Frequently Asked Questions

PFAS (per- and polyfluoroalkyl substances) are a large group of manufactured chemicals that EPA says have been used in industry and consumer products since the 1940s. There are thousands of different PFAS. More about PFAS

Their chains of carbon and fluorine atoms are held together by one of the strongest chemical bonds, so many PFAS break down very slowly in the environment. EPA notes that they are “also known as ‘forever chemicals’.” Why PFAS last so long

No. EPA says there are thousands of PFAS “with potentially varying effects and toxicity levels, yet most studies focus on a limited number of better known PFAS compounds,” mainly PFOA and PFOS. The PFAS family

According to ATSDR, “PFOA and PFOS have been phased out of production in the U.S. Other countries may still manufacture and use them.” They have been replaced in the U.S. by other PFAS. Legacy and replacement PFAS

U.S. agencies name nonstick cookware, stain- and water-resistant fabrics and carpets, firefighting foam, some cosmetics, shampoo and dental floss, cleaning products, paints and sealants, and some medical devices. PFAS grease-proofing agents are no longer sold for U.S. food packaging, according to FDA. PFAS uses

Possibly. A USGS study estimated that at least 45% of U.S. tap water has one or more PFAS, based on samples from 2016 to 2021 that tested for 32 types. EPA suggests finding out whether PFAS are in your drinking water. PFAS in tap water

EPA’s 2024 rule set enforceable limits of 4.0 parts per trillion each for PFOA and PFOS, plus limits for four other PFAS. In May 2026 EPA proposed keeping the PFOA and PFOS limits with a possible extension to 2031, and rescinding the others. Those proposals were not final as of September 2026. Drinking water limits

Some can. EPA advises looking for filters certified under NSF/ANSI 53 or NSF/ANSI 58 for PFAS reduction and replacing them on schedule, while noting that current certifications do not yet show a filter reaches EPA’s new limits. Treatment and filters

EPA lists drinking contaminated water, eating certain foods including fish, swallowing contaminated soil or dust, breathing air containing PFAS, using products made with PFAS, and working in occupations such as firefighting or chemical manufacturing. How people are exposed

Very likely. ATSDR states that “nearly all people in the U.S. have PFAS in their blood.” Average levels of PFOS and PFOA have fallen sharply since 1999-2000. PFAS in people’s blood

ATSDR says epidemiological evidence suggests associations between exposure to specific PFAS and increased cholesterol, lower antibody response to some vaccines, changes in liver enzymes, pregnancy-induced hypertension and preeclampsia, small decreases in birth weight, and kidney and testicular cancer. These are associations, and research is ongoing. What studies have found

In December 2023 IARC classified PFOA as carcinogenic to humans (Group 1) and PFOS as possibly carcinogenic to humans (Group 2B). ATSDR lists kidney and testicular cancer among the effects associated with PFOA. Cancer classification

The National Academies recommend that clinicians offer testing to people likely to have a history of elevated exposure. ATSDR notes that blood levels “do not predict future health outcomes.” Discuss testing with a healthcare provider. PFAS blood tests

ATSDR states that “for most PFAS, showering and bathing in water containing PFAS should not significantly increase exposure.” How people are exposed

PFASfacts is an independent information site. It is not affiliated with 3M or any manufacturer, and every fact on it links to a published source. About this site

From 2018 to 2025 this address hosted a website published by 3M. After the domain lapsed in 2025, it was relaunched independently. The 3M pages are preserved, unedited and dated, in the Archive. The Archive