PFAS Exposure: Cancer Risks & Health Effects

There are nearly 15,000 synthetic chemicals known as per- and polyfluoroalkyl substances (PFAS). Two of the most well-known PFAS are perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS). They’re popular in industrial and consumer products because they have several useful properties, such as chemical, water and temperature resistance.

These chemicals are often found in a wide variety of products, including carpet, clothing, furniture, food packaging, heat-resistant or nonstick cookware and fire-fighting foams. You can even find PFAS in creams, pharmaceuticals and cosmetics.

However, a growing body of research connects PFAS to cancer and other serious health risks. This has led to regulatory debates and PFAS lawsuits against chemical manufacturers.

Manufacturers use PFAS in many consumer products. Studies have shown that these synthetic chemicals may lead to serious health issues, including cancer, immune and thyroid problems, metabolic dysfunction (such as insulin and lipid issues) and liver disease.

Exposure to PFAS is difficult to avoid. Plus, they break down very slowly and stay in the body for years. In fact, they exist in most people’s blood.

How Do People Get Exposed to PFAS?

Exposure to PFAS occurs primarily through occupational hazards and consuming contaminated food and drinking water.

PFAS tests commonly detect these “forever chemicals” in water sources near industrial sites, airports and military bases due in part to the historical use of firefighting foam containing PFAS. Once inside the body, PFAS bind to proteins and accumulate in the liver, kidneys and other organs, leading to prolonged effects lasting long after exposure.

Drinking water contamination has led some people and water suppliers to file PFAS water contamination lawsuits. In April 2024, the U.S. District Court in Charleston, South Carolina, approved 3M’s proposed $10.3 billion settlement with public water suppliers.

Why PFAS Chemicals Stay in the Body for Years

PFAS remain in the body long after exposure because of their lengthy biological half-lives. The term “half-life” refers to how long it takes for a substance to degrade by 50%.

They can stick around for a decade or longer before the kidneys excrete them. This persistence is due to their strong carbon-fluorine bonds, which make PFAS difficult to degrade.

As these chemicals accumulate in the body, they can increase the risk of chronic diseases. The prolonged retention of PFAS highlights the importance of reducing exposure and implementing regulatory measures to mitigate health risks.

PFAS have potential links to cancer because they disrupt cell metabolism and immune function, damage DNA and disrupt hormone levels, according to Dr. Kirsten Moysich, PhD, a professor of Oncology, Cancer Prevention & Control at Roswell Park Comprehensive Cancer Center.

Studies are still ongoing. Most research has focused on PFOA because it’s the most frequently used PFAS, and it has potential links to cancer. Even so, regulatory agencies are still divided on whether PFOA is a carcinogen.

The International Agency for Research on Cancer (IARC) found enough evidence in animal and human studies to call PFOA “carcinogenic to humans.” In contrast, the U.S. Environmental Protection Agency (EPA) said there is “suggestive evidence of carcinogenicity,” but that evidence isn’t strong enough to say that PFOA causes cancer in humans.

What Types of Cancer Have Links to PFAS Exposure?

So far, kidney and testicular cancer have the strongest links to PFAS exposure, and a 2022 study was the first to connect liver cancer in humans to PFAS. Experts require more evidence to determine potential links to childhood leukemia, non-Hodgkin lymphoma and breast, ovarian, endometrial, prostate and thyroid cancers.

Studies Linking PFAS to Cancer Risks

Four key studies have uncovered potential links between PFAS and various cancers.

Who Is Most at Risk for PFAS-Related Cancer?

Certain groups of people may have higher risk factors for PFAS-related cancer, such as people who live near contaminated water sources and those exposed to PFAS at work.

Firefighters face significantly increased risks of PFAS exposure because these chemicals are present in their firefighting gear and the foams they use on the job. Firefighters have filed Aqueous Film-Forming Foam (AFFF) lawsuits and firefighter turnout gear lawsuits against manufacturers, including 3M and DuPont.

In addition to cancer, long-term exposure to PFAS may cause other health problems. PFAS also have links to immune system suppression, reproductive harm and metabolic disorders.

How PFAS Affect the Endocrine System

PFAS are endocrine disruptors because they mimic and affect hormone production.

For example, one study in Chemosphere found that PFAS compete with a thyroid hormone called thyroxine (T4) to bind to receptors in the body. This may cause reduced thyroid hormone levels and could contribute to thyroid disease.

PFAS can also lead to metabolic disorders, such as obesity. A study published in the journal Obesity found that people exposed to PFAS in drinking water gained more weight than those without PFAS exposure, no matter what they ate.

PFAS and Reproductive Health Risks

Reproductive health issues tied to PFAS may include fertility problems, increased high blood pressure during pregnancy and reproductive hormone disorders leading to altered estrogen and testosterone levels.

