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Exposure Limits (ELs)

Basis of WorkSafeBC’s ELs

The Occupational Health and Safety Regulation (OHSR) states that the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Values (TLVs) are generally used as a basis for WorkSafeBC’s Exposure Limits (ELs) for hazardous chemical substances.

The ACGIH is a professional association of industrial hygienists and practitioners that publishes a list of chemical substances with new or revised TLVs every year.

A TLV is the maximum allowed concentration for a chemical substance for which nearly all workers are believed to experience no adverse health effects over a working lifetime. These exposure limits may include an 8-hour time-weighted average concentration, a short term (15-minute) exposure limit, or a ceiling limit.

Determining WorkSafeBC’s ELs

Section 5.48 of the OHSR provides for the adoption of new or revised ACGIH TLVs as BC ELs, except as otherwise determined by WorkSafeBC. BC ELs that differ from the ACGIH TLVs are presented on the Table of Excluded Substances in Occupational Health and Safety (OHS) Policy Item R5.48-1 of the Prevention Manual.

The EL review and adoption process is set out here.

WorkSafeBC’s Exposure Limit Review Committee (ELRC) is responsible for reviewing the exposure limits provided for in Policy Item R5.48-1 of the Prevention Manual, as well as the new or revised TLVs recommended by the ACGIH. The ELRC makes recommendations as to which TLVs should be adopted as BC ELs. In reviewing the TLVs, the ELRC considers the following criteria:

  • Whether there are health effects reported by the ACGIH TLV documentation and other peer-reviewed literature;
  • Availability of validated sampling methods at commercial laboratories in North America; and
  • Whether there are any other implementation issues, such as technical and economic feasibility.

WorkSafeBC also consults with stakeholders before the Board of Directors (BOD) makes a decision to adopt the ACGIH TLVs as BC ELs. When the ACGIH recommends a new or revised TLV, WorkSafeBC places the existing BC ELs for the specific chemical substance on the Table of Excluded Substances in Policy Item R5.48-1 of the Prevention Manual; this is to ensure that the new or revised TLVs are not adopted as a BC EL until the BOD makes its decision.

By utilizing the expertise, resources, and review process of the ACGIH and the ELRC, WorkSafeBC is able to ensure that BC ELs remain consistent with the current health research, technological advances and other changes affecting occupational health and safety and occupational environment.

Table of Exposure Limits

WorkSafeBC maintains a Table of Exposure Limits for Chemical and Biological Substances associated with the OHS Guideline G5.48-1 (Part 5) which lists all substances with a BC exposure limit prescribed under section 5.48 of the OHSR. In addition to the exposure limits, the Table also lists the ACGIH and the International Agency for Research on Cancer (IARC) notations relevant to section 5.57 of the OHSR as a one-stop document to make it easier for stakeholders to reference.

WorkSafeBC Announcements on ELs

A list of announcements regarding WorkSafeBC’s ELs are referenced below:

BOD Decisions on New and Revised ELs

Other previous changes to the Table of Excluded Substances in Policy Item R5.48-1 of the Prevention Manual

WorkSafeBC References on Chemical Exposures

A list of references regarding WorkSafeBC’s ELs are referenced below: