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Appendix G: 1989 Air Contaminants Update Project – Exposure Limits NOT in Effect										Related Pages
										The OSHA permissible exposure limits (PELs), as found in Tables Z-1, Z-2, and Z-3 of the OSHA General Industry Air Contaminants Standard (29 CFR 1910.1000), that were effective on July 1, 1993* and which are currently enforced by OSHA are listed on the page for each chemical in the Pocket Guide.
*In July 1992, the 11th Circuit Court of Appeals in its decision in AFL-CIO v. OSHA, 965 F.2d 962 (11th Cir., 1992) vacated more protective PELs set by OSHA in 1989 for 212 substances, moving them back to PELs established in 1971. The appeals court also vacated new PELs for 164 substances that were not previously regulated. Enforcement of the court decision began on June 30, 1993. Although OSHA is currently enforcing exposure limits in Tables Z-1, Z-2, and Z-3 of 29 CFR 1910.1000 which were in effect before 1989, violations of the “general duty clause” as contained in Section 5(a) (1) of the Occupational Safety and Health Act may be considered when worker exposures exceed the 1989 PELs for the 164 substances that were not previously regulated. The substances for which OSHA PELs were vacated on June 30, 1993 are indicated by the symbol “†” following OSHA in the Exposure Limit section on the page for each chemical in the Pocket Guide. Appendix G lists the previous values (the PELs that were vacated).
”
Chemical
Vacated 1989 OSHA PELAcetaldehyde
TWA 100 ppm (180 mg/m 3)
ST 150 ppm (270 mg/m 3)Acetic anhydride
C 5 ppm (20 mg/m 3)Acetone
TWA 750 ppm (1800 mg/m 3)
ST 1000 ppm (2400 mg/m 3)Acetonitrile
TWA 40 ppm (70 mg/m 3)
ST 60 ppm (105 mg/m 3)Acetylsalicyclic acid
TWA 5 mg/m 3Acrolein
TWA 0.1 ppm (0.25 mg/m 3)
ST 0.3 ppm (0.8 mg/m 3)Acrylamide
TWA 0.03 mg/m 3 [skin]Acrylic acid
TWA 10 ppm (30 mg/m 3) [skin]Allyl alcohol
TWA 2 ppm (5 mg/m 3)
ST 4 ppm (10 mg/m 3) [skin]Allyl chloride
TWA 1 ppm (3 mg/m 3)
ST 2 ppm (6 mg/m 3)Allyl glycidyl ether
TWA 5 ppm (22 mg/m 3)
ST 10 ppm (44 mg/m 3)Allyl propyl disulfide
TWA 2 ppm (12 mg/m 3)
ST 3 ppm (18 mg/m 3)alpha-Alumina
TWA 10 mg/m 3 (total)
TWA 5 mg/m 3 (resp)Aluminum (pyro powders & welding fumes, as Al)
TWA 5 mg/m 3Aluminum (soluble salts & alkyls, as Al)
TWA 2 mg/m 3Amitrole
TWA 0.2 mg/m 3Ammonia
ST 35 ppm (27 mg/m 3)Ammonium chloride fume
TWA 10 mg/m 3
ST 20 mg/m 3Ammonium sulfamate
TWA 10 mg/m 3 (total)
TWA 5 mg/m 3 (resp)Aniline (and homologs)
