Note: This table only includes occupational exposure limits (OELs) for substances listed in the OSHA Z-1 Table. OELs for hundreds of additional substances have been adopted by Cal/OSHA, NIOSH, and ACGIH. These organizations periodically make revisions to their OELs and so they should be consulted directly for their most current values and substances, as well as special notations such as for skin absorption.

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OSHA Annotated Table Z-1(a)

*Go to list of all footnotes

Substance CAS No.(c) Regulatory Limits Recommended Limits
OSHA PEL(b) Cal/OSHA PEL(f)
(as of 11/12/2021)		 NIOSH REL(g)
(as of 11/15/2021)		 ACGIH® TLV® (h)
ppm(d) mg/m3(e) 8-hour TWA
(ST) STEL
(C) Ceiling		 Up to 10-hour TWA
(ST) STEL
(C) Ceiling		 Complimentary
access on acgih.org
Acetaldehyde 75-07-0 200 360 (C) 25 ppm Ca
See Appendix A
See Appendix C		 ACETALDEHYDE - ACGIH
Acetic acid 64-19-7 10 25 10 ppm
(ST) 15 ppm
(C) 40 ppm		 10 ppm
(ST) 15 ppm		 ACETIC ACID - ACGIH
Acetic anhydride 108-24-7 5 20 (C) 5 ppm (C) 5 ppm ACETIC ANHYDRIDE - ACGIH
Acetone 67-64-1 1000 2400 500 ppm
(ST) 750 ppm
(C) 3000 ppm		 250 ppm ACETONE - ACGIH
Acetonitrile 75-05-8 40 70 40 ppm
(ST) 60 ppm		 20 ppm ACETONITRILE - ACGIH
2-Acetylaminofluorene; see 1910.1014 53-96-3     See Section 5209 Ca
See Appendix A		  
Acetylene dichloride; see 1,2-Dichloroethylene           1,2-DICHLOROETHYLENE - ACGIH
Acetylene tetrabromide 79-27-6 1 14 1 ppm See Appendix D 1,1,2,2-TETRABROMOETHANE - ACGIH
Acrolein 107-02-8 0.1 0.25 (C) 0.1 ppm 0.1 ppm
(ST) 0.3 ppm See Appendix C (Aldehydes)		 ACROLEIN - ACGIH
Acrylamide 79-06-1   0.3 0.03 mg/m3 Ca
0.03 mg/m3
See Appendix A		 ACRYLAMIDE - ACGIH
Acrylonitrile; see 1910.1045 107-13-1     2 ppm
Section 5213		 Ca
1 ppm
(C) 10 ppm [15-min]
See Appendix A		 ACRYLONITRILE - ACGIH
Aldrin 309-00-2   0.25 0.25 mg/m3 Ca
0.25 mg/m3
See Appendix A		 ALDRIN - ACGIH
Allyl alcohol 107-18-6 2 5 0.5 ppm
(ST) 4 ppm		 2 ppm
(ST) 4 ppm		 ALLYL ALCOHOL - ACGIH
Allyl chloride 107-05-1 1 3 1 ppm
(ST) 2 ppm		 1 ppm
(ST) 2 ppm		 ALLYL CHLORIDE - ACGIH
Allyl glycidyl ether (AGE) 106-92-3 (C) 10 (C) 45 0.2 ppm 5 ppm
(ST) 10 ppm		 ALLYL GLYCIDYL ETHER - ACGIH
Allyl propyl disulfide 2179-59-1 2 12 2 ppm
(ST) 3 ppm		 2 ppm
(ST) 3 ppm		 ALLYL PROPYL DISULFIDE - ACGIH
alpha-Alumina 1344-28-1     see PNOR See Appendix D  
Total dust     15 10 mg/m3    
Respirable fraction     5 5 mg/m3    
Aluminum Metal (as Al) 7429-90-5         ALUMINUM METAL AND INSOLUBLE COMPOUNDS - ACGIH
Total dust     15 10 mg/m3 10 mg/m3  
Respirable fraction;     5 5 mg/m3 5 mg/m3  
4-Aminodiphenyl see 1910.1011 92-67-1     See Section 5209 Ca
See Appendix A		 4-AMINODIPHENYL - ACGIH
2-Aminoethanol; see Ethanolamine           ETHANOLAMINE - ACGIH
2-Aminopyridine 504-29-0 0.5 2 0.5 ppm 0.5 ppm 2-AMINOPYRIDINE - ACGIH
Ammonia 7664-41-7 50 35 25 ppm
(ST) 35 ppm		 25 ppm
(ST) 35 ppm		 AMMONIA - ACGIH
Ammonium sulfamate 7773-06-0         AMMONIUM SULFAMATE - ACGIH
Total dust     15 10 mg/m3 10 mg/m3  
Respirable fraction     5 5 mg/m3 5 mg/m3  
n-Amyl acetate 628-63-7 100 525 50 ppm
(ST) 100 ppm		 100 ppm PENTYL ACETATE, ALL ISOMERS - ACGIH
sec-Amyl acetate 626-38-0 125 650 50 ppm
(ST) 100 ppm		 125 ppm PENTYL ACETATE, ALL ISOMERS - ACGIH
Aniline and homologs 62-53-3 5 19 2 ppm
(aniline only)		 Ca
See Appendix A		 ANILINE - ACGIH
Anisidine (o-,p-isomers) 29191-52-4   0.5 0.5 mg/m3 Ca
0.5 mg/m3
See Appendix A		 ANISIDINE (o-, p-Isomers) - ACGIH
Antimony and compounds (as Sb) 7440-36-0   0.5 0.5 mg/m3 0.5 mg/m3 ANTIMONY and COMPOUNDS - ACGIH
ANTU (alpha Naphthylthiourea) 86-88-4   0.3 0.3 mg/m3 0.3 mg/m3 ANTU - ACGIH
Arsenic, inorganic compounds (as As) see 1910.1018 7440-38-2     0.01 mg/m3
See Section 5214		 Ca
(C) 0.002 mg/m3 [15-min]
See Appendix A		 ARSENIC AND ITS INORGANIC COMPOUNDS - ACGIH
Arsenic, organic compounds (as As) 7440-38-2   0.5 0.2 mg/m3 None  
Arsine 7784-42-1 0.05 0.2 0.05 ppm Ca
(C) 0.002 mg/m3 [15-min]
See Appendix A		 ARSINE - ACGIH
Asbestos; see 1910.1001 Varies with compound     See Section 5208 Ca
0.1 f/cm3
See Appendix A
See Appendix C		 ASBESTOS, ALL FORMS - ACGIH
Azinphos-methyl 86-50-0   0.2 0.2 mg/m3 0.2 mg/m3 AZINPHOS-METHYL - ACGIH
Barium, soluble compounds (as Ba) 7440-39-3   0.5 0.5 mg/m3 0.5 mg/m3 BARIUM AND SOLUBLE COMPOUNDS - ACGIH
Barium sulfate 7727-43-7     see PNOR   BARIUM SULFATE - ACGIH
Total dust     15 10 mg/m3 10 mg/m3  
Respirable fraction     5 5 mg/m3 5 mg/m3  
Benomyl 17804-35-2       See Appendix D BENOMYL - ACGIH
Total dust     15 10 mg/m3    
Respirable fraction     5 5 mg/m3    
Benzene; See 1910.1028; See Table Z-2 for the limits applicable in the operations or sectors excluded in 1910.1028(j) 71-43-2     1 ppm
(ST) 5 ppm
See Section 5218		 Ca
0.1 ppm
(ST) 1 ppm
See Appendix A		 BENZENE - ACGIH
Benzidine; See 1910.1010 92-87-5     See Section 5209 Ca
See Appendix A
See Appendix C		 BENZIDINE - ACGIH
p-Benzoquinone; see Quinone            
Benzo(a)pyrene; see Coal tar pitch volatiles           COAL TAR PITCH VOLATILES - ACGIH
Benzoyl peroxide 94-36-0   5 5 mg/m3 5 mg/m3 BENZOYL PEROXIDE - ACGIH
Benzyl chloride 100-44-7 1 5 0.03 ppm (C) 1 ppm [15 min] BENZYL CHLORIDE - ACGIH
Beryllium and beryllium compounds (as Be); see 1910.1024(n) 7440-41-7     BERYLLIUM AND COMPOUNDS - ACGIH
Biphenyl; see Diphenyl           BIPHENYL - ACGIH
Bismuth telluride, Undoped 1304-82-1         BISMUTH TELLURIDE - ACGIH
Total dust     15 10 mg/m3 10 mg/m3  
Respirable fraction     5 5 mg/m3 5 mg/m3  
Boron oxide 1303-86-2         BORON OXIDE - ACGIH
Total dust     15 10 mg/m3 10 mg/m3  
Boron trifluoride 7637-07-2 (C) 1 (C) 3 (C) 1 ppm (C) 1 ppm BORON TRIFLUORIDE - ACGIH
Bromine 7726-95-6 0.1 0.7 (C) 0.1 ppm 0.1 ppm
(ST) 0.3 ppm		 BROMINE - ACGIH
Bromoform 75-25-2 0.5 5 0.5 ppm 0.5 ppm BROMOFORM - ACGIH
Butadiene (1,3-Butadiene); See 29 CFR 1910.1051; 29 CFR 1910.19 106-99-0 1 ppm / 5 ppm STEL   1 ppm
