroethane | — | — | — | ||
| N-Ethylmorpholine | 100-74-3 | 20 | 94 | X | |
| Ferbam — Total dust | 14484-64-1 | — | 15 | ||
| Ferrovanadium dust | 12604-58-9 | — | 1 | ||
| Fluorides (as F) | (4) | — | 2.5 | ||
| Fluorine | 7782-41-4 | 0.1 | 0.2 | ||
| Fluorotrichloromethane (Trichlorofluoromethane) | 75-69-4 | 1000 | 5600 | ||
| Formaldehyde; see 1910.1048 | 50-00-0 | — | — | Z-2 (Formaldehyde; see 1910.1048): TWA — · Ceiling — · Peak — | |
| Formic acid | 64-18-6 | 5 | 9 | ||
| Furfural | 98-01-1 | 5 | 20 | X | |
| Furfuryl alcohol | 98-00-0 | 50 | 200 | ||
| Grain dust (oat, wheat, barley) | — | — | 10 | ||
| Glycerin (mist) — Total dust | 56-81-5 | — | 15 | ||
| Glycerin (mist) — Respirable fraction | 56-81-5 | — | 5 | ||
| Glycidol | 556-52-5 | 50 | 150 | ||
| Glycol monoethyl ether; see 2-Ethoxyethanol | — | — | — | ||
| Graphite, natural, respirable dust | 7782-42-5 | — | (3) | Z-3 (Graphite (Natural)): 15 mppcf · — — formula/count text, not computed | |
| Graphite, synthetic — Total dust | — | — | 15 | ||
| Graphite, synthetic — Respirable fraction | — | — | 5 | ||
| Guthion; see Azinphos methyl | — | — | — | ||
| Gypsum — Total dust | 13397-24-5 | — | 15 | ||
| Gypsum — Respirable fraction | 13397-24-5 | — | 5 | ||
| Hafnium | 7440-58-6 | — | 0.5 | ||
| Heptachlor | 76-44-8 | — | 0.5 | X | |
| Heptane (n-Heptane) | 142-82-5 | 500 | 2000 | ||
| Hexachloroethane | 67-72-1 | 1 | 10 | X | |
| Hexachloronaphthalene | 1335-87-1 | — | 0.2 | X | |
| n-Hexane | 110-54-3 | 500 | 1800 | ||
| 2-Hexanone (Methyl n-butyl ketone) | 591-78-6 | 100 | 410 | ||
| Hexone (Methyl isobutyl ketone) | 108-10-1 | 100 | 410 | ||
| sec-Hexyl acetate | 108-84-9 | 50 | 300 | ||
| Hydrazine | 302-01-2 | 1 | 1.3 | X | |
| Hydrogen bromide | 10035-10-6 | 3 | 10 | ||
| Hydrogen chloride | 7647-01-0 | (C)5 | (C)7 | ||
| Hydrogen cyanide | 74-90-8 | 10 | 11 | X | |
| Hydrogen fluoride (as F) | 7664-39-3 | — | (2) | Z-2 (Hydrogen fluoride (Z37.28-1969)): TWA 3 ppm · Ceiling — · Peak — | |
| Hydrogen peroxide | 7722-84-1 | 1 | 1.4 | ||
| Hydrogen selenide (as Se) | 7783-07-5 | 0.05 | 0.2 | ||
| Hydrogen sulfide | 7783-06-4 | — | (2) | Z-2 (Hydrogen sulfide (Z37.2-1966)): TWA — · Ceiling 20 ppm · Peak 50 ppm (10 mins once, only if no other measurable exposure occurs) | |
| Hydroquinone | 123-31-9 | — | 2 | ||
| Iodine | 7553-56-2 | (C)0.1 | (C)1 | ||
| Iron oxide fume | 1309-37-1 | — | 10 | ||
| Isoamyl acetate | 123-92-2 | 100 | 525 | ||
| Isoamyl alcohol (primary and secondary) | 123-51-3 | 100 | 360 | ||
| Isobutyl acetate | 110-19-0 | 150 | 700 | ||
| Isobutyl alcohol | 78-83-1 | 100 | 300 | ||
| Isophorone | 78-59-1 | 25 | 140 | ||
| Isopropyl acetate | 108-21-4 | 250 | 950 | ||
| Isopropyl alcohol | 67-63-0 | 400 | 980 | ||
| Isopropylamine | 75-31-0 | 5 | 12 | ||
| Isopropyl ether | 108-20-3 | 500 | 2100 | ||
| Isopropyl glycidyl ether (IGE) | 4016-14-2 | 50 | 240 | ||
| Kaolin — Total dust | 1332-58-7 | — | 15 | ||
| Kaolin — Respirable fraction | 1332-58-7 | — | 5 | ||
| Ketene | 463-51-4 | 0.5 | 0.9 | ||
| Lead, inorganic (as Pb); see 1910.1025 | 7439-92-1 | — | — | ||
| Limestone — Total dust | 1317-65-3 | — | 15 | ||
| Limestone — Respirable fraction | 1317-65-3 | — | 5 | ||
| Lindane | 58-89-9 | — | 0.5 | X | |
| Lithium hydride | 7580-67-8 | — | 0.025 | ||