TWA 2 ppm (8 mg/m 3) [skin]Atrazine
TWA 5 mg/m 3Barium sulfate
TWA 10 mg/m 3 (total)
TWA 5 mg/m 3 (resp)Benomyl
TWA 10 mg/m 3 (total)
TWA 5 mg/m 3 (resp)Benzenethiol
TWA 0.5 ppm (2 mg/m 3)Bismuth telluride (doped with selenium sulfide, as Bi2Te3)
TWA 5 mg/m 3Borates, tetra, sodium salts (Anhydrous)
TWA 10 mg/m 3Borates, tetra, sodium salts (Decahydrate)
TWA 10 mg/m 3Borates, tetra, sodium salts (Pentahydrate)
TWA 10 mg/m 3Boron oxide
TWA 10 mg/m 3Boron tribromide
C 1 ppm (10 mg/m 3)Bromacil
TWA 1 ppm (10 mg/m 3)Bromine
TWA 0.1 ppm (0.7 mg/m 3)
ST 0.3 ppm (2 mg/m 3)Bromine pentafluoride
TWA 0.1 ppm (0.7 mg/m 3)n-Butane
TWA 800 ppm (1900 mg/m 3)2-Butanone
TWA 200 ppm (590 mg/m 3)
ST 300 ppm (885 mg/m 3)2-Butoxyethanol
TWA 25 ppm (120 mg/m 3) [skin]n-Butyl acetate
TWA 150 ppm (710 mg/m 3)
ST 200 ppm (950 mg/m 3)Butyl acrylate
TWA 10 ppm (55 mg/m 3)n-Butyl alcohol
C 50 ppm (150 mg/m 3) [skin]sec-Butyl alcohol
TWA 100 ppm (305 mg/m 3)tert-Butyl alcohol
TWA 100 ppm (300 mg/m 3)
ST 150 ppm (450 mg/m 3)n-Butyl glycidyl ether
TWA 25 ppm (135 mg/m 3)n-Butyl lactate
TWA 5 ppm (25 mg/m 3)n-Butyl mercaptan
TWA 0.5 ppm (1.5 mg/m 3)o-sec-Butylphenol
TWA 5 ppm (30 mg/m 3) [skin]p-tert-Butyltoluene
TWA 10 ppm (60 mg/m 3)
ST 20 ppm (120 mg/m 3)Calcium cyanamide
TWA 0.5 mg/m 3Caprolactam
Dust:
TWA 1 mg/m 3
ST 3 mg/m 3Vapor:
TWA 5 ppm (20 mg/m 3)
ST 10 ppm (40 mg/m 3)Captafol
TWA 0.1 mg/m 3Captan
TWA 5 mg/m 3Carbofuran
TWA 0.1 mg/m 3Carbon dioxide
TWA 10,000 ppm (18,000 mg/m 3)
ST 30,000 ppm (54,000 mg/m 3)Carbon disulfide
TWA 4 ppm (12 mg/m 3)
ST 12 ppm (36 mg/m 3) [skin]Carbon monoxide
TWA 35 ppm (40 mg/m 3)
C 200 ppm (229 mg/m 3)Carbon tetrabromide
TWA 0.1 ppm (1.4 mg/m 3)
ST 0.3 ppm (4 mg/m 3)Carbon tetrachloride
TWA 2 ppm (12.6 mg/m 3)Carbonyl fluoride
TWA 2 ppm (5 mg/m 3)
ST 5 ppm (15 mg/m 3)Catechol
TWA 5 ppm (20 mg/m 3) [skin]Cesium hydroxide
TWA 2 mg/m 3Chlorinated camphene
TWA 0.5 mg/m 3
ST 1 mg/m 3 [skin]Chlorine
TWA 0.5 ppm (1.5 mg/m 3)
ST 1 ppm (3 mg/m 3)Chlorine dioxide
TWA 0.1 ppm (0.3 mg/m 3)
ST 0.3 ppm (0.9 mg/m 3)Chloroacetyl chloride
TWA 0.05 ppm (0.2 mg/m 3)o-Chlorobenzylidene malononitrile
C 0.05 ppm (0.4 mg/m 3) [skin]Chlorodifluoromethane
TWA 1000 ppm (3500 mg/m 3)Chloroform
TWA 2 ppm (9.78 mg/m 3)1-Chloro-1-nitropropane
TWA 2 ppm (10 mg/m 3)Chloropentafluoroethane
TWA 1000 ppm (6320 mg/m 3)beta-Chloroprene
TWA 10 ppm (35 mg/m 3) [skin]o-Chlorostyrene
TWA 50 ppm (285 mg/m 3)
ST 75 ppm (428 mg/m 3)o-Chlorotoluene
TWA 50 ppm (250 mg/m 3)Chlorpyrifos
TWA 0.2 mg/m 3 [skin]Coal dust
