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Guidelines Part 5

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Table of Exposure Limits for Chemical and Biological Substances

Explanation of table headings
Table of Exposure Limits
* Download PDF version (77 KB) of the table.
Explanation of table headings

Substance [CAS No.]

  • Lists chemicals and other substances in alphabetical order. Numerals and prefixes, for example, 1,3-, tert-, o-, sec-, cis-, are disregarded in determining alphabetical order.
  • In square brackets is the Chemical Abstracts Services (CAS) registry number. This is a unique identification number assigned specifically to that substance, and can be a convenient way to identify substances.
  • WorkSafeBC reviews and updates this Table annually. If the exposure limit for a substance has been revised or newly adopted since January 1, 2003 this Table reports the change with the words "Revised (year)." Each year, newly included substances and amended substances are highlighted. Recent deletions of substances from the Table are shown as strike through (e.g. Emery).
  • Additional explanation about this table is available at G5.48-2 Annual revisions to exposure limits.

TWA
This is the 8-hour time weighted average (TWA) limit, as defined in section 5.1 of the OHS Regulation.

  • Units: Exposure limits are reported in ppm, mg/m3, or f/cc. In general, substances present in air as a vapour or gas are reported in parts per million (ppm). Substances present in air as an aerosol (dust, fume, mist) and mixtures such as diesel fuel are typically reported in milligrams per cubic metre (mg/m3). See OHS Guideline G5.48-4 for a procedure to convert from one type of unit to the other. Fibrous substances, such as synthetic vitreous fibres (e.g., glass wool fibres) are reported in fibres per cubic centimetre (f/cc). This is equivalent to fibres per millilitre, or f/ml, which is another common term.
  • Endnotes: Letters in parentheses indicate endnotes, which are explained at the end of the table. Substances which have an "L " endnote are subject to section 5.57 (Designated substances) of the OHS Regulation. For more information see OHS Guideline G5.57.

STEL
This is the short-term exposure limit or STEL, which is defined in section 5.1 of the OHS Regulation. Note that:

  • "C" indicates a ceiling limit, which is defined in section 5.1 of the OHS Regulation.
  • The units ppm and mg/m3 are used as in the TWA column.
  • In some cases, the term "simple asphyxiant " is used. This is a gas or vapour that can displace oxygen in the air, resulting in possible suffocation from lack of oxygen. Because simple asphyxiants do not have other significant toxic effects, an exposure limit is not applicable. The limiting factor is the available oxygen. See section 5.56 of the OHS Regulation (Oxygen deficiency).

Notations
The notations identify substances considered to be carcinogens, sensitizers and those with adverse reproductive effect under section 5.57 of the OHS Regulation. Section 5.57 deals with requirements for substitution and keeping exposure as low as reasonably achievable below the exposure limit. The notations column also indicates substances that contribute significantly to overall exposure by the skin route, in which case section 5.52 of the OHS Regulation applies. Note that:

  • ACGIH notations A1 and A2 and IARC notations 1, 2A and 2B indicate substances designated as carcinogens under section 5.57(1) of the OHS Regulation. The different categories used by the two organizations indicate different levels of certainty of carcinogenic effect, eg. from confirmed carcinogen to probable or possible. For more information see OHS Guideline G5.57.
  • The letter "S" indicates that the substance is a sensitizer under section 5.57(1) of the OHS Regulation. For more information see OHS Guideline G5.57.
  • The letter "R" means that the substance has an adverse reproductive effect under section 5.57(1) of the OHS Regulation. For more information see OHS Guideline G5.57.
  • The term "Skin" identifies substances that contribute significantly to the overall exposure by the skin route. For more information see OHS Guideline G5.52.

