Base oils - information sheet

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  • The Government of Canada conducted a science-based evaluation, called a screening assessment, of 39 base oil substances, to address the potential for harm to Canadians and to the environment.
  • 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 this screening assessment, the 39 base oils substances are considered not harmful to human health or the environment at current levels of exposure.

About these substances

  • This screening assessment focuses on 39 substances, referred to collectively under the Chemicals Management Plan (CMP) as base oils.
  • Base oils are complex combinations of hydrocarbons produced during the refining process of crude oil. They are considered to be unknown or variable composition, complex reaction products or biological materials (UVCB) substances that may occur naturally in the environment or as a result of petroleum refining processes.
  • They are also identified by Chemical Abstracts Service Registry Numbers (CAS RNs). The CAS RN does not describe the details of the refining or chemical composition of the substance. Therefore, 2 base oils with the same CAS RN may vary greatly in their compositions, in terms of the proportion of aromatics, paraffins, and naphthenes.
  • Base oils can 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 health concern for base oils.
  • Base oils can contain varying proportions of aromatic components (including, parent and alkylated mono- and polyaromatics and heterocyclics) which are considered to contribute the greatest to the ecotoxicity of base oils.
  • The Government gathers information on substances, including details on their commercial status in Canada, to support the risk assessment and management of substances under the CMP.
  • Base oils may be used on-site at a refinery. They may also be transported to other petroleum or non-petroleum facilities for use as raw materials or blended with other raw material substances to produce a new product.
  • Base oils are widely used in industrial processes and in products available to consumers, including lubricants, transformer oils, automotive care products, processing aids (including oils for rubber-based products). They may also be found in printing inks, fuels and solvents, paints and coatings, soaps and detergents, adhesives and sealants, household cleaning products, lawn and garden care products and building products.
  • Testing of Canadian base oil in products available to consumers was carried out to determine the level of PAHs present in these products.

Exposure of Canadians and the environment

  • Exposure of Canadians to base oils from the environment (for example, drinking water) and food is not expected.
  • Canadians may be exposed through skin contact to low levels of base oils from the use of products available to consumers.
  • The health assessment also examined the potential for Canadians' exposure to base oils containing PAHs. Residual to low levels of PAHs were found in products available to consumers (primarily soft rubber and plastic products).
  • The ecological assessment focused on exposures from the potential release of base oils from 4 main sectors of activity: treatment of wastewater, lubricant plants, pulp and paper, and printing ink. Base oils used in these applications undergo wastewater treatment prior to release to the environment. In addition, base oils components removed from water during wastewater treatment may end up in soils.

Key health and ecological effects (hazard)

Risk assessment outcomes

  • Refined base oils (substances containing low levels of aromatics including PAHs) and related substances exhibit low toxicity, even at high doses in laboratory studies. Product testing also showed that the base oils used in products available to consumers have low levels of PAHs. Therefore, risk to human health from products available to consumers containing these base oils is low.
  • Considering all information presented, it was determined that there is no risk to the environment from base oils.
  • The Government of Canada published the Draft Screening Assessment for Base Oils on October 6, 2018. This publication has a 60-day public comment period ending on December 5, 2018.

Proposed screening assessment conclusions

  • As a result of this screening assessment, the Government is proposing that these 39 base oils are not harmful to human health at current levels of exposure.
  • The Government is also proposing that these 39 base oils are not entering the environment at levels that are harmful to the environment.

Important to know

  • These 39 base oils may be found in certain products available to consumers. Canadians can follow any safety warnings and directions on product labels and dispose of products responsibly.
  • Canadians who may be exposed to base oils in the workplace can consult with their employer and an occupational health and safety (OHS) representative about safe handling practices, applicable laws, and requirements under OHS legislation and the Workplace Hazardous Materials Information System (WHMIS).
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