TWA 2 mg/m 3 (<5% SiO 2)(resp dust)
TWA 0.1 mg/m 3 (> or = 5% SiO 2) (resp quartz)Cobalt metal dust & fume, as Co)
TWA 0.05 mg/m 3Cobalt carbonyl (as Co)
TWA 0.1 mg/m 3Cobalt hydrocarbonyl (as Co)
TWA 0.1 mg/m 3Crag® herbicide
TWA 10 mg/m 3 (total)
TWA 5 mg/m 3 (resp)Crufomate
TWA 5 mg/m 3Cyanamide
TWA 2 mg/m 3Cyanogen
TWA 10 ppm (20 mg/m 3)Cyanogen chloride
C 0.3 ppm (0.6 mg/m 3)Cyclohexanol
TWA 50 ppm (200 mg/m 3) [skin]Cyclohexanone
TWA 25 ppm (100 mg/m 3) [skin]Cyclohexylamine
TWA 10 ppm (40 mg/m 3)Cyclonite
TWA 1.5 mg/m 3 [skin]Cyclopentane
TWA 600 ppm (1720 mg/m 3)Cyhexatin
TWA 5 mg/m 3Decaborane
TWA 0.3 mg/m 3 (0.05 ppm)
ST 0.9 mg/m 3 (0.15 ppm) [skin]Diazinon
TWA 0.1 mg/m 3 [skin]2-N-Dibutylaminoethanol
TWA 2 ppm (14 mg/m 3)Dibutyl phosphate
TWA 1 ppm (5 mg/m 3)
ST 2 ppm (10 mg/m 3)Dichloroacetylene
C 0.1 ppm (0.4 mg/m 3)p-Dichlorobenzene
TWA 75 ppm (450 mg/m 3)
ST 110 ppm (675 mg/m 3)1,3-Dichloro-5,5-dimethylhydantoin
TWA 0.2 mg/m 3
ST 0.4 mg/m 3Dichloroethyl ether
TWA 5 ppm (30 mg/m 3)
ST 10 ppm (60 mg/m 3) [skin]Dichloromonofluoromethane
TWA 10 ppm (40 mg/m 3)1,1-Dichloro-1-nitroethane
TWA 2 ppm (10 mg/m 3)1,3-Dichloropropene
TWA 1 ppm (5 mg/m 3) [skin]2,2-Dichloropropionic acid
TWA 1 ppm (6 mg/m 3)Dicrotophos
TWA 0.25 mg/m 3 [skin]Dicyclopentadiene
TWA 5 ppm (30 mg/m 3)Dicyclopentadienyl iron
TWA 10 mg/m 3 (total)
TWA 5 mg/m 3 (resp)Diethanolamine
TWA 3 ppm (15 mg/m 3)Diethylamine
TWA 10 ppm (30 mg/m 3)
ST 25 ppm (75 mg/m 3)Diethylenetriamine
TWA 1 ppm (4 mg/m 3)Diethyl ketone
TWA 200 ppm (705 mg/m 3)Diethyl phthalate
TWA 5 mg/m 3Diglycidyl ether
TWA 0.1 ppm (0.5 mg/m 3)Diisobutyl ketone
TWA 25 ppm (150 mg/m 3)N,N-Dimethylaniline
TWA 5 ppm (25 mg/m 3)
ST 10 ppm (50 mg/m 3) [skin]Dimethyl-1,2-dibromo-2,2-dichlorethyl phosphate
TWA 3 mg/m 3 [skin]Dimethyl sulfate
TWA 0.1 ppm (0.5 mg/m 3) [skin]Dinitolmide
TWA 5 mg/m 3Di-sec octyl phthalate
TWA 5 mg/m 3
ST 10 mg/m 3Dioxane
TWA 25 ppm (90 mg/m 3) [skin]Dioxathion
TWA 0.2 mg/m 3 [skin]Diphenylamine
TWA 10 mg/m 3Dipropylene glycol methyl ether
TWA 100 ppm (600 mg/m 3)
ST 150 ppm (900 mg/m 3) [skin]Dipropyl ketone
TWA 50 ppm (235 mg/m 3)Diquat (Diquat dibromide)
TWA 0.5 mg/m 3Disulfiram
TWA 2 mg/m 3Disulfoton
TWA 0.1 mg/m 3 [skin]2,6-Di-tert-butyl-p-cresol
TWA 10 mg/m 3Diuron
TWA 10 mg/m 3Divinyl benzene
TWA 10 ppm (50 mg/m 3)Emery
TWA 10 mg/m 3 (total)
TWA 5 mg/m 3 (resp)Endosulfan
TWA 0.1 mg/m 3 [skin]Epichlorohydrin
TWA 2 ppm (8 mg/m 3) [skin]Ethanolamine
TWA 3 ppm (8 mg/m 3)
