Stream 4 Heavy Fuel Oils

What are they?

  • Heavy fuel oils, also known as HFOs, are a group of complex combinations of petroleum hydrocarbons.
  • HFOs are composed of varying lengths of carbon atom chains and rings, typically ranging between 20 and 50 carbon atoms. Their composition can vary depending on the source and how they are processed.
  • Stream 4 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), and may be used in commercial or industrial products.
  • Stream 4 HFOs are similar to site-restricted (Stream 1) and industry-restricted (Stream 2) HFOs, but may be used in commercial or industrial products.

How are they used?

  • Stream 4 HFOs are used as blending stocks in final heavy fuel oil products.
  • Industrial uses include their use as floatation oil in potash production, as a viscosity adjustor (for example, diluents and solvents) in various applications, and as a component in some road maintenance products.

Why did the Government of Canada assess them?

  • These HFOs were included in the Petroleum Sector Stream Approach (Stream 4) 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 Stream 4 HFOs were identified as a potential concern to human health. Furthermore, they are classified by international organizations as substances that may cause cancer.

How are Canadians exposed to them?

  • Exposure of the general population to Stream 4 HFOs is not expected from the current industrial products and processes in which they are used.

How are they released into the environment?

  • Potential releases of Stream 4 HFOs to the environment consist of spills to soil and/or water from storage, loading, transport and unloading operations.
  • These Stream 4 HFOs may also be released in small amounts during application of potash or use of some road maintenance products.

What are the results of the assessment?

  • The Government of Canada has conducted a science-based evaluation of Stream 4 HFOs, called a screening assessment.
  • Screening assessments address the potential for harm to the general population of Canada and the environment.
  • The frequency of spills of these Stream 4 HFOs of a sufficient size to cause harm to organisms is low.
  • The frequency and size of release of these Stream 4 HFOs from road maintenance products is low.
  • The quantity released during application of potash is low and below levels expected to cause harm to organisms.
  • The Government of Canada has concluded that Stream 4 HFOs are not entering the environment at levels that constitute a danger to the environment.
  • Exposure of the general population to Stream 4 HFOs is not expected and therefore the Government of Canada has also concluded that these substances are not harmful to human health.
  • Hazards related to chemicals used in the workplace should be classified accordingly under the Workplace Hazardous Materials Information System (WHMIS).

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 Stream 4 HFOs at current levels of exposure.
  • Canadians who may be exposed to Stream 4 HFOs in the workplace should consult with their employer and occupational health and safety (OHS) representative about safe handling practices, applicable laws and requirements under the OHS legislation and the Workplace Hazardous Materials Information System (WHMIS).
  • As a general precaution, Canadians are reminded when using any product to carefully follow any safety warnings and directions, and to dispose of the products appropriately.
Stream 4 HFOs assessed by the Government of Canada
CAS RN DSL Name
64741-57-7 Gas oils (petroleum), heavy vacuum
64741-62-4 Clarified oils (petroleum), catalytic cracked
64741-67-9 Residues (petroleum), catalytic reformer fractionator
64741-81-7 Distillates (petroleum), heavy thermal cracked
64742-59-2 Gas oils (petroleum), hydrotreated vacuum
64742-90-1 Residues (petroleum), steam-cracked
68955-27-1 Distillates (petroleum), petroleum residues vacuum
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