Table of Exposure Limits for Chemical and Biological Substances

 image October 23, 2009

Substance [CAS No.] TWA STEL Notations
Substance [CAS No.]TWASTEL/CeilingNotations
Abate (See Temephos)   
Acetaldehyde [75-07-0] C 25 ppm2B
Acetamide [60-35-5]  2B
Acetic acid [64-19-7]10 ppm15 ppm 
Acetic anhydride [108-24-7]5 ppm  
Acetone [67-64-1]250 ppm500 ppm 
Acetone cyanohydrin [75-86-5] C 1ppmSkin
Acetonitrile [75-05-8]20 ppm Skin
Acetophenone [98-86-2]10 ppm  
Acetylene [74-86-2] Simple asphyxiant 
Acetylene tetrabromide (See 1,1,2,2 Tetrabromoethane)   
Acetylsalicylic acid (Aspirin) [50-78-2]5 mg/m3  
Acrolein [107-02-8] C 0.1 ppmSkin
Acrylamide, Inhalable [79-06-1] Revised 20050.03 mg/m3 (V) Skin; 2A
Acrylic acid [79-10-7]2 ppm Skin; R
Acrylonitrile [107-13-1]2 ppm Skin; 2B
Adipic acid [124-04-9]5 mg/m3  
Adiponitrile [111-69-3]2 ppm Skin
Alachlor, Inhalable [15972-60-8] Revised 20071.0 mg/m3 (V) S
Aldrin, Inhalable [309-00-2] Revised 20070.05mg/m3 (V) Skin
Aliphatic hydrocarbon gases [C1-C4] Revised 20041000 ppm  
Allyl alcohol [107-18-6]0.5 ppm Skin
Allyl amine [107-11-9]2 ppm  
Allyl chloride [107-05-1]1 ppm2 ppm 
Allyl glycidyl ether [106-92-3]1 ppm S
Allyl propyl disulfide [2179-59-1] Revised 20060.5 ppm S
Aluminum metal and insoluble compounds [7429-90-5] , Respirable, Revised 20081.0 mg/m3  
4-Aminodiphenyl [92-67-1](L) Skin; A1, 1
2-Aminopyridine [504-29-0]0.5 ppm  
Amitrole [61-82-5] Revised 20060.2 mg/m3 R
Ammonia [7664-41-7]25 ppm35 ppm 
Ammonium chloride - Fume [12125-02-9]10 mg/m320 mg/m3 
Ammonium perfluorooctanoate [3825-26-1]0.01 mg/m3 Skin
Ammonium sulfamate [7773-06-0]10 mg/m3 (N)  
tert-Amyl methyl ether (TAME) [994-05-8]20 ppm R
Aniline [62-53-3]2 ppm Skin
o-Anisidine [90-04-0]0.5 mg/m3 Skin; 2B
p-Anisidine [104-94-9]0.5 mg/m3 Skin
Antimony and compounds, as Sb [7440-36-0]0.5 mg/m3  
Antimony hydride (Stibine) [7803-52-3]0.1 ppm  
Antimony trioxide - Production [1309-64-4](L) A2; 2B
ANTU [86-88-4]0.3 mg/m3  
Argon [7440-37-1] Simple asphyxiant 
Arsenic and inorganic compounds, as As [7440-38-2] 0.01 mg/m3 A1, 1
Arsine [7784-42-1] Revised 20070.005 ppm  
Asbestos - All forms [1332-21-4]0.1 f/cc (F) A1, 1
Asphalt (Bitumen) fume, as benzene-soluble aerosol, Inhalable [8052-42-4]0.5 mg/m3 2B
Atrazine [1912-24-9]5 mg/m3  
Azinphos-methyl, Inhalable [86-50-0]0.2 mg/m3 (V) Skin; S
Barium and soluble compounds, as Ba [7440-39-3] 0.5 mg/m3  
Barium sulfate [7727-43-7]10 mg/m3 (N)  
Benomyl, Inhalable [17804-35-2] Revised 20081 mg/m3 R, S
Benz[a]anthracene [56-55-3] Revised 2006(L) A2, 2B
Benzene [71-43-2]0.5 ppm2.5 ppmSkin; A1, 1
Benzidine [92-87-5](L) Skin; A1, 1
Benzidine based dyes   2A
Benzo[b]fluoranthene [205-99-2](L) A2, 2B
Benzo[a]pyrene [50-32-8] Revised 2006(L) A2, 1
Benzotrichloride [98-07-7] C 0.1 ppmSkin; A2, 2A
Benzoyl chloride [98-88-4] C 0.5 ppm2A
Benzoyl peroxide [94-36-0]5 mg/m3  
Benzyl acetate [140-11-4]10 ppm  
Benzyl chloride [100-44-7] C 1 ppm 2A
Beryllium and compounds, as Be, Inhalable [7440-41-7] Revised 20090.00005 mg/m3 Skin; S, A1, 1
Biphenyl [92-52-4]0.2 ppm  
Bis(2-dimethylaminoethyl) ether (DMAEE) [3033-62-3]0.05 ppm0.15 ppmSkin
Bismuth telluride - Se-doped [1304-82-1]5 mg/m3  
Bismuth telluride - Undoped [1304-82-1]10 mg/m3 (N)  
Borate compounds, Inorganic, Inhalable [1303-96-4; 1330-43-4; 10043-35-3; 12179-04-3] Revised 20052 mg/m36 mg/m3 
Boron oxide [1303-86-2]10 mg/m3  
Boron tribromide [10294-33-4] C 1 ppm 
Boron trifluoride [7637-07-02] C 1 ppm 
Bromacil [314-40-9]10 mg/m3  
Bromine [7726-95-6]0.1 ppm0.2 ppm 
Bromine pentafluoride [7789-30-2]0.1 ppm  
Bromochloromethane [74-97-5]200 ppm250 ppm 
Bromoform [75-25-2] Revised 20090.5 ppm  
1-Bromopropane [106-94-5] Revised 200510 ppm R
1,3-Butadiene [106-99-0]2 ppm A2, 1
n-Butane [106-97-8] 600 ppm750 ppm 
n-Butanol [71-36-3]15 ppm C 30 ppm 
sec-Butanol [78-92-2]100 ppm  
tert-Butanol [75-65-0]100 ppm  
Butenes, All isomers [106-98-9; 107-01-7; 590-18-1; 624-64-6; 25167-67-3]; including isobutene [115-11-7] Revised 2008250 ppm  
2-Butoxyethanol (EGBE) [111-76-2] Revised 200320 ppm  
2-Butoxyethyl acetate [112-07-2] Revised 200320 ppm  
n-Butyl acetate [123-86-4]20 ppm  
sec-Butyl acetate [105-46-4]200 ppm  
tert-Butyl acetate [540-88-5]200 ppm   
n-Butyl acrylate [141-32-2]2 ppm S
n-Butylamine [109-73-9] C 5 ppmSkin
Butylated hydroxytoluene (BHT), Inhalable, (2,6-Di-tert-butyl-p-cresol) [128-37-0]2 mg/m3 (V)  
tert-Butyl chromate, as CrO3 [1189-85-1] C 0.1 mg/m3Skin
n-Butyl glycidyl ether (BGE) [2426-08-6] Revised 20053 ppm Skin; S; R
n-Butyl lactate [138-22-7]5 ppm  
n-Butyl mercaptan [109-79-5]0.5 ppm R
n-Butyl methacrylate [97-88-1]50 ppm  
o-sec-Butylphenol [89-72-5]5 ppm Skin
p-tert-Butyltoluene [98-51-1]1 ppm  
Cadmium and compounds, as Cd [7440-43-9]0.01 mg/m3 A2, 1
Cadmium and compounds, Respirable, as Cd [7440-43-9]0.002 mg/m3 A2, 1
Calcium arsenate, as As [7778-44-1]0.01 mg/m3 A1, 1
Calcium carbonate (incl. Limestone, Marble) [1317-65-3]10 mg/m3 (N)20 mg/m3 
Calcium chromate, as Cr [13765-19-0]0.001 mg/m3 A2, 1
Calcium cyanamide [156-62-7]0.5 mg/m3  
Calcium hydroxide [1305-62-0]5 mg/m3  
Calcium oxide [1305-78-8]2 mg/m3  
Calcium silicate - Synthetic nonfibrous [1344-95-2]10 mg/m3 (E,N)  
Calcium sulfate, Inhalable [7778-18-9] 10 mg/m3  
Camphor - Synthetic [76-22-2]2 ppm3 ppm 
Caprolactam, Dust [105-60-2] 1 mg/m33 mg/m3 
Captafol [2425-06-1]0.1 mg/m3 Skin; 2A; S
Captan, Inhalable [133-06-2]5 mg/m3 S
Carbaryl, Inhalable [63-25-2] Revised 20080.5 mg/m3 (V) Skin; R
Carbofuran, Inhalable [1563-66-2] Revised 20040.1 mg/m3 (V)  
Carbon black [1333-86-4]3.5 mg/m3 2B
Carbon dioxide [124-38-9]5000 ppm15,000 ppm 
Carbon disulfide [75-15-0] 4 ppm12 ppmSkin
Carbon monoxide [630-08-0]25 ppm100 ppmR
