Perfluorooctanoic  Acid (PFOA), its salts, and its precursors - information sheet


Per- and polyfluoroalkyl substances (PFAS) are a class of over 4,700 human-made substances. In April 2021, the Government of Canada indicated that it is considering activities that would address PFAS as a class. Visit the PFAS web page for the latest information on publications and actions being considered under the Government’s Chemicals Management Plan related to PFAS.

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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 PFOA, its salts and its precursors. This assessment was completed in 2012.
  • 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 PFOA, its salts and its precursors are harmful to the environment, but not to human health, at levels of exposure current at the time of the assessment.

About these substances

  • Perfluorooctanoic acid, also known as PFOA, is a man-made substance belonging to a class of chemicals known as perfluorocarboxylic acids (PFCAs) that fall under a broader class of chemicals known as per- and polyfluoroalkyl substances (PFASs).
  • PFOA may be formed from the breakdown or transformation of PFOA precursors (for example, parent compounds, chemical products containing PFOA).
  • According to information gathered by the Government, PFOA and its salts, such as PFOA ammonium salt (APFO), were used in the manufacture of stain- and water-resistant coatings for textiles and carpets; hoses, cables, and gaskets; non-stick coatings on cookware; and personal care products.
  • PFOA, its salts and its precursors have also been used in the past in many industrial processes, commercial products, and products available to consumers.
  • Precursors of PFOA were not individually assessed, but were considered in terms of their contribution to total PFOA human exposure because they can break down to PFOA in the environment.
  • The ecological assessment focused on PFOA, but also considered its precursors given similar use applications and given that PFOA is the final degradation product of these precursors. While the assessment did not consider the additive effects of PFOA and its precursors, it is recognized that the precursors contribute to the ultimate environmental loading of PFOA. Precursors may also play a key role in the long-range transport and subsequent degradation to PFOA in the Canadian Arctic.

Human and ecological exposures

  • The assessment indicated that Canadians may be exposed to PFOA and its precursors from environmental sources (for example, air and drinking water), food (including human breast milk), and from using certain products available to consumers, such as PFAS-treated apparel, carpets, upholstery, and new non-stick cookware.
  • The assessment took into consideration the results of human biomonitoring studies, which is the measurement of substances in blood, urine or breast milk. The presence of a substance in the body does not necessarily mean that it is causing harm. Harmful effects will depend on the levels and the properties of the substances. The information on measured levels in humans is important to estimating exposure to Canadians.
  • Low concentrations of PFOA were found in blood samples from Canadians. These levels were used as a measure of exposure to PFOA from all sources and routes.
  • The assessment indicated that PFOA may have been released to the environment from fluoropolymer manufacturing or processing facilities located in other countries, in effluent releases from wastewater treatment plants, in landfill leachates and from the breakdown and transformation of PFOA precursors in the environment and/or in biota.

Key health and ecological effects (hazard)

  • For human health, information available at the time of the assessment indicated that PFOA and its salts may have reproductive effects, as well as effects on the liver. These were considered to be the important or “critical” effects used in characterizing the risk to human health in the assessment.
  • PFOA, and its salts are considered to have ecological effects of concern (such as on the liver, endocrine and immune systems) due to their persistence in the environment and their tendency to accumulate and biomagnify in a variety of terrestrial and marine mammals.

Risk assessment outcomes

  • Based upon a comparison of levels to which Canadians may be exposed to PFOA and its salts and the levels associated with health effects, the risk to human health from these substances was considered to be low.
  • It was also determined that there is risk of harm to the environment from PFOA and its salts based on a weight-of-evidence. Considerations included the persistence, bioaccumulation (the increase in concentrations of a substance in the tissues of organisms due to uptake from all sources, such as water and food), temporal trends in some species (such as the polar bear), long-range transport and the widespread occurrence and concentrations of PFOA in the environment and biota (including remote areas of Canada).
  • Additionally, PFOA and its salts meet the persistence criteria but not the bioaccumulation criteria as set out in the Persistence and Bioaccumulation Regulations of CEPA 1999. Nevertheless, the weight of evidence was sufficient to conclude that PFOA and their salts bioaccumulate and biomagnify (the increasing concentration of a substance in the tissues of organisms at successively higher levels in a food chain) in terrestrial and marine mammals.
  • The Government of Canada published the Final Screening Assessment on Perfluorooctanoic acid, its Salts and its Precursors on August 25, 2012.

Screening assessment conclusions

  • As a result of the final screening assessment, the Government concluded that PFOA and its salts are not harmful to human health at levels of exposure current at the time of the assessment.
  • The Government also concluded that PFOA, its salts and its precursors are entering the environment at concentrations that are harmful to the environment.  

Preventive actions and reducing risk

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