Per- and polyfluoroalkyl substances, or PFAS, are synthetic chemicals found in the blood of 97% of Americans, according to data from the Centers for Disease Control and Prevention (CDC). These "forever chemicals" have been used in consumer products since the 1950s and accumulate in the body over time because they break down slowly, if at all. The widespread contamination raises serious questions about long-term health impacts that scientists are only beginning to understand.

What Are PFAS and Where Do They Hide?

PFAS are a large group of nearly 15,000 synthetic chemicals used across multiple industries and consumer products . You've likely encountered them without realizing it. These chemicals keep food from sticking to packaging and cookware, make clothes and carpets resistant to stains, and are key ingredients in firefighting foam. The aerospace, automotive, construction, and electronics industries all rely on PFAS in their manufacturing processes.

The problem is structural. PFAS molecules contain a chain of linked carbon and fluorine atoms, and the carbon-fluorine bond is one of the strongest chemical bonds known. This strength means these chemicals resist breaking down in the environment, soil, water, and air. Over time, PFAS leak from products and industrial sites into groundwater, drinking water supplies, and the air we breathe .

How Are People Exposed to PFAS?

Exposure happens through multiple pathways, making it nearly impossible to avoid completely. Most people encounter PFAS by consuming contaminated drinking water or food, using products made with these chemicals, or breathing air containing them. Because PFAS accumulate in body tissues rather than being excreted, blood levels can build up over time, a process called bioaccumulation .

The CDC's National Health and Nutrition Examination Survey (NHANES) found PFAS in the blood of 97% of Americans tested, revealing just how pervasive this contamination has become. While blood levels of two specific PFAS chemicals, PFOS and PFOA, have decreased since those chemicals were removed from consumer products in the early 2000s, new PFAS chemicals have been created to replace them, and exposure to these newer variants is difficult to assess .

What Health Problems Are Linked to PFAS Exposure?

Research supported by the National Institute of Environmental Health Sciences (NIEHS) has identified multiple health effects associated with PFAS exposure. The National Toxicology Program, an interagency program headquartered at NIEHS, concluded that two types of PFAS, PFOA and PFOS, suppressed the antibody response and posed a hazard to immune system function in humans . This means exposure could reduce your body's ability to fight infections.

Beyond immune impacts, PFAS exposure has been linked to several concerning health outcomes:

• Metabolic and Weight Issues: Exposure to PFAS may alter metabolism and body weight regulation, increasing the risk of childhood obesity.
• Cancer Risk: Research has identified increased risk of some cancers associated with PFAS exposure.
• Reproductive and Developmental Effects: Studies show exposure to PFAS may delay the onset of puberty in girls, which can lead to negative long-term health outcomes including higher incidence of breast cancer, renal disease, and thyroid disease.
• Bone Health: Exposure to PFAS in adolescents was linked to a decrease in bone mineral density over time, which can lead to osteoporosis and other bone diseases.
• Type 2 Diabetes: A long-term study showed a link between PFAS exposure and increased risk of Type 2 diabetes in women.
• Thyroid Cancer: Exposure to certain PFAS may be associated with increased risk of thyroid cancer.
• Liver Damage: A large-scale study on exposure to PFAS in humans and rodents showed consistent evidence of liver damage, as PFAS are known to accumulate in body tissues such as the liver.

The NIEHS supports more than 40 research groups across the country to better understand these health effects, but scientists emphasize there is still much to learn about the full scope of PFAS-related health risks .

How to Reduce Your PFAS Exposure

While complete avoidance is difficult given how widespread PFAS contamination has become, research suggests several strategies that may help reduce your exposure and protect your health:

• Increase Folate Intake: Studies show folate may reduce PFAS accumulation in the body, which may protect against adverse birth outcomes and boost immune health. Folate-rich foods include leafy greens, legumes, and fortified grains.
• Eat a High-Fiber Diet: A high-fiber diet may decrease metabolic disease risks associated with PFOS, a type of PFAS. Although PFOS use has been phased out, it can still be found in drinking water, groundwater, soil, and air.
• Filter Your Drinking Water: Use water filtration systems designed to remove PFAS, particularly if you live in an area with known contamination or rely on well water.
• Reduce Non-Stick Cookware Use: Limit use of non-stick pans and cookware, which often contain PFAS. Choose stainless steel, cast iron, or ceramic alternatives when possible.
• Check Product Labels: Look for products labeled "PFAS-free" or "non-fluorinated" when purchasing water-resistant clothing, carpets, and food packaging.

What's Next for PFAS Regulation and Research?

The NIEHS participates in a government-wide approach led by the White House to advance clean drinking water and reduce pollutants. This collaboration works to identify routes of PFAS exposure, understand associated health risks, and reduce the public's dietary exposure to PFAS . Federal agencies like the Environmental Protection Agency (EPA) and CDC also conduct research related to PFAS to develop new standards and protect public health.

However, researchers face significant challenges. There are thousands of variations in PFAS chemicals, which makes them difficult to study comprehensively. Additionally, PFAS often occur in complex mixtures in the environment and in products, complicating efforts to understand which specific chemicals pose the greatest health risks. Scientists are working on developing technologies and devices to identify, detect, measure, and potentially destroy PFAS in the environment, but these solutions are still in development .

The bottom line: PFAS contamination is a widespread environmental health crisis that affects nearly everyone. While regulatory agencies work to reduce future exposure and develop treatment technologies, individuals can take steps to minimize their personal exposure through dietary choices, water filtration, and product selection. As research continues to evolve, staying informed about PFAS and its health impacts remains essential for protecting your family's long-term health.