The Ontario Ministry of Labour has published its proposed changes to Occupational Exposure Limits (OEL) for 2010. OELs are maximum exposure limits, with respect to duration and concentration, prescribed for exposure to an airborne hazardous chemical or biological agent. These limits are in place to provide protection to workers from adverse health effects. Ontario Regulation 833, Control of Exposure to Biological and Chemical Agents and Regulation 490, Designated Substances govern OELs.

The Ministry of Labour derived their proposed changes from recommendations from the American Conference of Governmental Industrial Hygienists (ACGIH). The ACGIH is a memberbased organization that aims to improve occupational and environmental health. Independent experts voluntarily work together to determine appropriate exposure limits that are relied upon across North America. Due to changes from the ACGIH, the Ministry of Labour has proposed the following changes:

  • Addition of the substance Citral and Methyl Isocyanate
  • Revisions to existing exposure limits for 10 substances ( Cotton dust, Cresol, Dieldrin, Hydrogen sulphide, Methyl isobutyl ketone, α- Methyl styrene, Oil mist – mineral, Portland cement, Thallium, Thionyl chloride)
  • Removal of Tantalum, metal and oxide
  • Removing short-term exposure limits for 22 substances and applying excursion limits instead

There is a 60-day consultation period for the proposed changes which provides stakeholders an opportunity to give feedback before the changes become law. September 17, 2010 is the date the consultation ends. Employers should familiarize themselves with the upcoming changes and ensure their respective control programs meet the new requirements.