ST 6 ppm (15 mg/m 3)Ethion
TWA 0.4 mg/m 3 [skin]Ethyl acrylate
TWA 5 ppm (20 mg/m 3)
ST 25 ppm (100 mg/m 3) [skin]Ethyl benzene
TWA 100 ppm (435 mg/m 3)
ST 125 ppm (545 mg/m 3)Ethyl bromide
TWA 200 ppm (890 mg/m 3)
ST 250 ppm (1110 mg/m 3)Ethylene chlorohydrin
C 1 ppm (3 mg/m 3) [skin]Ethylene dichloride
TWA 1 ppm (4 mg/m 3)
ST 2 ppm (8 mg/m 3)Ethylene glycol
C 50 ppm (125 mg/m 3)Ethylene glycol dinitrate
ST 0.1 mg/m 3 [skin]Ethyl ether
TWA 400 ppm (1200 mg/m 3)
ST 500 ppm (1500 mg/m 3)Ethylidene norbornene
C 5 ppm (25 mg/m 3)Ethyl mercaptan
TWA 0.5 ppm (1 mg/m 3)N-Ethylmorpholine
TWA 5 ppm (23 mg/m 3) [skin]Ethyl silicate
TWA 10 ppm (85 mg/m 3)Fenamiphos
TWA 0.1 mg/m 3 [skin]Fensulfothion
TWA 0.1 mg/m 3Fenthion
TWA 0.2 mg/m 3 [skin]Ferbam
TWA 10 mg/m 3Ferrovanadium dust
TWA 1 mg/m 3
ST 3 mg/m 3Fluorotrichloromethane
C 1000 ppm (5600 mg/m 3)Fonofos
TWA 0.1 mg/m 3 [skin]Formamide
TWA 20 ppm (30 mg/m 3)
ST 30 ppm (45 mg/m 3)Furfural
TWA 2 ppm (8 mg/m 3) [skin]Furfuryl alcohol
TWA 10 ppm (40 mg/m 3)
ST 15 ppm (60 mg/m 3) [skin]Gasoline
TWA 300 ppm (900 mg/m 3)
ST 500 ppm (1500 mg/m 3)Germanium tetrahydride
TWA 0.2 ppm (0.6 mg/m 3)Glutaraldehyde
C 0.2 ppm (0.8 mg/m 3)Glycerin (mist)
TWA 10 mg/m 3 (total)
TWA 5 mg/m 3 (resp)Glycidol
TWA 25 ppm (75 mg/m 3)Graphite (natural)
TWA 2.5 mg/m 3 (resp)Graphite (synthetic)
TWA 10 mg/m 3 (total)
TWA 5 mg/m 3 (resp)n-Heptane
TWA 400 ppm (1600 mg/m 3)
ST 500 ppm (2000 mg/m 3)Hexachlorobutadiene
TWA 0.02 ppm (0.24 mg/m 3)Hexachlorocyclopentadiene
TWA 0.01 ppm (0.1 mg/m 3)Hexafluoroacetone
TWA 0.1 ppm (0.7 mg/m 3) [skin]n-Hexane
TWA 50 ppm (180 mg/m 3)Hexane isomers (except n-Hexane)
TWA 500 ppm (1800 mg/m 3)
ST 1000 ppm (3600 mg/m 3)2-Hexanone
TWA 5 ppm (20 mg/m 3)Hexone
TWA 50 ppm (205 mg/m 3)
ST 75 ppm (300 mg/m 3)Hexylene glycol
C 25 ppm (125 mg/m 3)Hydrazine
TWA 0.1 ppm (0.1 mg/m 3) [skin]Hydrogenated terphenyls
TWA 0.5 ppm (5 mg/m 3)Hydrogen bromide
C 3 ppm (10 mg/m 3)Hydrogen cyanide
ST 4.7 ppm (5 mg/m 3) [skin]Hydrogen fluoride (as F)
TWA 3 ppm
ST 6 ppmHydrogen sulfide
TWA 10 ppm (14 mg/m 3)
ST 15 ppm (21 mg/m 3)2-Hydroxypropyl acrylate
TWA 0.5 ppm (3 mg/m 3) [skin]Indene
TWA 10 ppm (45 mg/m 3)Indium
TWA 0.1 mg/m 3Iodoform
TWA 0.6 ppm (10 mg/m 3)Iron pentacarbonyl (as Fe)
TWA 0.1 ppm (0.8 mg/m 3)
ST 0.2 ppm (1.6 mg/m 3)Iron salts (soluble, as Fe)
TWA 1 mg/m 3Isoamyl alcohol (primary & secondary)
TWA 100 ppm (360 mg/m 3)
ST 125 ppm (450 mg/m 3)Isobutane
TWA 800 ppm (1900 mg/m 3)Isobutyl alcohol
TWA 50 ppm (150 mg/m 3)Isooctyl alcohol
