Industry-restricted Gas Oils

CAS Registry Numbers 64741-59-9 & 64741-82-8

What are they?

  • Gas oils are a category of complex combinations of petroleum hydrocarbons. Their composition varies with the source of crude oil or bitumen, and the processing steps involved.
  • They are composed of varying lengths of carbon atom chains and rings generally ranging between 9 and 25 carbon atoms.
  • The industry-restricted gas oils may leave a petroleum-sector facility and may be transported to other industrial facilities, but are not expected to be available to the public.

How are they used?

  • Industry-restricted gas oils may be consumed on site as a fuel or serve as blending components and/or feedstocks in the production of fuels that are used in diesel engines and for both industrial and domestic heating.

Why did the Government of Canada assess them?

  • These two gas oils were included in the Petroleum Sector Stream Approach under the Chemicals Management Plan for the screening assessment of potential risks to the environment and to human health.
  • Prior to their assessment by the Government of Canada, these industry-restricted gas oils were identified as a potential concern for human health based on their classification by international organizations as substances that may cause cancer, and based on a high potential for exposure (not including workplace exposures) to the general population of Canada.
  • They were also identified as a potential concern to the environment based on available information regarding possible persistence, accumulation in organisms and potential to cause harm to aquatic organisms.

How are Canadians exposed to them?

  • Exposure of the general population of Canada to industry-restricted gas oils is expected to be limited to inhalation due to evaporative emissions during transportation.

How are they released into the environment?

  • Potential releases of industry-restricted gas oils to the environment consist of releases within facilities during processing of these substances, as well as releases related to transportation of these substances between industrial facilities.
  • Releases within facilities are captured into a closed system and then returned to the processing facility for re-use or they are sent to the facility wastewater treatment plant where they are removed from the wastewater.
  • Releases related to transportation of these substances between industrial facilities are considered to be low.

What are the results of the assessment?

  • The Government of Canada has conducted a science-based evaluation of two industry-restricted gas oils, called a screening assessment.
  • Screening assessments address the potential for harm to the general population of Canada (not including workplace exposures) and the environment. 
  • Results of the final screening assessment indicate that these gas oils may contain some components that have the potential to remain in the environment for a long time, accumulate in organisms and cause harm to organisms. However, the estimated frequency of exposure to the environment from unintentional spills of these gas oils is low.
  • The Government of Canada has therefore concluded that these two industry-restricted gas oils are not entering the environment in a quantity or under conditions that constitute a danger to the environment.
  • When present in air, gas oils are only expected to be found at low levels, therefore, exposure to the general population in Canada is expected to be low.
  • The Government of Canada has therefore also concluded that these industry-restricted gas oils are not harmful to the health of the general population at current levels of exposure.
  • Gas oils that are not considered industry-restricted and substances into which these industry-restricted gas oils may be blended will be addressed at a later stage under the Chemicals Management Plan. One site-restricted gas oil (CAS No. 68333-25-5) was previously assessed by the Government of Canada - the final screening assessment (CAS No. 68333-25-5) was released on September 3, 2011.

What is the Government of Canada doing?

What can Canadians do?

  • The health risks associated with a chemical depend on the hazard (its potential to cause health effects) and the dose (the amount of chemical to which you are exposed).
  • No concerns for the environment or human health have been identified for these two industry-restricted gas oils at current levels of exposure.
  • Canadians who may be exposed to gas oils in the workplace should consult with their occupational health and safety representative about safe handling practices, applicable laws and requirements under the Workplace Hazardous Materials Information System (WHMIS).
Industry-restricted gas oil assessed by the Government of Canada
CAS RN DSL Name
64741-59-9 Distillates (petroleum), light catalytic cracked
64741-82-8 Distillates (petroleum), light thermal cracked

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