2018 New or Revised ACGIH Threshold Limit Values and B.C. OELs

The Occupational Health and Safety Regulation (OHSR) provides that occupational exposure limits (OELs) for hazardous chemical substances are generally determined with reference to the threshold limit values (TLVs) set by the American Conference of Governmental Industrial Hygienists (ACGIH).

Each year, the ACGIH publishes a list of substances for which they have set new or revised TLVs. When the subtances are adopted, WorkSafeBC refers to these TLVs as OELs.

An OEL is the maximum allowed airborne concentration for a particular substance from which nearly all workers are believed to experience no adverse health effects over a working lifetime. OELs may be set out as an 8-hour time-weighted average concentration, short-term exposure limit, or ceiling limit.

When the ACGIH publishes its annual list, WorkSafeBC adds any changed or new OELs to the Table of Occupational Exposure Limits for Excluded Substances in OHS Policy R5.48-1. By doing so, WorkSafeBC ensures that the existing OELs for these substances continue to be in effect until WorkSafeBC’s Board of Directors (BOD) makes a decision on adoption of the changes. This gives WorkSafeBC the opportunity to consult stakeholders prior to adopting new or revised ACGIH OELs.

The ACGIH has published the 2018 new or revised TLVs. The following substances, for which there are new or revised ACGIH TLVs, have been added to the Table of Occupational Exposure Limits for Excluded Substances in OHS Policy R5.48-1. The current B.C. OELs are maintained for these substances until the BOD makes a decision on the adoption of their respective TLVs.

Allyl methacrylate
Boron trifluoride ethers, as BF3
tert-Butyl hydroperoxide
Calcium chromate, as Cr
Chlorine dioxide
Chromite ore processing (Chromate), as Cr
Chromium and inorganic compounds:

◦ Metallic chromium, as Cr(0), Inhalable
◦ Trivalent chromium compounds, as Cr(III), Inhalable
◦ Hexavalent chromium compounds, as Cr(VI), Inhalable
◦ Chromyl chloride, as Cr(VI), Inhalable Fraction & Vapour
◦ Chromite ore processing

Chromyl chloride
Cyanoacrylates, ethyl and methyl
Ethyl cyanoacrylate
Isopropyl acetate
Lead chromate, as Cr(VI)
Methyl 2-cyanoacrylate
Paraquat, as the cation
n-Propyl acetate
Propyl acetate isomers
Strontium chromate, as Cr
Thioglycolic acid and salts
Zinc chromates, as Cr

The ACGIH has also revised the TLV for Chromium, water soluble, CR(VI) compounds. This latter substance is already listed in the Table of Occupational Exposure Limits for Excluded Substances and the current B.C. OELs are maintained.

Housekeeping Items for OHS Policy R5.48-1

Editorial changes were made to the Table of Occupational Exposure Limits for Excluded Substances in OHS Policy R5.48-1 to help enhance readability and clarity. In addition, the following six substances will be removed from the Table of OELs for Excluded Substances in Policy R5.48-1, since the ACGIH TLVs, and their respective ACGIH notations, have been adopted previously in B.C.:


All WorkSafeBC OELs can be found in the updated Table of Exposure Limits for Chemical and Biological Substances.