Ontario reviewing occupational exposure limits

Province conducting a 60-day consultation on proposed changes for 2010

Ontario has announced plans to update occupational exposure limits (OELs) for a number of hazardous chemical substances such as hydrogen sulfide and thallium.

OELs restrict workers’ exposure to hazardous biological and chemical substances on the job such as those used in manufacturing and repair operations.

Ontario revises the OELs on a regular basis. The Ministry of Labour has opened a 60-day consultation on proposed changes for 2010. The consultation period allows stakeholders to comment on proposed new and revised limits for the listed hazardous substances. The submission deadline is Sept. 17, 2010.

“Ontario workers expect and deserve protection against occupational disease so they can do their work and go home safely to their families,” said Peter Fonseca, Minister of Labour. “I’m pleased that the Ministry of Labour’s regular review and updating of exposure limits for chemicals in the workplace helps improve these protections.”


Ontario currently has OELs for more than 725 hazardous biological and chemical substances.

In 2004 the province began annual reviews of Ontario’s OELs. The 2010 consultation is the seventh in this process.

Current limits are primarily based on the limits recommended by the American Conference of Governmental Industrial Hygienists (ACGIH). As a result of recommended changes to limits for 2010 by ACGIH, Ontario is proposing to adopt new or revised OELs for 12 substances. These changes include:

•Addition of one substance to regulation (Citral).

•Revisions to exposure limits or listings for 10 substances currently regulated.

•Withdrawal of the listing and specific exposure limit for one substance, tantalum, metal and oxide (total dust), on the basis that ACGIH concludes there is insufficient data or information to support an OEL. This substance will be regulated by the OELs for particles (insoluble or poorly soluble) not otherwise specified (PNOS).

In addition to the changes noted above, the Ministry of Labour is also proposing to:

•Add a specific listing and limit for “Methyl Isocyanate” in regulation 833 and O. Reg. 490/09 as per ACGIH. This proposed change is not a result of ACGIH 2010 recommendations but is a case where Ontario could better address workplace exposures and align with ACGIH by adopting the limit for this substance.

•Withdraw the short-term exposure limits for 22 substances listed in the Ontario Table in regulation 833 and regulating short-term exposures through the application of excursion limits determined in accordance with the rules set out in paragraph 3 of section 4 in regulation 833.

Stakeholder input is an essential part of the OEL updating process, the province said. Stakeholders are invited to submit comments on any or all of the proposed OEL changes. Specific concerns should contain a clear description of the rationale and appropriate documentation.

Where an exposure limit for a hazardous substance has not been recommended and is not under consideration by the ACGIH at this time, stakeholders are invited during this consultation period to nominate the substance for development of an OEL. The submission should include a proposed limit and supporting documentation used by a jurisdiction that has adopted the proposed limit.

Stakeholder input: How to get in touch with province

The 60-day consultation period ends Sept. 17, 2010. Submissions may be mailed, faxed, or sent electronically to the following addresses:


The 2010 OEL Update Project
Ontario Ministry of Labour
12th Floor, 400 University Ave.
Toronto, ON M7A 1T7

Fax: (416) 326-7650

Email: [email protected]

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