PFAS 101

What is PFAS?

Per- and polyfluoroalkyl substances (PFAS) are a large group of nearly 5,000 different synthetic chemicals that are resistant to heat, water, and oil. The U.S. Environmental Protection Agency (EPA) classifies PFAS as emerging contaminants on the national landscape. Invented in the 1930s, PFAS have since the 1940s and are still commonly used for their water- and grease-resistant properties in many industrial applications and consumer products such as carpeting, waterproof clothing, upholstery, food paper wrappings, cookware, personal care products, fire-fighting foams, and metal plating. A few of the most studied PFAS are known to be hazardous to human health. Some manufacturers have chosen to stop using them and EPA has established rules on some of their uses, but generally speaking PFAS continue to be used widely in industrial applications and consumer products.

Products that PFAS can be found in: non-stick cookware, waterproof clothing, furniture and carpeting, personal care products, and food packaging.

Some PFAS are persistent, which means they do not break down in the environment, and some of those PFAS also bioaccumulate, meaning the amount builds up in the body over time. PFAS have been found both in the environment and in blood samples of the general U.S. population.

Toxicological studies in animals who were exposed to some PFAS found links between the chemicals and changes in the body’s cholesterol levels, hormones and immune system; decreased fertility; and increased risk of certain cancers. Studies in which animals were given high levels of PFAS showed effects including low birth weight, delayed puberty onset, and elevated cholesterol levels. Animal studies like these help scientists understand what could happen in people. Some of these effects also have been observed in humans who have higher levels of PFAS in their blood: reduced immunologic responses to vaccination have also been reported in humans. This data also provides state agencies a basis to test drinking water, lakes, rivers, soil, and so forth to see if PFAS are present and could be posing a concern.

The information on the health risks for PFAS are also used to develop risk assessments and values for programs to use to prevent and remediate PFAS contamination. The MPCA has risk assessment information available for soil and sediment contamination and water quality criteria.

What is the difference between PFAS, PFOS, and PFOA?


PFAS are a large group of synthetic chemicals known as per- and polyfluoroalkyl substances.

There are nearly 5,000 unique PFAS chemicals in this group, but only a few individual PFAS are regularly monitored. PFAS have been manufactured and used extensively by a variety of industries around the globe since the 1940s.


PFOS and PFOA are the most recognized and most studied individual compounds in the larger group of PFAS chemicals. Major manufacturers of PFAS in the United States agreed to phase out the use of PFOS, PFOA and other select PFAS in 2006, but manufacturers that are not part of this agreement may still be producing them. PFOS and PFOA are still manufactured and used in products made overseas that may be shipped for sale in the United States.

  • PFOS – Perfluorooctane sulfonate (PFOS) was the key ingredient in the stain repellant Scotchgard, and was used in surface coatings for common household items such as carpets, furniture, and waterproof clothing.
  • PFOA – Perfluorooctanoic acid was used in the production of nonstick coatings for cookware. The best known of these coatings, PTFE or Teflon™, is made from PFOA and may contain some traces of PFOA. It was also used in production of carpets, upholstery, clothing, floor wax, and sealants.

How does PFAS get into drinking water and fish?

There are many ways PFAS can get into drinking water and fish. One way is when PFAS and PFAS-containing products are spilled on the ground or into lakes and rivers. PFAS move easily through the ground, getting into groundwater that may supply drinking water to home or cities. Or, as the figure shows, PFAS can be released from our homes and industries and enter surface waters directly or through wastewater treatment plants. PFAS can also be released into the air, where it can be taken up by rain or snow and end up in rivers and lakes.

Paths show how PFAS travels from sources like industries, firefighting foam, landfills, and wastewater treatment plants into our air, land, and water

How could I be exposed to PFAS?

The main ways people are exposed to these chemicals is by inhaling or swallowing them. Workers who make or process PFAS, or materials that contain PFAS, may be exposed through inhalation. PFAS chemicals are sometimes found in drinking water and in cooking or food packaging products. PFAS can be swallowed along with the water or food. People can be exposed to PFAS when they eat fish.

PFAS coatings on some products can degrade over time, creating dust particles that contain PFAS which also can be inhaled or swallowed. From there they can enter the bloodstream.

What is being done about this issue?

State and local agencies are actively working to obtain more information about PFAS as quickly as possible. Additional testing is ongoing, which will help us answer more questions and determine next steps.