Consultation on proposed B.C. Exposure Limits (ELs) based on the new or revised 2019 and 2020 ACGIH TLVs


Each year, the American Conference of Governmental Industrial Hygienists (ACGIH) publishes a list of substances for which they have set new or revised Threshold Limit Values (TLVs). A TLV is an airborne concentration of a chemical substance where it is believed that nearly all workers may be exposed over a working lifetime and experience no adverse health effects. TLVs may be expressed as an 8-hour time-weighted average (TWA), 15-minute short-term exposure limit (STEL), or ceiling limit.

Before adopting new or revised TLVs published by the ACGIH, WorkSafeBC reviews relevant data on health effects and the availability of validated sampling methods. WorkSafeBC also consults with stakeholders on potential implementation issues. WorkSafeBC’s existing B.C. Exposure Limits (ELs) continue to be in effect until the Board of Directors makes a decidsion on which new or revised ACGIH TLVs to adopt as B.C. ELs.

We are requesting stakeholder feedback on the proposed B.C. ELs for 22 substances.

(1) WorkSafeBC is proposing new or revised B.C. ELs for the following substances:

  • Cyclohexene
  • Methyl isobutyl carbinol

(2) WorkSafeBC is proposing to retain the existing B.C. ELs for the following substances:

  • 4-tert-Butylbenzoic acid
  • Chlordane
  • o-Chlorobenzylidene malononitrile
  • Cyanazine
  • Dimethylphenol, all isomers
  • Dinitrobenzene, all isomers
  • Dinitro-o-cresol
  • EPN
  • Hexazinone
  • 4,4’-Methylene bis(2-chloroaniline)
  • Nitrapyrin
  • 5-Nitro-o-toluidine
  • Pentachloronaphthalene
  • Sulfometuron methyl
  • Sulfoxaflor
  • Temephos
  • Tetramethyl succinonitrile
  • Thiacloprid
  • Thiodicarb
  • 2,4,6-Trinitrotoluene

Providing feedback

View the proposed B.C. ELs and provide feedback

Feedback will be accepted until 4:30 p.m. on Friday, January 20, 2023.


Lori Guiton
Director, Policy, Regulation and Research Department