Carbon tetrabromide [558-13-4]0.1 ppm0.3 ppm 
Carbon tetrachloride [56-23-5]2 ppm Skin; A2, 2B
Carbonyl fluoride [353-50-4]2 ppm5 ppm 
Catechol [120-80-9]5 ppm Skin; 2B
Cellulose [9004-34-6]10 mg/m3 (N)  
Cesium hydroxide [21351-79-1]2 mg/m3  
Chlordane [57-74-9]0.5 mg/m3 Skin; 2B
Chlorinated camphene [8001-35-2]0.5 mg/m31 mg/m3Skin; 2B
o-Chlorinated diphenyl oxide [31242-93-0]0.5 mg/m3  
Chlorine [7782-50-5]0.5 ppm1 ppm 
Chlorine dioxide [10049-04-4]0.1ppm0.3 ppm 
Chlorine trifluoride [7790-91-2] C 0.1 ppm 
Chloroacetaldehyde [107-20-0] C 1 ppm 
Chloroacetic acid [79-11-8]0.3 ppm  
Chloroacetone [78-95-5] C 1 ppmSkin
2-Chloroacetophenone [532-27-4]0.05 ppm S
Chloroacetyl chloride [79-04-9] 0.05 ppm0.15 ppmSkin
p-Chloroaniline [106-47-8]  2B
Chlorobenzene [108-90-7]10 ppm  
o-Chlorobenzylidene malononitrile [2698-41-1] C 0.05 ppmSkin
Chlorobromomethane (see Bromochloromethane)    
1-Chloro-1,1-difluoroethane [75-68-3]1000 ppm  
Chlorodifluoromethane [75-45-6]500 ppm1250 ppm 
Chlorodiphenyl (42% chloride) [53469-21-9]1 mg/m3 Skin; 2A
Chlorodiphenyl (54% chloride) [11097-69-1]0.5 mg/m3 Skin; 2A
Chloroform [67-66-3]2 ppm 2B; R
bis(Chloromethyl) ether [542-88-1]0.001 ppm A1, 1
Chloromethyl methyl ether [107-30-2](L) A2, 1
1-Chloro-1-nitropropane [600-25-9]2 ppm  
Chloropentafluoroethane [76-15-3]1000 ppm  
Chloropicrin [76-06-2]0.1 ppm  
1-Chloro-2-propanol [127-00-4] Revised 20081 ppm Skin; R
2-Chloro-1-propanol [78-89-7] Revised 20081 ppm Skin; R
beta-Chloroprene [126-99-8]10 ppm Skin; 2B; R
2-Chloropropionic acid [598-78-7]0.1 ppm Skin; R
o-Chlorostyrene [2039-87-4]50 ppm75 ppm 
o-Chlorotoluene [95-49-8]50 ppm  
4-Chloro-o-Toluidine [95-69-2]  2A
Chlorotrifluoromethane [75-72-9]1000 ppm  
Chlorpyrifos, Inhalable [2921-88-2] Revised 20030.1 mg/m3 (V) Skin
Chromite ore processing (Chromate), as Cr0.05 mg/m3 A1
Chromium - Metal [7440-47-3]0.5 mg/m3  
Chromium (III) inorganic compounds, as Cr [7440-47-3]0.5 mg/m3  
Chromium (VI) inorganic compounds - Insoluble, as Cr [7440-47-3]0.01 mg/m3 A1, 1
Chromium (VI) inorganic compounds - Water soluble, as Cr [7440-47-3]0.025 mg/m3C 0.1 mg/m3A1, 1
Chromyl chloride [14977-61-8]0.025 ppm  
Chrysene [218-01-9] Revised 2006(L) 2B
Clopidol [2971-90-6]10 mg/m3 (N)  
Coal dust - Anthracite, Respirable0.4 mg/m3  
Coal dust - Bituminous, Respirable0.9 mg/m3  
Coal tar pitch volatiles, as benzene-soluble aerosol [65996-93-2]0.2 mg/m3 A1, 1
Cobalt and inorganic compounds, as Co [7440-48-4]0.02 mg/m3 2B
Cobalt carbonyl, as Co [10210-68-1]0.1 mg/m3  
Cobalt hydrocarbonyl, as Co [16842-03-8]0.1 mg/m3  
Copper - Dusts and mists, as Cu [7440-50-8]1 mg/m3  
Copper - Fume, as Cu [7440-50-8]0.2 mg/m3  
Cotton dust - Raw0.2 mg/m3 (G)  
Coumaphos, Inhalable [56-72-4] Revised 20060.05 mg/m3 (V) Skin
Cresol, all isomers [1319-77-3; 95-48-7; 108-39-4; 106-44-5]10 mg/m3  Skin
Crotonaldehyde [4170-30-3] C 0.3 ppmSkin
Crufomate [299-86-5]5 mg/m3  
Cumene [98-82-8]25 ppm75 ppm 
Cyanamide [420-04-2]2 mg/m3  
Cyanogen [460-19-5]10 ppm  
Cyanogen chloride [506-77-4] C 0.3 ppm 
Cyclohexane [110-82-7]100 ppm  
Cyclohexanol [108-93-0]50 ppm Skin
Cyclohexanone [108-94-1] Revised 200320 ppm50 ppmSkin
Cyclohexene [110-83-8]300 ppm  
Cyclohexylamine [108-91-8]10 ppm  
Cyclonite [121-82-4]0.5 mg/m3 Skin
Cyclopentadiene [542-92-7]75 ppm  
Cyclopentane [287-92-3]600 ppm  
Cyhexatin [13121-70-5]5 mg/m3  
2,4-D (2,4-Dichlorophenoxy-acetic acid) [94-75-7] (see 2,4-Dichlorophenoxyacetic acid and its esters)   
DDT (Dichloro-diphenyltrichloroethane) [50-29-3]1 mg/m3 2B
Decaborane [17702-41-9]0.05 ppm0.15 ppmSkin
Demeton, Inhalable [8065-48-3]0.05 mg/m3 (V) Skin
Demeton-S-methyl, Inhalable [919-86-8]0.05 mg/m3 (V) Skin; S
Diacetone alcohol [123-42-2]50 ppm  
2,4-Diaminoanisole [615-05-4]  2B
2,4-Diaminotoluene [95-80-7]  2B
Diazinon, Inhalable [333-41-5] Revised 20030.01 mg/m3 (V)  Skin
Diazomethane [334-88-3]0.2 ppm A2
Diborane [19287-45-7]0.1 ppm  
1,2-Dibromo-3-chloropropane [96-12-8]  2B
2-N-Dibutylaminoethanol [102-81-8] 0.5 ppm Skin
Dibutyl phenyl phosphate [2528-36-1]0.3 ppm Skin
Dibutyl phosphate, Inhalable [107-66-4] Revised 20095 mg/m3 (V) Skin
Dibutyl phthalate [84-74-2]5 mg/m3 R
Dichloroacetic acid [79-43-6] Revised 20050.5 ppm Skin; 2B; R
Dichloroacetylene [7572-29-4] C 0.1 ppm 
o-Dichlorobenzene [95-50-1]25 ppm50 ppm 
p-Dichlorobenzene [106-46-7]10 ppm 2B
3,3'-Dichlorobenzidine [91-94-1](L) Skin; 2B
1,4-Dichloro-2-butene [764-41-0]0.005 ppm Skin; A2
2,2-Dichlorodiethyl sulfide (Mustard Gas) [505-60-2]  1
Dichlorodifluoromethane [75-71-8]1000 ppm  
1,3-Dichloro-5,5-dimethyl hydantoin [118-52-5]0.2 mg/m30.4 mg/m3 
1,1-Dichloroethane [75-34-3]100 ppm  
1,2-Dichloroethane (see ethylene dichloride)   
1,2-Dichloroethylene, all isomers [540-59-0; 156-59-2; 156-60-5]200 ppm  
Dichloroethyl ether [111-44-4]5 ppm10 ppmSkin
Dichlorofluoromethane [75-43-4]10 ppm  
Dichloromethane [75-09-2]25 ppm 2B
2,2'-Dichloro-n-methyldiethylamine (Nitrogen mustard) [51-75-2]  2A
1,1-Dichloro-1-nitroethane [594-72-9]2 ppm  
1,3-Dichloropropene [542-75-6]1 ppm Skin; 2B
2,4-Dichlorophenoxyacetic acid and its esters [94-75-7] Revised 200610 mg/m320 mg/m32B
2,2-Dichloropropionic acid, Inhalable [75-99-0]5 mg/m3  
Dichlorotetrafluoroethane (Cryofluorane) [76-14-2]1000 ppm  
Dichlorvos (DDVP), Inhalable [62-73-7]0.1 mg/m3 (V) Skin; 2B; S
Dicrotophos, Inhalable [141-66-2]0.05 mg/m3 (V) Skin
Dicyclohexylmethane-4,4'-diisocyanate [5124-30-1] (see Methylene bis (4-cyclohexyl-isocyanate))   
Dicyclopentadiene [77-73-6]5 ppm  
Dicyclopentadienyl iron [102-54-5]10 mg/m3 (N)  
Dieldrin [60-57-1]0.25 mg/m3 Skin
Diesel fuel, as total hydrocarbons, Inhalable [68334-30-5; 68476-30-2; 68476-31-3; 68476-34-6; 77650-28-3]100 mg/m3 (V) Skin
