Today is Thursday, Sep. 21, 2017

Department of Environmental Health

Risk Science Center (RSC)

Occupational Alliance for Risk Science (OARS) Workplace Environmental Exposure Levels (WEELs)™

Occupational exposure limits (OELs) are developed for protection of healthy workers; they are not intended for the general public, which includes sensitive populations such as infants, the elderly, or the infirm. OELs are based on repeated daily exposures over a working lifetime. They are normally averaged over an 8-hour workday and serve to protect against acute and chronic health effects.

Click here for a pdf of the WEEL Table.

Substance CAS Source 8-Hour TWA Ceiling or Short-Term TWA Last Revised
Acetone Cyanohydrin 75-86-5 AIHA 2 ppm (skin) 5 ppm (15 min, skin) 1992
Acetophenone 98-86-2 AIHA 10 ppm 2007
Aldicarb 116-06-3 AIHA 0.01 mg/m3 (skin) 2009
Allyl Isothiocyanate 57-06-7 AIHA 1 ppm (15-min, skin, DSEN) 1993
Aminobenzoic Acid, para- 150-13-0 AIHA 5 mg/m3 2001
Aminotri (Methylenephosphonic Acid) 6419-19-8 AIHA 10 mg/m3 2004
Amyl Alcohol, n- 71-41-0 AIHA 100 ppm 2001
Benzaldehyde 100-52-7 AIHA 2 ppm 4 ppm (15-min, DSEN) 1998
Benzenesulfonic acid, 5-chloro-2((2-Hydroxy-1-napthalenyl)-azo)-4-methyl, barium salt (2:1) 5160-02-1 AIHA 1 mg/m3 2008
Benzophenone 119-61-9 AIHA 0.5 mg/m3 2003
Benzoyl Chloride 98-88-4 AIHA 5 ppm (ceiling, skin, DSEN) 2008
Benzyl Alcohol 100-51-6 AIHA 10 ppm 2008
Butylcatechol, 4-tert- 98-29-3 AIHA 2 mg/m3 (ceiling, skin, DSEN) 2001
Butyraldehyde 123-72-8 OARS 25 ppm (75 mg/m3) 2016
Chloramphenicol 56-75-7 AIHA 0.5 mg/m3 2008
Chloro-1,1,1,2-Tetrafluoroethane, 2- 2837-89-0 AIHA 1000 ppm 2005
Chloro-1,1-Difluoroethane, 1- 75-68-3 AIHA 1000 ppm 1994
Chloroisopropyl)Ether, bis-(2- 39638-92-9 AIHA 3 ppm 2009
Chloropropane, 2- 75-29-6 OARS 50 ppm (161 mg/m3) 2016
Chlorosulfonic Acid 7790-94-5 OARS 2016*
Chlorotrifluoroethylene 79-38-9 AIHA 5 ppm 2010
cis-1,1,1,4,4,4-hexafluoro-2-butene (1336mzz-Z) 692-49-9 OARS 500 ppm (3350 mg/m3) 2014
Cumene Hydroperoxide 80-15-9 AIHA 1 ppm (skin) 2009
Decabromodiphenyl Oxide 1163-19-5 AIHA 5 mg/m3 2009
Decamethylcyclopentasiloxane (D5) 541-02-6 OARS 10 ppm 2015
Decene, 1- 872-05-9 AIHA 100 ppm 2000
Dehydrolinalool 29171-20-8 AIHA 2 ppm 2007
Diallylamine 124-02-7 AIHA 1 ppm (skin) 2009
Dibromoneopentyl Glycol 3296-90-0 AIHA 0.2 mg/m3 2010
Dibutylamine 111-92-2 AIHA 5 ppm (ceiling, skin) 2003
Dichloro-1-Fluoroethane, 1,1- 1717-00-6 AIHA 500 ppm 3000 ppm (5-min STEL) 2008
Dichlorophenol, 2,4- 120-83-2 AIHA 1 ppm (skin*) 2004
Diethylbenzenes,mixed isomers 25340-17-4 AIHA 5 ppm 2005
Diethylene Glycol 111-46-6 OARS 10 mg/m3 2016
Diethylene Glycol Monoethyl Ether 111-90-0 AIHA 25 ppm 1991
Difluoroethane, 1,1- 75-37-6 AIHA 1000 ppm 2005
Difluoromethane 75-10-5 AIHA 1000 ppm 1997
Diisobutylene 25167-70-8 OARS 75 ppm (344 mg/m3 ) 2016
Dimethyl Ether 115-10-6 AIHA 1000 ppm 2010
Dimethyl Sulfoxide 67-68-5 AIHA 250 ppm 2003
Dimethyl Terephthalate 120-61-6 AIHA 5 mg/m3 (total) 2000
Dimethyl-para-toluidine, n,n- 99-97-8 AIHA 0.5 ppm 2009
Dimethyldichlorosilane 75-78-5 AIHA 2 ppm (ceiling) 2001
Dimethylethylamine 598-56-1 AIHA 1 ppm 3 ppm 2011
Dinitroanisole, 2,4- (DNAN) 119-27-7 OARS 0.1 mg/m3 (0.01 ppm) 2014
Dowtherm Q 612-00-0, 68987-42-8 AIHA 7.8 mg/m3 2002
Epoxybutane, 1,2- 106-88-7 AIHA 2 ppm 2003
Erythromycin 114-07-8 AIHA 3 mg/m3 2007
Furan 110-00-9 AIHA Worker exposure by all routes should be minimalized to the fullest extent possible. 1993
GlycidylMethacrylate 106-91-2 AIHA 0.5 ppm (skin, DSEN) 2000
Glyoxal 107-22-2 AIHA 0.1 mg/m3 (DSEN) 2000
Hexadiene, 1,4- (mixed cis and trans) 592-45-0 AIHA 10 ppm 2009
Hexafluoropropane, 1,1,1,3,3,3- 690-39-1 AIHA 1000 ppm 1998
Hexamethylene Glycol 629-11-8 AIHA 10 mg/m3 2011
Hexanediamine, 1,6- 124-09-4 AIHA 1 ppm 2004
Hexanediol Diacrylate 13048-33-4 AIHA 1 mg/m3 (DSEN) 1998
Hexyl Alcohol, n- 111-27-3 AIHA 40 ppm (eye irritation) 2011
HFCO-1224yd(Z) 111512-60-8 OARS 1000 ppm 2017
HFE-7100 163702-07-6,