TWA 50 ppm (270 mg/m 3) [skin]Isophorone
TWA 4 ppm (23 mg/m 3)Isophorone diisocyanate
TWA 0.005 ppm
ST 0.02 ppm [skin]2-Isopropoxyethanol
TWA 25 ppm (105 mg/m 3)Isopropyl acetate
TWA 250 ppm (950 mg/m 3)
ST 310 ppm (1185 mg/m 3)Isopropyl alcohol
TWA 400 ppm (980 mg/m 3)
ST 500 ppm (1225 mg/m 3)Isopropylamine
TWA 5 ppm (12 mg/m 3)
ST 10 ppm (24 mg/m 3)N-Isopropylaniline
TWA 2 ppm (10 mg/m 3) [skin]Isopropyl glycidyl ether
TWA 50 ppm (240 mg/m 3)
ST 75 ppm (360 mg/m 3)Kaolin
TWA 10 mg/m 3 (total)
TWA 5 mg/m 3 (resp)Ketene
TWA 0.5 ppm (0.9 mg/m 3)
ST 1.5 ppm (3 mg/m 3)Magnesium oxide fume
TWA 10 mg/m 3Malathion
TWA 10 mg/m 3 [skin]Manganese compounds and fume (as Mn)
Compounds:
C 5 mg/m 3Fume:
TWA 1 mg/m 3
ST 3 mg/m 3Manganese cyclopentadienyl tricarbonyl (as Mn)
TWA 0.1 mg/m 3 [skin]Manganese tetroxide (as Mn)
TWA 1 mg/m 3Mercury compounds, as Hg [except(organo) alkyls]
Hg Vapor: TWA 0.05 mg/m3 [skin]
Non-alkyl compounds: C 0.1 mg/m3 [skin]Mercury (organo) alkyl compounds (as Hg)
TWA 0.01 mg/m 3ST 0.03 mg/m 3 [skin]Mesityl oxide
TWA 15 ppm (60 mg/m 3)
ST 25 ppm (100 mg/m 3)Methacrylic acid
TWA 20 ppm (70 mg/m 3) [skin]Methomyl
TWA 2.5 mg/m 3Methoxychlor
TWA 10 mg/m 34-Methoxyphenol
TWA 5 mg/m 3Methyl acetate
TWA 200 ppm (610 mg/m 3)
ST 250 ppm (760 mg/m 3)Methyl acetylene-propadiene mixture
TWA 1000 ppm (1800 mg/m 3)
ST 1250 ppm (2250 mg/m 3)Methylacrylonitrile
TWA 1 ppm (3 mg/m 3) [skin]Methyl alcohol
TWA 200 ppm (260 mg/m 3)
ST 250 ppm (325 mg/m 3) [skin]Methyl bromide
TWA 5 ppm (20 mg/m 3) [skin]Methyl chloride
TWA 50 ppm (105 mg/m 3)
ST 100 ppm (210 mg/m 3)Methyl chloroform
TWA 350 ppm (1900 mg/m 3)
ST 450 ppm (2450 mg/m 3)Methyl-2-cyanoacrylate
TWA 2 ppm (8 mg/m 3)
ST 4 ppm (16 mg/m 3)Methylcyclohexane
TWA 400 ppm (1600 mg/m 3)Methylcyclohexanol
TWA 50 ppm (235 mg/m 3)o-Methylcyclohexanone
TWA 50 ppm (230 mg/m 3)
ST 75 ppm (345 mg/m 3) [skin]Methyl cyclopentadienyl manganese tricarbonyl (as Mn)
TWA 0.2 mg/m 3 [skin]Methyl demeton
TWA 0.5 mg/m 3 [skin]4,4′-Methylenebis(2-chloroaniline)
TWA 0.02 ppm (0.22 mg/m 3) [skin]Methylene bis(4-cyclo-hexylisocyanate)
C 0.01 ppm (0.11 mg/m 3) [skin]Methyl ethyl ketone peroxide
C 0.7 ppm (5 mg/m 3)Methyl formate
TWA 100 ppm (250 mg/m 3)
ST 150 ppm (375 mg/m 3)Methyl iodide
TWA 2 ppm (10 mg/m 3) [skin]Methyl isoamyl ketone
TWA 50 ppm (240 mg/m 3)Methyl isobutyl carbinol
TWA 25 ppm (100 mg/m 3)
ST 40 ppm (165 mg/m 3) [skin]Methyl isopropyl ketone
TWA 200 ppm (705 mg/m 3)Methyl mercaptan
TWA 0.5 ppm (1 mg/m 3)Methyl parathion
