Industry-restricted Heavy Fuel Oils (Industry-restricted HFOs)

CAS Registry Numbers 64741-75-9, 68783-08-4, 70592-76-6, 70592-77-7 & 70592-78-8

What are they?

  • Heavy fuel oils, also known as HFOs, 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.
  • HFOs are composed of varying lengths of carbon atom chains and rings, ranging between 7 to 50 carbon atoms.
  • Industry-restricted HFOs may leave a petroleum-sector facility and may be transported to other industrial facilities (for example, for use as a feedstock, fuel or blending component), but are not expected to be available to the public. 

How are they used?

  • HFOs are used as blending stocks in final heavy fuel products or as an intermediate product of distillate or residue (leftover from the manufacturing process) derived from refinery distillation or cracking units.
  • The final fuel product usually consists of a mixture of HFOs as well as higher-quality hydrocarbons.

Why did the Government of Canada assess them?

  • These five HFOs 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 HFOs 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 moderate or 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 non-human organisms.

How are Canadians exposed to them?

  • Exposure of the general population of Canada to industry-restricted HFOs 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 HFOs 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 industry-restricted HFOs, 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 five HFOs likely 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 HFOs during ship loading and other activities is considered low.
  • Therefore, the Government of Canada has concluded that the five industry-restricted HFOs are not entering the environment in a quantity or under conditions that constitute a danger to the environment.
  • When present in air, HFOs 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 the five industry-restricted HFOs are not harmful to the health of the general population at current levels of exposure.
  • HFOs that are not considered industry-restricted and substances into which industry-restricted HFOs may be blended will be addressed at a later stage under the Chemicals Management Plan. Seven site-restricted HFOs were previously assessed by the Government of Canada - the final screening assessment was released on September 3, 2011.

What is the Government of Canada doing?

  • Based on the conclusion of the final screening assessment, the Government of Canada will take no further action on these five industry-restricted HFOs.
  • The final screening assessment report was published on July 27, 2013.

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 five industry-restricted HFOs at current levels of exposure.
  • Canadians who may be exposed to HFOs 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 HFOs assessed by the Government of Canada
64741-75-9 Residues (petroleum), hydrocracked
68783-08-4 Gas oils (petroleum), heavy atmospheric
70592-76-6 Distillates (petroleum), intermediate vacuum
70592-77-7 Distillates (petroleum), light vacuum
70592-78-8 Distillates (petroleum), vacuum
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