(ST) 5 ppm
See Section 5201		 Ca
See Appendix A		 1,3-BUTADIENE - ACGIH
Butanethiol; see Butyl mercaptan           n-BUTYL MERCAPTAN - ACGIH
2-Butanone (Methyl ethyl ketone) 78-93-3 200 590 200 ppm
(ST) 300 ppm		 200 ppm
(ST) 300 ppm		 METHYL ETHYL KETONE - ACGIH
2-Butoxyethanol 111-76-2 50 240 20 ppm 5 ppm 2-BUTOXYETHANOL - ACGIH
n-Butyl-acetate 123-86-4 150 710 150 ppm
(ST) 200 ppm		 150 ppm
(ST) 200 ppm		 BUTYL ACETATES, ALL ISOMERS - ACGIH
sec-Butyl acetate 105-46-4 200 950 200 ppm 200 ppm BUTYL ACETATES, ALL ISOMERS - ACGIH
tert-Butyl-acetate 540-88-5 200 950 200 ppm 200 ppm BUTYL ACETATES, ALL ISOMERS - ACGIH
n-Butyl alcohol 71-36-3 100 300 (C) 50 ppm (C) 50 ppm n-BUTANOL (n-BUTYL ALCOHOL)
sec-Butyl alcohol 78-92-2 150 450 100 ppm 100 ppm
(ST) 150 ppm		 sec-BUTANOL (sec-BUTYL ALCOHOL)
tert-Butyl alcohol 75-65-0 100 300 100 ppm
(ST) 150 ppm		 100 ppm
(ST) 150 ppm		 tert-BUTANOL (tert-BUTYL ALCOHOL)
Butylamine 109-73-9 (C) 5 (C) 15 (C) 5 ppm (C) 5 ppm n-BUTYLAMINE - ACGIH
tert-Butyl chromate (as CrO3)(k); see 1910.1026 1189-85-1     (C) 0.1 mg/m3 Ca
0.001 mg/m3 CR (VI)
See Appendix A
See Appendix C		 tert-BUTYL CHROMATE - ACGIH
n-Butyl glycidyl ether (BGE) 2426-08-6 50 270 25 ppm (C) 5.6 ppm [15-min] n-BUTYL GLYCIDYL ETHER - ACGIH
Butyl mercaptan 109-79-5 10 35 0.5 ppm (C) 0.5 ppm [15-min] n-BUTYL MERCAPTAN - ACGIH
p-tert-Butyltoluene 98-51-1 10 60 1 ppm
(ST) 20 ppm		 10 ppm
(ST) 20 ppm		 p-tert-BUTYLTOLUENE
Cadmium (as Cd); see 1910.1027 7440-43-9     0.005 mg/m3
see Sections 1532 & 5207		 Ca
See Appendix A		 CADMIUM and COMPOUNDS - ACGIH
Calcium Carbonate 1317-65-3     see PNOR    
Total dust     15 10 mg/m3 10 mg/m3  
Respirable fraction     5 5 mg/m3 5 mg/m3  
Calcium hydroxide 1305-62-0         CALCIUM HYDROXIDE - ACGIH
Total dust     15 5 mg/m3 5 mg/m3  
Respirable fraction     5      
Calcium oxide 1305-78-8   5 2 mg/m3 2 mg/m3 CALCIUM OXIDE - ACGIH
Calcium silicate 1344-95-2     see PNOR   CALCIUM SILICATE, NATURALLY OCCURRING AS WOLLASTONITE - ACGIH
Total dust     15 10 mg/m3 10 mg/m3  
Respirable fraction     5 5 mg/m3 5 mg/m3  
Calcium sulfate 7778-18-9     see PNOR   CALCIUM SULFATE - ACGIH
Total dust     15 10 mg/m3 10 mg/m3  
Respirable fraction     5 5 mg/m3 5 mg/m3  
Camphor, synthetic 76-22-2   2 2 mg/m3 2 mg/m3 CAMPHOR, SYNTHETIC - ACGIH
Carbaryl (Sevin) 63-25-2   5 5 mg/m3 5 mg/m3 CARBARYL - ACGIH
Carbon black 1333-86-4   3.5 3.5 mg/m3 3.5 mg/m3 (without PAHs); when PAHs are present, NIOSH considers carbon black to be a potential occupational carcinogen.
See Appendix A, See Appendix C		 CARBON BLACK - ACGIH
Carbon dioxide 124-38-9 5000 9000 5000 ppm
(ST) 30,000 ppm		 5000 ppm
(ST) 30,000 ppm		 CARBON DIOXIDE - ACGIH
Carbon disulfide 75-15-0 See Annotated Z-2 See Annotated Z-2 CARBON DISULFIDE - ACGIH
Carbon monoxide 630-08-0 50 55 25 ppm
(C) 200 ppm		 35 ppm
(C) 200 ppm		 CARBON MONOXIDE - ACGIH
Carbon tetrachloride 56-23-5 See Annotated Z-2 See Annotated Z-2 CARBON TETRACHLORIDE - ACGIH
Cellulose 9004-34-6     see PNOR   CELLULOSE - ACGIH
Total dust     15 10 mg/m3 10 mg/m3  
Respirable fraction     5 5 mg/m3 5 mg/m3  
Chlordane 57-74-9   0.5 0.5 mg/m3 Ca
0.5 mg/m3
See Appendix A		 CHLORDANE - ACGIH
Chlorinated camphene 8001-35-2   0.5 0.5 mg/m3
(ST) 1 mg/m3		 Ca
See Appendix A		 CHLORINATED CAMPHENE - ACGIH
Chlorinated diphenyl oxide 55720-99-5   0.5 0.5 mg/m3 0.5 mg/m3 CHLORINATED DIPHENYL OXIDE - ACGIH
Chlorine 7782-50-5 (C) 1 (C) 3 0.5 ppm
(ST) 1 ppm		 (C) 0.5 ppm [15-min] CHLORINE - ACGIH
Chlorine dioxide 10049-04-4 0.1 0.3 0.1 ppm
(ST) 0.3 ppm		 0.1 ppm
(ST) 0.3 ppm		 CHLORINE DIOXIDE - ACGIH
Chlorine trifluoride 7790-91-2 (C) 0.1 (C) 0.4 (C) 0.1 ppm (C) 0.1 ppm CHLORINE TRIFLUORIDE - ACGIH
Chloroacetaldehyde 107-20-0 (C) 1 (C) 3 (C) 1 ppm (C) 1 ppm CHLOROACETALDEHYDE - ACGIH
a-Chloroacetophenone (Phenacyl chloride) 532-27-4 0.05 0.3 0.05 ppm 0.05 ppm 2-CHLOROACETOPHENONE - ACGIH
Chlorobenzene 108-90-7 75 350 10 ppm See Appendix D CHLOROBENZENE - ACGIH
o-Chlorobenzylidene malononitrile 2698-41-1 0.05 0.4 (C) 0.05 ppm (C) 0.05 ppm o-CHLOROBENZYLIDENE MALONONITRILE - ACGIH
Chlorobromomethane 74-97-5 200 1050 200 ppm 200 ppm CHLOROBROMOMETHANE - ACGIH
2-Chloro-1,3-butadiene; See beta-Chloroprene           β-CHLOROPRENE - ACGIH
Chlorodiphenyl (42% Chlorine) (PCB) 53469-21-9   1 1 mg/m3 Ca
0.001 mg/m3
See Appendix A		 CHLORODIPHENYL — 42% CHLORINE - ACGIH
Chlorodiphenyl (54% Chlorine) (PCB) 11097-69-1   0.5 0.5 mg/m3 Ca
0.001 mg/m3
See Appendix A		 CHLORODIPHENYL — 54% CHLORINE - ACGIH
1-Chloro-2,3-epoxypropane; See Epichlorohydrin           EPICHLOROHYDRIN - ACGIH
2-Chloroethanol; See Ethylene chlorohydrin           ETHYLENE CHLOROHYDRIN - ACGIH
Chloroethylene; see Vinyl chloride           VINYL CHLORIDE - ACGIH
Chloroform (Trichloromethane) 67-66-3 (C) 50 (C) 240 2 ppm Ca
(ST) 2 ppm [60-min]
See Appendix A		 CHLOROFORM - ACGIH
bis(Chloromethyl) ether; see 1910.1008 542-88-1     0.001 ppm
See Section 5209		 Ca
See Appendix A		 BIS (CHLOROMETHYL) ETHER ACGIH
Chloromethyl methyl ether
see 1910.1006		 107-30-2     See Section 5209 Ca
See Appendix A		 CHLOROMETHYL METHYL ETHER - ACGIH
1-Chloro-1-nitropropane 600-25-9 20 100 2 ppm 2 ppm 1-CHLORO-1-NITROPROPANE - ACGIH
Chloropicrin 76-06-2 0.1 0.7 0.1 ppm 0.1 ppm CHLOROPICRIN - ACGIH
beta-Chloroprene 126-99-8 25 90 10 ppm Ca
(C) 1 ppm [15-min]
See Appendix A		 β-CHLOROPRENE - ACGIH
2-Chloro-6-(trichloromethyl)pyridine 1929-82-4         NITRAPYRIN - ACGIH
Total dust     15 10 mg/m3 10 mg/m3
(ST) 20 mg/m3		  
Respirable fraction     5 5 mg/m3 5 mg/m3  
Chromium (II) compounds (as Cr) 7440-47-3   0.5 0.5 mg/m3 0.5 mg/m3
See Appendix C		 CHROMIUM AND INORGANIC COMPOUNDS - ACGIH
Chromium (III) compounds (as Cr) 7440-47-3   0.5 0.5 mg/m3 0.5 mg/m3
See Appendix C		 CHROMIUM AND INORGANIC COMPOUNDS - ACGIH
Chromium (VI) compounds See 1910.1026(k)       0.005 mg/m3 as Cr
(C) 0.1 mg/m3
See Sections 1532.2, 5206, and 8359

