Litigation Guides

Aqueous Film-Forming Foam (AFFF) & Cancer

Exposure to PFAS chemicals, notably PFOA and PFOS in AFFFs, has been linked to different cancers. Presently, there's a moderate correlation between PFOA exposure and kidney cancer, and PFAS exposure and testicular cancer. However, establishing a causal link requires additional evidence.

Medically Reviewed


What are AFFFs?

Aqueous Film-Forming Foams (AFFFs) are specialized firefighting foams specifically designed to extinguish fires, especially those involving highly flammable liquids. They possess unique properties:1,2,3

  • Composition: On a chemical level, AFFFs are surfactants (molecules that help liquids mix by reducing surface tension, making soaps lather, and cleaning agents more effective) that have been fluorinated and hydrogenated (meaning fluoride and hydrogen have been added to their chemical structure). They are heat-resistant, non-flammable, and non-biodegradable.
  • Applications: AFFFs have widespread use in firefighting, textiles, paper products, electroplating, paints, waxes, and polishes.

Do AFFFs Pose PFAS Risks?

Historically, many AFFFs contain chemicals called PFASs (per- and polyfluoroalkyl substances).2

What are PFASs?

PFASs are human-made chemicals containing fluorine atoms bonded to a carbon chain. They are persistent and do not break down easily.

  • PFAAs, a subset of PFASs, possess an acidic functional group (carboxylate or sulfonate) that enhances water mixing.
  • Notably, PFOS (perfluorooctane sulfonic acid) and PFOA (perfluorooctanoic acid), present in AFFFs, are the most extensively researched PFAS compounds.2
Firefighter using foam

Complications Linked to AFFF Exposure

There were some associations between the development of different types of cancer and increased exposure to chemicals found in AFFFs.4

  • Prostate cancer
  • Kidney cancer
  • Liver cancer
  • Colorectal cancer
  • Bladder cancer
  • Hematopoietic and lymphatic malignancies

PFOA and Kidney Cancer

There is strong evidence linking exposure to PFOA, found in AFFFs, to kidney cancer, based on multiple studies.4

  • They cited 6 studies that found positive associations between PFOA and kidney cancer.4,5
  • However, one occupational study of 3M workers found no association between PFOA exposure and kidney cancer.6

PFOA and Testicular Cancer

Some studies have suggested an association between PFAS exposure and testicular cancer in humans.4 However, the evidence is limited. It can be summarized as follows:4,7

  • One cohort study showed higher testicular cancer rates with more PFOA exposure.
  • A case-control study also found a positive exposure-response relationship.
  • One ecological study linked higher testicular cancer rates to PFAS-exposed areas.
  • A preclinical study showed that PFAS caused testicular Leydig cell tumors in rats. But Leydig cell tumors are extremely rare in humans, so the rat study has unclear relevance to human disease.

PFOA and Pancreatic Cancer

There have been no human studies yet that link PFAS to pancreatic cancer. The evidence is limited to animal and cell studies, as follows:8,9,10

  • One rat study found increased pancreatic cell proliferation after exposure to a PFAS chemical.
  • Another study showed PFOA and PFOS were toxic to human pancreatic stem cells.
  • Proposed biological mechanisms involve PFAS disruption of bile acid transport or stimulation of pancreatic cell growth. But the mechanisms are still hypothetical and require more research.

PFOA and Prostate Cancer

No studies have yet established a direct link between PFAAs and the development of prostate cancer in humans. However, a 2014 study did find a correlation between certain PFAAs and an increased risk of hereditary prostate cancer, as described below:2

  • The study examined 201 cases of prostate cancer from 2007-2011 and measured the serum concentrations of specific perfluorinated sulfonates (PFHxS and PFOS) and carboxylates (PFOA, PFNA, PFDA, and PFUnDA).
  • The main takeaway was that individuals with a family history of prostate cancer and high concentrations of certain PFAAs were at a statistically significant higher risk for the disease.
  • However, it’s important to note that having a family history of prostate cancer without high concentrations of PFAAs, or having high concentrations of PFAAs without a family history, did not significantly increase the risk.

Limitations of Clinical Studies

The clinical studies reviewed had potential biases and weaknesses that limit the conclusions that can be drawn. Examples of biases and weaknesses include:4

  • Loss of study participants during follow-up periods may cause a selection bias, in which the process of selecting individuals for a study skews the results.
  • Research focusing solely on death rates may not provide comprehensive insights into non-lethal conditions, like testicular cancer. Yet, alternative approaches to identifying cases have their own drawbacks. For instance, self-reported data may not always be reliable, and the degree of inaccuracy can vary depending on the specific health outcome under consideration.
  • Pre-existing health conditions or genetic factors may be present before any exposure occurred and may be over or under-represented in the study population compared to the general population.

Another study examined cancer rates in 32,254 patients from a community exposed to PFOA in drinking water, where PFOA, also prevalent in aqueous film-forming foams (AFFFs) used in firefighting, is a concerning environmental contaminant.5

  • 2,507 total cancer cases were identified, spanning 21 different cancer types.
  • Positive associations were found between PFOA exposure and kidney and testicular cancers.