| L.P.G. (Liquefied petroleum gas) | 68476-85-7 | 1000 | 1800 | ||
| Magnesite — Total dust | 546-93-0 | — | 15 | ||
| Magnesite — Respirable fraction | 546-93-0 | — | 5 | ||
| Magnesium oxide fume — Total particulate | 1309-48-4 | — | 15 | ||
| Malathion — Total dust | 121-75-5 | — | 15 | X | |
| Maleic anhydride | 108-31-6 | 0.25 | 1 | ||
| Manganese compounds (as Mn) | 7439-96-5 | — | (C)5 | ||
| Manganese fume (as Mn) | 7439-96-5 | — | (C)5 | ||
| Marble — Total dust | 1317-65-3 | — | 15 | ||
| Marble — Respirable fraction | 1317-65-3 | — | 5 | ||
| Mercury (aryl and inorganic) (as Hg) | 7439-97-6 | — | (2) | Z-2 (Mercury (Z37.8-1971)): TWA — · Ceiling 1 mg/10m3 · Peak — | |
| Mercury (organo) alkyl compounds (as Hg) | 7439-97-6 | — | (2) | Z-2 (Organo (alkyl) mercury (Z37.30-1969)): TWA 0.01 mg/m3 · Ceiling 0.04 mg/m3 · Peak — | |
| Mercury (vapor) (as Hg) | 7439-97-6 | — | (2) | Z-2 (Mercury (Z37.8-1971)): TWA — · Ceiling 1 mg/10m3 · Peak — | |
| Mesityl oxide | 141-79-7 | 25 | 100 | ||
| Methanethiol; see Methyl mercaptan | — | — | — | ||
| Methoxychlor — Total dust | 72-43-5 | — | 15 | ||
| 2-Methoxyethanol (Methyl cellosolve) | 109-86-4 | 25 | 80 | X | |
| 2-Methoxyethyl acetate (Methyl cellosolve acetate) | 110-49-6 | 25 | 120 | X | |
| Methyl acetate | 79-20-9 | 200 | 610 | ||
| Methyl acetylene (Propyne) | 74-99-7 | 1000 | 1650 | ||
| Methyl acetylene-propadiene mixture (MAPP) | — | 1000 | 1800 | ||
| Methyl acrylate | 96-33-3 | 10 | 35 | X | |
| Methylal (Dimethoxy-methane) | 109-87-5 | 1000 | 3100 | ||
| Methyl alcohol | 67-56-1 | 200 | 260 | ||
| Methylamine | 74-89-5 | 10 | 12 | ||
| Methyl amyl alcohol; see Methyl isobutyl carbinol | — | — | — | ||
| Methyl n-amyl ketone | 110-43-0 | 100 | 465 | ||
| Methyl bromide | 74-83-9 | (C)20 | (C)80 | X | |
| Methyl butyl ketone; see 2-Hexanone | — | — | — | ||
| Methyl cellosolve; see 2-Methoxyethanol | — | — | — | ||
| Methyl cellosolve acetate; see 2-Methoxyethyl acetate | — | — | — | ||
| Methyl chloride | 74-87-3 | — | (2) | Z-2 (Methyl chloride (Z37.18-1969)): TWA 100 ppm · Ceiling 200 ppm · Peak 300 ppm (5 mins in any 3 hrs) | |
| Methyl chloroform (1,1,1-Trichloroethane) | 71-55-6 | 350 | 1900 | ||
| Methylcyclohexane | 108-87-2 | 500 | 2000 | ||
| Methylcyclohexanol | 25639-42-3 | 100 | 470 | ||
| o-Methylcyclohexanone | 583-60-8 | 100 | 460 | X | |
| Methylene chloride | 75-09-2 | — | (2) | Z-2 (Methylene Chloride: see 1910.52): TWA — · Ceiling — · Peak — | |
| Methyl ethyl ketone (MEK); see 2-Butanone | — | — | — | ||
| Methyl formate | 107-31-3 | 100 | 250 | ||
| Methyl hydrazine (Monomethyl hydrazine) | 60-34-4 | (C)0.2 | (C)0.35 | X | |
| Methyl iodide | 74-88-4 | 5 | 28 | X | |
| Methyl isoamyl ketone | 110-12-3 | 100 | 475 | ||
| Methyl isobutyl carbinol | 108-11-2 | 25 | 100 | X | |
| Methyl isobutyl ketone; see Hexone | — | — | — | ||
| Methyl isocyanate | 624-83-9 | 0.02 | 0.05 | X | |
| Methyl mercaptan | 74-93-1 | (C)10 | (C)20 | ||
| Methyl methacrylate | 80-62-6 | 100 | 410 | ||
| Methyl propyl ketone; see 2-Pentanone | — | — | — | ||
| alpha-Methyl styrene | 98-83-9 | (C)100 | (C)480 | ||
| Methylene bisphenyl isocyanate (MDI) | 101-68-8 | (C)0.02 | (C)0.2 | ||
| Mica; see Silicates | — | — | — | ||
