Base oils - information sheet

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  • The Government of Canada conducted a science-based evaluation, called a screening assessment to address the potential for harm to Canadians and to the environment from 39 base oil substances.
  • Under the Canadian Environmental Protection Act, 1999 (CEPA 1999), the risk posed by a substance is determined by considering both its hazardous properties (its potential to cause adverse human health or ecological effects) and the amount of exposure there is to people and the environment. A substance may have hazardous properties; however, the risk to human health or to the environment may be low depending upon the level of exposure.
  • As a result of the screening assessment, the Government concluded that these substances are not harmful to human health or to the environment at levels of exposure considered in the assessment.

About these substances

  • The screening assessment focused on 39 substances, referred to collectively under the Chemicals Management Plan as base oils.
  • Base oils are of Unknown or Variable composition, Complex reaction products or Biological materials (UVCBs) produced during the refining of crude oil. They are complex combinations of hydrocarbon molecules that may occur naturally in the environment or as a result of petroleum refining processes.
  • Base oils are identified by Chemical Abstracts Service Registry Numbers (CAS RNs); however, the CAS RN does not describe the complete details of the refining process or chemical composition of the substance. Therefore, 2 base oils with the same CAS RN may vary greatly in composition, in terms of the proportion of aromatics, alkanes, and cycloalkanes.
  • Base oils may contain Polycyclic Aromatic Hydrocarbons (PAHs), which are naturally-occurring components of crude oil. The proportion of PAHs in base oils varies depending on the source of crude oil and the refining steps. The presence of PAHs in base oils can be significantly reduced through refining processes. The PAHs are considered to be the components of greatest human health concern for base oils.
  • Base oils can also contain varying proportions of aromatic components (including, parent and alkylated mono- and polycyclic aromatics and heterocyclic aromatics), which contribute greatly to the ecotoxicity of these substances.
  • According to information gathered by the Government, base oils are produced and used on-site at refineries. They may also be transported to other petroleum and non-petroleum facilities for use as raw materials, or blended with other raw materials to produce a new CAS RN.
  • Base oils are used in industrial facilities, such as lubricant plants, wastewater treatment facilities, pulp and paper industries, and printing ink operations (for example, as lubricants, industrial processing aids, fuels and solvents).
  • They are also used in products available to consumers, for example automotive care products (such as engine cleaners and mirror glazes), lubricants (such as motor oils and multipurpose lubricants), household cleaning products (such as wood and steel polishes/cleaners), and soft rubber and plastic products (such as toys, tires, and sandals).

Human and ecological exposures

  • Canadians may be exposed to base oils primarily through the use of products available to consumers.
  • The human health assessment examined the potential for Canadians’ exposure to base oils containing PAHs.
    • Testing was carried out on products available to Canadian consumers which contain base oils to determine the level of PAHs present in these products.
    • Residual to low levels of PAHs were found in the products available to consumers that were tested (for example, in soft rubber and plastic products).
  • Base oils may be released to the environment primarily through industrial activities. Base oils used in these applications undergo wastewater treatment prior to release to the environment, which is expected to remove a large fraction of the substance.

Key health and ecological effects (hazard)

  • To inform the health effects characterization in the screening assessment, international reports of data on these substances were considered, including assessments by the European Commission and the International Agency for Research on Cancer.
  • The critical effect identified for characterizing the risk to human health for these substances was carcinogenicity (ability to cause cancer).
  • For the ecological assessment, base oils with aromatic contents ranging from 10 to 45% by weight were considered. Empirical and modelled data for base oils indicated low to high hazard.

Risk assessment outcomes

  • The risk to human health from these 39 base oils is considered to be low, based upon the information presented in the screening assessment.
  • Considering all information presented, it was determined that there is low risk of harm to the environment from these substances.
  • The Government of Canada published the Final Screening Assessment for Base Oils on July 11, 2020.

Screening assessment conclusions

  • As a result of the screening assessment, the Government concluded that the 39 base oils are not harmful to human health at levels of exposure considered in the assessment, and that these substances are not entering the environment at levels that are harmful to the environment.

Related information

  • These substances may be found in products available to consumers. Canadians should follow any safety warnings and directions related to the product and dispose of products responsibly.
  • The screening assessment focused on potential risks from exposure of the general population of Canada, rather than occupational exposure. Hazards related to chemicals used in the workplace are defined within the Workplace Hazardous Materials Information System. For information concerning workplace health and safety and what steps to take in the workplace, Canadians should consult their employer and/or the Occupational Health and Safety Regulator in their jurisdiction.

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