TWA 0.2 mg/m 3 [skin]Methyl silicate
TWA 1 ppm (6 mg/m 3)alpha-Methyl styrene
TWA 50 ppm (240 mg/m 3)
ST 100 ppm (485 mg/m 3)Metribuzin
TWA 5 mg/m 3Mica
TWA 3 mg/m 3 (resp)Molybdenum (insoluble compounds, as Mo)
TWA 10 mg/m 3Monocrotophos
TWA 0.25 mg/m 3Monomethyl aniline
TWA 0.5 ppm (2 mg/m 3) [skin]Morpholine
TWA 20 ppm (70 mg/m 3)
ST 30 ppm (105 mg/m 3) [skin]Naphthalene
TWA 10 ppm (50 mg/m 3)
ST 15 ppm (75 mg/m 3)Nickel metal & other compounds (as Ni)
Metal & insoluble compounds: TWA 1 mg/m3Soluble compounds: TWA 0.1 mg/m3Nitric acid
TWA 2 ppm (5 mg/m 3)
ST 4 ppm (10 mg/m 3)p-Nitroaniline
TWA 3 mg/m 3 [skin]Nitrogen dioxide
ST 1 ppm (1.8 mg/m 3)Nitroglycerine
ST 0.1 mg/m 3 [skin]2-Nitropropane
TWA 10 ppm (35 mg/m 3)Nitrotoluene (o-, m-, p-isomers)
TWA 2 ppm (11 mg/m 3) [skin]Nonane
TWA 200 ppm (1050 mg/m 3)Octachloronaphthalene
TWA 0.1 mg/m 3
ST 0.3 mg/m 3 [skin]Octane
TWA 300 ppm (1450 mg/m 3)
ST 375 ppm (1800 mg/m 3)Osmium tetroxide (as Os)
TWA 0.002 mg/m 3 (0.0002 ppm)
ST 0.006 mg/m 3 (0.0006 ppm)Oxalic acid
TWA 1 mg/m 3
ST 2 mg/m 3Oxygen difluoride
C 0.05 ppm (0.1 mg/m 3)Ozone
TWA 0.1 ppm (0.2 mg/m 3)
ST 0.3 ppm (0.6 mg/m 3)Paraffin wax fume
TWA 2 mg/m 3Paraquat
TWA 0.1 mg/m 3 (resp) [skin]Pentaborane
TWA 0.005 ppm (0.01 mg/m 3)
ST 0.015 ppm (0.03 mg/m 3)Pentaerythritol
TWA 10 mg/m 3 (total)
TWA 5 mg/m 3 (resp)n-Pentane
TWA 600 ppm (1800 mg/m 3)
ST 750 ppm (2250 mg/m 3)2-Pentanone
TWA 200 ppm (700 mg/m 3)
ST 250 ppm (875 mg/m 3)Perchloryl fluoride
TWA 3 ppm (14 mg/m 3)
ST 6 ppm (28 mg/m 3)Petroleum distillates (naphtha)
TWA 400 ppm (1600 mg/m 3)Phenothiazine
TWA 5 mg/m 3 [skin]Phenyl glycidyl ether
TWA 1 ppm (6 mg/m 3)Phenylhydrazine
TWA 5 ppm (20 mg/m 3)
ST 10 ppm (45 mg/m 3) [skin]Phenylphosphine
C 0.05 ppm (0.25 mg/m 3)Phorate
TWA 0.05 mg/m 3
ST 0.2 mg/m 3 [skin]Phosdrin
TWA 0.01 ppm (0.1 mg/m 3)
ST 0.03 ppm (0.3 mg/m 3) [skin]Phosphine
TWA 0.3 ppm (0.4 mg/m 3)
ST 1 ppm (1 mg/m 3)Phosphoric acid
TWA 1 mg/m 3
ST 3 mg/m 3Phosphorus oxychloride
TWA 0.1 ppm (0.6 mg/m 3)Phosphorus pentasulfide
TWA 1 mg/m 3
ST 3 mg/m 3Phosphorus trichloride
TWA 0.2 ppm (1.5 mg/m 3)
ST 0.5 ppm (3 mg/m 3)Phthalic anhydride
TWA 6 mg/m 3 (1 ppm)m-Phthalodinitrile
TWA 5 mg/m 3Picloram
TWA 10 mg/m 3 (total)
TWA 5 mg/m 3 (resp)Piperazine dihydrochloride
TWA 5 mg/m 3Platinum metal (as Pt)
TWA 1 mg/m 3Portland cement
TWA 10 mg/m 3 (total)
TWA 5 mg/m 3 (resp)Potassium hydroxide
TWA 2 mg/m 3Propargyl alcohol
TWA 1 ppm (2 mg/m 3) [skin]Propionic acid
TWA 10 ppm (30 mg/m 3)Propoxur