| Molybdenum (as Mo) — Soluble compounds | 7439-98-7 | — | 5 | ||
| Molybdenum (as Mo) — Insoluble compounds, Total dust | 7439-98-7 | — | 15 | ||
| Monomethyl aniline | 100-61-8 | 2 | 9 | X | |
| Monomethyl hydrazine; see Methyl hydrazine | — | — | — | ||
| Morpholine | 110-91-8 | 20 | 70 | X | |
| Naphtha (Coal tar) | 8030-30-6 | 100 | 400 | ||
| Naphthalene | 91-20-3 | 10 | 50 | ||
| alpha-Naphthylamine; see 1910.1004 | 134-32-7 | — | — | ||
| beta-Naphthylamine; see 1910.1009 | 91-59-8 | — | — | ||
| Nickel carbonyl (as Ni) | 13463-39-3 | 0.001 | 0.007 | ||
| Nickel, metal and insoluble compounds (as Ni) | 7440-02-0 | — | 1 | ||
| Nickel, soluble compounds (as Ni) | 7440-02-0 | — | 1 | ||
| Nicotine | 54-11-5 | — | 0.5 | X | |
| Nitric acid | 7697-37-2 | 2 | 5 | ||
| Nitric oxide | 10102-43-9 | 25 | 30 | ||
| p-Nitroaniline | 100-01-6 | 1 | 6 | X | |
| Nitrobenzene | 98-95-3 | 1 | 5 | X | |
| p-Nitrochlorobenzene | 100-00-5 | — | 1 | X | |
| 4-Nitrodiphenyl; see 1910.1003 | 92-93-3 | — | — | ||
| Nitroethane | 79-24-3 | 100 | 310 | ||
| Nitrogen dioxide | 10102-44-0 | (C)5 | (C)9 | ||
| Nitrogen trifluoride | 7783-54-2 | 10 | 29 | ||
| Nitroglycerin | 55-63-0 | (C)0.2 | (C)2 | X | |
| Nitromethane | 75-52-5 | 100 | 250 | ||
| 1-Nitropropane | 108-03-2 | 25 | 90 | ||
| 2-Nitropropane | 79-46-9 | 25 | 90 | ||
| N-Nitrosodimethylamine; see 1910.1016 | — | — | — | ||
| Nitrotoluene (all isomers) [o 88-72-2, m 99-08-1, p 99-99-0] | — | 5 | 30 | X | |
| Nitrotrichloromethane; see Chloropicrin | — | — | — | ||
| Octachloronaphthalene | 2234-13-1 | — | 0.1 | X | |
| Octane | 111-65-9 | 500 | 2350 | ||
| Oil mist, mineral | 8012-95-1 | — | 5 | ||
| Osmium tetroxide (as Os) | 20816-12-0 | — | 0.002 | ||
| Oxalic acid | 144-62-7 | — | 1 | ||
| Oxygen difluoride | 7783-41-7 | 0.05 | 0.1 | ||
| Ozone | 10028-15-6 | 0.1 | 0.2 | ||
| Paraquat, respirable dust | 4685-14-7; 1910-42-5; 2074-50-2 | — | 0.5 | X | |
| Parathion | 56-38-2 | — | 0.1 | X | |
| Particulates not otherwise regulated (PNOR) (fn f) — Total dust | — | — | 15 | ||
| Particulates not otherwise regulated (PNOR) (fn f) — Respirable fraction | — | — | 5 | ||
| PCB; see Chlorodiphenyl (42% and 54% chlorine) | — | — | — | ||
| Pentaborane | 19624-22-7 | 0.005 | 0.01 | ||
| Pentachloronaphthalene | 1321-64-8 | — | 0.5 | X | |
| Pentachlorophenol | 87-86-5 | — | 0.5 | X | |
| Pentaerythritol — Total dust | 115-77-5 | — | 15 | ||
| Pentaerythritol — Respirable fraction | 115-77-5 | — | 5 | ||
| Pentane | 109-66-0 | 1000 | 2950 | ||
| 2-Pentanone (Methyl propyl ketone) | 107-87-9 | 200 | 700 | ||
| Perchloroethylene (Tetrachloroethylene) | 127-18-4 | — | (2) | Z-2 (Tetrachloroethylene (Z37.22-1967)): TWA 100 ppm · Ceiling 200 ppm · Peak 300 ppm (5 mins in any 3 hrs) | |
| Perchloromethyl mercaptan | 594-42-3 | 0.1 | 0.8 | ||
| Perchloryl fluoride | 7616-94-6 | 3 | 13.5 | ||
| Petroleum distillates (Naphtha) (Rubber Solvent) | — | 500 | 2000 | ||
| Phenol | 108-95-2 | 5 | 19 | X | |
| p-Phenylene diamine | 106-50-3 | — | 0.1 | X | |
| Phenyl ether, vapor | 101-84-8 | 1 | 7 | ||
| Phenyl ether-biphenyl mixture, vapor | — | 1 | 7 | ||
| Phenylethylene; see Styrene | — | — | — | ||
| Phenyl glycidyl ether (PGE) | 122-60-1 | 10 | 60 | ||
| Phenylhydrazine | 100-63-0 | 5 | 22 | X | |
| Phosdrin (Mevinphos) | 7786-34-7 | — | 0.1 | X | |