In children, PFAS exposure could lead to developmental delays, accelerated puberty, behavioral changes, bone variations and low birth weight. Research on the health effects of low-level PFAS exposure over time is ongoing, especially in children.

PFAS Effects on High Cholesterol and Liver Damage

PFAS exposure affects various organs, potentially leading to negative long-term health outcomes, such as liver disease and high cholesterol.

A 2023 study in JHEP Reports looked at data from 1,135 eligible participants, and 446 had fatty liver disease. The study found that high blood levels of PFAS are associated with fatty liver disease and decreased liver function. The risk of developing liver disease or decreased liver function with PFAS exposure is even higher in people who are obese, heavy alcohol drinkers or those who eat a high-fat diet.

High cholesterol also has links to PFAS exposure, potentially increasing cardiovascular health risks. A 2022 study published in Environmental Health Perspectives revealed that PFAS exposure increased cholesterol levels. PFOS and PFNA were the chemicals most associated with this effect.

In the U.S., health agencies — including the EPA and Centers for Disease Control and Prevention (CDC) — have expressed concerns about the increased health risks of PFAS exposure and enacted cleanup and regulatory plans.

Individual states and organizations have also introduced regulations and limits governing PFAS. The Safer States website details the actions that states are taking to stop the manufacture and distribution of PFAS, including cleanup plans, restrictions and bans.

The European Union has restricted or banned some PFAS. Canada has also established guidelines for drinking water.

What Does the EPA Say About PFAS in Drinking Water?

The EPA recognized the health risks posed by PFAS in drinking water and has been aggressive in its new advisories. In 2022, the agency reduced the previously acceptable drinking water limits for PFOS and PFOA from 70 parts per trillion (ppt) to 0.02 ppt for PFOS and 0.004 ppt for PFOA. In 2024, the EPA established “legally enforceable levels” of 4 ppt for both PFOA and PFOS.

The regulatory agency has also established a three-pronged approach to restrict, remediate and research PFAS effects. This approach proactively prevents PFAS from entering the air, enacts cleanup of existing PFAS and invests in more studies to better understand their impact.

How Have the CDC & WHO Responded to PFAS Health Concerns?

Since 1999, the CDC has been measuring PFAS — including PFOA, PFOS, PFHxS and PFNA — in the blood samples of people living in the U.S. through its National Health and Nutrition Examination Survey (NHANES).

As of 2024, the results show that levels of PFOA, PFOS and PFHxS are declining. This may be due to EPA regulations requiring manufacturers to reduce PFAS facility emissions and phase out the chemicals’ production.

In 2022, the World Health Organization (WHO) set a drinking water limit of 100 ppt for PFOA and PFOS, a level that would still expose people to health risks. In response, 116 scientists sent a letter to the WHO asking them to revise their recommendation.

While PFAS have an extensive presence in our environment, there are steps you can take to reduce your exposure. These include checking your water for PFAS, avoiding PFAS in everyday products and taking action if you think you have PFAS-related health risks.

How to Check if Your Drinking Water Contains PFAS

If you own a well, conduct regular water tests with a company that uses EPA-developed testing methods. You can contact your state environmental or health agency for advice. If you are concerned about PFAS levels in your water, try to find an alternative water source.

Consider getting home filtration treatments that filter out PFAS, such as activated carbon and ion exchange treatments. You can also install high-pressure membranes — like nanofiltration or reverse osmosis membranes — to remove PFAS from your drinking water. Read more about these options on the EPA’s website.

Tips for Avoiding PFAS in Everyday Products

In addition to avoiding drinking water contaminated with PFAS, there are other products known to contain PFAS that you should avoid as much as possible.

• Food and packaging: Avoid food packaging made to be grease-resistant, like fast food wrappers and microwave popcorn bags. Researchers at the Environmental Working Group found that some freshwater fish caught in various bodies of water across the country may contain PFAS because of water contamination. You can check EWG’s interactive map for PFAS levels in local freshwater bodies of water and the PFAS levels of certain species of fish in your area.
• Clothing: Avoid PFAS-treated fabric, which may include anything labeled as resistant to water, grease or stains.
• Cookware: Avoid nonstick pans made with one or more PFAS. Check for labels that say “PFAS-free” or “PFOA-free.” Ceramic or stainless steel cookware is also a safe bet, especially if you cook with high heat.

While you might not be able to control all aspects of PFAS exposure, focusing on these three areas could reduce your risk.

What to Do if You Think You Have PFAS-Related Health Problems

If you’re concerned about PFAS-related health problems, talk to your doctor. You can get a medical evaluation for high cholesterol and other health concerns.

Your health care provider can suggest tests that may help you address potential health issues, especially if you are a firefighter, in the military, live near a military base or work in an industrial job with chemicals.

You can also ask your provider for PFAS blood testing options. For example, Quest Diagnostics offers a PFAS test panel you can purchase online.

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