Wednesday, June 5, 2013

Occupational Exposure Limits in Canada Compared to the US.

The primary goal of this blog article is to allow readers to easily find exposure data in the US and Canada, by following the links in the text. Hydrogen peroxide will be used as an exemplary chemical to compare exposure limits, but the exposure limits for other chemicals are usually in the same sources, though some jurisdictions list carcinogens separately.

The Canadian provinces each set their own occupational exposure limits, though the majority of them follow the American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit values (TLVs). The occupational exposure limits for each Canadian province (P) and Territory (T) is set out below:

Note: Regulations are always subject to change and to the readers should verify that the above information is correct before relying on this information. 

The current ACGIH TLV for hydrogen peroxide is 1 ppm calculated as an 8 hour TWA.  The ACGIH TLVs are time weighted exposures (TWA) that are reviewed periodically based on the available scientific data.

For the US, the OSHA PEL for hydrogen peroxide is 1 ppm (8 hr TWA) with no short term exposure limit. Hawaii and Washington have the same 8 hr PEL, but also have a STEL of 3 ppm (15 min. TWA). 

There are significant jurisdictional differences between the US and Canada. In the United States, the Occupational Safety and Health Administration (OSHA) establishes safety standards for the entire country including permissible exposure limits (PELs) for workplace exposure to chemicals. Most state agencies with responsibility for workplace safety follow the federal limits, though a few, such as California, Washington and Hawaii set their own PELs but these state PELs are either the same or more restrictive than the OSHA PELs because of the Supremacy clause in Article VI of the US constitution.

Unlike the United States which has a strong federal government and relatively weak states, in Canada the opposite is true. In Canada there are ten provinces and three territories. The provinces are considered co-sovereign states with the federal government; and the territories though under the egis of the federal government, also promulgate their own laws. Thus people working with chemicals in Canada need to look at the requirements of each province and territory separately.

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