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Immediately Dangerous To Life or Health (IDLH) Values

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Occupational exposures to chemicals have long been recognized as having the potential to adversely affect the lives and health of workers. Acute or short-term exposures to high concentrations of some airborne chemicals have the ability to quickly overwhelm workers, resulting in a wide spectrum of undesirable health outcomes that may include irritation of the eyes and respiratory tract, severe irreversible health effects, impairment of the ability to escape from the exposure environment, and, in extreme cases, death.

NIOSH IDLH values characterize these high-risk exposure concentrations and conditions and are used as a component of respirator selection criteria first developed in the mid-1970s. IDLH values are established (1) to ensure that the worker can escape from a given contaminated environment in the event of failure of the respiratory protection equipment and (2) to indicate a maximum level above which only a highly reliable breathing apparatus, providing maximum worker protection, is permitted.

Since the development of the original IDLH values in the 1970s and their subsequent revision in 1994 (NIOSH Documentation for Immediately Dangerous to Life or Health Concentrations (IDLH) (1994)). NIOSH has continued to review relevant scientific data and conduct research on methods for developing acute exposure guidelines.

For more information about the development of IDLH values, refer toNIOSH Current Intelligence Bulletin 66: Derivation of Immediately Dangerous to Life or Health Values (DHHS (NIOSH) Publication Number 2014-100).

Table of Values

NIOSH’s goal is to re-evaluate all IDLH values included in the list below using the guidelines and criteria included in theNIOSH Current Intelligence Bulletin 66: Derivation of Immediately Dangerous to Life or Health Values. Until this happens, this list contains IDLH values based on both the 1994 revised criteria and CIB 66. It is important to note which criteria was applied to develop a specific IDLH value. When a chemical entry contains more than one IDLH value, the IDLH value based on CIB 66 should be treated as current NIOSH policy.

SubstanceCAS no.IDLH Value (1994)*New/Updated Values
(2016-present)**
Acetaldehyde75-07-02,000 ppm
Acetic acid64-19-750 ppm
Acetic anhydride108-24-7200 ppm
Acetone67-64-12,500 ppm
Acetonitrile75-05-8500 ppm137 ppm (NIOSH Pub. No. 2017-203)
Acetylene tetrabromide79-27-68 ppm
Acrolein107-02-82 ppm
Acrylamide79-06-160 mg/m3 
Acrylonitrile107-13-185 ppm60 ppm (NIOSH Pub. No. 2016-167)
Aldrin309-00-225 mg/m3 
Allyl alcohol107-18-620 ppm 
Allyl chloride107-05-1250 ppm 
Allyl glycidyl ether106-92-350 ppm 
2 Aminopyridine504-29-05 ppm 
Ammonia7664-41-7300 ppm 
Ammonium sulfamate7773-06-01,500 mg/m3 
n-Amyl acetate628-63-71,000 ppm 
sec-Amyl acetate626-38-01,000 ppm 