163702-08-7
AIHA 750 ppm 1999
Hydroxybenzoic Acid, 4- 99-96-7 OARS 5 mg/m3 2016
Isobutyraldehyde 78-84-2 AIHA 25 ppm 2002
Isocyanuric Acid 108-80-5 AIHA 5 mg/m3 (respirable) 2005
Isocyanuric Acid 108-80-5 AIHA 10 mg/m3 (total); 2005
Isophthalic Acid 121-91-5 AIHA 5 mg/m3 (respirable) 1991
Isophthalic Acid 121-91-5 AIHA 10 mg/m3 (total); 1991
Isoprene 78-79-5 AIHA 2 ppm 2004
Limonene, d- 5989-27-5 AIHA 30 ppm 1993
Lithium Hydroxide 1310-65-2 AIHA 1 mg/m3 (ceiling) 1999
Lithium Oxide 12057-24-8 AIHA 1 mg/m3 (ceiling) 1999
Mancozeb 8018-01-7 AIHA 1 mg/m3 (total, DSEN) 2008
Melamine 108-78-1 OARS 3 mg/m3 2016
Menthol 1490-04-6 OARS 1 ppm 3 ppm (15 min) 2014
Mercaptobenzothiazole, 2- 149-30-4 AIHA 5 mg/m3 (skin, DSEN) 2010
Mercaptoethanol 60-24-2 AIHA 0.2 ppm (skin) 2002
Methoxypropylamine, 3- 5332-73-0 AIHA 5 ppm 15 ppm (15 min) 2009
Methyl Ethyl Ketoxime 96-29-7 AIHA 10 ppm (DSEN) 1990
Methyl-2-Pyrrolidone, n- 872-50-4 AIHA 10 ppm (skin) 2010
Methyltrichlorosilane 75-79-6 AIHA 1 ppm (ceiling) 2001
Monochloroacetic Acid 79-11-8 AIHA 0.5 ppm (skin) 2004
Nitro-1,2,4-Triazol-5-One, 3- (NTO) 932-64-9 OARS 2 mg/m3 2014
Nitroguanidine, 1- (NQ) 556-88-7 OARS 7 mg/m3 2016
Octamethylcyclotetrasiloxane (D4) 556-67-2 OARS 10 ppm 2014
Octanol, 1- 111-87-5 AIHA 50 ppm 2005
Octene, 1- 111-66-0 AIHA 75 ppm 2000
Pentaerythritol Triacrylate 3524-68-3 AIHA 1 mg/m3 (DSEN) 1999
Pentafluoroethane, 1,1,1,2,2- 354-33-6 AIHA 1000 ppm 2009
Pentafluoropropane, 1,1,1,3,3- 460-73-1 AIHA 300 ppm 2001
Phosphono-1,2,4 butanetricarboxylic, 2-acid 37971-36-1 AIHA 10 mg/m3 2006
Picolines 109-06-8, 108-99-6, 108-89-4 AIHA 2 ppm (skin) 5 ppm (15-min, skin) 1988
Piperidine 110-89-4 AIHA 1 ppm (skin) 1996
Polyethylene Glycols (MW > 200) 25322-68-3 AIHA 10 mg/m3 2009
Polypropylene Glycols 25322-69-4 AIHA 10 mg/m3 1997
Potassium Bromate 7758-01-2 AIHA 0.1 mg/m3 2004
Propargyl Bromide 106-96-7 AIHA 0.1 ppm (skin) 1997
Propenoic Acid, isooctyl ester, 2- 29590-42-9 AIHA 5 ppm 2010
Propionaldehyde 123-38-6 AIHA 20 ppm 2002
Propylene Glycol 57-55-6 AIHA 10 mg/m3 2004
Propylene Glycol Monomethyl Ether Acetate 108-65-6 AIHA 50 ppm 2005
Quinoline 91-22-5 AIHA 0.001 ppm (skin) 2006
Sodium Chloroacetate 3926-62-3 OARS 0.5 ppm (2.5 mg/m3 ) 2016
Sodium Hypochlorite 7681-52-9 AIHA 2 mg/m3 (15 min) 2010
Tetrachloropyridine, 2,3,5,6- 2402-79-1 OARS 5 mg/m3 2016
Tetrachlorosilane 10026-04-7 AIHA 1 ppm (ceiling) 1999