Ca
0.0002 mg/m3 (8-hr-TWA)
See Appendix A
See Appendix C

 CHROMIUM AND INORGANIC COMPOUNDS - ACGIH
Chromium metal and insol. salts (as Cr) 7440-47-3   1 0.5 mg/m3 0.5 mg/m3
See Appendix C		 CHROMIUM AND INORGANIC COMPOUNDS - ACGIH
Chrysene; see Coal tarpitch volatiles           CHRYSENE - ACGIH
Clopidol 2971-90-6         CLOPIDOL - ACGIH
Total dust     15 10 mg/m3 10 mg/m3
(ST) 20 mg/m3		  
Respirable fraction     5 5 mg/m3 5 mg/m3  
Coal dust (less than 5% SiO2, respirable fraction)   See Annotated Z-3 See Annotated Z-3 COAL DUST - ACGIH
Coal dust (greater than or equal to 5% SiO2 respirable fraction)   See Annotated Z-3 See Annotated Z-3 COAL DUST - ACGIH
Coal tar pitch volatiles (benzene soluble fraction), anthracene, BaP, phenanthrene, acridine, chrysene, pyrene) 65966-93-2   0.2 0.2 mg/m3 Ca
0.1 mg/m3 (cyclohexane-extractable fraction)
See Appendix A
See Appendix C		 COAL TAR PITCH VOLATILES - ACGIH
Cobalt metal, dust, and fume (as Co) 7440-48-4   0.1 0.02 mg/m3 0.05 mg/m3 COBALT AND INORGANIC COMPOUNDS - ACGIH
Coke oven emissions; see 1910.1029       0.15 mg/m3
See Section 5211		 Ca
0.2 mg/m3(benzene-soluble fraction)
See Appendix A
See Appendix C		  
Copper 7440-50-8         COPPER - ACGIH
Fume (as Cu)     0.1 0.1 mg/m3 0.1 mg/m3 COPPER - ACGIH
Dusts and mists (as Cu)     1 1 mg/m3 1 mg/m3 COPPER - ACGIH
Cotton dust(l), see 1910.1043     1 1 mg/m3 (in waste processing)
See Section 5190		 < 0.200 mg/m3
See Appendix C		 COTTON DUST, RAW, UNTREATED - ACGIH
Crag herbicide (Sesone) 136-78-7         SESONE - ACGIH
Total dust     15 10 mg/m3 10 mg/m3  
Respirable fraction     5 5 mg/m3 5 mg/m3  
Cresol, all isomers 1319-77-3 5 22 5 ppm 2.3 ppm CRESOL, ALL ISOMERS - ACGIH
Crotonaldehyde 123-73-9 /
4170-30-3		 2 6 (C) 0.3 ppm 2 ppm
See Appendix C
(Aldehydes)		 CROTONALDEHYDE - ACGIH
Cumene 98-82-8 50 245 50 ppm 50 ppm CUMENE - ACGIH
Cyanides (as CN) Varies with compound   5 5 mg/m3 (C) 5 mg/m3 [10-min] HYDROGEN CYANIDE AND CYANIDE SALTS ACGIH
Cyclohexane 110-82-7 300 1050 300 ppm 300 ppm CYCLOHEXANE - ACGIH
Cyclohexanol 108-93-0 50 200 50 ppm 50 ppm CYCLOHEXANOL - ACGIH
Cyclohexanone 108-94-1 50 200 25 ppm 25 ppm CYCLOHEXANONE - ACGIH
Cyclohexene 110-83-8 300 1015 300 ppm 300 ppm CYCLOHEXENE - ACGIH
Cyclopentadiene 542-92-7 75 200 75 ppm 75 ppm  
2,4-D (Dichlorophen-oxyacetic acid) 94-75-7   10 10 mg/m3 10 mg/m3 2,4-D - ACGIH
Decaborane 17702-41-9 0.05 0.3 0.05 ppm
(ST) 0.15 ppm		 0.05 ppm
(ST) 0.15 ppm		 DECABORANE - ACGIH
Demeton (Systox) 8065-48-3   0.1 0.1 mg/m3 0.1 mg/m3 DEMETON - ACGIH
Diacetone alcohol (4-Hydroxy-4-methyl-2-pentanone) 123-42-2 50 240 50 ppm 50 ppm DIACETONE ALCOHOL - ACGIH
1,2-Diaminoethane; see Ethylenediamine           ETHYLENEDIAMINE - ACGIH
Diazomethane 334-88-3 0.2 0.4 0.2 ppm 0.2 ppm DIAZOMETHANE - ACGIH
Diborane 19287-45-7 0.1 0.1 0.1 ppm 0.1 ppm DIBORANE - ACGIH
1,2-Dibromo-3-chloropropane (DBCP); see 1910.1044 96-12-8     0.001 ppm
See Section 5212		 Ca
See Appendix A		  
1,2-Dibromoethane; see Ethylene dibromide           ETHYLENE DIBROMIDE - ACGIH
Dibutyl phosphate 107-66-4 1 5 1 ppm
(ST) 2 ppm		 1 ppm
(ST) 2 ppm		 DIBUTYL PHOSPHATE - ACGIH
Dibutyl phthalate 84-74-2   5 5 mg/m3 5 mg/m3 DIBUTYL PHTHALATE - ACGIH
o-Dichlorobenzene 95-50-1 (C) 50 (C) 300 25 ppm
(C) 50 ppm		 (C) 50 ppm o-DICHLOROBENZENE - ACGIH
p-Dichlorobenzene 106-46-7 75 450 10 ppm
(ST) 110 ppm
(C) 200 ppm		 Ca
See Appendix A		 p-DICHLOROBENZENE - ACGIH
3,3'-Dichlorobenzidine;
see 1910.1007		 91-94-1     See Section 5209 Ca
See Appendix A		 3,3'-DICHLOROBENZIDINE - ACGIH
Dichlorodifluoromethane 75-71-8 1000 4950 1000 ppm
(C) 6200 ppm		 1000 ppm DICHLORODIFLUOROMETHANE - ACGIH
1,3-Dichloro-5,5-dimethyl hydantoin 118-52-5   0.2 0.2 mg/m3
(ST) 0.4 mg/m3		 0.2 mg/m3
(ST) 0.4 mg/m3		 1,3-DICHLORO-5,5-DIMETHYLHYDANTOIN - ACGIH
Dichlorodiphenyltrichloroethane (DDT) 50-29-3   1 1 mg/m3 Ca
0.5 mg/m3
See Appendix A		 DDT - ACGIH
1,1-Dichloroethane 75-34-3 100 400 100 ppm 100 ppm
See Appendix C
(Chloroethanes)		 1,1-DICHLOROETHANE - ACGIH
1,2-Dichloroethane; see Ethylene dichloride           ETHYLENE DICHLORIDE - ACGIH
1,2-Dichloroethylene 540-59-0 200 790 200 ppm 200 ppm 1,2-DICHLOROETHYLENE - ACGIH
Dichloroethyl ether 111-44-4 (C) 15 (C) 90 5 ppm
(ST) 10 ppm		 Ca
5 ppm
(ST) 10 ppm
See Appendix A		 DICHLOROETHYL ETHER - ACGIH
Dichloromethane; see Methylene chloride           DICHLOROMETHANE - ACGIH
Dichloromonofluoromethane 75-43-4 1000 4200 10 ppm 10 ppm DICHLOROFLUOROMETHANE - ACGIH
1,1-Dichloro-1-nitroethane 594-72-9 (C) 10 (C) 60 2 ppm 2 ppm 1,1-DICHLORO-1-NITROETHANE - ACGIH
1,2-Dichloropropane; see Propylene dichloride           PROPYLENE DICHLORIDE - ACGIH
Dichlorotetrafluoroethane 76-14-2 1000 7000 1000 ppm 1000 ppm DICHLOROTETRAFLUOROETHANE - ACGIH
Dichlorvos (DDVP) 62-73-7   1 1 mg/m3 1 mg/m3 DICHLORVOS - ACGIH
Dicyclopentadienyl iron 102-54-5         DICYCLOPENTADIENYL IRON - ACGIH
Total dust     15 10 mg/m3 10 mg/m3  
Respirable fraction     5 5 mg/m3 5 mg/m3  
Dieldrin 60-57-1   0.25 0.25 mg/m3 Ca
0.25 mg/m3
See Appendix A		 DIELDRIN - ACGIH
Diethylamine 109-89-7 25 75 (C) 5 ppm 10 ppm
(ST) 25 ppm		 DIETHYLAMINE - ACGIH
2-Diethylaminoethanol 100-37-8 10 50 2 ppm 10 ppm 2-DIETHYLAMINOETHANOL - ACGIH
Diethyl ether; see Ethyl ether           ETHYL ETHER - ACGIH
Difluorodibromomethane 75-61-6 100 860 100 ppm 100 ppm DIFLUORODIBROMOMETHANE - ACGIH
Diglycidyl ether (DGE) 2238-07-5 (C) 0.5 (C) 2.8 0.1 ppm Ca
0.1 ppm
See Appendix A		 DIGLYCIDYL ETHER - ACGIH
Dihydroxybenzene; see Hydroquinone           HYDROQUINONE - ACGIH
Diisobutyl ketone 108-83-8 50 290 25 ppm 25 ppm DIISOBUTYL KETONE - ACGIH
Diisopropylamine 108-18-9 5 20 5 ppm 5 ppm DIISOPROPYLAMINE - ACGIH
4-Dimethylaminoazo-benzene; see 1910.1015 60-11-7     See Section 5209 Ca
See Appendix A		  
Dimethoxymethane; see Methylal           METHYLAL - ACGIH
Dimethyl acetamide 127-19-5 10 35 10 ppm 10 ppm DIMETHYLACETAMIDE - ACGIH
Dimethylamine 124-40-3 10 18 5 ppm
(ST) 15 ppm		 10 ppm DIMETHYLAMINE - ACGIH
Dimethylaminobenzene; see Xylidine           XYLIDINE (MIXED ISOMERS) - ACGIH
Dimethylaniline (N,N-Dimethylaniline) 121-69-7 5 25 5 ppm
(ST) 10 ppm		 5 ppm
(ST) 10 ppm		 DIMETHYLANILINE - ACGIH
Dimethylbenzene; see Xylene           XYLENE (ALL ISOMERS) - ACGIH
Dimethyl-1,2-dibromo-2,2-dichloroethylphosphate 300-76-5   3 3 mg/m3 3 mg/m3 NALED - ACGIH
Dimethylformamide 68-12-2 10 30 10 ppm 10 ppm DIMETHYLFORMAMIDE - ACGIH
2,6-Dimethyl-4-heptanone; see Diisobutyl ketone           DIISOBUTYL KETONE - ACGIH
1,1-Dimethylhydrazine 57-14-7 0.5 1 0.01 ppm Ca
(C) 0.06 ppm [2-hr]
See Appendix A		 1,1-DIMETHYLHYDRAZINE - ACGIH
Dimethylphthalate 131-11-3   5 5 mg/m3 5 mg/m3 DIMETHYL PHTHALATE - ACGIH
Dimethyl sulfate 77-78-1 1 5 0.1 ppm Ca
0.1 ppm
See Appendix A		 DIMETHYL SULFATE - ACGIH
Dinitrobenzene (all isomers)     1 0.15 ppm 1 mg/m3 DINITROBENZENE, ALL ISOMERS - ACGIH
(ortho) 528-29-0         DINITROBENZENE, ALL ISOMERS - ACGIH
(meta) 99-65-0         DINITROBENZENE, ALL ISOMERS - ACGIH
(para) 100-25-4         DINITROBENZENE, ALL ISOMERS - ACGIH
Dinitro-o-cresol 534-52-1   0.2 0.2 mg/m3 0.2 mg/m3 DINITRO-o-CRESOL - ACGIH
Dinitrotoluene 25321-14-6   1.5 0.15 mg/m3 Ca
1.5 mg/m3
See Appendix A		 DINITROTOLUENE - ACGIH
Dioxane (Diethylene dioxide) 123-91-1 100 360 0.28 ppm Ca
(C) 1 ppm [30-min]
See Appendix A		 1,4-DIOXANE - ACGIH
Diphenyl (Biphenyl) 92-52-4 0.2 1 0.2 ppm 0.2 ppm BIPHENYL - ACGIH
Diphenylmethane diisocyanate; see Methylene bisphenylisocyanate           METHYLENE BISPHENYL ISOCYANATE - ACGIH
Dipropylene glycol methyl ether 34590-94-8 100 600 100 ppm
(ST) 150 ppm		 100 ppm