| Phosgene (Carbonyl chloride) | 75-44-5 | 0.1 | 0.4 | ||
| Phosphine | 7803-51-2 | 0.3 | 0.4 | ||
| Phosphoric acid | 7664-38-2 | — | 1 | ||
| Phosphorus (yellow) | 7723-14-0 | — | 0.1 | ||
| Phosphorus pentachloride | 10026-13-8 | — | 1 | ||
| Phosphorus pentasulfide | 1314-80-3 | — | 1 | ||
| Phosphorus trichloride | 7719-12-2 | 0.5 | 3 | ||
| Phthalic anhydride | 85-44-9 | 2 | 12 | ||
| Picloram — Total dust | 1918-02-1 | — | 15 | ||
| Picloram — Respirable fraction | 1918-02-1 | — | 5 | ||
| Picric acid | 88-89-1 | — | 0.1 | X | |
| Pindone (2-Pivalyl-1,3-indandione) | 83-26-1 | — | 0.1 | ||
| Plaster of Paris — Total dust | 26499-65-0 | — | 15 | ||
| Plaster of Paris — Respirable fraction | 26499-65-0 | — | 5 | ||
| Platinum (as Pt) — Soluble salts | 7440-06-4 | — | 0.002 | ||
| Portland cement — Total dust | 65997-15-1 | — | 15 | ||
| Portland cement — Respirable fraction | 65997-15-1 | — | 5 | ||
| Propane | 74-98-6 | 1000 | 1800 | ||
| beta-Propriolactone; see 1910.1013 | 57-57-8 | — | — | ||
| n-Propyl acetate | 109-60-4 | 200 | 840 | ||
| n-Propyl alcohol | 71-23-8 | 200 | 500 | ||
| n-Propyl nitrate | 627-13-4 | 25 | 110 | ||
| Propylene dichloride | 78-87-5 | 75 | 350 | ||
| Propylene imine | 75-55-8 | 2 | 5 | X | |
| Propylene oxide | 75-56-9 | 100 | 240 | ||
| Propyne; see Methyl acetylene | — | — | — | ||
| Pyrethrum | 8003-34-7 | — | 5 | ||
| Pyridine | 110-86-1 | 5 | 15 | ||
| Quinone | 106-51-4 | 0.1 | 0.4 | ||
| RDX; see Cyclonite | — | — | — | ||
| Rhodium (as Rh), metal fume and insoluble compounds | 7440-16-6 | — | 0.1 | ||
| Rhodium (as Rh), soluble compounds | 7440-16-6 | — | 0.001 | ||
| Ronnel | 299-84-3 | — | 15 | ||
| Rotenone | 83-79-4 | — | 5 | ||
| Rouge — Total dust | — | — | 15 | ||
| Rouge — Respirable fraction | — | — | 5 | ||
| Selenium compounds (as Se) | 7782-49-2 | — | 0.2 | ||
| Selenium hexafluoride (as Se) | 7783-79-1 | 0.05 | 0.4 | ||
| Silica, amorphous, precipitated and gel | 112926-00-8 | — | (3) | Z-3 (Silica, amorphous, incl. natural diatomaceous earth): 20 mppcf · 80 mg/m3 / %SiO2 — formula/count text, not computed | |
| Silica, amorphous, diatomaceous earth (<1% crystalline silica) | 61790-53-2 | — | (3) | Z-3 (Silica, amorphous, incl. natural diatomaceous earth): 20 mppcf · 80 mg/m3 / %SiO2 — formula/count text, not computed | |
| Silica, crystalline, respirable dust — Cristobalite; see 1910.1053 (fn 7) | 14464-46-1 | — | — | Primary standard: 1910.1053. Stay fallback, Z-3 (Silica, crystalline: Cristobalite (fn f)): use 1/2 the value calculated from the quartz count or mass formulae mppcf · same — formula/count text, not computed | |
| Silica, crystalline, respirable dust — Quartz; see 1910.1053 (fn 7) | 14808-60-7 | — | — | Primary standard: 1910.1053. Stay fallback, Z-3 (Silica, crystalline: Quartz (Respirable) (fn f)): 250 / (%SiO2 + 5) mppcf · 10 mg/m3 / (%SiO2 + 2) (fn e) — formula/count text, not computed | |
| Silica, crystalline, respirable dust — Tripoli (as quartz); see 1910.1053 (fn 7) | 1317-95-9 | — | — | Primary standard: 1910.1053. Stay fallback, Z-3 (Silica, crystalline: Quartz (Respirable) (fn f)): 250 / (%SiO2 + 5) mppcf · 10 mg/m3 / (%SiO2 + 2) (fn e) — formula/count text, not computed | |
