Government of Canada
Symbol of the Government of Canada

Common menu bar links

Perfluorooctane sulfonate (PFOS)

What is it?

  • Perfluorooctane sulfonate, also known as PFOS, is a synthetic chemical substance belonging to a large family of compounds known as perfluorinated chemicals.

How is it used?

  • Prior to the announcement of a global voluntary phase-out of the production of PFOS by the major manufacturer beginning in 2000, PFOS was imported into Canada and used primarily in water, oil, soil and grease repellents for paper and packaging,  carpets and fabrics, and in fire-fighting foams used to fight fuel-based fires.
  • Based on a 2004 survey of remaining PFOS uses, only 3000 kg of PFOS was imported into Canada for use as a surfactant in the chromium electroplating sector.
  • There are no manufacturers or exporters of PFOS in Canada.

Why did the Government of Canada assess it?

  • A screening assessment was undertaken of PFOS, its salts, and its precursors on the basis of the potential persistence and bioaccumulation of PFOS in the environment, and its inherent toxicity to organisms.
  • The assessment was also undertaken in response to a public nomination to the Minister of Environment to add these substances to the Priority Substances List. Precursors considered to have the potential to degrade to PFOS were included in the assessment.

How are Canadians exposed to it?

  • Given the historic use patterns, exposure of the general population of Canada to these substances would likely result from contact with, and/or the use of certain products used by consumers.
  • Exposure may also occur through environmental media (for example, air, water, food, and dust); however, given that data on these levels is limited, exposure was assessed using levels of these substances measured in humans (biomonitoring data).
  • The assessment took into consideration the results of biomonitoring studies. Measuring chemicals in blood, urine or breast milk is called biomonitoring and is done through health studies or surveys, such as the Canadian Health Measures Survey. Finding the chemical in the body does not necessarily mean that it is causing harm. Harmful effects will depend on the levels and the properties of the chemicals. The information on measured levels in humans is important to estimating exposure to Canadians.

How is it released into the environment?

  • PFOS can be released to the environment throughout its lifecycle; from the handling of the chemical to the use and disposal of products which contain it.

What are the results of the assessment?

  • The Government of Canada conducted science-based evaluations of PFOS, its salts, and its precursors to address the potential for harm to the general population of Canada and the environment. More information describing different types of assessments can be found in the Types of Risk Assessment Documents fact sheet.
  • The Ministers of the Environment and Health published their final decision on the screening assessment of PFOS, its salts and precursors on July 1, 2006.
  • Results of the final State of the Science Report for Perfluorooctane Sulfonate, its Salts, and its Precursors for health indicated that current levels of exposure to these substances are below levels that would have an adverse effect on human health. However, the final Ecological Screening Assessment Report on Perfluorooctane Sulfonate, its Salts and its Precursors indicated that some wildlife (for example, polar bears, fish-eating bird species) could have levels that may cause effects and could be harmed by current exposures to PFOS.
  • Therefore, the Government of Canada concluded that PFOS, its salts, and its precursors are entering the environment at levels that constitute a danger to the environment.

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 amount of chemical to which a person is exposed. PFOS is not presently a concern for the health of the general population in Canada at current levels of exposure.
  • 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.
  • Canadians who may be exposed to PFOS in the workplace should consult with their employer and 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).
  • Please consult Environment Canada's Management of Toxic Substances Website for more information on PFOS.