This edition of the Prevention Manual reflects the following updates.

2012 New or Revised ACGIH Threshold Limit Values

This notice is to advise stakeholders that the American Conference of Governmental Industrial Hygienists (ACGIH) has published the 2012 new or revised Threshold Limit Values (TLVs). The following substances have been added to the Table of Occupational Exposure Limits for Excluded Substances in Prevention Policy R5.48-1:

• Allyl bromide
• Ethyl formate
• Carbonyl sulfide
• Nonane
• Diacetyl
• o-Phthalodinitrile

Two other substances, nitrogen dioxide, and piperazine and salts, are already listed in the Table in Policy.

Each year, the ACGIH publishes a list of substances for which they have set new or revised 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 8-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, WorkSafeBC reviews and stakeholders are consulted on potential implementation issues. WorkSafeBC's Board of Directors (BOD) then decides which of the new or revised ACGIH TLVs are to be adopted as BC OELs. The existing OELs for these substances continue to be in effect until the BOD makes the decision to adopt the ACGIH TLVs as BC OELs.

In order to retain the existing BC OELs, the substances are added to the Table of Occupational Exposure Limits for Excluded Substances in Prevention Policy R5.48-1. Once the BOD approves the adoption of the ACGIH TLVs as BC OELs, the substances are removed from the Table of Occupational Exposure Limits for Excluded Substances, and the ACGIH TLVs then apply.