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.

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.

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