Aniline62-53-3100 ppm 
o-Anisidine90-04-050 mg/m3 
p-Anisidine104-94-950 mg/m3 
Antimony compounds (as Sb)7440-36-050 mg Sb/m3 
ANTU86-88-4100 mg/m3 
Arsenic (inorganic compounds, as As)7440-38-2 (metal)5 mg As/m3 
Arsine7784-42-13 ppm 
Azinphosmethyl86-50-010 mg/m3 
Barium (soluble compounds, as Ba)7440-39-350 mg Ba/m3 
Benzene71-43-2500 ppm 
Benzonitrile14 ppm (66 mg/m3) (NIOSH Pub. No. 2017-104)
Benzoyl peroxide94-36-01,500 mg/m3 
Benzyl chloride100-44-710 ppm 
Beryllium compounds (as Be)7440-41-7 (metal)4 mg Be/m3 
Boron oxide1303-86-22,000 mg/m3 
Boron trifluoride7637-07-225 ppm 
Bromine7726-95-63 ppm 
Bromine Pentafluoride1.7 ppm (NIOSH Pub. No. 2017-106)
Bromine trifluoride7787-71-512 ppm (67 mg/m3) (NIOSH Pub. No. 2020-123)
Bromoform75-25-2850 ppm
Butane106-97-81,600 ppm (>10% LEL) (NIOSH Pub. No. 2016-174)
1,3-Butadiene106-99-02,000 ppm2,000 ppm (10% LEL) (NIOSH Pub. No. 2017-107)
2-Butanone78-93-33,000 ppm
2-Butoxyethanol111-76-2700 ppm
n-Butyl acetate123-86-41,700 ppm
sec-Butyl acetate105-46-41,700 ppm
tert-Butyl acetate540-88-51,500 ppm
n-Butyl alcohol71-36-31,400 ppm
sec-Butyl alcohol78-92-22,000 ppm
tert-Butyl alcohol75-65-01,600 ppm
n-Butylamine109-73-9300 ppm
tert-Butyl chromate1189-85-115 mg Cr(VI)/m3
n-Butyl Acrylate141-32-2113 ppm (NIOSH Pub. No. 2016-173)
n-Butyl glycidyl ether2426-08-6250 ppm
n-Butyl mercaptan109-79-5500 ppm
p-tert-Butyltoluene98-51-1100 ppm 
Cadmium dust (as Cd)7440-43-9 (metal)9 mg Cd/m3 
Cadmium fume (as Cd)1306-19-0 (CdO)9 mg Cd/m3[Unc h] 
Calcium arsenate (as As)7778-44-15 mg As/m3 
Calcium oxide1305-78-825 mg/m3 
Camphor (synthetic)76-22-2200 mg/m3 
Carbaryl63-25-2100 mg/m3 
Carbon black1333-86-41,750 mg/m3 
Carbon dioxide124-38-940,000 ppm 
Carbon disulfide75-15-0500 ppm 
Carbon monoxide630-08-01,200 ppm 
Carbon tetrachloride56-23-5200 ppm 
Chlordane57-74-9100 mg/m3 
Chlorinated camphene8001-35-2200 mg/m3 
Chlorinated diphenyl oxiden/a5 mg/m3 
Chlorine7782-50-510 ppm 
Chlorine dioxide10049-04-45 ppm 
Chlorine Pentafluoride13637-63-31.7 ppm (NIOSH Pub. No. 2016-170)
Chlorine Trifluoride7790-91-212 ppm (45 mg/m3) (NIOSH Pub. No. 2020-124)
Chloroacetaldehyde107-20-045 ppm
Chloroacetonitrile107-14-214 ppm (NIOSH Pub. No. 2017-201)
alpha-Chloroacetophenone532-27-415 mg/m3
Chlorobenzene108-90-71,000 ppm
o-Chlorobenzylidene malononitrile2698-41-12 mg/m3
Chlorobromomethane74-97-52,000 ppm
Chlorodiphenyl (42% chlorine)53469-21-95 mg/m3
Chlorodiphenyl (54% chlorine)11097-69-15 mg/m3
Chloroform67-66-3500 ppm
1-Chloro-1-nitropropane600-25-9100 ppm
Chloroacetyl Chloride79-04-91.3 ppm (6 mg/m3)(NIOSH Pub. No. 2016-169)
Chloropicrin76-06-22 ppm
beta-Chloroprene126-99-8300 ppm
Chromic acid and chromates1333-82-0 (CrO3)15 mg Cr(VI)/m3
Chromium (II) compounds [as Cr(II)]n/a250 mg Cr(II)/m3 
Chromium (III) compounds [as Cr(III)]n/a25 mg Cr(III)/m3 
Chromium metal (as Cr)7440-47-3250 mg Cr/m3 
Coal tar pitch volatiles65996-93-280 mg/m3 
