What are PFAS?
Per- and polyfluoroalkyl substances (or PFAS) are a class of over 20,000 synthetic chemicals that are widely used in consumer products, industrial applications, manufacturing processes, and certain firefighting foams. PFAS were first produced in the 1930s, and their first industrial scale use was in the 1940s for the Manhattan Project and the creation of nuclear weapons. Commercially, PFAS have been in use since 1946, when DuPont developed non-stick cookware using Teflon. Since then, these fluorinated chemicals have been widely applied in products for their waterproof, stain-resistant, and non-stick properties. Although there are thousands of different PFAS, one common characteristic of these chemicals is that they are persistent, bioaccumulative, toxic, and widespread in our bodies and environment.
How are people exposed to PFAS?
PFAS exposure can occur in a variety of ways, including drinking contaminated water, eating contaminated food, and using consumer products that contain PFAS. People can also be exposed to PFAS in the workplace, especially firefighters and people who work in industries that produce or use PFAS. PFAS can cross the placenta and accumulate in breast milk, so children can be exposed in the womb and during early life through breastfeeding. Because PFAS break down so slowly, they can accumulate in people and animals through repeated exposure, which can result in increased levels in the body over time.
How widespread is exposure to PFAS?
PFAS have been detected in all corners of the Earth, contaminating the blood of virtually all Americans and even passing through the umbilical cord and into the womb. Researchers estimate that more than 96% of Americans have measurable levels of PFAS in their blood. PFAS are extremely resistant to breakdown, which is why they are often called “forever chemicals.” They can remain in the body from months to years, and in the environment for thousands of years. The PFAS Project Lab has identified over 2,000 known contamination sites and over 79,000 sites likely to be contaminated by PFAS across the United States and its Territories.
What are the health effects of PFAS?
Most health studies have focused on PFOA, PFOS, and a handful of other PFAS chemicals, though research increasingly suggests that many other PFAS chemicals also pose significant risks. In epidemiological studies in people and experimental studies in animals, PFAS exposure has been associated with:
- Increase in total cholesterol and LDL cholesterol
- Decreased antibody response to vaccines in children
- Decreased fertility in women
- Increased risk of pregnancy-induced hypertension and/or pre-eclampsia
- Kidney and testicular cancer
- Thyroid disease
- Chronic kidney disease, elevated uric acid, hyperuricemia, and gout
- Liver damage
- Immune system disruption
- Adverse developmental outcomes, including small decrease in birth weight and altered mammary gland development
To learn more about PFAS and how it impacts you:
Find PFAS contamination sites in your area using our PFAS Contamination Site Database
Learn more about PFAS and links to other organizations
References
Richter et al., Social Studies of Science, 2018
Gaber et al., Annals of Global Health, 2023
De Silva et al., Environmental Toxicology and Chemistry, 2021
Garrett et al., Environmental Science Technology, 2025
Cousins et al., Environmental Science Technology, 2022
Sunderland et al., J Expo Sci Environ Epidemiol., 2019
Botelho et al., Environmental Research, 2020
Dosunmu et al., Environmental Science and Policy, 2025
PFAS Interstate Technology Regulatory Council Fact Sheets