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) 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 new or revised TLVs for substances 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 identifies the substances with new or revised TLVs and adds these substances (together with their existing 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 TLVs as OELs.

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

• Aldicarb
• Allyl methacrylate
• Bendiocarb
• Boron trifluoride ethers, as BF3
• tert-Butyl hydroperoxide
• Calcium chromate, as Cr
• Carfentrazone-ethyl
• Chlorine
• 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
• Dimethylacetamide
• Dimethylformamide
• Ethyl cyanoacrylate
• Fludioxonil
• Isopropyl acetate
• Lead chromate, as Cr(VI)
• Methyl 2-cyanoacrylate
• Paraquat, as the cation
• Phosphine
• 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 BC 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 BC:

• Acetylene
• Argon
• Helium
• Hydrogen
• Neon
• Nitrogen

All WorkSafeBC OELs can be found in the updated Convenience Table.