(ST) 150 ppm		 DIPROPYLENE GLYCOL METHYL ETHER (DPGME) - ACGIH
Di-sec octyl phthalate (Di-(2-ethylhexyl) phthalate) 117-81-7   5 5 mg/m3 Ca
5 mg/m3
(ST) 10 mg/m3
See Appendix A		 DI(2-ETHYLHEXYL) PHTHALATE: Notice of Intended Change - ACGIH
Emery 12415-34-8     see PNOR See Appendix D  
Total dust     15 10 mg/m3    
Respirable fraction     5 5 mg/m3    
Endrin 72-20-8   0.1 0.1 mg/m3 0.1 mg/m3 ENDRIN - ACGIH
Epichlorohydrin 106-89-8 5 19 0.05 ppm Ca
See Appendix A		 EPICHLOROHYDRIN - ACGIH
EPN 2104-64-5   0.5 0.1 mg/m3 0.5 mg/m3 EPN - ACGIH
1,2-Epoxypropane; see Propylene oxide           PROPYLENE OXIDE - ACGIH
2,3-Epoxy-1-propanol; see Glycidol           GLYCIDOL - ACGIH
Ethanethiol; see Ethyl mercaptan           ETHYL MERCAPTAN - ACGIH
Ethanolamine 141-43-5 3 6 3 ppm
(ST) 6 ppm		 3 ppm
(ST) 6 ppm		 ETHANOLAMINE - ACGIH
2-Ethoxyethanol (Cellosolve) 110-80-5 200 740 5 ppm 0.5 ppm 2-ETHOXYETHANOL - ACGIH
2-Ethoxyethyl acetate (Cellosolve acetate) 111-15-9 100 540 5 ppm 0.5 ppm 2-ETHOXYETHYL ACETATE - ACGIH
Ethyl acetate 141-78-6 400 1400 400 ppm 400 ppm ETHYL ACETATE - ACGIH
Ethyl acrylate 140-88-5 25 100 5 ppm
(ST) 25 ppm		 Ca
See Appendix A		 ETHYL ACRYLATE - ACGIH
Ethyl alcohol (Ethanol) 64-17-5 1000 1900 1000 ppm 1000 ppm ETHANOL - ACGIH
Ethylamine 75-04-7 10 18 (C) 5 ppm 10 ppm ETHYLAMINE - ACGIH
Ethyl amyl ketone (5-Methyl-3-heptanone) 541-85-5 25 130 25 ppm 25 ppm ETHYL AMYL KETONE - ACGIH
Ethyl benzene 100-41-4 100 435 5 ppm
(ST) 30 ppm		 100 ppm
(ST) 125 ppm		 ETHYL BENZENE - ACGIH
Ethyl bromide 74-96-4 200 890 5 ppm See Appendix D ETHYL BROMIDE - ACGIH
Ethyl butyl ketone (3-Heptanone) 106-35-4 50 230 50 ppm
(ST) 75 ppm		 50 ppm ETHYL BUTYL KETONE - ACGIH
Ethyl chloride 75-00-3 1000 2600 100 ppm See Appendix C (Chloroethanes) ETHYL CHLORIDE - ACGIH
Ethyl ether 60-29-7 400 1200 400 ppm
(ST) 500 ppm		 See Appendix D ETHYL ETHER - ACGIH
Ethyl formate 109-94-4 100 300 100 ppm 100 ppm ETHYL FORMATE - ACGIH
Ethyl mercaptan 75-08-1 (C) 10 (C) 25 0.5 ppm (C) 0.5 ppm [15-min] ETHYL MERCAPTAN - ACGIH
Ethyl silicate 78-10-4 100 850 10 ppm 10 ppm ETHYL SILICATE - ACGIH
Ethylene chlorohydrin 107-07-3 5 16 (C) 1 ppm (C) 1 ppm ETHYLENE CHLOROHYDRIN - ACGIH
Ethylenediamine 107-15-3 10 25 10 ppm 10 ppm ETHYLENEDIAMINE - ACGIH
Ethylene dibromide 106-93-4 See Annotated Z-2 See Annotated Z-2 ETHYLENE DIBROMIDE - ACGIH
Ethylene dichloride (1,2-Dichloroethane) 107-06-2 See Annotated Z-2 See Annotated Z-2 ETHYLENE DICHLORIDE - ACGIH
Ethylene glycol dinitrate 628-96-6 (C) 0.2 (C) 1 0.05 ppm for exposures to mixture of ethylene glycol dinitrate and nitroglycerin
(ST) 0.1 mg/m3		 (ST) 0.1 mg/m3 ETHYLENE GLYCOL DINITRATE - ACGIH
Ethylene glycol methylacetate; see Methylcellosolve acetate            
Ethyleneimine; see 1910.1012 151-56-4     0.5 ppm
See Section 5209		 Ca
See Appendix A		 ETHYLENEIMINE - ACGIH
Ethylene oxide; see 1910.1047 75-21-8     1 ppm
(ST) 5 ppm
See Section 5220		 Ca
< 0.1 ppm
(C) 5 ppm [10-min/day]
See Appendix A		 ETHYLENE OXIDE - ACGIH
Ethylidene chloride; see 1,1-Dichlorethane           1,1-DICHLOROETHANE - ACGIH
N-Ethylmorpholine 100-74-3 20 94 5 ppm 5 ppm N-ETHYLMORPHOLINE - ACGIH
Ferbam 14484-64-1         FERBAM - ACGIH
Total dust   ........ 15 10 mg/m3 10 mg/m3  
Ferrovanadium dust 12604-58-9 ........ 1 1 mg/m3
(ST) 3 mg/m3		 1 mg/m3
(ST) 3 mg/m3		 FERROVANADIUM DUST - ACGIH
Fluorides (as F) Varies with compound ........ 2.5 2.5 mg/m3 2.5 mg/m3 FLUORIDES - ACGIH
Fluorine 7782-41-4 0.1 0.2 0.1 ppm 0.1 ppm FLUORINE - ACGIH
Fluorotrichloromethane (Trichlorofluoromethane) 75-69-4 1000 5600 (C) 1000 ppm (C) 1000 ppm TRICHLOROFLUOROMETHANE - ACGIH
Formaldehyde; see 1910.1048 50-00-0     0.75 ppm
(ST) 2 ppm
See Section 5217		 Ca
0.016 ppm
(C) 0.1 ppm [15-min]
See Appendix A		 FORMALDEHYDE - ACGIH
Formic acid 64-18-6 5 9 5 ppm
(ST) 10 ppm		 5 ppm FORMIC ACID - ACGIH
Furfural 98-01-1 5 20 2 ppm See Appendix D FURFURAL - ACGIH
Furfuryl alcohol 98-00-0 50 200 10 ppm
(ST) 15 ppm		 10 ppm
(ST) 15 ppm		 FURFURYL ALCOHOL - ACGIH
Grain dust (oat, wheat barley)     10 10 mg/m3 4 mg/m3 GRAIN DUST (OAT, WHEAT, AND BARLEY) - ACGIH
Glycerin (mist) 56-81-5     PNOR See Appendix D  
Total dust     15 10 mg/m3    
Respirable fraction     5 5 mg/m3    
Glycidol 556-52-5 50 150 2 ppm 25 ppm GLYCIDOL - ACGIH
Glycol monoethyl ether; see 2-Ethoxyethanol           2-ETHOXYETHANOL - ACGIH
Graphite, natural respirable dust 7782-42-5 See Annotated Z-3 See Annotated Z-3 GRAPHITE, ALL FORMS EXCEPT GRAPHITE FIBERS - ACGIH
Graphite, synthetic           GRAPHITE, ALL FORMS EXCEPT GRAPHITE FIBERS - ACGIH
Total dust     15 10 mg/m3 See Appendix D  
Respirable Fraction     5 5 mg/m3    
Guthion; see Azinphos methyl           AZINPHOS-METHYL - ACGIH
Gypsum 13397-24-5     PNOR    
Total dust     15 10 mg/m3 10 mg/m3  
Respirable fraction     5 5 mg/m3 5 mg/m3  
Hafnium 7440-58-6   0.5 0.5 mg/m3 0.5 mg/m3 HAFNIUM and COMPOUNDS - ACGIH
Heptachlor 76-44-8   0.5 0.05 mg/m3 Ca
0.5 mg/m3
See Appendix A		 HEPTACHLOR and HEPTACHLOR EPOXIDE - ACGIH
Heptane (n-Heptane) 142-82-5 500 2000 400 ppm
(ST) 500 ppm		 85 ppm
(ST) 440 ppm [15-min]		 HEPTANE, ISOMERS - ACGIH
Hexachloroethane 67-72-1 1 10 1 ppm Ca
1 ppm
See Appendix A
See Appendix C
(Chloroethanes)		 HEXACHLOROETHANE - ACGIH
Hexachloronaphthalene 1335-87-1   0.2 0.2 mg/m3 0.2 mg/m3 HEXACHLORONAPHTHALENE - ACGIH
n-Hexane 110-54-3 500 1800 50 ppm 50 ppm HEXANE (n-HEXANE) - ACGIH
2-Hexanone (Methyl n-butyl ketone) 591-78-6 100 410 1 ppm
(ST) 10 ppm		 1 ppm METHYL n-BUTYL KETONE - ACGIH
Hexone (Methyl isobutyl ketone) 108-10-1 100 410 50 ppm
(ST) 75 ppm		 50 ppm
(ST) 75 ppm		 METHYL ISOBUTYL KETONE - ACGIH
sec-Hexyl acetate 108-84-9 50 300 50 ppm 50 ppm sec-HEXYL ACETATE - ACGIH
Hydrazine 302-01-2 1 1.3 0.01 ppm Ca
(C) 0.03 ppm [2-hr]
See Appendix A		 HYDRAZINE - ACGIH
Hydrogen bromide 10035-10-6 3 10 (C) 3 ppm (C) 3 ppm HYDROGEN BROMIDE - ACGIH
Hydrogen chloride 7647-01-0 (C) 5 (C) 7 0.3 ppm
(C) 2 ppm		 (C) 5 ppm HYDROGEN CHLORIDE - ACGIH
Hydrogen cyanide 74-90-8 10 11 (C) 4.7 ppm (ST) 4.7 ppm HYDROGEN CYANIDE AND CYANIDE SALTS - ACGIH
Hydrogen fluoride (as F) 7664-39-3 See Annotated Z-2 See Annotated Z-2 HYDROGEN FLUORIDE - ACGIH
Hydrogen peroxide 7722-84-1 1 1.4 1 ppm 1 ppm HYDROGEN PEROXIDE - ACGIH
Hydrogen selenide (as Se) 7783-07-5 0.05 0.2 0.05 ppm 0.05 ppm HYDROGEN SELENIDE - ACGIH
Hydrogen sulfide 7783-06-4 See Annotated Z-2 See Annotated Z-2 HYDROGEN SULFIDE - ACGIH
Hydroquinone 123-31-9 ........ 2 2 mg/m3 (C) 2 mg/m3 [15-min] HYDROQUINONE - ACGIH
Iodine 7553-56-2 (C) 0.1 (C) 1 (C) 0.1 ppm (C) 0.1 ppm IODINE AND IODIDES - ACGIH
Iron oxide 1309-37-1   10 (fume) 5 mg/m3 (fume) 5 mg/m3 (dust and fume) IRON OXIDE - ACGIH
Isoamyl acetate 123-92-2 100 525 50 ppm
(ST) 100 ppm		 100 ppm PENTYL ACETATE, ALL ISOMERS - PENTYL ACETATE, ALL ISOMERS - ACGIH
Isoamyl alcohol (primary and secondary) 123-51-3 100 360 100 ppm
(ST) 125 ppm		 100 ppm
(ST) 125 ppm		 ISOAMYL ALCOHOL - ACGIH
Isobutyl acetate 110-19-0 150 700 150 ppm 150 ppm BUTYL ACETATES, ALL ISOMERS - ACGIH
Isobutyl alcohol 78-83-1 100 300 50 ppm 50 ppm ISOBUTANOL - ACGIH
Isophorone 78-59-1 25 140 4 ppm 4 ppm ISOPHORONE - ACGIH
Isopropyl acetate 108-21-4 250 950 250 ppm
(ST) 310 ppm		 See Appendix D  
Isopropyl alcohol 67-63-0 400 980 400 ppm
(ST) 500 ppm		 400 ppm
(ST) 500 ppm		  
Isopropylamine 75-31-0 5 12 5 ppm
(ST) 10 ppm		 See Appendix D ISOPROPYLAMINE - ACGIH
Isopropyl ether 108-20-3 500 2100 250 ppm 500 ppm ISOPROPYL ETHER - ACGIH
Isopropyl glycidyl ether (IGE) 4016-14-2 50 240 50 ppm
(ST) 75 ppm		 (C) 50 ppm [15-min] ISOPROPYL GLYCIDYL ETHER - ACGIH
Kaolin 1332-58-7         KAOLIN - ACGIH