Diethanolamine, Inhalable [111-42-2] Revised 20091mg/m3 (V) Skin
Diethylamine [109-89-7]5 ppm15 ppmSkin
2-Diethylaminoethanol [100-37-8]2 ppm Skin
Diethylene triamine [111-40-0]1 ppm Skin; S
Di(2-ethylhexyl)phthalate (DEHP) [117-81-7]5 mg/m3  
Diethyl ketone [96-22-0]200 ppm300 ppm 
Diethyl phthalate [84-66-2]5 mg/m3  
Diethyl sulfate [64-67-5]  2A
Difluorodibromomethane [75-61-6]100 ppm  
Diglycidyl ether (DGE) [2238-07-5] Revised 20070.01 ppm R
Diisobutyl ketone [108-83-8]25 ppm  
Diisocyanates, not elsewhere specified, NOS0.005 ppmC 0.01ppm 
Diisopropylamine [108-18-9]5 ppm Skin
3,3'-Dimethoxybenzidine [119-90-4]  2B
Dimethoxymethane [109-87-5]1000 ppm1250 ppm 
N,N-Dimethylacetamide [127-19-5]10 ppm Skin; R
Dimethylamine [124-40-3]5 ppm15 ppm 
Dimethylaniline [121-69-7]5 ppm10 ppmSkin
3,3'-Dimethylbenzidine [119-93-7]  2B
Dimethyl carbamoyl chloride [79-44-7] Revised 20070.005 ppm Skin; A2, 2A
Dimethyl disulfide [624-92-0] Revised 20070.5 ppm Skin
Dimethyl ether [115-10-6]1000 ppm  
Dimethylethoxysilane [14857-34-2]0.5 ppm1.5 ppm 
Dimethylformamide [68-12-2]10 ppm Skin
1,1-Dimethylhydrazine [57-14-7]0.01 ppm Skin; 2B
1,2-Dimethylhydrazine [540-73-8]  2A
Dimethyl phthalate [131-11-3]5 mg/m3  
Dimethyl sulfate [77-78-1] C 0.1 ppmSkin; 2A
Dimethyl sulfide [75-18-3] Revised 200410 ppm  
Dinitolmide [148-01-6] (See 3,5-Dinitro-o-toluamide)   
Dinitrobenzene, all isomers [528-29-0; 99-65-0; 100-25-4; 25154-54-5]0.15 ppm Skin
Dinitrol-o-cresol [534-52-1]0.2 mg/m3 Skin
3,5-Dinitro-o-toluamide [148-01-6] Revised 20071 mg/m3  
Dinitrotoluene [25321-14-6]0.2 mg/m3 Skin; 2B; R
n-Dioctyl phthalate [117-84-0]5 mg/m3  
1,4-Dioxane [123-91-1]20 ppm Skin; 2B
Dioxathion, Inhalable [78-34-2]0.1 mg/m3 (V) Skin
1,3-Dioxolane [646-06-0]20 ppm  R
Diphenylamine [122-39-4]10 mg/m3  
Dipropyl ketone [123-19-3]50 ppm  
Diproplyene glycol methyl ether [34590-94-8]100 ppm150 ppmSkin
Diquat, Inhalable [2764-72-9]0.5 mg/m3 Skin
Diquat, Respirable [2764-72-9]0.1 mg/m3 Skin
Disulfiram [97-77-8]2 mg/m3  
Disulfoton, Inhalable [298-04-4]0.05 mg/m3 (V) Skin
Diuron [330-54-1]10 mg/m3  
Divinyl benzene [1321-74-0]10 ppm  
Dodecyl mercaptan [112-55-0] Revised 20040.1 ppm S
Dyfonate, Inhalable [944-22-9] Revised 20060.1 mg/m3 (V) Skin
Endosulfan, Inhalable [115-29-7] Revised 20090.1 mg/m3 (V) Skin
Endrin [72-20-8]0.1 mg/m3 Skin
Enflurane [13838-16-9]2 ppm  
Epichlorohydrin [106-89-8]0.1 ppm Skin; 2A; R
EPN, Inhalable [2104-64-5] Revised 20030.1 mg/m3 Skin
Ethane [74-84-0] Revised 2004 See Aliphatic Hydrocarbon gases [C1-C4] Revised 2008   
Ethanol [64-17-5] Revised 2009 1000 ppm 
Ethanolamine [141-43-5]3 ppm6 ppm 
Ethion, Inhalable [563-12-2] Revised 2003 0.05 mg/m3 Skin
2-Ethoxyethanol (EGEE) [110-80-5]5 ppm Skin; R
2-Ethoxyethyl acetate (EGEEA) [111-15-9]5 ppm Skin; R
Ethyl acetate [141-78-6]150 ppm  
Ethyl acrylate [140-88-5]5 ppm15 ppm2B; S
Ethylamine [75-04-7]5 ppm15 ppmSkin
Ethyl amyl ketone [541-85-5] Revised 200710 ppm  
Ethyl benzene [100-41-4]100 ppm125 ppm2B
Ethyl bromide [74-96-4]5 ppm  Skin
Ethyl tert-butyl ether (ETBE) [637-92-3]5 ppm R
Ethyl butyl ketone [106-35-4]50 ppm75 ppm 
Ethyl chloride [75-00-3]100 ppm Skin
Ethyl cyanoacrylate [7085-85-0]0.2 ppm  
Ethyl methacrylate [97-63-2]50 ppm  
Ethylene [74-85-1] Revised 2005200 ppm  
Ethylene chlorohydrin [107-07-3] C 1 ppmSkin
Ethylenediamine [107-15-3]10 ppm Skin; S
Ethylene dibromide [106-93-4]0.5 ppm Skin; 2A
Ethylene dichloride (1,2-dichloroethane) [107-06-2]1 ppm2 ppm2B
Ethylene glycol - Aerosol [107-21-1] C 100 mg/m3 
Ethylene glycol - Particulate [107-21-1]10 mg/m320 mg/m3 
Ethylene glycol - Vapour [107-21-1] C 50 ppm 
Ethylene glycol dinitrate (EGDN) [628-96-6]0.05 ppm Skin
Ethylene oxide [75-21-8]0.1 ppm1 ppmA2, 1; R
Ethyleneimine [151-56-4] Revised 20090.05 ppm0.1 ppmSkin; 2B
Ethyl ether [60-29-7]400 ppm500 ppm 
Ethyl formate [109-94-4]100 ppm  
2-Ethylhexanoic acid, Inhalable [149-57-5]5 mg/m3 (V) R
Ethylidene norbornene [16219-75-3] C 5 ppm 
Ethyl mercaptan [75-08-1]0.5 ppm  
N-Ethylmorpholine [100-74-3]5 ppm Skin
Ethyl silicate [78-10-4]10 ppm  
Fenamiphos, Inhalable [22224-92-6] Revised 20060.05 mg/m3 (V) Skin
Fensulfothion, Inhalable [115-90-2] Revised 20050.01 mg/m3 (V) Skin
Fenthion, Inhalable [55-38-9] Revised 20060.05 mg/m3 (V) Skin
Ferbam, Inhalable [14484-64-1] Revised 20095 mg/m3  
Ferrovanadium dust [12604-58-9]1 mg/m33 mg/m3 
Flour dust, Inhalable0.5 mg/m3 S
Fluorides (as F)2.5 mg/m3  
Fluorine [7782-41-4]0.1 ppm  
Fluroxene [406-90-6]2 ppm  
Fonofos (see Dyfonate) [944-22-9]   
Formaldehyde [50-00-0]0.3 ppmC 1 ppmA2, 1; S
Formamide [75-12-7]10 ppm Skin
Formic acid [64-18-6]5 ppm10 ppm 
Furfural [98-01-1]2 ppm Skin
Furfuryl alcohol [98-00-0]5 ppm 10 ppmSkin
Gallium arsenide, Respirable [1303-00-0] Revised 20050.0003 mg/m3 1
Gasoline [86290-81-5]300 ppm500 ppm2B
Germanium tetrahydride [7782-65-2]0.2 ppm  
Glutaraldehyde, Activated & inactivated [111-30-8] C 0.05 ppmS
Glycerin - mist [56-81-5]10 mg/m3  
Glycerin - mist, Respirable [56-81-5]3 mg/m3  
Glycidol [556-52-5]2 ppm 2A
Glyoxal, Inhalable [107-22-2]0.1 mg/m3 (V) S
Grain dust (oat, wheat, barley)4 mg/m3 (E)  
Graphite - All forms except graphite fibres, Respirable [7782-42-5]2 mg/m3  
Gypsum [13397-24-5]10 mg/m3 (N)20 mg/m3 
Hafnium and compounds, as Hf [7440-58-6]0.5 mg/m3  
Halothane [151-67-7]2 ppm R
Helium [7440-59-7] Simple asphyxiant 
Heptachlor [76-44-8]0.05 mg/m3 Skin; 2B
Heptachlor epoxide [1024-57-3]0.05 mg/m3 Skin
Heptane (n-Heptane) [142-82-5]400 ppm500 ppm 
Hexachlorobenzene (HCB) [118-74-1]0.002 mg/m3 Skin; 2B
Hexachlorobutadiene [87-68-3]0.02 ppm Skin
Hexachlorocyclopentadiene [77-47-4]0.01 ppm  
Hexachloroethane [67-72-1]1 ppm Skin; 2B
Hexachloronaphthalene [1335-87-1]0.2 mg/m3 Skin
