What is PFAS?


Per- and polyfluoroalkyl substances (PFAS) are a large group of man-made chemicals that have been used in industry and consumer products worldwide since the 1950s. These chemicals are used to make products to resist stains, grease, and water. The most studied PFAS are perfluorooctanoic acid (PFOA or C8) and perfluorooctane sulfonic acid (PFOS).

Common Uses of PFAS:

  • Firefighting foam
  • Food packaging
  • Non-stick cookware
  • Stain-resistant carpet and clothing

PFAS do not occur naturally but are widespread in the environment. PFAS can be found in the environment near areas where they are manufactured or where products containing PFAS are often used. PFAS are found in people, wildlife, and fish all over the world. Most PFAS do not break down easily in the environment. Some PFAS can stay in people's bodies a long time.

There are currently four per- and polyfluoroalkyl substances (PFAS) that have health advisory levels established by the Environmental Protection Agency (EPA): PFOA, PFOS, GenX, and PFBS.


Perfluorooctanoic acid (PFOA) has been a manufactured perfluorochemical and a byproduct in producing fluoropolymers. Perfluorochemicals (PFCs) are a group of chemicals used to make fluoropolymer coatings and products that resist heat, oil, stains, grease, and water. PFOA was used particularly for manufacturing polytetrafluoroethylene, but since 2002, manufacturers have used a new process not requiring this chemical. PFOA persists in the environment and does not break down. PFOA has been identified in bodies of water and in a variety of land and water animals.


Perfluorooctane sulfonic acid (PFOS) (PDF) is a synthetic, fully fluorinated organic acid; it is used in a variety of consumer products and is generated as a degradation product of other perfluorinated compounds. Because of strong carbon-fluorine bonds, PFOS is stable to metabolic and environmental degradation. PFOS is one of a large group of perfluoroalkyl substances (PFAS) that are used to make products more resistant to stains, grease, and water. These compounds have been widely found in consumer and industrial products, as well as in food items. Water resources contaminated by PFOS have been associated with releases from manufacturing sites, industrial sites, fire/crash training areas, and industrial or municipal waste sites where products are disposed of or applied.


GenX is a trade name for a man‐made and unregulated chemical used in manufacturing nonstick coatings and for other purposes. Chemours' facility in Fayetteville began producing GenX commercially in 2009 as a replacement for PFOA. The same chemical is also produced as a byproduct during other manufacturing processes, and it may have been present in the environment for many years before being produced commercially as GenX.


PFBS is a replacement chemical for PFOS, a chemical that was voluntarily phased out by the primary U.S. manufacturer by 2002. PFBS has been identified in the environment and consumer products, including surface water, wastewater, drinking water, dust, carpeting and carpet cleaners, and floor wax.

Show All Answers

1. What is PFAS?
2. What are the health advisory levels for PFAS compounds?
3. What is the difference between an interim and final health advisory level?
4. Will EPA release an enforceable regulation for GenX in drinking water?
5. How do I know if my drinking water contains PFAS?
6. PFAS (PFOA, PFOS, GenX, PFBS) has been detected in my water. Is it safe to drink?
7. PFAS (PFOA, PFOS, GenX, PFBS) has been detected in my water supply. Can I shower, bathe, wash clothes/dishes, water my plants, etc.?
8. Can I use my water to mix my babies’ formula?
9. PFAS (PFOA, PFOS, GenX, PFBS) has been detected in my water supply. Is it safe for pets or animals?
10. What health effects should I be worried about?
11. How can I be exposed to PFAS?
12. What can I do to reduce my exposures to PFAS?
13. Is there one location where PFAS studies are summarized?