Total dust     15   10 mg/m3  
Respirable fraction     5 2 mg/m3
(no asbestos, < 1% crystalline silica)		 5 mg/m3  
Ketene 463-51-4 0.5 0.9 0.5 ppm
(ST) 1.5 ppm		 0.5 ppm
(ST) 1.5 ppm		 KETENE - ACGIH
Lead inorganic (as Pb);
see 1910.1025		 7439-92-1     0.05 mg/m3
See Section 5198		 0.05 mg/m3
See Appendix C		 LEAD AND INORGANIC COMPOUNDS - ACGIH
Limestone 1317-65-3     see PNOR    
Total dust     15 10 mg/m3 10 mg/m3  
Respirable fraction     5 5 mg/m3 5 mg/m3  
Lindane 58-89-9   0.5 0.5 mg/m3 0.5 mg/m3 LINDANE - ACGIH
Lithium hydride 7580-67-8   0.025 0.025 mg/m3 0.025 mg/m3 LITHIUM HYDRIDE - ACGIH
L.P.G. (Liquified petroleum gas) 68476-85-7 1000 1800 1000 ppm 1000 ppm APPENDIX F: MINIMAL OXYGEN CONTENT - ACGIH
Magnesite 546-93-0     See PNOR    
Total dust     15 10 mg/m3 10 mg/m3  
Respirable fraction     5 5 mg/m3 5 mg/m3  
Magnesium oxide fume - Total Particulate 1309-48-4   15 10 mg/m3 See Appendix D MAGNESIUM OXIDE - ACGIH
Malathion - Total dust 121-75-5   15 10 mg/m3 10 mg/m3 MALATHION - ACGIH
Maleic anhydride 108-31-6 0.25 1 0.1 ppm 1 mg/m3 MALEIC ANHYDRIDE - ACGIH
Manganese compounds (as Mn) 7439-96-5   (C) 5 0.2 mg/m3 1 mg/m3
(ST) 3 mg/m3		 MANGANESE, ELEMENTAL AND INORGANIC COMPOUNDS - ACGIH
Manganese fume (as Mn) 7439-96-5   (C) 5 0.2 mg/m3 1 mg/m3
(ST) 3 mg/m3		 MANGANESE, ELEMENTAL AND INORGANIC COMPOUNDS - ACGIH
Marble 1317-65-3     See PNOR    
Total dust     15 10 mg/m3 10 mg/m3  
Respirable fraction     5 5 mg/m3 5 mg/m3  
Mercury (aryl and inorganic) (as Hg) 7439-97-6 See Annotated Z-2 See Annotated Z-2 MERCURY, ALL FORMS EXCEPT ALKYL - ACGIH
Mercury (organo) alkylcompounds (as Hg) 7439-97-6 See Annotated Z-2 See Annotated Z-2 MERCURY, ALKYL COMPOUNDS - ACGIH
Mercury (vapor) (as Hg) 7439-97-6 See Annotated Z-2 See Annotated Z-2 MERCURY, ALL FORMS EXCEPT ALKYL - ACGIH
Mesityl oxide 141-79-7 25 100 15 ppm
(ST) 25 ppm		 10 ppm MESITYL OXIDE - ACGIH
Methanethiol; see Methyl mercaptan           METHYL MERCAPTAN - ACGIH
Methoxychlor - Total dust 72-43-5   15 10 mg/m3 Ca
See Appendix A		 METHOXYCHLOR - ACGIH
2-Methoxyethanol; (Methyl cellosolve) 109-86-4 25 80 5 ppm 0.1 ppm 2-METHOXYETHANOL - ACGIH
2-Methoxyethyl acetate (Methyl cellosolve acetate) 110-49-6 25 120 5 ppm 0.1 ppm 2-METHOXYETHYL ACETATE - ACGIH
Methyl acetate 79-20-9 200 610 200 ppm
(ST) 250 ppm		 200 ppm
(ST) 250 ppm		 METHYL ACETATE - ACGIH
Methyl acetylene (Propyne) 74-99-7 1000 1650 1000 ppm 1000 ppm METHYLACETYLENE - ACGIH
Methyl acetylene propadiene mixture (MAPP)   1000 1800 1000 ppm
(ST) 1250 ppm		 1000 ppm
(ST) 1250 ppm		 METHYLACETYLENE-PROPADIENE MIXTURE - ACGIH
Methyl acrylate 96-33-3 10 35 10 ppm 10 ppm METHYL ACRYLATE - ACGIH
Methylal (Dimethoxy-methane) 109-87-5 1000 3100 1000 ppm 1000 ppm METHYLAL - ACGIH
Methyl alcohol 67-56-1 200 260 200 ppm
(ST) 250 ppm
(C) 1000 ppm		 200 ppm
(ST) 250 ppm		  
Methylamine 74-89-5 10 12 5 ppm
(ST) 15 ppm		 10 ppm METHYLAMINE - ACGIH
Methyl amyl alcohol; see Methyl Isobutylcarbinol           METHYL ISOBUTYL CARBINOL - ACGIH
Methyl n-amyl ketone 110-43-0 100 465 50 ppm 100 ppm METHYL n-AMYL KETONE - ACGIH
Methyl bromide 74-83-9 (C) 20 (C) 80 1 ppm
(C) 20 ppm		 Ca
See Appendix A		 METHYL BROMIDE - ACGIH
Methyl butyl ketone; see 2-Hexanone           METHYL n-BUTYL KETONE - ACGIH
Methyl cellosolve; see 2-Methoxyethanol           2-METHOXYETHANOL - ACGIH
Methyl cellosolve acetate; see 2-Methoxyethylacetate           2-METHOXYETHYL ACETATE - ACGIH
Methyl chloride 74-87-3 See Annotated Z-2 See Annotated Z-2 METHYL CHLORIDE - ACGIH
Methyl chloroform (1,1,1-Trichloro-ethane) 71-55-6 350 1900 350 ppm
(ST) 450 ppm
(C) 800 ppm		 (C) 350 ppm [15-min]
See Appendix C
(Chloroethanes)		 METHYL CHLOROFORM - ACGIH
Methylcyclohexane 108-87-2 500 2000 400 ppm 400 ppm METHYLCYCLOHEXANE - ACGIH
Methylcyclohexanol 25639-42-3 100 470 50 ppm 50 ppm METHYLCYCLOHEXANOL - ACGIH
o-Methylcyclohexanone 583-60-8 100 460 50 ppm
(ST) 75 ppm		 50 ppm
(ST) 75 ppm		 METHYLCYCLOHEXANONE, ALL ISOMERS - ACGIH
Methylene chloride 75-09-2 See Annotated Z-2 See Annotated Z-2
Methyl ethyl ketone (MEK); see 2-Butanone           METHYL ETHYL KETONE - ACGIH
Methyl formate 107-31-3 100 250 100 ppm
(ST) 150 ppm		 100 ppm
(ST) 150 ppm		 METHYL FORMATE - ACGIH
Methyl hydrazine (Monomethylhydrazine) 60-34-4 (C) 0.2 (C) 0.35 0.01 ppm Ca
(C) 0.04 ppm [2-hr]
See Appendix A		 METHYLHYDRAZINE - ACGIH
Methyl iodide 74-88-4 5 28 2 ppm Ca
2 ppm
See Appendix A		 METHYL IODIDE - ACGIH
Methyl isoamyl ketone 110-12-3 100 475 50 ppm 50 ppm METHYL ISOAMYL KETONE - ACGIH
Methyl isobutyl carbinol 108-11-2 25 100 25 ppm
(ST) 40 ppm		 25 ppm
(ST) 40 ppm		 METHYL ISOBUTYL CARBINOL - ACGIH
Methyl isobutyl ketone; see Hexone           METHYL ISOBUTYL KETONE - ACGIH
Methyl isocyanate 624-83-9 0.02 0.05 0.02 ppm 0.02 ppm METHYL ISOCYANATE - ACGIH
Methyl mercaptan 74-93-1 (C) 10 (C) 20 0.5 ppm (C) 0.5 ppm [15-min] METHYL MERCAPTAN - ACGIH
Methyl methacrylate 80-62-6 100 410 50 ppm
(ST) 100 ppm		 100 ppm METHYL METHACRYLATE - ACGIH
Methyl propyl ketone; see 2-Pentanone           METHYL PROPYL KETONE - ACGIH
alpha-Methyl styrene 98-83-9 (C) 100 (C) 480 50 ppm
(ST) 100 ppm		 50 ppm
(ST) 100 ppm		 α-METHYLSTYRENE - ACGIH
Methylene bisphenyl isocyanate (MDI) 101-68-8 (C) 0.02 (C) 0.2 0.005 ppm 0.05 mg/m3
(C) 0.2 mg/m3 [10-min]		 METHYLENE BISPHENYL ISOCYANATE - ACGIH
Mica; see Silicates   See Annotated Z-3 See Annotated Z-3 MICA - ACGIH
Molybdenum (as Mo) 7439-98-7         MOLYBDENUM AND COMPOUNDS - ACGIH
Soluble compounds     5 0.5 mg/m3 See Appendix D MOLYBDENUM AND COMPOUNDS - ACGIH
Insoluble Compounds - Total dust     15 10 mg/m3 See Appendix D MOLYBDENUM AND COMPOUNDS - ACGIH
Insoluble Compounds       3 mg/m3 (resp.)   MOLYBDENUM AND COMPOUNDS - ACGIH
Monomethyl aniline 100-61-8 2 9 0.5 ppm 0.5 ppm N-METHYLANILINE - ACGIH
Monomethyl hydrazine; see Methyl hydrazine           METHYLHYDRAZINE - ACGIH
Morpholine 110-91-8 20 70 20 ppm
(ST) 30 ppm		 20 ppm
(ST) 30 ppm		 MORPHOLINE - ACGIH
Naphtha (Coal tar) 8030-30-6 100 400 100 ppm 100 ppm  
Naphthalene 91-20-3 10 50 0.1 ppm 10 ppm
(ST) 15 ppm		 NAPHTHALENE - ACGIH
alpha-Naphthylamine; see 1910.1004 134-32-7     See Section 5209 Ca
See Appendix A		  
beta-Naphthylamine; see 1910.1009 91-59-8     See Section 5209 Ca
See Appendix A		 β-NAPHTHYLAMINE - ACGIH
Nickel carbonyl (as Ni) 13463-39-3 0.001 0.007 0.001 ppm Ca
0.001 ppm
See Appendix A		 NICKEL CARBONYL - ACGIH
Nickel, metal and insoluble compounds (as Ni) 7440-02-0   1 metal 0.5 mg/m3
insoluble 0.1 mg/m3		 Ca
0.015 mg/m3
See Appendix A		 NICKEL AND INORGANIC COMPOUNDS, INCLUDING NICKEL SUBSULFIDE - ACGIH
Nickel, soluble compounds (as Ni) 7440-02-0   1 0.05 mg/m3 Ca
0.015 mg/m3		 NICKEL AND INORGANIC COMPOUNDS, INCLUDING NICKEL SUBSULFIDE - ACGIH
Nicotine 54-11-5   0.5 0.075 ppm 0.5 mg/m3 NICOTINE - ACGIH
Nitric acid 7697-37-2 2 5 2 ppm
(ST) 4 ppm		 2 ppm
(ST) 4 ppm		 NITRIC ACID - ACGIH
Nitric oxide 10102-43-9 25 30 25 ppm 25 ppm NITRIC OXIDE - ACGIH
p-Nitroaniline 100-01-6 1 6 3 mg/m3 3 mg/m3 p-NITROANILINE - ACGIH
Nitrobenzene 98-95-3 1 5 1 ppm 1 ppm NITROBENZENE - ACGIH
p-Nitrochlorobenzene 100-00-5   1 0.1 ppm Ca
See Appendix A		 p-NITROCHLOROBENZENE - ACGIH
4-Nitrodiphenyl; see 1910.1003 92-93-3     See Section 5209 Ca
See Appendix A		 4-NITRODIPHENYL - ACGIH
Nitroethane 79-24-3 100 310 100 ppm 100 ppm NITROETHANE - ACGIH
Nitrogen dioxide 10102-44-0 (C) 5 (C) 9 (ST) 1 ppm (ST) 1 ppm NITROGEN DIOXIDE - ACGIH
Nitrogen trifluoride 7783-54-2 10 29 10 ppm 10 ppm NITROGEN TRIFLUORIDE - ACGIH
Nitroglycerin 55-63-0 (C) 0.2 (C) 2 0.05 ppm for mixture of nitroglycerine and ethylene glycol dinitrate
