Toxic substances list: petroleum and refinery gases

Petroleum and refinery gases are complex combinations of petroleum hydrocarbons produced by petroleum refineries, upgraders and natural gas processing facilities. Their composition varies based on the source of the crude oil, bitumen or natural gas as well as the process operating conditions and processing units used. Many components of petroleum and refinery gases are volatile organic compounds (VOCs) that participate in atmospheric photochemical reactions.

The Government of Canada has conducted screening assessments of three groups of petroleum and refinery gases:

The screening assessments examined the potential for harm to the general population (not including workplace exposures) and the environment. Some potential components of petroleum and refinery gases, including 1,3-butadiene, benzene and isoprene, are known to be carcinogenic. 1,3-Butadiene was selected as a high hazard component to characterize potential exposure to the general population. It was recognized that a small portion of the general population may be exposed to petroleum and refinery gases in the vicinity of certain petroleum facilities.

The screening assessments concluded that each group of petroleum and refinery gases meets the criteria for toxicity to human health under paragraph 64(c) of the Canadian Environmental Protection Act, 1999 (CEPA) as they are entering or may enter the environment in a quantity or concentration or under conditions that constitute or may constitute a danger in Canada to human life or health.

Based on the conclusions of the assessments, it was recommended that petroleum and refinery gases be added to the List of Toxic Substances in Schedule 1 of CEPA. The final Order to add 40 site-restricted petroleum and refinery gases and four industry-restricted petroleum and refinery gases to Schedule 1 was published in the Canada Gazette, Part II on October 5, 2016. The final Order to add two liquefied petroleum gases to Schedule 1 was published in the Canada Gazette, Part II on April 14, 2018.

Along with the final screening assessments, the Government published proposed risk management approach documents to explain how risks associated with petroleum and refinery gases would be managed. The proposed risk management instrument for petroleum and refinery gases was a regulation under CEPA focusing on additional practices and technologies, or the improved implementation of existing requirements, for reducing fugitive emissions from petroleum facilities. The Reduction in the Release of Volatile Organic Compounds Regulations (Petroleum Sector) were published in the Canada Gazette, Part II on November 11, 2020.

Risk assessment

Risk management tools

Tools developed to manage risks associated with the substances:


Consultation (past and present) on the substances:

Other information


Substances Management Information Line
Chemicals Management Plan
Environment and Climate Change Canada
Gatineau, QC K1A 0H3

Telephone: 1-800-567-1999 (in Canada) or 819-938-3232
Fax: 819-938-3231

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