However, the study had limitations, including:5

  • Only surviving patients were included, excluding fatal cancers.
  • Cancer reporting relied on patient self-reporting, which may be incomplete.
  • Pre-existing conditions were not accounted for.
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Environmental Concerns & Regulatory Action

The use of PFOS and PFOA has raised environmental and health concerns leading to regulatory action.2,3

  • For example, environmental concerns have led to a phased-out production of PFASs by companies like 3M since 2002.
  • Products containing PFOS have been banned in several European countries.
  • Additionally, the use of AFFFs as fire extinguishers by firefighters has ceased.

Confounding Factors of AFFF Exposure

Some lab animal studies have demonstrated a causal link between exposure to chemicals found in AFFFs and certain cancers, but the relevance to human disease is uncertain.

  • For example, rats developed rare testicular and pancreatic cancers in one study.7 However, these specific cancers are extremely uncommon in humans.
  • Cancer has a complex, multifactorial origin involving genetics, environment, and lifestyle factors making proof of causality from environmental exposure more difficult.

Works Cited


Rotander, A., Toms, LM. L., et al. (2015). Elevated levels of PFOS and PFHxS in firefighters exposed to aqueous film forming foam (AFFF). Environment International, 82: 28-34.


Hardell, E., Karrman, A., et al. (2014). Case-control study on perfluorinated alkyl acids (PFAAs) and the risk of prostate cancer. Environment International, 63: 35-39.


Laitinen, J. A., Koponen, J., et al. (2014). Firefighters’ exposure to perfluoroalkyl acids and 2-butoxyethanol present in firefighting foams. Toxicology Letters, 231: 227-232.


Steenland, K., Winquist, A. (2021). PFAS and cancer, a scoping review of the epidemiologic evidence. Environmental Research, 194, 110690.


Perfluorooctanoic Acid (PFOA) Exposures and Incident Cancers among Adults Living Near a Chemical Plant. (2013). Retrieved July 27, 2021, from Environmental Health Perspectives website:


Raleigh, K. K., Alexander, B. H., Olsen, G. W., Ramachandran, G., Morey, S. Z., Church, T. R., et al. (2014). Mortality and cancer incidence in ammonium perfluorooctanoate production workers. Occupational and Environmental Medicine, 71(7), 500–506.


Kennedy GL, Butenhoff JL, et al. The Toxicology of Perflurooctanoate. Critical Reviews in Toxicology. 2004; 34(4): 351-384. doi: 10.1080/10408440490464705.


International Agency for Research on Cancer. (2016). Some chemicals used as solvents and in polymer manufacture. IARC monographs, 110.


Liu, S., Yang, R., et al. (2020). Effects of per- and poly-fluorinated alkyl substances on pancreatic and endocrine differentiation of human pluripotent stem cells. Chemosphere. 254, 126709.


Agency for Toxic Substances and Disease Registry. (2018). Toxicological Profile for Perfluoroalkyls. U.S. Department of Health and Human Services.

About the authors

 Rena Zheng, MD

Rena Zheng, MD

Dr. Rena Zheng, MD, combines a rich background in clinical practice with medical research, making her an exceptional contributor to the medical community. Her journey began with a Bachelor’s degree in Biology from Rutgers University, followed by earning her MD from Ross University School of Medicine. Rena’s dedication to medicine is evident from her intensive residency at Nassau University Hospital and Rush University Medical Center, where she gained comprehensive clinical experience.

Currently serving as a Physician Contractor with the Expert Institute, Dr. Zheng has seamlessly transitioned from patient care to the intricacies of medical-legal consulting. Her work, including notable research on podocyte foot processes, showcases her commitment to advancing medical knowledge and her capability to elucidate complex medical concepts. Rena’s unique blend of clinical expertise and research acumen makes her contributions to medical content not just informative, but also engaging and accessible.

Wendy Ketner, M.D.

Wendy Ketner, M.D.

Dr. Wendy Ketner is a distinguished medical professional with a comprehensive background in surgery and medical research. Currently serving as the Senior Vice President of Medical Affairs at the Expert Institute, she plays a pivotal role in overseeing the organization's most important client relationships. Dr. Ketner's extensive surgical training was completed at Mount Sinai Beth Israel, where she gained hands-on experience in various general surgery procedures, including hernia repairs, cholecystectomies, appendectomies, mastectomies for breast cancer, breast reconstruction, surgical oncology, vascular surgery, and colorectal surgery. She also provided care in the surgical intensive care unit.

Her research interests have focused on post-mastectomy reconstruction and the surgical treatment of gastric cancer, including co-authoring a textbook chapter on the subject. Additionally, she has contributed to research on the percutaneous delivery of stem cells following myocardial infarction.

Dr. Ketner's educational background includes a Bachelor's degree from Yale University in Latin American Studies and a Doctor of Medicine (M.D.) from SUNY Downstate College of Medicine. Moreover, she is a member of the Board of Advisors for Opollo Technologies, a fintech healthcare AI company, contributing her medical expertise to enhance healthcare technology solutions. Her role at Expert Institute involves leveraging her medical knowledge to provide insights into legal cases, underscoring her unique blend of medical and legal acumen.

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