| Silica, crystalline, respirable dust — Tridymite; see 1910.1053 (fn 7) | 15468-32-3 | — | — | Primary standard: 1910.1053. Stay fallback, Z-3 (Silica, crystalline: Tridymite (fn f)): use 1/2 the value calculated from the quartz formulae mppcf · same — formula/count text, not computed | |
| Silica, fused, respirable dust | 60676-86-0 | — | (3) | ||
| Silicates (<1% crystalline silica) — Mica (respirable dust) | 12001-26-2 | — | (3) | Z-3 (Silicates (<1% crystalline silica): Mica): 20 mppcf · — — formula/count text, not computed | |
| Silicates — Soapstone, total dust | — | — | (3) | Z-3 (Silicates: Soapstone): 20 mppcf · — — formula/count text, not computed | |
| Silicates — Soapstone, respirable dust | — | — | (3) | Z-3 (Silicates: Soapstone): 20 mppcf · — — formula/count text, not computed | |
| Silicates — Talc (containing asbestos); use asbestos limit; see 1910.1001 | — | — | (3) | Z-3 (Silicates: Talc (containing asbestos)): use asbestos limit mppcf · — — formula/count text, not computed | |
| Silicates — Talc (no asbestos), respirable dust | 14807-96-6 | — | (3) | ||
| Tremolite, asbestiform; see 1910.1001 | — | — | — | ||
| Silicon — Total dust | 7440-21-3 | — | 15 | ||
| Silicon — Respirable fraction | 7440-21-3 | — | 5 | ||
| Silicon carbide — Total dust | 409-21-2 | — | 15 | ||
| Silicon carbide — Respirable fraction | 409-21-2 | — | 5 | ||
| Silver, metal and soluble compounds (as Ag) | 7440-22-4 | — | 0.01 | ||
| Soapstone; see Silicates | — | — | — | ||
| Sodium fluoroacetate | 62-74-8 | — | 0.05 | X | |
| Sodium hydroxide | 1310-73-2 | — | 2 | ||
| Starch — Total dust | 9005-25-8 | — | 15 | ||
| Starch — Respirable fraction | 9005-25-8 | — | 5 | ||
| Stibine | 7803-52-3 | 0.1 | 0.5 | ||
| Stoddard solvent | 8052-41-3 | 500 | 2900 | ||
| Strychnine | 57-24-9 | — | 0.15 | ||
| Styrene | 100-42-5 | — | (2) | Z-2 (Styrene (Z37.15-1969)): TWA 100 ppm · Ceiling 200 ppm · Peak 600 ppm (5 mins in any 3 hrs) | |
| Sucrose — Total dust | 57-50-1 | — | 15 | ||
| Sucrose — Respirable fraction | 57-50-1 | — | 5 | ||
| Sulfur dioxide | 7446-09-5 | 5 | 13 | ||
| Sulfur hexafluoride | 2551-62-4 | 1000 | 6000 | ||
| Sulfuric acid | 7664-93-9 | — | 1 | ||
| Sulfur monochloride | 10025-67-9 | 1 | 6 | ||
| Sulfur pentafluoride | 5714-22-7 | 0.025 | 0.25 | ||
| Sulfuryl fluoride | 2699-79-8 | 5 | 20 | ||
| Systox; see Demeton | — | — | — | ||
| 2,4,5-T (2,4,5-trichlorophenoxyacetic acid) | 93-76-5 | — | 10 | ||
| Talc; see Silicates | — | — | — | ||
| Tantalum, metal and oxide dust | 7440-25-7 | — | 5 | ||
| TEDP (Sulfotep) | 3689-24-5 | — | 0.2 | X | |
| Tellurium and compounds (as Te) | 13494-80-9 | — | 0.1 | ||
| Tellurium hexafluoride (as Te) | 7783-80-4 | 0.02 | 0.2 | ||
| Temephos — Total dust | 3383-96-8 | — | 15 | ||
| Temephos — Respirable fraction | 3383-96-8 | — | 5 | ||
| TEPP (Tetraethyl pyrophosphate) | 107-49-3 | — | 0.05 | X | |
| Terphenyls | 26140-60-3 | (C)1 | (C)9 | ||
| 1,1,1,2-Tetrachloro-2,2-difluoroethane | 76-11-9 | 500 | 4170 | ||
| 1,1,2,2-Tetrachloro-1,2-difluoroethane | 76-12-0 | 500 | 4170 | ||
| 1,1,2,2-Tetrachloroethane | 79-34-5 | 5 | 35 | X | |
| Tetrachloroethylene; see Perchloroethylene | — | — | — | ||
| Tetrachloromethane; see Carbon tetrachloride | — | — | — | ||
| Tetrachloronaphthalene | 1335-88-2 | — | 2 | X | |