Cobalt metal, dust and fume (as Co)7440-48-420 mg Co/m3 
Copper (dusts and mists, as Cu)7440-50-8100 mg Cu/m3 
Copper fume (as Cu)1317-38-0 (CuO)100 mg Cu/m3 
Cotton dust (raw)n/a100 mg/m3 
Crag (r) herbicide136-78-7500 mg/m3 
Cresol (o, m, p isomers)95-48-7250 ppm 
Crotonaldehyde4170-30-350 ppm 
Cumene98-82-8900 ppm [10% LEL] 
Cyanides (as CN)n/a25 mg/m3(as CN) 
Cyclohexane110-82-71,300 ppm [10% LEL] 
Cyclohexanol108-93-0400 ppm 
Cyclohexanone108-94-1700 ppm 
Cyclohexene110-83-82,000 ppm 
Cyclopentadiene542-92-7750 ppm 
2,4-D94-75-7100 mg/m3 
DDT50-29-3500 mg/m3 
Decaborane17702-41-915 mg/m3 
Demeton8065-48-310 mg/m3 
Diacetone alcohol123-42-21,800 ppm [10% LEL] 
Diazomethane334-88-32 ppm 
Diborane19287-45-715 ppm 
Dibutyl phosphate107-66-430 ppm 
Dibutyl phthalate84-74-24,000 mg/m3 
o-Dichlorobenzene95-50-1200 ppm 
p-Dichlorobenzene106-46-7150 ppm 
Dichlorodifluoromethane75-71-815,000 ppm 
1,3-Dichloro 5,5-dimethylhydantoin118-52-55 mg/m3 
1,1-Dichloroethane75-34-33,000 ppm 
1,2-Dichloroethylene540-59-01,000 ppm 
Dichloroethyl ether111-44-4100 ppm 
Dichloromonofluoromethane75-43-45,000 ppm 
1,1-Dichloro-1-Fluoroethane (HCFC-141b)1717-00-61,700 ppm (8,245 mg/m3) (NIOSH Pub. No. 2016-168)
1,1-Dichloro 1-nitroethane594-72-925 ppm
Dichlorotetrafluoroethane76-14-215,000 ppm 
Dichlorvos62-73-7100 mg/m3 
Dieldrin60-57-150 mg/m3 
Diethylamine109-89-7200 ppm 
2-Diethylaminoethanol100-37-8100 ppm 
Difluorodibromomethane75-61-62,000 ppm 
Diglycidyl ether2238-07-510 ppm 
Diisobutyl ketone108-83-8500 ppm 
Diisopropylamine108-18-9200 ppm 
Diketene7.6 ppm(NIOSH Pub. No. 2017-108)
Dimethyl acetamide127-19-5300 ppm 
Dimethylamine124-40-3500 ppm 
N,N-Dimethylaniline121-69-7100 ppm 
Dimethyl 1,2-dibromo 2,2-dichlorethyl phosphate300-76-5200 mg/m3 
Dimethylformamide68-12-2500 ppm 
1,1-Dimethylhydrazine57-14-715 ppm 
Dimethylphthalate131-11-32,000 mg/m3 
Dimethyl sulfate77-78-17 ppm 
Dinitrobenzene (o, m, p isomers)528-29-050 mg/m3 
Dinitroocresol534-52-15 mg/m3 
Dinitrotoluene25321-14-650 mg/m3 
Di sec-octyl phthalate117-81-75,000 mg/m3 
Dioxane123-91-1500 ppm 
Diphenyl92-52-4100 mg/m3 
Dipropylene glycol methyl ether34590-94-8600 ppm 
Endrin72-20-82 mg/m3 
Epichlorohydrin106-89-875 ppm 
EPN2104-64-55 mg/m3 
Ethanolamine141-43-530 ppm 
2-Ethoxyethanol110-80-5500 ppm 
2-Ethoxyethyl acetate111-15-9500 ppm 
Ethyl acetate141-78-62,000 ppm [10% LEL] 
Ethyl acrylate140-88-5300 ppm 
Ethyl alcohol64-17-53,300 ppm [10% LEL] 
Ethylamine75-04-7600 ppm 
Ethyl benzene100-41-4800 ppm [10% LEL] 
Ethyl bromide74-96-42,000 ppm 
Ethyl butyl ketone106-35-41,000 ppm 
Ethyl chloride75-00-33,800 ppm [10% LEL] 
Ethylene chlorohydrin107-07-37 ppm 
Ethylenediamine107-15-31,000 ppm 
Ethylene Dibromide106-93-446 ppm (354 mg/m3) (NIOSH Pub. No. 2020-125)
Ethylene dichloride107-06-250 ppm 
Ethylene glycol dinitrate628-96-675 mg/m3 
Ethyleneimine151-56-4100 ppm 
Ethylene oxide75-21-8800 ppm 
Ethyl ether60-29-71,900 ppm [10% LEL] 
