The more scientists learn about the health risks of PFAS, found in everything from nonstick cookware to carpets to ski wax, the more concerning these “forever chemicals” become.

The U.S. Environmental Protection Agency now believes there is no safe level for two common PFAS – PFOA and PFOS – in drinking water, and it acknowledges that very low concentrations of other PFAS present human health risks. The agency issued the first legally enforceable national drinking water standards for five common types of PFAS chemicals, as well as PFAS mixtures, on April 10, 2024.

I study PFAS as an environmental health scientist. Here’s a quick look at the risks these chemicals pose and efforts to regulate them.

What exactly are PFAS?

PFAS stands for per- and polyfluoroalkyl substances. This is a large group of human-made chemicals – currently estimated to be nearly 15,000 individual chemical compounds – that are used widely in consumer products and industry. They can make products resistant to water, grease and stains and protect against fire.

Waterproof outdoor apparel and cosmetics, stain-resistant upholstery and carpets, food packaging that is designed to prevent liquid or grease from leaking through, and certain firefighting equipment often contain PFAS.

In fact, studies have found that most products labeled stain- or water-resistant contain PFAS, and another study found that this is even true among products labeled as “nontoxic” or “green.” PFAS are also found in unexpected places such as high-performance ski and snowboard waxes, floor waxes and medical devices.

At first glance, PFAS sound pretty useful, so you might be wondering what’s the big deal?

The short answer is that PFAS are harmful to human health and the environment.

Some of the very same chemical properties that make PFAS attractive in products also mean these chemicals will persist in the environment for generations. Because of the widespread use of PFAS, these chemicals are now present in water, soil and living organisms and can be found across almost every part of the planet, including Arctic glaciers, marine mammals, remote communities living on subsistence diets and in 98% of the American public.

The U.S. Geological Survey estimates common types of PFAS are now in at least 45% of the country’s tap water. PFAS maker 3M, facing lawsuits, announced a settlement worth at least US$10.3 billion in June 2023, with public water systems to pay for PFAS testing and treatment.

What are the health risks from PFAS exposure?

Once people are exposed to PFAS, the chemicals remain in their bodies for a long time – months to years, depending on the specific compound – and they can accumulate over time.

Research consistently demonstrates that PFAS are associated with a variety of adverse health effects. A review by a panel of experts looking at research on PFAS toxicity concluded with a high degree of certainty that PFAS contribute to thyroid disease, elevated cholesterol, liver damage, and kidney and testicular cancer.

Further, they concluded with a high degree of certainty that PFAS also affect babies exposed in utero by increasing their likelihood of being born at a lower birth weight and responding less effectively to vaccines, while impairing women’s mammary gland development, which may adversely affect a mom’s ability to breastfeed.

The review also found evidence that PFAS may contribute to a number of other disorders, though further research is needed to confirm existing findings: inflammatory bowel disease, reduced fertility, breast cancer, and an increased likelihood of miscarriage and developing high blood pressure and preeclampsia during pregnancy. Additionally, current research suggests that babies exposed prenatally are at higher risk of experiencing obesity, early-onset puberty and reduced fertility later in life.

Collectively, this is a formidable list of diseases and disorders.

Who’s regulating PFAS?

PFAS chemicals have been around since the late 1930s, when a DuPont scientist created one by accident during a lab experiment. DuPont called it Teflon, which eventually became a household name for its use on nonstick pans.

Decades later, in 1998, Scotchgard maker 3M notified the Environmental Protection Agency that a PFAS chemical was showing up in human blood samples. At the time, 3M said low levels of the manufactured chemical had been detected in people’s blood as early as the 1970s.

The Agency for Toxic Substances and Disease Registry has a toxicological profile for PFAS. And the EPA had issued advisories and health-based guidelines. But despite the lengthy list of serious health risks linked to PFAS and a tremendous amount of federal investment in PFAS-related research in recent years, PFAS hadn’t been regulated at the federal level in the United States until now.

The new drinking water standards set limits for five individual PFAS – PFOA, PFOS, PFNA, PFHxS and HFPO-DA – as well as mixtures of these chemicals. The standards are part of the EPA’s road map for PFAS regulations.

The EPA has also proposed listing nine PFAS as hazardous substances under the Resource Conservation and Recovery Act, a move that worries utilities and businesses that use PFAS-containing products or processes because of the expense of cleanup.

While waiting for federal action, states have taken their own steps to protect residents against the risk of PFAS exposure.

At least 28 states have laws targeting PFAS in various uses, such as in food packaging and carpets. About a dozen have drinking water standards for PFAS. But relying on state laws creates a patchwork of regulations, which places burdens on businesses and consumers to navigate regulatory nuances across state lines.

How can you reduce your PFAS exposure?

Based on current scientific understanding, most people are exposed to PFAS primarily through their diet, though drinking water and airborne exposures may be significant among some people, especially if they live near known PFAS-related industries or contamination.

The best ways to protect yourself and your family from risks associated with PFAS are to educate yourself about potential sources of exposure.

Products labeled as water- or stain-resistant have a good chance of containing PFAS. When possible, check the ingredients on products you buy and watch for chemical names containing “fluor-.” Specific trade names, such as Teflon and Gore-Tex, are also likely to contain PFAS.

Check whether there are sources of contamination near you, such as in drinking water or PFAS-related industries in the area. Strategies for monitoring and reporting PFAS contamination vary by location and PFAS source, so the absence of readily available information does not necessarily mean the region is free of PFAS problems.

For additional information about PFAS, check out the Agency for Toxic Substances and Disease Registry, EPA and U.S. Centers for Disease Control and Prevention websites, or contact your state or local public health department.

If you believe you have been exposed to PFAS and are concerned about your health, contact your health care provider. The National Academies of Sciences, Engineering, and Medicine have published guidance on PFAS exposure, testing and clinical follow-up, which includes information to help health care professionals understand monitoring and clinical implications of PFAS exposure.

This is an update to an article originally published June 21, 2022.

Kathryn Crawford receives funding from National Institutes of Health and US Geological Survey.