Litigation Guides

PFAS Exposure & Cancer

Exposure to PFAS-containing firefighting foam is now linked to cancer. This guide examines the connection and the existing litigation on the subject.

Medically Reviewed


What is PFAS?

Per- and polyfluoroalkyl substances (PFAS) is a class of compounds that includes two industrial solvents: perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). PFAS chemicals have been used in consumer products worldwide since the 1950s.

Because the carbon-fluoride bond in the chemicals is among the strongest chemical bonds in nature, these chemicals do not break down in the environment. They are thus among the substances known as “forever chemicals.”1

What Products Contain PFAS?

PFAS chemicals appear in:

  • Non-stick cookware
  • Stain-resistant fabrics
  • Firefighting foams
Firefighter using foam

How Does PFAS Cause Cancer?

“How does PFAS cause cancer?” remains a question under investigation. One exploratory study of PFOA and breast cancer, however, suggests that exposure to the chemical may increase the levels of certain cellular messengers while decreasing the levels of compounds that protect cells from becoming cancerous.4

In particular, the study focuses on how PFAS chemicals interact with hormone-sensitive cells. Further study may help to explain PFAS chemicals’ effects on other hormone-sensitive cells, such as those in the testicles, liver, and pancreas.

Medical Consensus on PFAS

Studies of PFAS have found the substances to be “linked to many harmful health effects, including cancer,” and thus to rank as a “serious global health threat.”2

Medical studies of PFAS chemicals indicate that exposure to one or more chemicals in the class is connected to an increased risk of cancer. A medical panel convened in a PFOA-related class-action lawsuit determined that the most likely outcomes of PFOA exposure included:

  • Kidney cancer
  • Testicular cancer
  • Ulcerative colitis
  • Thyroid disease
  • Hypercholesterolemia
  • Pregnancy-induced hypertension3

These findings are consistent with multiple independent medical studies connecting PFOA exposure to the listed medical conditions.

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PFAS in Firefighting Foam

AFFFs are used to fight liquid fuel fires. They work by forming a barrier over the liquid fuel, containing flammable vapors to prevent the spread of the fire and extinguish it.7

The US Fire Administration (USFA) states that while foams that contain PFAS are more effective at extinguishing liquid-fuel fires, they are also linked to “harmful effects on humans and animals” and do not degrade in the environment.

In January 2023, the Department of Defense issued new guidelines for firefighting foams used on military bases. These foams must effectively fight liquid-fuel fires without containing PFAS chemicals.8


Who Is at Risk of Cancer from PFAS Exposure?

Firefighting is associated with higher risks of several types of cancer, as well as higher cancer risks from non-PFAS sources like smoke.6

Determining whether exposure to AFFFs is the primary cause of a firefighter’s cancer requires careful attention on a case-by-case basis and poses an ongoing medical-legal challenge.

Specific Risks Firefighters Face

PFAS chemicals have various uses. One is as an ingredient in aqueous film-forming foams (AFFFs), which are used in firefighting. Because firefighters come into contact with PFAS as part of their job, they may face higher risks of forming PFAS-related cancers than members of the general population.

The risk is heightened by the fact that many firefighters aren’t aware of the potentially dangerous outcomes of AFFFs exposure. One study found that over 80 percent of surveyed Florida fire departments used AFFFs - and that most of the firefighters surveyed did not know PFAS chemicals are linked to cancer.5

In one study of female firefighters in San Francisco, researchers found elevated carcinogen levels in the firefighters’ blood samples - an early warning sign of a heightened risk of developing future cancers.6


Major Lawsuits and Legislation

As awareness of PFAS and its effects expands, so do lawsuits and legislative actions intended to address PFAS contamination and exposure.