(ST) 0.1 mg/m3		 (ST) 0.1 mg/m3 NITROGLYCERIN - ACGIH
Nitromethane 75-52-5 100 250 2 ppm See Appendix D NITROMETHANE - ACGIH
1-Nitropropane 108-03-2 25 90 25 ppm 25 ppm 1-NITROPROPANE - ACGIH
2-Nitropropane 79-46-9 25 90 10 ppm Ca
See Appendix A		 2-NITROPROPANE - ACGIH
N-Nitrosodimethylamine; see 1910.1016       See Section 5209 Ca
See Appendix A		 N-NITROSODIMETHYLAMINE - ACGIH
Nitrotoluene (all isomers)   5 30 2 ppm 2 ppm NITROTOLUENE, ISOMERS - ACGIH
o-isomer 88-72-2         NITROTOLUENE, ISOMERS - ACGIH
m-isomer 99-08-1         NITROTOLUENE, ISOMERS - ACGIH
p-isomer 99-99-0         NITROTOLUENE, ISOMERS - ACGIH
Nitrotrichloromethane; see Chloropicrin           CHLOROPICRIN - ACGIH
Octachloronaphthalene 2234-13-1   0.1 0.1 mg/m3
(ST) 0.3 mg/m3		 0.1 mg/m3
(ST) 0.3 mg/m3		 OCTACHLORONAPHTHALENE - ACGIH
Octane 111-65-9 500 2350 300 ppm
(ST) 375 ppm		 75 ppm
(C) 385 ppm [15-min]		 OCTANE, ALL ISOMERS - ACGIH
Oil mist, mineral 8012-95-1   5 5 mg/m3 (excluding vapor) 5 mg/m3
(ST) 10 mg/m3		 MINERAL OIL,EXCLUDING MWF - ACGIH
Osmium tetroxide (as Os) 20816-12-0   0.002 0.002 mg/m3
(ST) 0.006 mg/m3		 0.002 mg/m3
(ST) 0.006 mg/m3		 OSMIUM TETROXIDE - ACGIH
Oxalic acid 144-62-7   1 1 mg/m3
(ST) 2 mg/m3		 1 mg/m3
(ST) 2 mg/m3		 OXALIC ACID, ANHYDROUS AND DIHYDRATE - ACGIH
Oxygen difluoride 7783-41-7 0.05 0.1 (C) 0.05 ppm (C) 0.05 ppm OXYGEN DIFLUORIDE - ACGIH
Ozone 10028-15-6 0.1 0.2 0.1 ppm
(ST) 0.3 ppm		 (C) 0.1 ppm OZONE - ACGIH
Paraquat, respirable dust 4685-14-7   0.5     PARAQUAT - ACGIH
  1910-42-5     0.1 mg/m3 0.1 mg/m3  
  2074-50-2          
Parathion 56-38-2   0.1 0.1 mg/m3 0.05 mg/m3 PARATHION - ACGIH
Particulates Not Otherwise Regulated (PNOR)(i)         See Appendix D APPENDIX B: Particles - ACGIH
Total dust     15 10 mg/m3    
Respirable fraction     5 5 mg/m3    
PCB; see Chlorodiphenyl (42% and 54% chlorine)           CHLORODIPHENYL — 42% CHLORINE - ACGIH
Pentaborane 19624-22-7 0.005 0.01 0.005 ppm
(ST) 0.015 ppm		 0.005 ppm
(ST) 0.015 ppm		 PENTABORANE - ACGIH
Pentachloronaphthalene 1321-64-8   0.5 0.5 mg/m3 0.5 mg/m3 PENTACHLORONAPHTHALENE - ACGIH
Pentachlorophenol 87-86-5   0.5 0.5 mg/m3 0.5 mg/m3 PENTACHLOROPHENOL - ACGIH
Pentaerythritol 115-77-5     See PNOR   PENTAERYTHRITOL - ACGIH
Total dust     15 10 mg/m3 10 mg/m3  
Respirable fraction     5 5 mg/m3 5 mg/m3  
Pentane 109-66-0 1000 2950 600 ppm 120 ppm
(C) 610 ppm [15-min]		 PENTANE, ALL ISOMERS - ACGIH
2-Pentanone (Methylpropyl ketone) 107-87-9 200 700 200 ppm
(ST) 250 ppm		 150 ppm METHYL PROPYL KETONE - ACGIH
Perchloroethylene (Tetrachloroethylene) 127-18-4 See Annotated Z-2 See Annotated Z-2 TETRACHLOROETHYLENE - ACGIH
Perchloromethyl mercaptan 594-42-3 0.1 0.8 0.1 ppm 0.1 ppm PERCHLOROMETHYL MERCAPTAN - ACGIH
Perchloryl fluoride 7616-94-6 3 13.5 3 ppm
(ST) 6 ppm		 3 ppm
(ST) 6 ppm		 PERCHLORYL FLUORIDE - ACGIH
Petroleum distillates (Naphtha) (Rubber Solvent)   500 2000 1600 mg/m3 350 mg/m3
(C) 1800 mg/m3 [15-min]		  
Phenol 108-95-2 5 19 5 ppm 5 ppm
(C) 15.6 ppm [15-min]		 PHENOL - ACGIH
p-Phenylene diamine 106-50-3   0.1 0.1 mg/m3 0.1 mg/m3 p-PHENYLENEDIAMINE - ACGIH
Phenyl ether, vapor 101-84-8 1 7 1 ppm 1 ppm PHENYL ETHER - ACGIH
Phenyl ether-biphenyl mixture, vapor   1 7   1 ppm  
Phenylethylene; see Styrene           STYRENE - ACGIH
Phenyl glycidyl ether (PGE) 122-60-1 10 60 0.1 ppm Ca
(C) 1 ppm [15-min]
See Appendix A		 PHENYL GLYCIDYL ETHER - ACGIH
Phenylhydrazine 100-63-0 5 22 5 ppm
(ST) 10 ppm		 Ca
(C) 0.14 ppm [2-hr]
See Appendix A		 PHENYLHYDRAZINE - ACGIH
Phosdrin (Mevinphos) 7786-34-7   0.1 0.01 ppm
(ST) 0.03 ppm		 0.01 ppm
(ST) 0.03 ppm		 MEVINPHOS - ACGIH
Phosgene (Carbonyl chloride) 75-44-5 0.1 0.4 0.1 ppm 0.1 ppm
(C) 0.2 ppm [15-min]		 PHOSGENE - ACGIH
Phosphine 7803-51-2 0.3 0.4 0.3 ppm
(ST) 1 ppm		 0.3 ppm
(ST) 1 ppm		 PHOSPHINE - ACGIH
Phosphoric acid 7664-38-2   1 1 mg/m3
(ST) 3 mg/m3		 1 mg/m3
(ST) 3 mg/m3		 PHOSPHORIC ACID - ACGIH
Phosphorus (yellow) 7723-14-0   0.1 0.1 mg/m3 0.1 mg/m3 PHOSPHORUS (YELLOW) - ACGIH
Phosphorus pentachloride 10026-13-8   1 0.1 ppm 1 mg/m3 PHOSPHORUS PENTACHLORIDE - ACGIH
Phosphorus pentasulfide 1314-80-3   1 1 mg/m3
(ST) 3 mg/m3		 1 mg/m3
(ST) 3 mg/m3		 PHOSPHORUS PENTASULFIDE - ACGIH
Phosphorus trichloride 7719-12-2 0.5 3 0.2 ppm
(ST) 0.5 ppm		 0.2 ppm
(ST) 0.5 ppm		 PHOSPHORUS TRICHLORIDE - ACGIH
Phthalic anhydride 85-44-9 2 12 1 ppm 6 mg/m3 PHTHALIC ANHYDRIDE - ACGIH
Picloram 1918-0-21         PICLORAM - ACGIH
Total dust     15 10 mg/m3 See Appendix D  
Respirable fraction     5 5 mg/m3    
Picric acid 88-89-1   0.1 0.1 mg/m3 0.1 mg/m3
(ST) 0.3 mg/m3		 PICRIC ACID - ACGIH
Pindone (2-Pivalyl-1,3-indandione) 83-26-1   0.1 0.1 mg/m3 0.1 mg/m3 PINDONE - ACGIH
Plaster of paris 26499-65-0     See PNOR    
Total dust     15 10 mg/m3 10 mg/m3  
Respirable fraction     5 5 mg/m3 5 mg/m3  
Platinum (as Pt) Metal 7440-06-4     1 mg/m3 1 mg/m3 PLATINUM AND SOLUBLE SALTS - ACGIH
Soluble Salts     0.002 0.002 mg/m3 0.002 mg/m3 PLATINUM AND SOLUBLE SALTS - ACGIH
Portland cement 65997-15-1     See PNOR   PORTLAND CEMENT - ACGIH
Total dust     15 10 mg/m3 10 mg/m3  
Respirable fraction     5 5 mg/m3 5 mg/m3  
Propane 74-98-6 1000 1800 1000 ppm 1000 ppm APPENDIX F: MINIMAL OXYGEN CONTENT - ACGIH
beta-Propriolactone; see 1910.1013 57-57-8     0.5 ppm
See Section 5209		 Ca
See Appendix A		 β-PROPIOLACTONE - ACGIH
n-Propyl acetate 109-60-4 200 840 200 ppm
(ST) 250 ppm		 200 ppm
(ST) 250 ppm		 PROPYL ACETATE ISOMERS - ACGIH
n-Propyl alcohol 71-23-8 200 500 200 ppm
(ST) 250 ppm		 200 ppm
(ST) 250 ppm		 n-PROPANOL - ACGIH
n-Propyl nitrate 627-13-4 25 110 25 ppm
(ST) 40 ppm		 25 ppm
(ST) 40 ppm		 n-PROPYL NITRATE - ACGIH
Propylene dichloride 78-87-5 75 350 75 ppm
(ST) 110 ppm		 Ca
See Appendix A		 PROPYLENE DICHLORIDE - ACGIH
Propylene imine 75-55-8 2 5 2 ppm Ca
2 ppm
See Appendix A		 PROPYLENEIMINE - ACGIH
Propylene oxide 75-56-9 100 240 2 ppm Ca
See Appendix A		 PROPYLENE OXIDE - ACGIH
Propyne; see Methylacetylene           METHYLACETYLENE - ACGIH
Pyrethrum 8003-34-7   5 5 mg/m3 5 mg/m3 PYRETHRUM - ACGIH
Pyridine 110-86-1 5 15 5 ppm 5 ppm PYRIDINE - ACGIH
Quinone 106-51-4 0.1 0.4 0.1 ppm 0.4 mg/m3  
RDX: see Cyclonite           CYCLONITE - ACGIH
Rhodium (as Rh), metal fume and insoluble compounds 7440-16-6   0.1 0.1 mg/m3 0.1 mg/m3 RHODIUM AND COMPOUNDS - ACGIH
Rhodium (as Rh), soluble compounds 7440-16-6   0.001 0.001 mg/m3 0.001 mg/m3 RHODIUM AND COMPOUNDS - ACGIH
Ronnel 299-84-3   15 10 mg/m3 10 mg/m3 RONNEL - ACGIH
Rotenone 83-79-4   5 5 mg/m3 5 mg/m3 ROTENONE (COMMERCIAL) - ACGIH
Rouge       See PNOR See Appendix D  
Total dust     15 10 mg/m3    
Respirable fraction     5 5 mg/m3    
Selenium compounds (as Se) 7782-49-2   0.2 0.2 mg/m3 0.2 mg/m3 SELENIUM AND COMPOUNDS - ACGIH
Selenium hexafluoride (as Se) 7783-79-1 0.05 0.4 0.05 ppm 0.05 ppm SELENIUM HEXAFLUORIDE - ACGIH
Silica, amorphous, precipitated and gel 112926-00-8 See Annotated Z-3 See Annotated Z-3
Silica, amorphous, diatomaceous earth, containing less than 1% crystalline silica 61790-53-2 See Annotated Z-3 See Annotated Z-3
Silica, crystalline, respirable dust       SILICA, CRYSTALLINE — α-QUARTZ AND CRISTOBALITE - ACGIH
Cristobalite; see 1910.1053(m) 14464-46-1     0.05 mg/m3
(See Sections 1532.3 & 5204)		 Ca
0.05 mg/m3
See Appendix A		 SILICA, CRYSTALLINE — α-QUARTZ AND CRISTOBALITE - ACGIH
Quartz: see 1910.1053(m) 14808-60-7     0.05 mg/m3
(See Sections 1532.3 & 5204)		 Ca
0.05 mg/m3
See Appendix A		 SILICA, CRYSTALLINE — α-QUARTZ AND CRISTOBALITE - ACGIH
Tripoli (as quartz); see 1910.1053(m) 1317-95-9     0.05 mg/m3
(See Sections 1532.3 & 5204)

