May 1, 2015
Each year, the American Conference of Governmental Industrial Hygienists (ACGIH) publishes a list of substances for which it has set new or revised Threshold Limit Values (TLVs). A TLV is an exposure limit that is the suggested maximum allowed airborne concentration for a particular substance where nearly all workers are believed to experience no adverse health effects over a working lifetime. TLVs may be an eight-hour time-weighted average, short-term exposure limit, or ceiling limit.
Prior to the adoption of the new or revised ACGIH TLVs that are published each year as B.C. occupational exposure limits (OELs), WorkSafeBC reviews and stakeholders are consulted on potential implementation issues. WorkSafeBCs Board of Directors (BOD) then decides which of the new or revised ACGIH TLVs are to be adopted as B.C. OELs. The existing OELs for these substances continue to be in effect until the BOD makes the decision to adopt the ACGIH TLVs as B.C. OELs.
In order to retain the existing B.C. OELs, the substances are added to the Table of Occupational Exposure Limits for Excluded Substances in Prevention Policy R5.48-1.
The ACGIH has published the 2015 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 Prevention Policy R5.48-1 on May 1, 2015. 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.
- Cyanogen bromide (new TLV)
- Lithium hydride
- Methyl formate
- Oxalic acid, anhydrous and dihydrate
The ACGIH has also revised the TLVs for acetone and phenyl isocyanate. These substances are already listed in the Table of Occupational Exposure Limits for Excluded Substances and the current B.C. OELs are maintained.
Director, OHS Regulation, Policy & Governance