Hexafluoroacetone [684-16-2]0.1 ppm Skin; R
Hexafluoropropylene [116-15-4] Revised 20070.1 ppm  
Hexahydrophthalic anhydride, all isomers, Inhalable [85-42-7; 13149-00-3; 14166-21-3] Revised 2004 C 0.005 mg/m3 (V)S
Hexamethyl phosphoramide [680-31-9]  Skin; 2B
Hexamethylene diisocyanate (HDI) [822-06-0]0.005 ppmC 0.01 ppmS
n-Hexane [110-54-3]20 ppm Skin
Hexane, other isomers 200 ppm  
1,6-Hexanediamine [124-09-4]0.5 ppm  
1-Hexene [592-41-6]50 ppm R
sec-Hexyl acetate [108-84-9]50 ppm  
Hexylene glycol [107-41-5] C 25 ppm 
Hydrazine [302-01-2]0.01 ppm Skin; 2B
Hydrogen [1333-74-0] Simple asphyxiant 
Hydrogenated terphenyls - Nonirradiated [61788-32-7]0.5 ppm  
Hydrogen bromide [10035-10-6] Revised 2004 C 2 ppm 
Hydrogen chloride [7647-01-0] Revised 2003 C 2 ppm 
Hydrogen cyanide, as CN [74-90-8] C 4.7 ppmSkin
Cyanide salts, as CN [592-01-8; 151-50-8; 143-33-9] C 5 mg/m3Skin
Hydrogen fluoride, as F [7664-39-3] C 2 ppm 
Hydrogen peroxide [7722-84-1]1 ppm  
Hydrogen selenide [7783-07-5]0.05 ppm  
Hydrogen sulfide [7783-06-4] C10 ppm 
Hydroquinone [123-31-9] Revised 20081 mg/m3 S
2-Hydroxypropyl acrylate [999-61-1]0.5 ppm Skin; S
Indene [95-13-6] Revised 20085 ppm  
Indium and compounds, as In [7440-74-6]0.1 mg/m3  
Iodides, Inhalable Revised 20080.01 ppm (V)  
Iodine, Inhalable [7553-56-2] Revised 20080.01 ppm (V)0.1 ppm 
Iodoform [75-47-8]0.6 ppm  
Iron oxide dust, as Fe [1309-37-1]5 mg/m3  
Iron oxide fume , as Fe [1309-37-1]5 mg/m310 mg/m3 
Iron pentacarbonyl [13463-40-6]0.01 ppm  
Iron salts - soluble, as Fe1 mg/m32 mg/m3 
Isoamyl alcohol [123-51-3]100 ppm125 ppm 
Isobutanol [78-83-1]50 ppm  
Isobutyl acetate [110-19-0]150 ppm  
Isobutyl nitrite, Inhalable [542-56-3]  C 1 ppm (V) 
Isooctyl alcohol [26952-21-6]50 ppm Skin
Isophorone [78-59-1] C 5 ppm 
Isophorone diisocyanate [4098-71-9]0.005 ppmC 0.01 ppmS
Isopropanol (Isopropyl alcohol) [67-63-0] Revised 2003200 ppm400 ppm 
2-Isopropoxyethanol [109-59-1]25 ppm Skin
Isopropyl acetate [108-21-4] Revised 2003100 ppm200 ppm 
Isopropylamine [75-31-0]5 ppm10 ppm 
N-Isopropylaniline [768-52-5]2 ppm Skin
Isopropyl ether [108-20-3]250 ppm310 ppm 
Isopropyl glycidyl ether (IGE) [4016-14-2] C 50 ppm 
Kaolin, Respirable [1332-58-7]2 mg/m3 (E)  
Kerosene [8008-20-6]/Jet fuels [64742-47-8], as total hydrocarbon vapour, Revised 2003200 mg/m3 (P) Skin
Ketene [463-51-4]0.5 ppm1.5 ppm 
Lead - elemental and inorganic compounds, as Pb [7439-92-1]0.05 mg/m3 Elemental 2B; R/Other inorganic 2A, R
Lead arsenate, as Pb3(AsO4)2 [3687-31-8]0.15 mg/m3 2A ; R
Lead chromate, as Cr [7758-97-6]0.012 mg/m3 A2; 2A; R
Lead chromate, as Pb [7758-97-6]0.05 mg/m3 A2; 2A; R
Lindane [58-89-9]0.5 mg/m3 Skin
Liquified petroleum gas (L.P.G.) [68476-85-7] 1000 ppm1250 ppm 
Lithium hydroxide [1310-65-2] C 1 mg/m3 
Lithium hydride [7580-67-8]0.025 mg/m3  
Magnesite [546-93-0] Revised 2006 (See Particles Not Otherwise Classified (PNOC))   
Magnesium oxide (fume), Inhalable [1309-48-4] Revised 200310 mg/m3  
Magnesium oxide, Respirable dust and fume, as Mg [1309-48-4] 3 mg/m310 mg/m3 
Malathion, Inhalable [121-75-5] Revised 20031 mg/m3 (V)  Skin
Maleic anhydride [108-31-6]0.1 ppm S
Manganese - Elemental & inorganic compounds, as Mn [7439-96-5]0.2 mg/m3 R
Manganese cyclopentadienyl tricarbonyl, as Mn [12079-65-1]0.1 mg/m3 Skin
Mercury - Alkyl compounds, as Hg [7439-97-6]0.01 mg/m30.03 mg/m3Skin
Mercury - Aryl compounds, as Hg [7439-97-6]0.05 mg/m3C 0.1 mg/m3Skin
Mercury - Elemental, as Hg [7439-97-6]0.025 mg/m3 Skin; R
Mercury - Inorganic compounds, as Hg [7439-97-6]0.025 mg/m3 Skin; R
Mercury -- Methyl, as Hg [7439-97-6]0.01 mg/m30.03 mg/m3Skin
Mesityl oxide [141-79-7]10 ppm25 ppm 
Methacrylic acid [79-41-4]20 ppm  
Methane [74-82-8] Revised 2004 See Aliphatic Hydrocarbon gases [C1-C4] Revised 2008   
Methanol [67-56-1]200 ppm250 ppmSkin
Methomyl [16752-77-5]2.5 mg/m3  
Methoxychlor [72-43-5]10 mg/m3  
2-Methoxyethanol (EGME) [109-86-4] Revised 20060.1 ppm Skin; R
2-Methoxyethyl acetate (EGMEA) [110-49-6] Revised 20060.1 ppm Skin; R
Methoxyflurane [76-38-0]2 ppm  
4-Methoxyphenol [150-76-5]5 mg/m3  
1-Methoxy-2-propanol (PGME) [107-98-2]50 ppm75 ppm 
2-Methoxy-1-propanol [1589-47-5]20 ppm40 ppm 
1-Methoxypropyl-2-acetate [108-65-6]50 ppm75 ppm 
2-Methoxypropyl-1-acetate [70657-70-4]20 ppm40 ppm 
bis-(2-Methoxypropyl) ether (DPGME) (see Dipropylene glycol methyl ether) [34590-94-8]   
Methyl acetate [79-20-9]200 ppm250 ppm 
Methyl acetylene [74-99-7]1000 ppm  
Methyl acetylene-propadiene mixture (MAPP) [59355-75-8]1000 ppm1250 ppm 
Methyl acrylate [96-33-3]2 ppm Skin; S
Methylacrylonitrile [126-98-7]1 ppm Skin
Methylal (see Dimethoxymethane) [109-87-5]   
Methylamine [74-89-5]5 ppm15 ppm 
Methyl n-amyl ketone [110-43-0]50 ppm  
N-Methyl aniline [100-61-8]0.5 ppm Skin
Methyl bromide [74-83-9]1 ppm Skin
Methyl tert-butyl ether (MTBE) [1634-04-4]50 ppm R
Methyl n-butyl ketone [591-78-6] Revised 20085 ppm10 ppmSkin; R
Methyl chloride [74-87-3]50 ppm100 ppmSkin; R
Methyl chloroform [71-55-6]350 ppm450 ppm 
Methyl 2-cyanoacrylate [137-05-3]0.2 ppm  
Methylcyclohexane [108-87-2]400 ppm  
Methylcyclohexanol [25639-42-3]50 ppm  
o-Methylcyclohexanone [583-60-8]50 ppm75 ppmSkin
2-Methylcyclopentadienyl manganese tricarbonyl, as Mn [12108-13-3]0.2 mg/m3 Skin
Methyl demeton, Inhalable [8022-00-2] Revised 20070.05 mg/m3 (V) Skin
Methylene bisphenyl isocyanate (MDI) [101-68-8]0.005 ppmC 0.01 ppmSkin; S
4,4'-Methylene bis(2-chloroaniline) (MBOCA; MOCA) [101-14-4] Revised 20090.01 ppm Skin; A2, 1
Methylene bis (4-cyclo-hexyl-isocyanate), [5124-30-1]0.005 ppmC 0.01 ppm 
Methylene chloride (See Dichloromethane)   
4,4'-Methylene dianiline [101-77-9]0.01 ppm Skin; 2B
