PFAS Pose a Serious Threat to Human Health

Overview

Per- and polyfluoroalkyl substances (PFAS) are a large group of synthetic chemicals that were created in the mid20th century and quickly became popular for their water-, grease-, and stain-resistant properties.

A growing body of research has linked certain PFAS to various health issues, including reduced fertility; immune system suppression; some cancers; and metabolic changes, including altered cholesterol and liver enzyme levels and increased potential for insulin resistance.¹ Studies also show that PFAS transfer from mother to fetus, sometimes with multigenerational impacts, and that PFAS can build up in people’s bodies faster than they can be removed.²

Further, PFAS are very mobile—moving easily through the environment and frequently detected far from where they were first introduced—and last a long time because their chemical structure makes them highly resistant to breaking down, earning them the moniker, “forever chemicals.”

Although government and industry largely phased out two of the most well-studied PFAS—perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS)—thousands of others remain in use in everyday products and industrial applications, such as nonstick pans, water- and stain-resistant textiles, firefighting foam, and building materials. Most of these have not been individually studied for health effects—and chemical manufacturers continue to introduce new PFAS.³

How people are exposed to PFAS

PFAS are often released into the air, water, and soil when they or products containing them are made, used, or discarded. People are then exposed to PFAS by eating or drinking contaminated food and water; through skin contact, such as touching PFAS-treated products; and by breathing in contaminated dust or air.

As a result, PFAS are commonly found in human blood and urine, as well as breast milk, semen, and umbilical cord blood. Virtually all Americans—at least 99%—have detectable levels of PFAS in their blood.⁴

Certain populations—including firefighters; people who work in PFAS manufacturing facilities; and people who live, work, or play near or downstream of military bases, airports, and industrial sites—are at heightened risk of exposure and potential harm.

PFAS act as endocrine disruptors

One way that some PFAS harm human health is by interfering with the endocrine system—a complex network of glands and organs that make and release hormones that are essential for biological functions including growth, development, metabolism, mood, sleep, and reproduction. (See Figure 1.) PFAS are just one class of chemicals that behave in this manner, known collectively as endocrine-disrupting chemicals (EDCs).

Some notable features of PFAS and other EDCs

• Low-dose toxicity. Substantial evidence suggests that even relatively low PFAS exposures can be harmful— including some concentrations measured in parts per trillion (ppt), where 1 ppt is equivalent to a single drop of water spread across 20 Olympic-sized swimming pools.⁵
• Time delay. Negative health impacts linked to PFAS can emerge long after exposure and affect not only the people exposed directly but also their children and even later generations.⁶
• Cumulative effects. Because of the large number and ubiquity of PFAS, people are commonly exposed to multiple PFAS, which can compound the health risks.⁷

Looking forward

Community members, scientists, industry, and public health advocates are contributing to monitoring programs, pollution restrictions, and other federal and state government efforts to limit PFAS’ manufacture, import, use, and disposal. Government and industry can help further protect public health by reducing exposures, improving transparency, and supporting the development of safer alternatives.

Endnotes

1. Suzanne E. Fenton et al., “Per- and Polyfluoroalkyl Substance Toxicity and Human Health Review: Current State of Knowledge and Strategies for Informing Future Research,” Environmental Toxicology and Chemistry 40, no. 3 (2020): 606-30, https://doi.org/10.1002/etc.4890. Augustina Odediran et al., “Association of PFAS and Metals With Cardiovascular Disease Risk: Exploring the Mediating Effect of Diet,” Environments 12, no. 6 (2025): 178, https://doi.org/10.3390/environments12060178.
2. Mareike Appel et al., “The Transplacental Transfer Efficiency of Per- and Polyfluoroalkyl Substances (PFAS): A First Meta-Analysis,” Journal of Toxicology and Environmental Health, Part B 25, no. 1 (2022): 23-42, https://doi.org/10.1080/10937404.2021.2009946. Si-Yu Gui et al., “Association Between Per- and Polyfluoroalkyl Substances Exposure and Risk of Diabetes: A Systematic Review and Meta-Analysis,” Journal of Exposure Science & Environmental Epidemiology 33, no. 1 (2023): 40-55, https://www.nature.com/articles/s41370-022-00464-3. Alex Haimbaugh et al., “Multi- and Transgenerational Effects of Developmental Exposure to Environmental Levels of PFAS and PFAS Mixture in Zebrafish (Danio Rerio),” Toxics 10, no. 6 (2022): 334, https://doi.org/10.3390/toxics10060334. Erika Norén et al., “Transplacental Transfer Efficiency of Perfluoroalkyl Substances (PFAS) After Long-Term Exposure to Highly Contaminated Drinking Water: A Study in the Ronneby Mother-Child Cohort,” Journal of Exposure Science & Environmental Epidemiology 35, no. 3 (2025): 445-53, https://doi.org/10.1038/s41370-025-00758-2. Yasmyn E. Winstanley et al., “Perfluoroalkyl and Polyfluoroalkyl Substances (PFAS) in Trace Levels via Drinking Water Diminishes Mouse Embryo Mitochondria Function Across Three Generations,” Environmental Research 296 (April 2026): 124043, https://doi.org/10.1016/j.envres.2026.124043.
3. U.S. Environmental Protection Agency, “PFAS|EPA: PFAS Structures in DSSTox (Update January 2026),” accessed April 30, 2026, https:// comptox.epa.gov/dashboard/chemical-lists/PFASSTRUCTV6. Zhanyun Wang et al., “A Never-Ending Story of Per- and Polyfluoroalkyl Substances (PFASs)?” Environmental Science & Technology 51, no. 5 (2017): 2508-2518, https://doi.org/10.1021/acs.est.6b04806.
4. Julianne Cook Botelho et al., “Per- and Polyfluoroalkyl Substances (PFAS) Exposure in the U.S. Population NHANES 1999-March 2020,” Environmental Research. (April 1, 2025): 270:120916, https://pubmed.ncbi.nlm.nih.gov/39848516/.
5. Yun Jeong Lee et al., “Early-Life Exposure to Per- and Poly-Fluorinated Alkyl Substances and Growth, Adiposity, and Puberty in Children: A Systematic Review,” Frontiers in Endocrinology 12 (September 2021): 683297, https://doi.org/10.3389/fendo.2021.683297. Brittany P. Rickard et al., “Per- and Poly-Fluoroalkyl Substances (PFAS) and Female Reproductive Outcomes: PFAS Elimination, Endocrine-Mediated Effects, and Disease,” Toxicology 465 (January 2022): 153031, https://doi.org/10.1016/j.tox.2021.153031. Scott Young, “(P)FASten Your Seatbelts,” Harvard Law Today, May 1, 2024, https://hls.harvard.edu/today/the-impact-of-the-epas-first-ever-federal-pfas-rule-limiting-toxic-forever-chemicals-in-drinking-water/.
6. Sujin Kim et al., “Epigenetic Changes by Per- and Polyfluoroalkyl Substances (PFAS),” Environmental Pollution 279 (June 2021): 116929, https://doi.org/10.1016/j.envpol.2021.116929.
7. Jordan R. Kuiper et al., “Estimating Effects of Longitudinal and Cumulative Exposure to PFAS Mixtures on Early Adolescent Body Composition,” American Journal of Epidemiology 193, no. 6 (2024): 917-25, https://doi.org/10.1093/aje/kwae014.