  • November 2023: The city of Wausau, Wisconsin files a complaint against 15 PFAS manufacturers and 61 insurers, alleging the city’s water supply has been contaminated by PFAS from the manufacturers.9 The lawsuit follows filings by other Wisconsin localities, including Eau Claire, Campbell, and Rhinelander, according to Wisconsin Public Radio.10
  • August 2023: Manufacturer DuPont agrees to pay $1.185 billion. The settlements affected the trajectory of the PFAS MDL filed in South Carolina.11
  • June 2023: PFAS manufacturer 3M agrees to pay at least $10.3 billion to settle PFAS water contamination lawsuits.12
  • December 2018: Multidistrict litigation commenced in the District of South Carolina on a transfer order from the Judicial Panel on Multidistrict Litigation. The cases generally alleged that AFFFs containing PFAS chemicals contaminated groundwater on or near various military bases, airports, and industrial sites, causing injuries to plaintiffs. The cases were consolidated as MDL 2873.13


Legislative steps related to PFAS include:

  • November 2023: The EPA announces changes to TRI reporting requirements for PFAS chemicals and to supplier notifications for chemicals of special concern. 14
  • October 2023: The EPA proposes adding PFAS chemicals to the list of substances that qualify an area for Superfund designation under CERCLA. 15
  • February 2020: The EPA announces a proposed decision to regulate levels of PFOA and PFOS in drinking water.16

Works Cited


National Institute of Environmental Health Sciences. Perfluoroakyl and polyfluoroalkyl substances (PFAS).


Pelch, K. E., Reade, A., Wolffe, T. A. M., & Kwiatkowski, C. F. (2019). PFAS health effects database: Protocol for a systematic evidence map. In Environment International.


Nicole, W. (2013). PFOA and cancer in a highly exposed community: New findings from the C8 science panel. In Environmental Health Perspectives.


Pierozan, P., Jerneren, F., & Karlsson, O. (2018). Perfluorooctanoic acid (PFOA) exposure promotes proliferation, migration and invasion potential in human breast epithelial cells. Archives of Toxicology.


Caban-Martinez, A. J., Solle, N. S., Feliciano, P. L., Griffin, K., Santiago, K. M., Lee, D. J., Daunert, S., Deo, S. K., Fent, K., Calkins, M., Burgess, J. L., & Kobetz, E. N. (2019). Aqueous Film-Forming Foams and Knowledge of Perfluorinated Compounds among Florida Firefighters. In Journal of Occupational and Environmental Medicine.


Trowbridge, J., Gerona, R. R., Lin, T., Rudel, R. A., Bessonneau, V., Buren, H., & Morello-Frosch, R. (2020). Exposure to Perfluoroalkyl Substances in a Cohort of Women Firefighters and Office Workers in San Francisco. Environmental Science and Technology.


US Fire Administration. Firefighting foams: PFAS vs fluorine-free foams.


Department of Defense. Performance specification: fire extinguishing agent, fluorine-free foam (F3) liquid concentrate, for land-based, fresh water applications.


Napoli Shkolnik files complaint on behalf of the City of Wausau, Wisconsin against fifteen PFAS manufacturers and sixty-one major players in the insurance industry.


Mentzer R. PFSA lawsuits involve complex science and law, but settlements can be worth millions.


Scully M and Ledger B. PFAS settlements: future of PFAS litigation landscape to be determined by upcoming decision. Reuters, August 31, 2023.


Hardin T. 3M agrees to $10.3 billion settlement in PFAS-related lawsuits. DC Report.


United States District Court for the District of South Carolina. Aqueous film-forming foams (AFFF) products liability litigation MDL No. 2873.


US Environmental Protection Agency. Changes to TRI reporting requirements for per- and polyfluoroalkyl substances and to supplier notifications for chemicals of special concern.


US Environmental Protection Agency. Proposed designation of perfluorooctanoic acid (PFOA) and perfluorooctainesulfonic acid (PFOS) as CERCLA hazardous substances.


United States Environmental Protection Agency. EPA announces proposed decision to regulate PFOA and PFOS in drinking water. February 20, 2020.

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