Ca
0.05 mg/m3
See Appendix A

  
Tridymite; see 1910.1053(m) 15468-32-3     0.05 mg/m3
(See Sections 1532.3 & 5204)

Ca
0.05 mg/m3
See Appendix A

  
Silica, fused, respirable dust 60676-86-0 See Annotated Z-3 See Annotated Z-3
Silicates (less than 1% crystalline silica)      
Mica (respirable dust) 12001-26-2 See Annotated Z-3 See Annotated Z-3
Soapstone, total dust   See Annotated Z-3 See Annotated Z-3
Soapstone, respirable dust   See Annotated Z-3 See Annotated Z-3
Talc (containing asbestos): use asbestos limit: see 29 CFR 1910.1001   See Annotated Z-3 See Annotated Z-3
Talc (containing no asbestos), respirable dust 14807-96-6 See Annotated Z-3 See Annotated Z-3
Tremolite, asbestiform; see 1910.1001   See Annotated Z-3 See Annotated Z-3
Silicon 7440-21-3     See PNOR    
Total dust     15 10 mg/m3 10 mg/m3  
Respirable fraction     5 5 mg/m3 5 mg/m3  
Silicon carbide 409-21-2     See PNOR   SILICON CARBIDE - ACGIH
Total dust     15 10 mg/m3 10 mg/m3  
Respirable fraction     5 5 mg/m3 5 mg/m3  
Silver, metal and soluble compounds (as Ag) 7440-22-4   0.01 0.01 mg/m3 0.01 mg/m3 SILVER AND COMPOUNDS - ACGIH
Soapstone   See Annotated Z-3 See Annotated Z-3
Sodium fluoroacetate 62-74-8   0.05 0.05 mg/m3
(ST) 0.15 mg/m3		 0.05 mg/m3
(ST) 0.15 mg/m3		 SODIUM FLUOROACETATE - ACGIH
Sodium hydroxide 1310-73-2   2 (C) 2 mg/m3 (C) 2 mg/m3 SODIUM HYDROXIDE - ACGIH
Starch 9005-25-8     See PNOR   STARCH - ACGIH
Total dust     15 10 mg/m3 10 mg/m3  
Respirable fraction     5 5 mg/m3 5 mg/m3  
Stibine 7803-52-3 0.1 0.5 0.1 ppm 0.1 ppm ANTIMONY HYDRIDE - ACGIH
Stoddard solvent 8052-41-3 500 2900 100 ppm 350 mg/m3
(C) 1800 mg/m3 [15-min]		 STODDARD SOLVENT - ACGIH
Strychnine 57-24-9   0.15 0.15 mg/m3 0.15 mg/m3 STRYCHNINE - ACGIH
Styrene 100-42-5 See Annotated Z-2 See Annotated Z-2 STYRENE - ACGIH
Sucrose 57-50-1     See PNOR   SUCROSE - ACGIH
Total dust     15 10 mg/m3 10 mg/m3  
Respirable fraction     5 5 mg/m3 5 mg/m3  
Sulfur dioxide 7446-09-5 5 13 2 ppm
(ST) 5 ppm		 2 ppm
(ST) 5 ppm		 SULFUR DIOXIDE - ACGIH
Sulfur hexafluoride 2551-62-4 1000 6000 1000 ppm 1000 ppm SULFUR HEXAFLUORIDE - ACGIH
Sulfuric acid 7664-93-9   1 0.1 mg/m3
(ST) 3 mg/m3		 1 mg/m3 SULFURIC ACID - ACGIH
Sulfur monochloride 10025-67-9 1 6 (C) 1 ppm (C) 1 ppm SULFUR MONOCHLORIDE - ACGIH
Sulfur pentafluoride 5714-22-7 0.025 0.25 (C) 0.01 ppm (C) 0.01 ppm SULFUR PENTAFLUORIDE - ACGIH
Sulfuryl fluoride 2699-79-8 5 20 5 ppm
(ST) 10 ppm		 5 ppm
(ST) 10 ppm		 SULFURYL FLUORIDE - ACGIH
Systox; see Demeton           DEMETON - ACGIH
2,4,5-T (2,4,5-tri-chlorophenoxyacetic acid) 93-76-5   10 10 mg/m3 10 mg/m3 2,4,5-T - ACGIH
Talc; see Silicates   See Annotated Z-3 See Annotated Z-3 TALC - ACGIH
Tantalum, metal and oxide dust 7440-25-7   5 5 mg/m3 5 mg/m3
(ST) 10 mg/m3		  
TEDP (Sulfotep) 3689-24-5   0.2 0.2 mg/m3 0.2 mg/m3 SULFOTEPP - ACGIH
Tellurium and compounds (as Te) 13494-80-9   0.1 0.1 mg/m3 0.1 mg/m3 TELLURIUM AND COMPOUNDS (NOT OTHERWISE SPECIFIED), EXCLUDING HYDROGEN TELLURIDE - ACGIH
Tellurium hexafluoride (as Te) 7783-80-4 0.02 0.2 0.02 ppm 0.02 ppm TELLURIUM HEXAFLUORIDE - ACGIH
Temephos 3383-96-8         TEMEPHOS - ACGIH
Total dust     15 10 mg/m3 10 mg/m3  
Respirable fraction     5 5 mg/m3 5 mg/m3  
TEPP (Tetraethyl pyrophosphate) 107-49-3   0.05 0.004 ppm 0.05 mg/m3 TETRAETHYL PYROPHOSPHATE - ACGIH
Terphenyls 26140-60-3 (C) 1 (C) 9 (C) 0.5 ppm (C) 0.5 ppm TERPHENYLS (o-, m-, p-ISOMERS) - ACGIH
1,1,1,2-Tetrachloro-2,2-difluoroethane 76-11-9 500 4170 500 ppm 500 ppm 1,1,1,2-TETRACHLORO-2,2-DIFLUOROETHANE - ACGIH
1,1,2,2-Tetrachloro-1,2-difluoroethane 76-12-0 500 4170 500 ppm 500 ppm 1,1,2,2-TETRACHLORO-1,2-DIFLUOROETHANE - ACGIH
1,1,2,2-Tetrachloroethane 79-34-5 5 35 1 ppm Ca
1 ppm
See Appendix A
See Appendix C
(Chloroethanes)		 1,1,2,2-TETRACHLOROETHANE - ACGIH
Tetrachoroethylene; see Perchloroethylene           TETRACHLOROETHYLENE - ACGIH
Tetrachloromethane; see Carbon tetrachloride           CARBON TETRACHLORIDE - ACGIH
Tetrachloronaphthalene 1335-88-2   2 2 mg/m3 2 mg/m3 TETRACHLORONAPHTHALENE - ACGIH
Tetraethyl lead (as Pb) 78-00-2   0.075 0.075 mg/m3 0.075 mg/m3 TETRAETHYL LEAD - ACGIH
Tetrahydrofuran 109-99-9 200 590 200 ppm
(ST) 250 ppm		 200 ppm
(ST) 250 ppm		 TETRAHYDROFURAN - ACGIH
Tetramethyl lead, (as Pb) 75-74-1   0.075 0.075 mg/m3 0.075 mg/m3 TETRAMETHYL LEAD - ACGIH
Tetramethyl succinonitrile 3333-52-6 0.5 3 0.5 ppm 3 mg/m3 TETRAMETHYL SUCCINONITRILE - ACGIH
Tetranitromethane 509-14-8 1 8 0.005 ppm 1 ppm TETRANITROMETHANE - ACGIH
Tetryl (2,4,6-Trinitrophenylmethylnitramine) 479-45-8   1.5 1.5 mg/m3 1.5 mg/m3 TETRYL - ACGIH
Thallium, soluble compounds (as Tl) 7440-28-0   0.1 0.1 mg/m3 0.1 mg/m3 THALLIUM AND COMPOUNDS - ACGIH
4,4'-Thiobis (6-tert,Butyl-m-cresol) 96-69-5         4,4'-THIOBIS(6-tert-BUTYL-m-CRESOL) - ACGIH
Total dust     15 10 mg/m3 10 mg/m3  
Respirable fraction     5 5 mg/m3 5 mg/m3  
Thiram 137-26-8   5 5 mg/m3 5 mg/m3 THIRAM - ACGIH
Tin, inorganic compounds (except oxides) (as Sn) 7440-31-5   2 2 mg/m3; also tin oxide; except SnH4 2 mg/m3; except tin oxides TIN AND INORGANIC COMPOUNDS, EXCLUDING TIN HYDRIDE AND INDIUM TIN OXIDE - ACGIH
Tin, organic compounds (as Sn) 7440-31-5   0.1 0.1 mg/m3
(ST) 0.2 mg/m3		 0.1 mg/m3 except Cyhexatin TIN, ORGANIC COMPOUNDS - ACGIH
Titanium dioxide - Total dust 13463-67-7   15 See PNOR Ca
(ultrafine particles)
2.4 mg/m3 (fine)
0.3 mg/m3 (ultrafine)
See Appendix A
See NIOSH Intelligence Bulletin 63		 TITANIUM DIOXIDE - ACGIH
Toluene 108-88-3 See Annotated Z-2 See Annotated Z-2 TOLUENE - ACGIH
Toluene-2,4-diisocyanate (TDI) 584-84-9 (C) 0.02 (C) 0.14 0.005 ppm
(ST) 0.02 ppm
(C) 0.02 ppm		 Ca
See Appendix A		 TOLUENE DIISOCYANATE, 2,4- OR 2,6- (OR AS A MIXTURE) - ACGIH
o-Toluidine 95-53-4 5 22 2 ppm Ca
See Appendix A		 o-TOLUIDINE - ACGIH
Toxaphene; see Chlorinated camphene           CHLORINATED CAMPHENE - ACGIH
Tremolite   See Annotated Z-3 See Annotated Z-3
Tributyl phosphate 126-73-8   5 0.2 ppm 0.2 ppm TRIBUTYL PHOSPHATE - ACGIH
1,1,1-Trichloroethane; see Methyl chloroform           METHYL CHLOROFORM - ACGIH
1,1,2-Trichloroethane 79-00-5 10 45 10 ppm Ca
10 ppm
See Appendix A
See Appendix C
(Chloroethanes)		 1,1,2-TRICHLOROETHANE - ACGIH
Trichloroethylene 79-01-6 See Annotated Z-2 See Annotated Z-2 TRICHLOROETHYLENE - ACGIH
Trichloromethane; see Chloroform           CHLOROFORM - ACGIH
Trichloronaphthalene 1321-65-9   5 5 mg/m3 5 mg/m3 TRICHLORONAPHTHALENE - ACGIH
1,2,3-Trichloropropane 96-18-4 50 300 10 ppm Ca
10 ppm
See Appendix A		 1,2,3-TRICHLOROPROPANE - ACGIH
1,1,2-Trichloro-1,2,2-trifluoroethane 76-13-1 1000 7600 1000 ppm
(ST) 1250 ppm
(C) 2000 ppm		 1000 ppm
(ST) 1250 ppm		 1,1,2-TRICHLORO-1,2,2-TRIFLUORO-ETHANE - ACGIH
Triethylamine 121-44-8 25 100 (C) 1 ppm See Appendix D TRIETHYLAMINE - ACGIH
Trifluorobromomethane 75-63-8 1000 6100 1000 ppm 1000 ppm TRIFLUOROBROMOMETHANE - ACGIH
2,4,6-Trinitrophenol;see Picric acid           PICRIC ACID - ACGIH
2,4,6-Trinitrophenyl-methyl nitramine; see Tetryl           TETRYL - ACGIH
2,4,6-Trinitrotoluene (TNT) 118-96-7   1.5 0.5 mg/m3 0.5 mg/m3 2,4,6-TRINITROTOLUENE - ACGIH
Triorthocresyl phosphate 78-30-8   0.1 0.1 mg/m3 0.1 mg/m3 TRIORTHOCRESYL PHOSPHATE - ACGIH
Triphenyl phosphate 115-86-6   3 3 mg/m3 3 mg/m3 TRIPHENYL PHOSPHATE - ACGIH
Turpentine 8006-64-2 100 560 100 ppm 100 ppm TURPENTINE AND SELECTED MONOTERPENES - ACGIH
Uranium (as U) 7440-61-1         URANIUM (NATURAL) AND ITS SOLUBLE and INSOLUBLE COMPOUNDS - ACGIH
Soluble compounds     0.05 0.05 mg/m3 Ca
0.05 mg/m3,
See Appendix A		 URANIUM (NATURAL) AND ITS SOLUBLE and INSOLUBLE COMPOUNDS - ACGIH
Insoluble compounds     0.25 0.2 mg/m3
(ST) 0.6 mg/m3		 Ca
0.2 mg/m3
(ST) 0.6 mg/m3
See Appendix A		 URANIUM (NATURAL) AND ITS SOLUBLE and INSOLUBLE COMPOUNDS - ACGIH
Vanadium 1314-62-1         VANADIUM PENTOXIDE - ACGIH
Respirable dust (as V2O5)     (C) 0.5 0.05 mg/m3, vanadium pentoxide (C) 0.05 mg V/m3 [15-min],
except Vanadium metal and Vanadium carbide		  
Fume (as V2O5)     (C) 0.1 0.05 mg/m3 (C) 0.05 mg V/m3 [15-min]  
Vegetable oil mist       Vegetable oil mists (except castor, cashew nut or similar irritant oils)
See PNOR		    
Total dust     15 10 mg/m3 10 mg/m3  
Respirable fraction     5 5 mg/m3 5 mg/m3  
Vinyl benzene; see Styrene           STYRENE - ACGIH
Vinyl chloride; see 1910.1017 75-01-4     1 ppm
See Section 5210		 Ca
See Appendix A		 VINYL CHLORIDE - ACGIH
Vinyl cyanide; see Acrylonitrile           ACRYLONITRILE - ACGIH
Vinyl toluene 25013-15-4 100 480 50 ppm 100 ppm VINYLTOLUENE, ALL ISOMERS: Notice of Intended Change - ACGIH
Warfarin 81-81-2   0.1 0.1 mg/m3 0.1 mg/m3 WARFARIN - ACGIH
Xylenes (o-, m-, p-isomers) 1330-20-7 100 435 100 ppm
(ST) 150 ppm
(C) 300 ppm		 100 ppm
(ST) 150 ppm		 XYLENE (ALL ISOMERS) - ACGIH
Xylidine 1300-73-8 5 25 0.5 ppm 2 ppm XYLIDINE (MIXED ISOMERS) - ACGIH
Yttrium 7440-65-5   1 1 mg/m3 1 mg/m3 YTTRIUM AND COMPOUNDS - ACGIH
Zinc chloride fume 7646-85-7   1 1 mg/m3
(ST) 2 mg/m3		 1 mg/m3
(ST) 2 mg/m3		 ZINC CHLORIDE FUME - ACGIH
Zinc oxide fume 1314-13-2   5 5 mg/m3
(ST) 10 mg/m3		 5 mg/m3
(ST) 10 mg/m3		 ZINC OXIDE - ACGIH
Zinc oxide 1314-13-2     See PNOR   ZINC OXIDE - ACGIH
Total dust     15 10 mg/m3 5 mg/m3
(C) 15 mg/m3		  
Respirable fraction     5 5 mg/m3    
Zinc stearate 557-05-1         STEARATES - ACGIH
Total dust     15 10 mg/m3 10 mg/m3  
Respirable fraction     5   5 mg/m3  
Zirconium compounds (as Zr) 7440-67-7   5 5 mg/m3
(ST) 10 mg/m3		 5 mg/m3
(ST) 10 mg/m3		 ZIRCONIUM AND COMPOUNDS - ACGIH