Tetraethylene Glycol Diacrylate 17831-71-9 AIHA 1 mg/m3 (skin, DSEN) 1981
TetraethylenePentamine 112-57-2 AIHA 5 mg/m3 (skin, DSEN) 2004
Tetrafluoroethane, 1,1,1,2- 811-97-2 AIHA 1000 ppm 2003
Tetrafluoropropene, 2,3,3,3,- (HFO-1234yf) 754-12-1 AIHA 500 ppm 2009
Tetrafluoropropene, (Z)-1-Chloro-2,3,3,3- (HCFO-1224yd(Z)) 111512-60-8 OARS 1000 ppm 2017
Tetrafluoropropylene, 1,3,3,3- 1645-83-6 AIHA 800 ppm 2011
Tetrahydrofurfuryl Alcohol 97-99-4 AIHA 0.5 ppm (skin) 1993
Titanium Tetrachloride 7550-45-0 AIHA 0.5 mg/m3 2009
Toluene Diamine, 2,4- and mixed isomers 95-80-7; 25376-45-8 AIHA 0.005 ppm (skin) 2010
Toluenesulfonyl Chloride, para- 98-59-9 AIHA 5 mg/m3 (ceiling) 2009
trans-1-Chloro-3,3,3-trifluoropropylene (HCFO-1233zd(E)) 102687-65-0 OARS 800 ppm 2013
Trichlorosilane 10025-78-2 AIHA 0.5 ppm (ceiling) 1998
Triethoxysilane 998-30-1 AIHA 0.05 ppm 2000
Triethylene Glycol Diacrylate 1680-21-3 AIHA 1 mg/m3 (skin) 1981
Triethylenetetramine 112-24-3 AIHA 1 ppm (skin) 2009
Triethylphosphate 78-40-0 AIHA 7.45 mg/m3 2010
Trifluoro-2,2-Dichloroethane, 1,1,1- 306-83-2 AIHA 50 ppm 2001
Trifluoroethane, 1,1,1- 420-46-2 AIHA 1000 ppm 1996
Trifluoroethanol, 2,2,2- 75-89-8 OARS 0.3 ppm 2016
Trimethoxysilane 2487-90-3 AIHA 0.05 ppm 2010
Trimethylamine 75-50-3 AIHA 1 ppm 2005
Trimethylchlorosilane 75-77-4 AIHA 5 ppm (ceiling) 2001
Trimethylolpropane Triacrylate 15625-89-5 AIHA 1 mg/m3 (skin) 1981
Trimethylolpropane Trimethacrylate 3290-92-4 AIHA 1 mg/m3 (skin) 1981
Trisodium Phosphate 7601-54-9 AIHA 5 mg/m3 (15 min) 2009
Urea 57-13-6 AIHA 10 mg/m3 2007
Vanillin 121-33-5 AIHA 10 mg/m3 2009
Vinylcyclohexene 100-40-3 AIHA 1 ppm 2009
Vinyltrichlorosilane 75-94-5 AIHA 1 ppm (ceiling) 2002

*Absorbed rapidly through the skin in molten or heated liquid form in amounts that have caused rapid death in humans.

Worker exposure by all routes should be minimalized to the fullest extent possible.

Acronyms

AIHA - American Industrial Hygiene Association

DSEN - Potential for Dermal Sensitization

mg/m3- milligrams per cubic meter

PPM - Parts Per Million

RSEN - Potential for Respiratory Sensitization

STEL - Short Term Exposure Limit

TWA - Time Weighted Average

For information related to AIHA values, please refer directly to http://www.aiha.org/get-involved/AIHAGuidelineFoundation/WEELs/Pages/default.aspx.

Inquiries regarding AIHA WEELs can be sent to AIHA Customer Service at 703-849-8888 or Infonet@aiha.org