| Tetraethyl lead (as Pb) | 78-00-2 | — | 0.075 | X | |
| Tetrahydrofuran | 109-99-9 | 200 | 590 | ||
| Tetramethyl lead (as Pb) | 75-74-1 | — | 0.075 | X | |
| Tetramethyl succinonitrile | 3333-52-6 | 0.5 | 3 | X | |
| Tetranitromethane | 509-14-8 | 1 | 8 | ||
| Tetryl (2,4,6-Trinitrophenylmethylnitramine) | 479-45-8 | — | 1.5 | X | |
| Thallium, soluble compounds (as Tl) | 7440-28-0 | — | 0.1 | X | |
| 4,4'-Thiobis (6-tert, Butyl-m-cresol) — Total dust | 96-69-5 | — | 15 | ||
| 4,4'-Thiobis (6-tert, Butyl-m-cresol) — Respirable fraction | 96-69-5 | — | 5 | ||
| Thiram | 137-26-8 | — | 5 | ||
| Tin, inorganic compounds (except oxides) (as Sn) | 7440-31-5 | — | 2 | ||
| Tin, organic compounds (as Sn) | 7440-31-5 | — | 0.1 | ||
| Titanium dioxide — Total dust | 13463-67-7 | — | 15 | ||
| Toluene | 108-88-3 | — | (2) | Z-2 (Toluene (Z37.12-1967)): TWA 200 ppm · Ceiling 300 ppm · Peak 500 ppm (10 minutes) | |
| Toluene-2,4-diisocyanate (TDI) | 584-84-9 | (C)0.02 | (C)0.14 | ||
| o-Toluidine | 95-53-4 | 5 | 22 | X | |
| Toxaphene; see Chlorinated camphene | — | — | — | ||
| Tremolite; see Silicates | — | — | — | ||
| Tributyl phosphate | 126-73-8 | — | 5 | ||
| 1,1,1-Trichloroethane; see Methyl chloroform | — | — | — | ||
| 1,1,2-Trichloroethane | 79-00-5 | 10 | 45 | X | |
| Trichloroethylene | 79-01-6 | — | (2) | Z-2 (Trichloroethylene (Z37.19-1967)): TWA 100 ppm · Ceiling 200 ppm · Peak 300 ppm (5 mins in any 2 hrs) | |
| Trichloromethane; see Chloroform | — | — | — | ||
| Trichloronaphthalene | 1321-65-9 | — | 5 | X | |
| 1,2,3-Trichloropropane | 96-18-4 | 50 | 300 | ||
| 1,1,2-Trichloro-1,2,2-trifluoroethane | 76-13-1 | 1000 | 7600 | ||
| Triethylamine | 121-44-8 | 25 | 100 | ||
| Trifluorobromomethane | 75-63-8 | 1000 | 6100 | ||
| 2,4,6-Trinitrophenol; see Picric acid | — | — | — | ||
| 2,4,6-Trinitrophenylmethylnitramine; see Tetryl | — | — | — | ||
| 2,4,6-Trinitrotoluene (TNT) | 118-96-7 | — | 1.5 | X | |
| Triorthocresyl phosphate | 78-30-8 | — | 0.1 | ||
| Triphenyl phosphate | 115-86-6 | — | 3 | ||
| Turpentine | 8006-64-2 | 100 | 560 | ||
| Uranium (as U) — Soluble compounds | 7440-61-1 | — | 0.05 | ||
| Uranium (as U) — Insoluble compounds | 7440-61-1 | — | 0.25 | ||
| Vanadium — Respirable dust (as V2O5) | 1314-62-1 | — | (C)0.5 | ||
| Vanadium — Fume (as V2O5) | 1314-62-1 | — | (C)0.1 | ||
| Vegetable oil mist — Total dust | — | — | 15 | ||
| Vegetable oil mist — Respirable fraction | — | — | 5 | ||
| Vinyl benzene; see Styrene | — | — | — | ||
| Vinyl chloride; see 1910.1017 | 75-01-4 | — | — | ||
| Vinyl cyanide; see Acrylonitrile | — | — | — | ||
| Vinyl toluene | 25013-15-4 | 100 | 480 | ||
| Warfarin | 81-81-2 | — | 0.1 | ||
| Xylenes (o-, m-, p-isomers) | 1330-20-7 | 100 | 435 | ||
| Xylidine | 1300-73-8 | 5 | 25 | X | |
| Yttrium | 7440-65-5 | — | 1 | ||
| Zinc chloride fume | 7646-85-7 | — | 1 | ||
| Zinc oxide fume | 1314-13-2 | — | 5 | ||
| Zinc oxide — Total dust | 1314-13-2 | — | 15 | ||
| Zinc oxide — Respirable fraction | 1314-13-2 | — | 5 | ||
| Zinc stearate — Total dust | 557-05-1 | — | 15 | ||
| Zinc stearate — Respirable fraction | 557-05-1 | — | 5 | ||
| Zirconium compounds (as Zr) | 7440-67-7 | — | 5 |
Table Z-1 legend
- PELs are 8-hour time-weighted averages (TWA) unless noted; a "(C)" prefix denotes a ceiling limit.
