Occupational Exposure Limits

• Content last reviewed: January 2013

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.

Update

Changes to the occupational exposure limits (OELs) in Regulation 833 and O. Reg 490/09 have been made by O. Reg. 149/12 and O. Reg. 148/12.

The proposals included in the Ministry’s 2010 and 2011 consultation documents have been adopted other than the Ministry’s proposal for the substance hydrogen sulfide which remains under review.

In addition to the changes to the OELs noted above, a few administrative/technical housekeeping changes have also been made:

• A correction in the temperature units from Celsius to Fahrenheit in one of the listings for Stoddard Solvent.
• The adoption of the asbestos fibre criteria for measurement set by ACGIH.
• Reinstatement of the Provincial Physician’s powers to designate other physicians to retain certain records in O. Reg. 490/09 which were removed in error.

The changes to Regulation 833 and O. Reg. 490/09 took effect January 1, 2013, with the exception of the reinstatement of the Provincial Physician’s designation powers, which came into force on filing.