Methyl ethyl ketone (MEK) [78-93-3]50 ppm100 ppm 
Methyl ethyl ketone peroxide (MEKP) [1338-23-4] C 0.2 ppm 
Methyl formate [107-31-3]100 ppm150 ppm 
Methyl hydrazine [60-34-4]0.01 ppm Skin
Methyl iodide [74-88-4]2 ppm Skin
Methyl isoamyl ketone [110-12-3]50 ppm  
Methyl isobutyl carbinol [108-11-2]25 ppm40 ppmSkin
Methyl isobutyl ketone [108-10-1]50 ppm75 ppm 
Methyl isocyanate [624-83-9]0.02 ppm Skin; S
Methyl isopropyl ketone [563-80-4]200 ppm  
Methyl mercaptan [74-93-1]0.5 ppm  
Methyl methacrylate [80-62-6]50 ppm100 ppmS
1-Methyl naphthalene [90-12-0] Revised 20070.5 ppm Skin
2-Methyl naphthalene [91-57-6] Revised 20070.5 ppm Skin
Methyl parathion, Inhalable [298-00-0] Revised 20090.02 mg/m3 (V) Skin
Methyl propyl ketone (2-pentanone) [107-87-9]150 ppm250 ppm 
Methyl silicate [681-84-5]1 ppm  
alpha-Methyl styrene [98-83-9]50 ppm75 ppm 
  C 100 ppm 
Methyl vinyl ketone [78-94-4] C 0.2 ppmSkin; S
Metribuzin [21087-64-9]5 mg/m3  
Mevinphos, Inhalable [7786-34-7] Revised 20030.01 mg/m3 (V) Skin
Mica, Respirable [12001-26-2]3 mg/m3  
Molybdenum - Metal and insoluble compounds, Respirable [7439-98-7]3 mg/m3  
Molybdenum - Metal and insoluble compounds, Inhalable [7439-98-7]10 mg/m3  
Molybdenum - Soluble compounds, as Mo, Respirable [7439-98-7]0.5 mg/m3  
Monochloroacetic acid [79-11-8] See Chloroacetic acid   
Monocrotophos, Inhalable [6923-22-4]0.05 mg/m3 (V) Skin
Morpholine [110-91-8]20 ppm Skin
Naled, Inhalable [300-76-5]0.1 mg/m3 (V) Skin; S
Naphthalene [91-20-3]10 ppm15 ppmSkin; 2B
1,5-Naphthalene diisocyanate [3173-72-6]0.005 ppmC 0.01 ppm 
beta-Naphthylamine [91-59-8](L) A1, 1
Natural gas [8006-14-2] Revised 2004 See Aliphatic Hydrocarbon gases [C1-C4] Revised 2008   
Natural rubber latex, as Total proteins, Inhalable [9006-04-6] Revised 2004, 20080.0001 mg/m3 Skin; S
Neon [7440-01-9]  Simple asphyxiant 
Nickel - Insoluble inorganic compounds, as Ni [7440-02-0]0.05 mg/m3 A1, 1
Nickel - Elemental, Soluble inorganic compounds, as Ni [7440-02-0]0.05 mg/m3 A1, 1
Nickel carbonyl, as Ni [13463-39-3]0.001 ppm  
Nickel subsulfide, as Ni, Inhalable [12035-72-2]0.1 mg/m3 A1, 1
Nicotine [54-11-5]0.5 mg/m3 Skin
Nitrapyrin [1929-82-4]10 mg/m3 (N)20 mg/m3 
Nitric acid [7697-37-2]2 ppm4 ppm 
Nitric oxide [10102-43-9]25 ppm  
p-Nitroaniline [100-01-6]3 mg/m3 Skin
Nitrobenzene [98-95-3]1 ppm Skin; 2B
p-Nitrochlorobenzene [100-00-5]0.1 ppm Skin
4-Nitrodiphenyl [92-93-3](L) Skin; A2
Nitroethane [79-24-3]100 ppm  
Nitrogen [7727-37-9] Simple asphyxiant 
Nitrogen dioxide [10102-44-0] C 1 ppm 
Nitrogen trifluoride [7783-54-2]10 ppm  
Nitroglycerin (NG) [55-63-0]0.05 ppm Skin
Nitromethane [75-52-5]20 ppm 2B
1-Nitropropane [108-03-2]25 ppm 2B
2-Nitropropane [79-46-9]5 ppm 2B
Nitropyrene, mono, di, tri, tetra, isomers [5522-43-0; 57835-92-4]  2B
n-Nitrosodiethanolamine [1116-54-7]  2B
n-Nitrosodiethylamine [55-18-5]  2A
n-Nitrosodimethylamine [62-75-9](L) Skin; 2A
n-Nitrosomethylethylamine [10595-95-6]  2B
n-Nitrosomorpholine [59-89-2]  2B
n-Nitrosopiperidine [100-75-4]  2B
n-Nitrosopyrrolidine [930-55-2]  2B
Nitrotoluene, all isomers [88-72-2; 99-08-1; 99-99-0]2 ppm Skin
5-Nitro-o-toluidine, Inhalable [99-55-8] Revised 20071 mg/m3  
Nitrous oxide [10024-97-2]25 ppm R
Nonane - All isomers [111-84-2]200 ppm  
Octachloronaphthalene [2234-13-1]0.1 mg/m30.3 mg/m3Skin
Octane, all isomers [111-65-9]300 ppm  
Oil mist - mineral, mildly refined0.2 mg/m3 1
Oil mist - mineral, severely refined1 mg/m3  
Osmium tetroxide [20816-12-0]0.0002 ppm0.0006 ppm 
Oxalic acid [144-62-7]1 mg/m32 mg/m3 
p,p'-Oxybis(benzenesulfonyl hydrazide), Inhalable [80-51-3] Revised 20080.1 mg/m3 R
Oxygen difluoride [7783-41-7] C 0.05 ppm 
Ozone - Heavy work [10028-15-6]0.05 ppm  
Ozone - Moderate work [10028-15-6]0.08 ppm  
Ozone - Light work [10028-15-6]0.1 ppm  
Ozone - Light, mod., or heavy workload =/< 2 hrs [10028-15-6]0.2 ppm  
Paraffin wax fume [8002-74-2]2 mg/m3  
Paraquat, Respirable [4685-14-7]0.1 mg/m3  
Paraquat [4685-14-7]0.5 mg/m3  
Parathion, Inhalable [56-38-2] Revised 20030.05 mg/m3 (V) Skin
Particles (Insoluble or Poorly Soluble) Not Otherwise Classified (PNOC)10 mg/m3 (N)  
Pentaborane [19624-22-7]0.005 ppm0.015 ppm 
Pentachloronaphthalene [1321-64-8]0.5 mg/m3 Skin
Pentachloronitrobenzene [82-68-8]0.5 mg/m3  
Pentachlorophenol [87-86-5]0.5 mg/m3 Skin
Pentaerythritol [115-77-5]10 mg/m3 (N)  
Pentane, all isomers [78-78-4; 109-66-0; 463-82-1]600 ppm  
Pentyl acetate, all isomers [628-63-7; 626-38-0; 123-92-2; 625-16-1; 624-41-9; 620-11-1]50 ppm100 ppm 
Perchloroethylene (See Tetrachloroethylene)   
Perchloromethyl mercaptan [594-42-3]0.1 ppm  
Perchloryl fluoride [7616-94-6]3 ppm6 ppm 
Perfluorobutyl ethylene [19430-93-4] Revised 2004100 ppm  
Perfluoroisobutylene [382-21-8] C 0.01 ppm 
Perlite [93763-70-3] Revised 2006 (See Particles Not Otherwise Classified (PNOC))   
Persulfates, as persulfate0.1 mg/m3  
Phenol [108-95-2]5 ppm Skin
Phenothiazine [92-84-2]5 mg/m3 Skin
N-Penyl-beta-naphthylamine [135-88-6]   
o-Phenylenediamine [95-54-5]0.1 mg/m3  
m-Phenylenediamine [108-45-2]0.1 mg/m3  
p-Phenylenediamine [106-50-3]0.1 mg/m3 S
Phenyl ether - Vapour (Diphenyl ether) [101-84-8]1 ppm2 ppm 
Phenyl glycidyl ether (PGE) [122-60-1] Revised 20080.1 ppm Skin; 2B; S; R
Phenyl isocyanate [103-71-9]0.005 ppmC 0.01 ppm 
Phenylhydrazine [100-63-0]0.1 ppm Skin
Phenyl mercaptan [108-98-5] C 0.1 ppm 
Phenylphosphine [638-21-1] C 0.05 ppmR
Phorate, Inhalable [298-02-2] Revised 20050.05 mg/m3 (V) Skin
Phosgene [75-44-5]0.1 ppm  
Phosphine [7803-51-2]0.3 ppm1 ppm 
Phosphoric acid [7664-38-2]1 mg/m33 mg/m3 
Phosphorus (yellow) [12185-10-3]0.1 mg/m3  
Phosphorus oxychloride [10025-87-3]0.1 ppm  
Phosphorus pentachloride [10026-13-8]0.1 ppm  