- ppm values are referenced to 25°C and 760 torr.
- mg/m3 values are exact when no ppm is given, and approximate when paired with a ppm value.
- CAS numbers are informational only — OSHA enforcement is by substance name.
- "Skin" (X) denotes a skin-absorption designation.
- "(2)" = see Table Z-2; "(3)" = see Table Z-3; "(4)" = varies with compound.
- Entries reading "see 1910.xxxx" are governed by their own substance-specific standard — this tool shows that pointer, not a number.
Footnotes
- (5) Chromium VI stay fallback.
- (6) Chromium VI (as CrO3) stay fallback.
- (7) Silica stay fallback to Table Z-3.
- (8) Beryllium stay fallback to Table Z-2.
- (d) Benzene Z-2 limits apply only to 1910.1028-excepted segments.
- (e) Cotton dust TWA = vertical-elutriator respirable dust, waste-processing operations.
- (f) Unlisted inert/nuisance dusts covered by PNOR = Table Z-3 inert dust limit.
Table Z-2 — 8-hr TWA, Acceptable Ceiling & Acceptable Maximum Peak
| Substance | 8-hr TWA | Acceptable ceiling | Peak concentration | Peak max duration |
|---|---|---|---|---|
| Benzene (a) (Z37.40-1969) | 10 ppm | 25 ppm | 50 ppm | 10 minutes |
| Beryllium and beryllium compounds (d) (Z37.29-1970) | 2 ug/m3 | 5 ug/m3 | 25 ug/m3 | 30 minutes |
| Cadmium fume (b) (Z37.5-1970) | 0.1 mg/m3 | 0.3 mg/m3 | — | — |
| Cadmium dust (b) (Z37.5-1970) | 0.2 mg/m3 | 0.6 mg/m3 | — | — |
| Carbon disulfide (Z37.3-1968) | 20 ppm | 30 ppm | 100 ppm | 30 minutes |
| Carbon tetrachloride (Z37.17-1967) | 10 ppm | 25 ppm | 200 ppm | 5 min in any 4 hrs |
| Chromic acid and chromates (c) (Z37.7-1971) (as CrO3) | — | 1 mg/10m3 | — | — |
| Ethylene dibromide (Z37.31-1970) | 20 ppm | 30 ppm | 50 ppm | 5 minutes |
| Ethylene dichloride (Z37.21-1969) | 50 ppm | 100 ppm | 200 ppm | 5 min in any 3 hrs |
| Fluoride as dust (Z37.28-1969) | 2.5 mg/m3 | — | — | — |
| Formaldehyde; see 1910.1048 | — | — | — | — |
| Hydrogen fluoride (Z37.28-1969) | 3 ppm | — | — | — |
| Hydrogen sulfide (Z37.2-1966) | — | 20 ppm | 50 ppm | 10 mins once, only if no other measurable exposure occurs |
| Mercury (Z37.8-1971) | — | 1 mg/10m3 | — | — |
| Methyl chloride (Z37.18-1969) | 100 ppm | 200 ppm | 300 ppm | 5 mins in any 3 hrs |
| Methylene Chloride: see 1910.52The official table text prints "see 1910.52" for this row; the methylene chloride substance-specific standard is actually 1910.1052. | — | — | — | — |
| Organo (alkyl) mercury (Z37.30-1969) | 0.01 mg/m3 | 0.04 mg/m3 | — | — |
| Styrene (Z37.15-1969) | 100 ppm | 200 ppm | 600 ppm | 5 mins in any 3 hrs |
| Tetrachloroethylene (Z37.22-1967) | 100 ppm | 200 ppm | 300 ppm | 5 mins in any 3 hrs |
| Toluene (Z37.12-1967) | 200 ppm | 300 ppm | 500 ppm | 10 minutes |
| Trichloroethylene (Z37.19-1967) | 100 ppm | 200 ppm | 300 ppm | 5 mins in any 2 hrs |
Table Z-3 — Mineral Dusts
Values below are the formula or count text as tabulated. This tool does not compute a mineral-dust PEL from a %SiO2 or any other input.