Ethyl formate109-94-41,500 ppm 
Ethyl mercaptan75-08-1500 ppm 
N-Ethylmorpholine100-74-3100 ppm 
Ethyl silicate78-10-4700 ppm 
Ferbam14484-64-1800 mg/m3 
Ferrovanadium dust12604-58-9500 mg/m3 
Fluorides (as F)n/a250 mg F/m3 
Fluorine7782-41-425 ppm 
Fluorotrichloromethane75-69-42,000 ppm 
Formaldehyde50-00-020 ppm 
Formic acid64-18-630 ppm 
Furan110-00-913 ppm (35.1 mg/m3) (NIOSH Pub. No. 2016-171)
Furfural98-01-1100 ppm
Furfuryl alcohol98-00-075 ppm
Glycidol556-52-5150 ppm
Graphite (natural)7782-42-51,250 mg/m3
Hafnium compounds (as Hf)7440-58-650 mg Hf/m3
Heptachlor76-44-835 mg/m3
n-Heptane142-82-5750 ppm
Hexachloroethane67-72-1300 ppm
Hexachloronaphthalene1335-87-12 mg/m3
Hexafluoroactone684-16-29 ppm (61 mg/m3) (NIOSH Pub. No. 2016-172)
n-Hexane110-54-31,100 ppm [10% LEL] 
2-Hexanone591-78-61,600 ppm 
Hexone108-10-1500 ppm 
sec Hexyl acetate108-84-9500 ppm 
Hydrazine302-01-250 ppm 
Hydrogen bromide10035-10-630 ppm 
Hydrogen chloride7647-01-050 ppm 
Hydrogen cyanide74-90-850 ppm 
Hydrogen fluoride (as F)7664-39-330 ppm 
Hydrogen peroxide7722-84-175 ppm 
Hydrogen selenide (as Se)7783-07-51 ppm 
Hydrogen sulfide7783-06-4100 ppm 
Hydroquinone123-31-950 mg/m3 
Iodine7553-56-22 ppm 
Iron oxide dust and fume (as Fe)1309-37-12,500 mg Fe/m3 
Iron Pentacarbonyl13463-40-60.4 ppm (NIOSH Pub. No. 2016-166)
Isoamyl acetate123-92-21,000 ppm 
Isoamyl alcohol (primary and secondary)123-51-3500 ppm 
Isobutyl acetate110-19-01,300 ppm [10% LEL] 
Isobutyl alcohol78-83-11,600 ppm 
Isophorone78-59-1200 ppm 
Isopropyl acetate108-21-41,800 ppm 
Isopropyl alcohol67-63-02,000 ppm [10% LEL] 
Isopropylamine75-31-0750 ppm 
Isopropyl ether108-20-31,400 ppm [10% LEL] 
Isopropyl glycidyl ether4016-14-2400 ppm 
Ketene463-51-45 ppm 
Lead compounds (as Pb)7439-92-1100 mg Pb/m3 
Lindane58-89-950 mg/m3 
Lithium hydride7580-67-80.5 mg/m3 
L.P.G.68476-85-72,000 ppm [10% LEL] 
Magnesium oxide fume1309-48-4750 mg/m3 
Malathion121-75-5250 mg/m3 
Maleic anhydride108-31-610 mg/m3 
Manganese compounds (as Mn)7439-96-5 (metal)500 mg Mn/m3 
Mercury compounds [except (organo) alkyls, as Hg]7439-97-6 (metal)10 mg Hg/m3 
Mercury (organo) alkyl compounds(as Hg)n/a2 mg Hg/m3 
Mesityl oxide141-79-71,400 ppm [10% LEL] 
Methacrylonitrile126-98-74.0 ppm (NIOSH Pub. No. 2017-204)
Methoxychlor72-43-55,000 mg/m3 
Methyl acetate79-20-93,100 ppm [10% LEL] 
Methyl acetylene74-99-71,700 ppm [10% LEL] 
Methyl acetylenepropadiene mixture59355-75-83,400 ppm [10% LEL] 
Methyl acrylate96-33-3250 ppm 
Methylal109-87-52,200 ppm [10% LEL] 
Methyl alcohol67-56-16,000 ppm 
Methylamine74-89-5100 ppm 
Methyl (namyl) ketone110-43-0800 ppm 
Methyl bromide74-83-9250 ppm 
Methyl Cellosolve (r)109-86-4200 ppm 
Methyl Cellosolve (r) acetate110-49-6200 ppm 
Methyl chloride74-87-32,000 ppm 
Methyl chloroform71-55-6700 ppm 
Methylcyclohexane108-87-21,200 ppm [10% LEL] 
Methylcyclohexanol25639-42-3500 ppm 
o-Methylcyclohexanone583-60-8600 ppm 
