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 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 ACGIH publishes its annual list, WorkSafeBC adds any changed or new OELs to the table of excluded substances in OHS Policy R5.48-1. By doing so, the existing OELs for these substances continue to be in effect until WorkSafeBC’s Board of Directors 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 2016 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 BC OELs are maintained for the substances below until such time as the BOD makes a decision on the adoption of their respective TLVs.

The ACGIH has also revised the TLVs for n-butyl acetate, 2,4-toluene diisocyanate and 2,6-toluene diisocyanate. These substances are already listed in the Table of Occupational Exposure Limits for Excluded Substances and the current BC OELs are maintained.