| Substance | mppcf | mg/m³ |
|---|---|---|
| Silica, crystalline: Quartz (Respirable) (fn f) | 250 / (%SiO2 + 5) | 10 mg/m3 / (%SiO2 + 2) (fn e) |
| Silica, crystalline: Cristobalite (fn f) | use 1/2 the value calculated from the quartz count or mass formulae | same |
| Silica, crystalline: Tridymite (fn f) | use 1/2 the value calculated from the quartz formulae | same |
| Silica, amorphous, incl. natural diatomaceous earth | 20 | 80 mg/m3 / %SiO2 |
| Silicates (<1% crystalline silica): Mica | 20 | — |
| Silicates: Soapstone | 20 | — |
| Silicates: Talc (not containing asbestos) (fn c: <1% quartz; if >=1% quartz use quartz limit) | 20 | — |
| Silicates: Talc (containing asbestos) | use asbestos limit | — |
| Silicates: Tremolite, asbestiform | see 1910.1001 | — |
| Silicates: Portland cement | 50 | — |
| Graphite (Natural) | 15 | — |
| Coal dust: Respirable fraction <5% SiO2 | — | 2.4 mg/m3 (fn e; MRE instrument; 4.5 mg/m3 equivalent noted) |
| Coal dust: Respirable fraction >=5% SiO2 | — | 10 mg/m3 / (%SiO2 + 2) (fn e) |
| Inert or Nuisance Dust (fn d): Respirable fraction | 15 | 5 mg/m3 |
| Inert or Nuisance Dust (fn d): Total dust | 50 | 15 mg/m3 |
Table Z-3 footnotes
- (a) mppcf definition: millions of particles per cubic foot (light-field impinger count).
- (b) %crystalline silica from airborne samples unless other methods shown applicable.
- (c) Talc quartz rule: applies below 1% quartz content; at or above 1% quartz, use the quartz limit instead.
- (d) Unlisted inert/nuisance dusts covered by this limit = PNOR (Particulates Not Otherwise Regulated) in Table Z-1.
- (e) Concentration and %quartz determined from the size-selector-passing fraction (aerodynamic diameter/percent passing: 2µm/90, 2.5/75, 3.5/50, 5.0/25, 10/0).
- (f) Applies where the respirable crystalline silica standard 1910.1053 is stayed/not in effect.
This tool covers federal OSHA permissible exposure limits (PELs) only — no NIOSH RELs/IDLHs, no ACGIH TLVs (licensed content), and no state PELs. Many OSHA PELs date to the original 1971 tables and are widely considered outdated protection levels; OSHA's own annotated PEL tables note this. Absence of a listing here does not mean absence of hazard.
Reference only. Not legal or regulatory advice. Verify against the primary source before you act.
How it works
A permissible exposure limit (PEL) is the legal airborne-concentration ceiling OSHA has set for a substance under 29 CFR 1910.1000 — Tables Z-1 (general air contaminants), Z-2 (substance-specific 8-hour TWA / acceptable ceiling / acceptable maximum peak), and Z-3 (mineral dusts, given as formulas rather than fixed numbers).
Many entries in Table Z-1 point to a substance's own standard (e.g. 1910.1028 for benzene, 1910.1025 for lead) instead of listing a number directly — this tool shows that pointer rather than guessing a value. Table Z-3's mineral-dust limits are %SiO2-dependent formulas; this tool displays the formula text and does not compute a number from it.
This is a federal-OSHA-PEL-only reference (v1): no NIOSH RELs/IDLHs, no ACGIH TLVs, no state limits. It does not compare a measured exposure against a limit — use the TWA/STEL calculator for that, then compare its result against the PEL shown here yourself.
Worked example
Searching Toluene shows a Table Z-1 row with mg/m3 reading (2) — a pointer to Table Z-2, where Toluene has an 8-hour TWA of 200 ppm, an acceptable ceiling of 300 ppm, and an acceptable maximum peak of 500 ppm for 10 minutes.
Searching a crystalline silica variant (e.g. Quartz) shows the Z-1 row pointing to its own standard, 1910.1053, plus the Z-3 stay-fallback formula — 250 / (%SiO2 + 5) mppcf — shown as formula text, not a computed number.
Sources
29 CFR 1910.1000, Tables Z-1/Z-2/Z-3
U.S. Occupational Safety and Health Administration, CFR 2024 annual edition; eCFR cross-checked 2026-07-12; as of 2026-07-13
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Related tools
Data vintage
- Data: OSHA permissible exposure limits (Tables Z-1, Z-2, Z-3), U.S. Occupational Safety and Health Administration CFR 2024 annual edition (CFR-2024-title29-vol6, govinfo); section last amended 82 FR 2735, Jan 9 2017, retrieved 2026-07-13, 584 rows across the three tables.CAS numbers in Table Z-1 are informational only; enforcement is by substance name. A row reading "see 1910.xxxx" is governed by its own substance standard, so the tool shows that pointer rather than a number.
last updated 2026-07-13