TWA 0.5 mg/m 3n-Propyl acetate
TWA 200 ppm (840 mg/m 3)
ST 250 ppm (1050 mg/m 3)n-Propyl alcohol
TWA 200 ppm (500 mg/m 3)
ST 250 ppm (625 mg/m 3)Propylene dichloride
TWA 75 ppm (350 mg/m 3)
ST 110 ppm (510 mg/m 3)Propylene glycol dinitrate
TWA 0.05 ppm (0.3 mg/m 3)Propylene glycol monomethyl ether
TWA 100 ppm (360 mg/m 3)
ST 150 ppm (540 mg/m 3)Propylene oxide
TWA 20 ppm (50 mg/m 3)n-Propyl nitrate
TWA 25 ppm (105 mg/m 3)
ST 40 ppm (170 mg/m 3)Resorcinol
TWA 10 ppm (45 mg/m 3)
ST 20 ppm (90 mg/m 3)Ronnel
TWA 10 mg/m 3Rosin core solder, pyrolysis products (as formaldehyde)
TWA 0.1 mg/m 3Rouge
TWA 10 mg/m 3 (total)
TWA 5 mg/m 3 (resp)Silica, amorphous
TWA 6 mg/m 3
TWA 0.1 mg/m 3 (fused)Silica, crystalline (as respirable dust)
TWA 0.05 mg/m 3 (cristobalite)
TWA 0.05 mg/m 3 (tridymite)
TWA 0.1 mg/m 3 (quartz)
TWA 0.1 mg/m 3 (tripoli)Silicon
TWA 10 mg/m 3 (total)
TWA 5 mg/m 3 (resp)Silicon carbide
TWA 10 mg/m 3 (total)
TWA 5 mg/m 3 (resp)Silicon tetrahydride
TWA 5 ppm (7 mg/m 3)Soapstone
TWA 6 mg/m 3 (total)
TWA 3 mg/m 3 (resp)Sodium azide
C 0.1 ppm (as HN 3) [skin]
C 0.3 mg/m 3 (as NaN 3) [skin]Sodium bisulfite
TWA 5 mg/m 3Sodium fluoroacetate
TWA 0.05 mg/m 3
ST 0.15 mg/m 3 [skin]Sodium hydroxide
C 2 mg/m 3Sodium metabisulfite
TWA 5 mg/m 3Stoddard solvent
TWA 525 mg/m 3 (100 ppm)Styrene
TWA 50 ppm (215 mg/m 3)
ST 100 ppm (425 mg/m 3)Subtilisins
ST 0.00006 mg/m 3 [60-minute]Sulfur dioxide
TWA 2 ppm (5 mg/m 3)
ST 5 ppm (13 mg/m 3)Sulfur monochloride
C 1 ppm (6 mg/m 3)Sulfur pentafluoride
C 0.01 ppm (0.1 mg/m 3)Sulfur tetrafluoride
C 0.1 ppm (0.4 mg/m 3)Sulfuryl fluoride
TWA 5 ppm (20 mg/m 3)
ST 10 ppm (40 mg/m 3)Sulprofos
TWA 1 mg/m 3Talc
TWA 2 mg/m 3 (resp)Temephos
TWA 10 mg/m 3 (total)
TWA 5 mg/m 3 (resp)Terphenyl (o-, m-, p-isomers)
C 5 mg/m 3 (0.5 ppm)1,1,2,2-Tetrachloroethane
TWA 1 ppm (7 mg/m 3) [skin]Tetrachloroethylene
TWA 25 ppm (170 mg/m 3)Tetrahydrofuran
TWA 200 ppm (590 mg/m 3)
ST 250 ppm (735 mg/m 3)Tetrasodium pyrophosphate
TWA 5 mg/m 34,4′-Thiobis(6-tert-butyl-m-cresol)
TWA 10 mg/m 3 (total)
TWA 5 mg/m 3 (resp)Thioglycolic acid
TWA 1 ppm (4 mg/m 3) [skin]Thionyl chloride
C 1 ppm (5 mg/m 3)Tin (organic compounds, as Sn)
TWA 0.1 mg/m 3 [skin]Tin(II) oxide (as Sn)
TWA 2 mg/m 3Tin(IV) oxide (as Sn)
TWA 2 mg/m 3Titanium dioxide
TWA 10 mg/m 3Toluene
TWA 100 ppm (375 mg/m 3)
ST 150 ppm (560 mg/m 3)Toluene-2,4-diisocyanate
TWA 0.005 ppm (0.04 mg/m 3)
ST 0.02 ppm (0.15 mg/m 3)m-Toluidine
TWA 2 ppm (9 mg/m 3) [skin]p-Toluidine