Phosphorus pentasulfide [1314-80-3]1 mg/m33 mg/m3 
Phosphorus trichloride [7719-12-2]0.2 ppm0.5 ppm 
Phthalic anhydride [85-44-9]1 ppm S
m-Phthalodinitrile [626-17-5]5 mg/m3  
Picloram [1918-02-1]10 mg/m3 (N)  
Picric acid [88-89-1]0.1 mg/m3 S
Pindone [83-26-1]0.1 mg/m3  
Piperazine and its Salts, as Piperazine [110-85-0]0.3 mg/m31 mg/m3S
Piperidine [110-89-4]1 ppm  
Plaster of Paris [26499-65-0]10 mg/m3 (N)20 mg/m3 
Platinum - Metal [7440-06-4]1 mg/m3  
Platinum - Soluble salts (as Pt) [7440-06-4]0.002 mg/m3 S
Polyvinyl chloride (PVC), Respirable [9002-86-2] Revised 20081 mg/m3  
Portland cement [65997-15-1]10 mg/m3 (E,N)  
Potassium hydroxide [1310-58-3] C 2 mg/m3 
Propane [74-98-6] Revised 2004 See Aliphatic Hydrocarbon gases [C1-C4] Revised 2008   
Propane sultone [1120-71-4](L) 2B
n-Propanol (n-Propyl alcohol) [71-23-8] Revised 2007100 ppm  
Propargyl alcohol [107-19-7]1 ppm Skin
beta-Propiolactone [57-57-8]0.5 ppm 2B
Propionaldehyde [123-38-6]20 ppm  
Propionic acid [79-09-4]10 ppm  
Propoxur [114-26-1]0.5 mg/m3  
n-Propyl acetate [109-60-4]200 ppm250 ppm 
Propylene [115-07-1] Revised 2006500 ppm  
Propylene dichloride [78-87-5] Revised 200675 ppm110 ppmS
Propylene glycol dinitrate [6423-43-4]0.05 ppm Skin
Propylene oxide [75-56-9]2 ppm 2B; S
Propyleneimine [75-55-8] Revised 20090.2 ppm0.4 ppmSkin
n-Propyl nitrate [627-13-4]25 ppm40 ppm 
Pyrethrum [8003-34-7]5 mg/m3 S
Pyridine [110-86-1] Revised 20041 ppm  
Quinone [106-51-4]0.1 ppm  
Resorcinol [108-46-3]10 ppm20 ppm 
Rhodium, Metal and insoluble compounds as Rh [7440-16-6]0.1 mg/m30.3 mg/m3 
Rhodium - Soluble compounds, as Rh [7440-16-6] 0.001 mg/m30.003 mg/m3 
Ronnel, Inhalable [299-84-3] Revised 20065 mg/m3 (V)  
Rosin core solder thermal decomposition products (colophony) [8050-09-7](L) S
Rotenone (commercial) [83-79-4]5 mg/m3  
Rouge [1309-37-1]10 mg/m3 (E,N)  
Rubber solvent (Naphtha) [8030-30-6] Revised 2009(H)  
Selenium and compounds, as Se [7782-49-2]0.1 mg/m3  
Selenium hexafluoride [7783-79-1]0.05 ppm  
Sesone [136-78-7]10 mg/m3 (N)  
Silica, Amorphous - Diatomaceous earth (uncalcined) Total [61790-53-2]4 mg/m3  
Silica, Amorphous - Diatomaceous earth (uncalcined), Respirable [61790-53-2]1.5 mg/m3  
Silica, Amorphous - Fume Total [69012-64-2]4 mg/m3  
Silica, Amorphous - Fume, Respirable [69012-64-2]1.5 mg/m3  
Silica, Amorphous - Precipitated and gel, Total [112926-00-8]4 mg/m3  
Silica, Amorphous - Precipitated and gel, Respirable [112926-00-8]1.5 mg/m3  
Silica, Crystalline - alpha quartz [14808-60-7; 1317-95-9] and Cristobalite, Respirable [14464-46-1] Revised 20060.025 mg/m3 A2, 1
Silicon [7440-21-3] Revised 2006 (See Particles Not Otherwise Classified (PNOC))   
Silicon carbide Nonfibrous, Inhalable, [409-21-2] Revised 2003 10 mg/m3 (E)  
Silicon carbide, Nonfibrous, Respirable, [409-21-2] Revised 2003 3 mg/m3 (E)  
Silicon carbide, Fibrous (including whiskers) [409-21-2] Revised 20030.1 f/cc (F)  A2
Silicon tetrahydride (Silane) [7803-62-5]0.5 ppm1 ppm 
Silver and Compounds (as Ag) [7440-22-4]0.01 mg/m30.03 mg/m3 
Soapstone6 mg/m3 (E)  
Soapstone, Respirable3 mg/m3 (E)  
Sodium azide (as Sodium azide) [26628-22-8] C 0.29 mg/m3 
Sodium azide (as Hydrazoic acid vapour) [26628-22-8] C 0.11 ppm 
Sodium bisulfite [7631-90-5]5 mg/m3  
Sodium fluoroacetate [62-74-8]0.05 mg/m3 Skin
Sodium hydroxide [1310-73-2] C 2 mg/m3 
Sodium metabisulfite [7681-57-4]5 mg/m3  
Starch [9005-25-8]10 mg/m3 (N)  
Stearates 10 mg/m3 (J)  
Stoddard solvent (mineral spirits) [8052-41-3]290 mg/m3580 mg/m3 
Strontium chromate, as Cr [7789-06-2]0.0005 mg/m3 A2
Strychnine [57-24-9]0.15 mg/m3  
Styrene - monomer [100-42-5]50 ppm75 ppm2B
Subtilisins, as crystalline active enzyme [1395-21-7; 9014-01-1] C 0.00006 mg/m3S
Sucrose [57-50-1]10 mg/m3 (N)  
Sulfometuron methyl [74222-97-2]5 mg/m3  
Sulfotepp (TEDP), Inhalable [3689-24-5] Revised 20050.1 mg/m3 (V) Skin
Sulfur dioxide [7446-09-5] Under review. See G5.48-132 ppm5 ppm 
Sulfur hexafluoride [2551-62-4]1000 ppm  
Sulfuric acid, Thoracic [7664-93-9] Revised 20040.2 mg/m3 (M) A2, 1
Sulfur monochloride [10025-67-9] C 1ppm 
Sulfur pentafluoride [5714-22-7] C 0.01 ppm 
Sulfur tetrafluoride [7783-60-0] C 0.1 ppm 
Sulfuryl fluoride [2699-79-8]5 ppm10 ppm 
Sulprofos, Inhalable [35400-43-2] Revised 20090.1 mg/m3 (V) Skin
Synthetic Vitreous Fibres - Continuous filament glass fibres1 f/cc (F)  
Synthetic Vitreous Fibres - Continuous filament glass fibres, Inhalable5 mg/m3  
Synthetic Vitreous Fibres - Glass wool fibres1 f/cc (F)  
Synthetic Vitreous Fibres - Rock wool fibres1 f/cc (F)  
Synthetic Vitreous Fibres -Slag wool fibres1 f/cc (F)  
Synthetic Vitreous Fibres - Special purpose glass fibres1 f/cc (F) 2B
Synthetic Vitreous Fibres - Refractory ceramic fibres0.2 f/cc (F) A2, 2B
2,4,5-T (2,4,5-Trichlorophenoxyacetic acid) [93-76-5]10 mg/m3  
Talc - Containing no asbestos fibres, Respirable [14807-96-6]2 mg/m3 (E)  
Talc - Containing asbestos fibres [14807-96-6]0.1 f/cc (K) A1, 1
Tantalum - Metal [7440-25-7]5 mg/m3  
Tantalum oxide dusts, as Ta [1314-61-0]5 mg/m3  
Tellurium and compounds (NOS), as Te, excluding hydrogen telluride [13494-80-9]0.1 mg/m3  
Tellurium hexafluoride [7783-80-4]0.02 ppm  
Temephos, Inhalable [3383-96-8] Revised 20051 mg/m3 (V)  Skin
Terbufos, Inhalable [13071-79-9]0.01 mg/m3 (V) Skin
Terepthalic acid [100-21-0]10 mg/m3 (N)  
Terphenyls [26140-60-3] C 5 mg/m3 
1,1,2,2-Tetrabromoethane, Inhalable [79-27-6] Revised 20060.1 ppm (V)  
1,1,1,2-Tetrachloro-2,2-difluoroethane [76-11-9] Revised 2008100 ppm  
1,1,2,2-Tetrachloro-1,2-difluoroethane [76-12-0] Revised 200850 ppm  
1,1,2,2-Tetrachloroethane [79-34-5]1 ppm Skin
Tetrachloroethylene (Perchloroethylene) [127-18-4]25 ppm100 ppm2A
Tetrachloronaphthalene [1335-88-2]2 mg/m3  