Methylene bisphenyl isocyanate101-68-875 mg/m3 
Methylene chloride75-09-22,300 ppm 
Methyl formate107-31-34,500 ppm 
5-Methyl 3-heptanone541-85-5100 ppm 
Methyl hydrazine60-34-420 ppm 
Methyl iodide74-88-4100 ppm 
Methyl isobutyl carbinol108-11-2400 ppm 
Methyl isocyanate624-83-93 ppm0.12 ppm (0.28 mg/m3) (NIOSH Pub. No. 2017-105)
Methyl mercaptan74-93-1150 ppm 
Methyl methacrylate80-62-61,000 ppm 
Methyl styrene98-83-9700 ppm 
Mica12001-26-21,500 mg/m3 
Molybdenum (insoluble compounds, as Mo)n/a5,000 mg Mo/m3 
Molybdenum (soluble compounds, as Mo)n/a1,000 mg Mo/m3 
Monomethyl aniline100-61-8100 ppm 
Morpholine110-91-81,400 ppm [10% LEL] 
Naphtha (coal tar)8030-30-61,000 ppm [10% LEL] 
Naphthalene91-20-3250 ppm 
Nickel carbonyl (as Ni)13463-39-32 ppm 
Nickel metal and other compounds (as Ni)7440-02-0 (Metal)10 mg Ni/m3 
Nicotine54-11-55 mg/m3 
Nitric acid7697-37-225 ppm 
Nitric oxide10102-43-9100 ppm 
p-Nitroaniline100-01-6300 mg/m3 
Nitrobenzene98-95-3200 ppm 
p-Nitrochlorobenzene100-00-5100 mg/m3 
Nitroethane79-24-31,000 ppm 
Nitrogen dioxide10102-44-020 ppm13 ppm (NIOSHPub. No. 2017-202)
Nitrogen trifluoride7783-54-21,000 ppm 
Nitroglycerine55-63-075 mg/m3 
Nitromethane75-52-5750 ppm 
1-Nitropropane108-03-21,000 ppm 
2-Nitropropane79-46-9100 ppm 
Nitrotoluene (o, m, p isomers)88-72-2200 ppm 
Octachloronaphthalene2234-13-1Unknown 
Octane111-65-91,000 ppm [10% LEL] 
Oil mist (mineral)8012-95-12,500 mg/m3 
Osmium tetroxide (as Os)20816-12-01 mg Os/m3 
Oxalic acid144-62-7500 mg/m3 
Oxygen difluoride7783-41-70.5 ppm 
Ozone10028-15-65 ppm 
Paraquat1910-42-51 mg/m3 
Parathion56-38-210 mg/m3 
Pentaborane19624-22-71 ppm 
Pentachloronaphthalene1321-64-8Unknown 
Pentachlorophenol87-86-52.5 mg/m3 
n-Pentane109-66-01,500 ppm [10% LEL] 
2-Pentanone107-87-91,500 ppm 
Perchloromethyl mercaptan594-42-310 ppm 
Perchloryl fluoride7616-94-6100 ppm 
Petroleum distillates (naphtha)8002-05-91,100 ppm [10% LEL] 
Phenol108-95-2250 ppm 
p-Phenylene diamine106-50-325 mg/m3 
Phenyl ether (vapor)101-84-8100 ppm 
Phenyl etherbiphenyl mixture (vapor)8004-13-510 ppm 
Phenyl glycidyl ether122-60-1100 ppm 
Phenylhydrazine100-63-015 ppm 
Phosdrin7786-34-74 ppm 
Phosgene75-44-52 ppm 
Phosphine7803-51-250 ppm 
Phosphoric acid7664-38-21,000 mg/m3 
Phosphorus (yellow)7723-14-05 mg/m3 
Phosphorus pentachloride10026-13-870 mg/m3 
Phosphorus pentasulfide1314-80-3250 mg/m3 
Phosphorus trichloride7719-12-225 ppm 
Phthalic anhydride85-44-960 mg/m3 
Picric acid88-89-175 mg/m3 
Pindone83-26-1100 mg/m3 
Platinum (soluble salts, as Pt)n/a4 mg Pt/m3 
Portland cement65997-15-15,000 mg/m3 
Propane74-98-62,100 ppm [10% LEL] 
n-Propyl acetate109-60-41,700 ppm 
n-Propyl alcohol71-23-8800 ppm 
Propylene dichloride78-87-5400 ppm 
Propylene imine75-55-8100 ppm 
Propylene oxide75-56-9400 ppm 
n-Propyl nitrate627-13-4500 ppm 
Pyrethrum8003-34-75,000 mg/m3 
Pyridine110-86-11,000 ppm 
Quinone106-51-4100 mg/m3 
Rhodium (metal fume and insoluble compounds, as Rh)7440-16-6 (metal)100 mg Rh/m3 
