2016 New or Revised ACGIH Threshold Limit Values and B.C. OELs

July 15, 2016

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 these TLVs are adopted, WorkSafeBC refers to them 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 excluded substances in OHS Policy R5.48-1. 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 before adopting new or revised ACGIH TLVs.

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 B.C. OELs are maintained for the substances below until such time as the BOD makes a decision on the adoption of their respective TLVs.

Boron tribromide

Boron trichloride

Boron trifluoride

sec-Butyl acetate

tert-Butyl acetate

Calcium silicate, naturally

  occurring as Wollastonite

Calcium silicate, synthetic



Hard metals, containing Cobalt

  and Tungsten carbide as Co

Isobutyl acetate



Toluene diisocyanate, 2,4- and

  2,6- as a mixture

Triorthocresyl phosphate


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 their current B.C. OELs are maintained.