TWA 2 ppm (9 mg/m 3) [skin]Tributyl phosphate
TWA 0.2 ppm (2.5 mg/m 3)Trichloroacetic acid
TWA 1 ppm (7 mg/m 3)1,2,4-Trichlorobenzene
C 5 ppm (40 mg/m 3)Trichloroethylene
TWA 50 ppm (270 mg/m 3)
ST 200 ppm (1080 mg/m 3)1,2,3-Trichloropropane
TWA 10 ppm (60 mg/m 3)1,1,2-Trichloro-1,2,2-trifluoroethane
TWA 1000 ppm (7600 mg/m 3)
ST 1250 ppm (9500 mg/m 3)Triethylamine
TWA 10 ppm (40 mg/m 3)
ST 15 ppm (60 mg/m 3)Trimellitic anhydride
TWA 0.005 ppm (0.04 mg/m 3)Trimethylamine
TWA 10 ppm (24 mg/m 3)
ST 15 ppm (36 mg/m 3)1,2,3-Trimethylbenzene
TWA 25 ppm (125 mg/m 3)1,2,4-Trimethylbenzene
TWA 25 ppm (125 mg/m 3)1,3,5-Trimethylbenzene
TWA 25 ppm (125 mg/m 3)Trimethyl phosphite
TWA 2 ppm (10 mg/m 3)2,4,6-Trinitrotoluene
TWA 0.5 mg/m 3 [skin]Triorthocresyl phosphate
TWA 0.1 mg/m 3 [skin]Triphenylamine
TWA 5 mg/m 3Tungsten (insoluble compounds, as W)
TWA 5 mg/m 3
ST 10 mg/m 3Tungsten (soluble compounds, as W)
TWA 1 mg/m 3
ST 3 mg/m 3Tungsten carbide (cemented)
TWA 5 mg/m 3 (as W)
ST 10 mg/m 3 (as W)
TWA 0.05 mg/m 3 (as Co)
TWA 1 mg/m 3 (as Ni)Uranium (insoluble compounds, as U)
TWA 0.2 mg/m 3
ST 0.6 mg/m 3n-Valeraldehyde
TWA 50 ppm (175 mg/m 3)Vanadium dust
TWA 0.05 mg V 2O 5/m 3 (resp)Vanadium fume
C 0.05 mg V 2O 5/m 3Vinyl acetate
TWA 10 ppm (30 mg/m 3)
ST 20 ppm (60 mg/m 3)Vinyl bromide
TWA 5 ppm (20 mg/m 3)Vinyl cyclohexene dioxide
TWA 10 ppm (60 mg/m 3) [skin]Vinylidene chloride
TWA 1 ppm (4 mg/m 3)VM & P Naphtha
TWA 1350 mg/m 3 (300 ppm)
ST 1800 mg/m 3 (400 ppm)Welding fumes
TWA 5 mg/m 3Wood dust (all wood dusts except Western red cedar)
TWA 5 mg/m 3
ST 10 mg/m 3Wood dust (Western red cedar)
TWA 2.5 mg/m 3Xylene (o-, m-, p-isomers)
TWA 100 ppm (435 mg/m 3)
ST 150 ppm (655 mg/m 3)m-Xylene alpha, alpha’-diamine
C 0.1 mg/m 3 [skin]Xylidine
TWA 2 ppm (10 mg/m 3) [skin]Zinc chloride fume
TWA 1 mg/m 3
ST 2 mg/m 3Zinc oxide
TWA 5 mg/m 3 (fume)
ST 10 mg/m 3 (fume)
TWA 10 mg/m 3 (total dust)
TWA 5 mg/m 3 (resp dust)Zinc stearate
TWA 10 mg/m 3 (total)
TWA 5 mg/m 3 (resp)Zirconium compounds (as Zr)
TWA 5 mg/m 3
ST 10 mg/m 3
							
					
						Page last reviewed:  October 18, 2018					Content source: 	National Institute for Occupational Safety and Health NIOSH Pocket Guide to Chemical Hazards
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A – NIOSH Potential Occupational Carcinogens
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F – Miscellaneous Notes
G – 1989 Air Contaminants Update Project: Exposure Limits NOT in Effect
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