Occupational Exposure Limits

• Issued: July 2010
• Revised: December 2011
• Content last reviewed: December 2011

Occupational Exposure Limits (OELs) restrict the amount and length of time a worker is exposed to airborne concentrations of hazardous biological or chemical agents.

There are OELs for over 725 substances set out in R.R.O. 1990, Regulation 833 (Control of Exposure to Biological or Chemical Agents) and Ontario Regulation 490/09 (Designated Substances) under Ontario’s Occupational Health and Safety Act.

In 2004, the Ministry of Labour introduced a review process for OELs to ensure that these limits are regularly reviewed and updated. Under this process, the MOL releases for public consultation proposals for new or revised OELs based on the annual recommendations of the American Conference of Governmental Industrial Hygienists (ACGIH). During consultations, stakeholders are invited to submit comment on any or all of the proposed changes.