Perfluorooctane sulfonic acid (PFOS), its salts and perfluorooctane sulfonyl fluoride (PFOSF)

PFOS is both intentionally produced and is created through unintended degradation of related anthropogenic chemicals. The current intentional use of PFOS is widespread and found in products such as in electric and electronic parts, fire fighting foam, photo imaging, hydraulic fluids and textiles. PFOS are still produced in several countries today.

The historical use of PFOS-related substances in the following applications has been confirmed in the US and the EU:

  • Fire fighting foams
  • Carpets
  • Leather/apparel
  • Textiles/upholstery
  • Paper and packaging
  • Coatings and coating additives
  • Industrial and household cleaning products
  • Pesticides and insecticides

In the UK study (RPA and BRE, 2004), detailed information has been received from the following sectors that currently use PFOS-related substances:

  • Use of existing fire fighting foam stock
  • Photographic industry
  • Photolithography and semiconductor
  • Hydraulic fluids
  • Metal plating


PFOS is extremely persistent. It has not showed any degradation in tests of hydrolysis, photolysis or biodegradation at any environmental condition tested. The only known condition whereby PFOS is degraded is through high temperature incineration.


PFOS fulfils the criteria for bioaccumulation based on the much higher concentrations of

PFOS in top predators, such as the polar bear, seal, bald eagle and mink (in the Arctic, the US

and Sweden), than at lower trophic levels.


The UK and Sweden have proposed the following classification for PFOS in EU (2005):

  • Toxic
  • limited evidence of carcinogenic effect
  • danger of serious damage to health by prolonged exposure if swallowed
  • May cause harm to the unborn child
  • Toxic to aquatic organisms
  • May cause long-term adverse effects in the aquatic environment.

PFOS has demonstrated toxicity towards mammals in subchronic repeated dose studies at low concentrations, as well as rat reproductive toxicity with mortality of pups occurring shortly after birth. PFOS is toxic to aquatic organisms with mysid shrimp and Chironomus tentans being the most sensitive organisms.

More information



Adapted from the Proposal for listing PFOS in the Stockholm Convention (PDF), the US EPA preliminary risk assessment of PFOS (PDF), and the Stockholm Convention PFOS Risk Profile (PDF)

Hatfield Consultants The World Bank funded by the Canadian POPs Trust Fund through the      
Canadian International Development Agency
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