Rhodium (soluble compounds, as Rh)n/a2 mg Rh/m3 
Ronnel299-84-3300 mg/m3 
Rotenone83-79-42,500 mg/m3 
Selenium compounds (as Se)7782-49-21 mg Se/m3 
Selenium hexafluoride7783-79-12 ppm 
Silica, amorphous7631-86-93,000 mg/m3 
Silica, crystalline (respirable dust)14808-60-7 
cristobalite/tridymite14808-60-725 mg/m3 
quartz/tripoli14808-60-750 mg/m3 
Silver (metal dust and soluble compounds, as Ag)7440-22-4 (metal)10 mg Ag/m3 
Soapstonen/a3,000 mg/m3 
Sodium fluoroacetate62-74-82.5 mg/m3 
Sodium hydroxide1310-73-210 mg/m3 
Stibine7803-52-35 ppm 
Stoddard solvent8052-41-320,000 mg/m3 
Strychnine57-24-93 mg/m3 
Styrene100-42-5700 ppm 
Sulfur dioxide7446-09-5100 ppm 
Sulfuric acid7664-93-915 mg/m3 
Sulfur monochloride10025-67-95 ppm 
Sulfur pentafluoride5714-22-71 ppm 
Sulfuryl fluoride2699-79-8200 ppm 
2,4,5-T93-76-5250 mg/m3 
Talc14807-96-61,000 mg/m3 
Tantalum (metal and oxide dust, as Ta)7440-25-7 (metal)2,500 mg Ta/m3 
TEDP3689-24-510 mg/m3 
Tellurium compounds (as Te)13494-80-925 mg Te/m3 
Tellurium hexafluoride7783-80-41 ppm 
TEPP107-49-35 mg/m3 
Terphenyl (o, m, p isomers)84-15-1500 mg/m3 
1,1,1,2-Tetrachloro 2,2-difluoroethane76-11-92,000 ppm 
1,1,2,2-Tetrachloro 1,2-difluoroethane76-12-02,000 ppm 
1,1,2,2-Tetrachloroethane79-34-5100 ppm 
Tetrachloroethylene127-18-4150 ppm 
Tetrachloronaphthalene1335-88-2Unknown 
Tetraethyl lead (as Pb)78-00-240 mg Pb/m3 
Tetrahydrofuran109-99-92,000 ppm [10% LEL] 
Tetramethyl lead (as Pb)75-74-140 mg Pb/m3 
Tetramethyl succinonitrile3333-52-65 ppm 
Tetranitromethane509-14-84 ppm 
Tetryl479-45-8750 mg/m3 
Thallium (soluble compounds, as Tl)n/a15 mg Tl/m3 
Thiram137-26-8100 mg/m3 
Tin (inorganic compounds, as Sn)n/a100 mg Sn/m3 
Tin (organic compounds, as Sn)n/a25 mg Sn/m3 
Titanium dioxide13463-67-75,000 mg/m3 
Toluene108-88-3500 ppm 
Toluene 2,4-diisocyanate584-84-92.5 ppm 
o-Toluidine95-53-450 ppm 
Tributyl phosphate126-73-830 ppm 
1,1,2-Trichloroethane79-00-5100 ppm 
Trichloroethylene79-01-61,000 ppm 
Trichloronaphthalene1321-65-9Unknown 
1,2,3-Trichloropropane96-18-4100 ppm 
1,1,2-Trichloro 1,2,2-trifluoroethane76-13-12,000 ppm 
Triethylamine121-44-8200 ppm 
Trifluorobromomethane75-63-840,000 ppm 
2,4,6-Trinitrotoluene118-96-7500 mg/m3 
Triorthocresyl phosphate78-30-840 mg/m3 
Triphenyl phosphate115-86-61,000 mg/m3 
Turpentine8006-64-2800 ppm 
Uranium (insoluble compounds, as U)7440-61-1 (metal)10 mg U/m3 
Uranium (soluble compounds, as U)n/a10 mg U/m3 
Vanadium dust1314-62-135 mg V/m3 
Vanadium fume1314-62-135 mg V/m3 
Vinyl toluene25013-15-4 (inhibited)400 ppm 
Warfarin81-81-2100 mg/m3 
Xylene (o, m, p isomers)95-47-6900 ppm 
Xylidine1300-73-850 ppm 
Yttrium compounds (as Y)7440-65-5500 mg Y/m3 
Zinc chloride fume7646-85-750 mg/m3 
Zinc oxide1314-13-2500 mg/m3 
Zirconium compounds (as Zr)7440-67-7 (Metal)25 mg Zr/m3
Last Reviewed:May 10, 2019
Source:National Institute for Occupational Safety and Health