Annotated Z-1 Table Footnotes, Abbreviations, References

(a) The unshaded area on this page lists PELs from OSHA Table Z-1 in 29 CFR 1910.1000. The shaded area of this page lists other occupational exposure limits (OELs) from Cal/OSHA, NIOSH, and ACGIH®.

(b) Occupational Safety and Health Administration (OSHA) Permissible Exposure Limits (PELS) from 29 CFR 1910.1000 Z-1 Table [58 FR 35340, June 30, 1993; 58 FR 40191, July 27, 1993, as amended at 61 FR 56831, Nov. 4, 1996; 62 FR 1600, Jan 10,1997; 62 FR 42018, Aug. 4,1997; 71 FR 10373, Feb. 28, 2006; 71 FR 16673, Apr. 3, 2006; 71 FR 36008, June 23, 2006.]. [OSHA entries for respirable crystalline silica from 81 FR 16285, March 25, 2016; OSHA entries for beryllium and beryllium compounds from 82 FR 2470, January 9, 2017]. PELs are 8-hour time weighted averages (TWAs) unless otherwise indicated. OSHA enforces these limits under section 5(a)(2) of the OSH Act. In addition to the values listed in this table, the Z tables in 29 CFR 1910.1000 list skin absorption designations.

(c) The CAS number is for information only. Enforcement is based on the substance name. For an entry covering more than one metal compound measured as the metal, the CAS number for the metal is given - not CAS numbers for the individual compounds.

(d) Parts of vapor or gas per million parts of contaminated air by volume at 25 degrees C and 760 torr.

(e) Milligrams of substance per cubic meter of air. When entry is in this column only, the value is exact; when listed with a ppm entry, it is approximate.

(f) California Division of Occupational Safety and Health (Cal/OSHA) Permissible Exposure Limits (PELs) from Table AC-1 last viewed October 2, 2019, viewable at http://www.dir.ca.gov/title8/5155table_ac1.html. Cal/OSHA enforces its PELs in workplaces under its jurisdiction. Cal/OSHA has established occupational exposure limits for compounds not included in the OSHA Z Tables. Please see Cal/OSHA Table AC-1 for additional limits, the most current limits, and other designations such as skin absorption. The Cal/OSHA AC-1 table and regulations should be consulted for explanations.

(g) National Institute for Occupational Safety and Health (NIOSH) Recommended Exposure Limits (RELs) from the NIOSH Pocket Guide to Chemical Hazards (https://www.cdc.gov/niosh/npg) (Web site last accessed on October 18, 2019). RELs are for up to 10-hour time weighted averages (TWAs) during a 40-hour work week unless otherwise indicated. NIOSH has established occupational exposure limits for compounds not included in the OSHA Z Tables. Please see the NIOSH Pocket Guide for additional limits, skin absorption and other designations, and explanations.

(h) ACGIH® Threshold Limit Values (TLVs®) (ACGIH®). ACGIH® has established TLVs® for compounds not included in the OSHA Z Tables. Please see ACGIH® Documentation for additional limits, skin absorption and other designations, and explanations. The TLV® and BEI® Book and Documentation of the Threshold Limit Values on Chemical Substances, 7th Edition are available through the ACGIH® website at http://www.acgih.org. The TLVs® and BEIs® are copyrighted by ACGIH® and are not publicly available. Permission must be requested from ACGIH® to reproduce the TLVs® and BEIs®. Click here for permission request form.

(i) In 29 CFR 1000, all inert or nuisance dusts, whether mineral, inorganic, or organic, not listed specifically by substance name are covered by the Particulates Not Otherwise Regulated (PNOR) limit which is the same as the inert or nuisance dust limit of Table Z-3.

(j) The final benzene standard in 1910.1028 applies to all occupational exposures to benzene except in some circumstances the distribution and sale of fuels, sealed containers and pipelines, coke production, oil and gas drilling and production, natural gas processing, and the percentage exclusion for liquid mixtures; for the excepted subsegments, the benzene limits in Table Z-2 apply. See 1910.1028 for specific circumstances.

(k) See Table Z-2 for the exposure limits for any operations or sectors where the exposure limits in 1910.1026 are stayed or are otherwise not in effect.

(l) This 8-hour TWA applies to respirable dust as measured by a vertical elutriator cotton dust sampler or equivalent instrument. The time-weighted average applies to the cotton waste processing operations of waste recycling (sorting, blending, cleaning and willowing) and garnetting. See also 1910.1043 for cotton dust limits applicable to other sectors.

(m) See Table Z-3 for the exposure limit for any operations or sectors where the exposure limit in § 1910.1053 is stayed or is otherwise not in effect.

(n) See Table Z–2 for the exposure limits for any operations or sectors where the exposure limits in § 1910.1024 are stayed or otherwise not in effect.

Abbreviations

  • C = Ceiling limit
  • Ca = Potential occupational carcinogens
  • CAS No. = Chemical Abstract Service Number
  • f/cm3 = fibers/cubic centimeter
  • hr = hour
  • m3 = cubic meters
  • min = Minute
  • mg/m3 = milligrams/meter cubed
  • PAH = Polycyclic aromatic hydrocarbons
  • PNOR = Particulates not otherwise regulated
  • ppm = parts per million
  • ST = Short Term Exposure Limit
  • TLV® = Threshold Limit Value
  • TWA – Time weighted average

References

ACGIH® Threshold Limit Values for Chemical Substances in the Work Environment. Adopted by ACGIH® with Intended Changes. See http://www.acgih.org/.

California Division of Occupational Safety and Health (Cal/OSHA) Table AC-1, Permissible Exposure Limits (PELs), in California Code of Regulations (CCR) Title 8 Section 5155, last viewed October 2, 2019. Viewable at http://www.dir.ca.gov/title8/5155table_ac1.html.

National Institute for Occupational Safety and Health (NIOSH) (2019) NIOSH Pocket Guide to Chemical Hazards. Department of Health and Human Services. Centers for Disease Control and Prevention. National Institute for Occupational Safety and Health (NIOSH). Web site last accessed on October 18, 2019. Available at https://www.cdc.gov/niosh/npg

Occupational Safety and Health Administration (OSHA) (2017) Air Contaminants. 29 CFR 1910.1000 [82 FR 2735, January 9, 2017]. Web site accessed on April 4, 2018. Available at https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1000