Tetraethyl lead, as Pb [78-00-2]0.075 mg/m3 Skin
Tetraethyl pyrophosphate (TEPP), Inhalable [107-49-3] Revised 20070.01 mg/m (V) Skin
Tetrafluoroethylene [116-14-3]2 ppm 2B
Tetrahydrofuran [109-99-9] Revised 200550 ppm100 ppmSkin
Tetramethyl lead, as Pb [75-74-1]0.075 mg/m3 Skin
Tetramethyl succinonitrile [3333-52-6]0.5 ppm Skin
Tetranitromethane [509-14-8]0.005 ppm 2B
Tetrakis (hydroxymethyl) phosphonium chloride [124-64-1] Revised 20052 mg/m3  
Tetrakis (hydroxymethyl) phosphonium sulfate [55566-30-8] Revised 20052 mg/m3 S
Tetryl [479-45-8]1.5 mg/m3 S
Thallium and soluble compounds, as Tl [7440-28-0]0.1 mg/m3 Skin
4,4' Thiobis (6-tert-butyl-m-cresol) [96-69-5] (see Cresol, all isomers)   
Thioglycolic acid [68-11-1]1 ppm Skin
Thionyl chloride [7719-09-7] C 1ppm 
Thiram, Inhalable [137-26-8] Revised 20080.05 mg/m3 (V) S
Tin - Metal [7440-31-5]2 mg/m3  
Tin - Oxide and inorganic compounds, except tin hydride, as Sn [7440-31-6]2 mg/m3  
Tin - Organic compounds, as Sn [7440-31-6]0.1 mg/m30.2 mg/m3Skin
Titanium dioxide [13463-67-7] Revised 200610 mg/m3 (N) 2B
o-Tolidine [119-93-7]  Skin; 2B
Toluene [108-88-3] Revised 2007, 200820 ppm R
Toluene-2,4-diisocyanate (2,4-TDI) [584-84-9]0.005 ppmC 0.01 ppm2B; S
Toluene-2,6-diisocyanate (2,6-TDI) [91-08-7]0.005 ppmC 0.01 ppm2B; S
o-Toluidine [95-53-4] Revised 20092 ppm Skin; 1
m-Toluidine [108-44-1]2 ppm Skin
p-Toluidine [106-49-0]2 ppm Skin
Tributyl phosphate [126-73-8]0.2 ppm  
Trichloroacetic acid [76-03-9]1 ppm  
1,2,4-Trichlorobenzene [120-82-1] C 5 ppm 
1,1,2-Trichloroethane [79-00-5]10 ppm Skin
Trichloroethylene [79-01-6] Revised 200710 ppm25 ppmA2, 2A
Trichlorofluoromethane [75-69-4] C 1000 ppm 
Trichloronaphthalene [1321-65-9]5 mg/m3 Skin
1,2,3-Trichloropropane [96-18-4]10 ppm Skin; 2A
1,1,2-Trichloro-1,2,2-trifluoroethane [76-13-1]500 ppm1250 ppm 
Trichlorphon, Inhalable [52-68-6] Revised 20031 mg/m3  
Triethanolamine [102-71-6]5 mg/m3  
Triethylamine [121-44-8]1 ppm3 ppmSkin
Trifluorobromomethane [75-63-8]1000 ppm  
1,3,5-Triglycidyl-s-triazinetrione [2451-62-9]0.05 mg/m3 R; S
Trimellitic anhydride, Inhalable [552-30-7] Revised 20080.0005mg/m3 (V)0.002 mg/m3Skin; S
Trimethylamine [75-50-3]5 ppm15 ppm 
Trimethyl benzene (mixed isomers) [25551-13-7]25 ppm  
Trimethyl hexamethylene diisocyanate [28679-16-5]0.005 ppmC 0.01 pm 
Trimethyl phosphite [121-45-9]2 ppm  
Tri-n-Butyltin compounds [688-73-3]0.05 mg/m3  
2,4,6-Trinitrotoluene (TNT) [118-96-7]0.1 mg/m3 Skin
Triorthocresyl phosphate [78-30-8]0.1 mg/m3 Skin
Triphenyl phosphate [115-86-6]3 mg/m3  
Tungsten - Metal and insoluble compounds [7440-33-7]5 mg/m310 mg/m3 
Tungsten - Soluble compounds, as W [7440-33-7]1 mg/m33 mg/m3 
Turpentine [8006-64-2] and selected monoterpenes [80-56-8; 127-91-3; 13466-78-9] Revised 200320 ppm S
Uranium (Natural) - Insoluble compounds, as U [7440-61-1]0.2 mg/m30.6 mg/m3A1, 1
Uranium (Natural) - Soluble compounds, as U [7440-61-1]0.05 mg/m3 A1
n-Valeraldehyde [110-62-3]50 ppm  
Vanadium pentoxide, Respirable dust and fume, as V2O5 [1314-62-1] C 0.05 mg/m32B
Vanadium pentoxide, Total dust, as V2O5 [1314-62-1]0.2 mg/m3 2B
Vegetable oil - Mist, except castor, cashew nut, or similar irritant oils [8008-89-7]10 mg/m3  
Vegetable oil, Mist, Respirable, except castor, cashew nut, or similar irritating oil [8008-89-7]3 mg/m3  
Vinyl acetate [108-05-4]10 ppm15 ppm2B
Vinyl bromide [593-60-2]0.5 ppm A2, 2A
Vinyl chloride [75-01-4]1 ppm A1, 1
4-Vinyl cyclohexene [100-40-3]0.1 ppm 2B; R
Vinyl cyclohexene dioxide [106-87-6]0.1 ppm Skin; 2B; R
Vinyl fluoride [75-02-5]1 ppm A2, 2A
N-Vinyl-2-pyrrolidone [88-12-0] Revised 20030.05 ppm  
Vinylidene chloride [75-35-4]1 ppm  
Vinylidene fluoride [75-38-7]500 ppm  
Vinyl toluene, all isomers [25013-15-4]25 ppm75 ppm 
VM & P Naphtha [8032-32-4] Revised 2009(H)  
Warfarin [81-81-2]0.1 mg/m3  
Wood dust - Allergenic species1 mg/m3 1
Wood dust - Non-Allergenic Hardwood1 mg/m3 A1, 1
Wood dust - Non-Allergenic Softwood2.5 mg/m3 1
Xylene [1330-20-7] (o, m & p isomers) [95-47-6; 108-38-3; 106-42-3]100 ppm150 ppm 
m-Xylene alpha,alpha'-diamine [1477-55-0] C 0.1 mg/m3Skin
Xylidine - Mixed isomers, Inhalable [1330-73-8]0.5 ppm (V) Skin
Yttrium - Metal [7440-65-5]1 mg/m3  
Yttrium and compounds, as Y [7440-65-5]1 mg/m3  
Zinc chloride - Fume [7646-85-7]1 mg/m32 mg/m3 
Zinc chromates, as Cr [13530-65-9; 11103-86-9; 37300-23-5] 0.01 mg/m3 A1
Zinc oxide, Respirable [1314-13-2] Revised 20032 mg/m310 mg/m3 
Zinc stearate [557-05-1]10 mg/m3 (N)20 mg/m3 
Zirconium [7440-67-7] and compounds, as Zr [7440-67-7]5 mg/m310 mg/m3 

Endnotes

(E) - the value is for particulate matter containing no asbestos and less than 1% crystalline silica.
(F) - the value for fibres longer than 5 microns, with an aspect ratio of equal than/greater than 3:1, as determined by the membrane filter method at 400 - 450 times magnification (4 mm objective), using phase-contrast illumination.<
(G) - as measured by the vertical elutriator, cotton-dust sampler, see TLV Documentation.
(H) - reciprocal calculation method, see OHS Guideline G5.48-11.
(J) - does not include stearates of toxic metals.
(K) - should not exceed 2 mg/m3 respirable particulate.
(L) - exposure by all routes should be carefully controlled to levels as low as possible.
(M) - refers to sulfuric acid contained in strong inorganic acid mists.
(N) - the 8-hour TWA listed in the Table is for the total dust. The substance also has an 8-hour TWA of 3 mg/m3 for the respirable fraction.
(O) - sampled by method that does not collect vapour.
(P) - application restricted to conditions in which there are negligible aerosol exposures.
(V) - vapour and aerosol.

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