Some 70 years after they entered widespread chemical use, the federal government is finally regulating the so-called “forever chemicals” found in everything from nonstick cookware to menstrual products.

The Environmental Protection Agency on Wednesday announced the nation’s first drinking water standards for six types of per- and polyfluoroalkyl substances, known as PFAS. These long-lasting synthetic chemicals don’t break down naturally in the environment and have been linked to cancer, heart and liver problems, developmental damage, and other health issues.

Under the new rule, drinking water concentrations of two of the most thoroughly studied and prevalent of these substances — PFOA and PFOS — will be capped at the lowest limit that the EPA believes is technologically possible, about 4 parts per trillion, reflecting scientists’ understanding that there is no safe exposure level for them. Three other common PFAS will be limited to 10 parts per trillion, either measured on their own, in combination with each other, or with one otherwise unregulated chemical. 

The compounds being regulated represent a fraction of the entire class of chemicals — more than 15,000 distinct variants fall under the PFAS umbrella. Still, the EPA estimates that its new rules will protect some 100 million people from exposure and prevent tens of thousands of serious illnesses, especially cancers.

“We are one huge step closer to shutting off the tap for forever chemicals once and for all,” agency head Michael Regan told reporters on Tuesday. He also announced nearly $1 billion in funding through the Bipartisan Infrastructure Law to help states and private well owners test for and clean up any contamination. The funding adds to the $21 billion that Congress already made available through the legislation to improve drinking water systems, $9 billion of which had been earmarked specifically for cleaning up this class of chemicals.

The regulations announced Tuesday represent the EPA’s strongest action yet to address the threat of forever chemicals, one likely motivated by escalating concerns about ubiquitous contamination in people’s bodies and the environment. According to the Centers for Disease Control and Prevention, virtually all Americans have PFAS in their blood, and researchers have found the chemicals in people’s brains, placentas, livers, and umbilical cords. 

Forever chemicals have grown so widespread that rainwater in most places on Earth contains unsafe concentrations. A study published this week found harmful levels in 31 percent of groundwater tested around the world — even though the samples were taken far from any obvious source of contamination. 

Chemical companies knew as early as the 1970s that PFAS were building up in people’s bodies and could cause serious consequences but continued to use them for decades. Big U.S. manufacturers like 3M voluntarily stopped producing the chemicals in the early 2000s, but face potentially billions of dollars in damages from consumer protection lawsuits filed by more than half of the attorneys general in the United States.

“How do you regulate something that’s already out of the box?” asked Daniel Jones, associate director for the Michigan State University Center for PFAS Research. “They’re still in the environment, in the soil, and in the water.” Now, he says, the focus is on cleaning up.

In 2016, the EPA published a nonbinding public health advisory recommending that drinking water contain no more than 70 parts per trillion of PFOA and PFOS. In 2021, it began working on a “strategic roadmap” to formalize regulations and released a proposal last year that drew some 120,000 comments. The final regulation adds maximum contaminant levels for PFNA, PFHxS, and GenX chemicals, rather than just restricting their combined use as previously proposed, although at higher concentrations than allowed for PFOA and PFOS. 

While the EPA deliberated, at least 11 states adopted rules limiting PFAS in drinking water. Those regulations will be superseded by the federal guideline.

Environmental and public health experts cheered the rule, even as they acknowledged its shortcomings. Katie Pelch, an environmental health scientist for the Natural Resources Defense Council, said regulating PFAS on a chemical-by-chemical basis is risky. Manufacturers could swap a restricted compound for something similar that might be less studied yet equally hazardous. 

“We need to define PFAS more broadly and take action on the entire class of chemicals, so we’re not just trading one toxic chemical for another,” Pelch told Grist. Although the EPA is testing for over two dozen of the chemicals in drinking water, a 2023 study by Pelch and her colleagues found a dozen compounds that the agency isn’t including. The other problem is the sheer amount of time it would take to evaluate every PFAS individually — potentially many lifetimes.

The EPA did not respond to Grist’s request for comment, but a senior Biden administration impliedsaid during a press call that, to make the most robust policy possible, the agency chose to address chemicals for which there is the largest body of evidence proving their toxicity.

“We feel very confident that we have designed a very durable rule, well within our statutory authority, that begins to protect people from harmful pollutants that are showing up in their drinking water,” the official said.

States have five years to comply with the new drinking water standards — three years to test their water supplies and two to reduce concentrations of the regulated PFAS, if necessary. For up to 10 percent of the 66,000 water systems subject to the rule, that could mean upgrading their filtering processes, according to the EPA. Available options, funded by the Bipartisan Infrastructure Law, include common filtration methods already in use today, such as a granular activated carbon system, similar to a charcoal filter, or reverse osmosis which filters out contaminants using a semi-permeable membrane. 

The agency lets utilities decide which method works best for their community. In Wilmington, North Carolina, a granular activated carbon system has already been effective in removing the PFAS targeted by the EPA’s rule, and the same technology may help remove others that are not subject to the regulation.

“The state that you live in shouldn’t influence whether or not PFAS are in your drinking water,” said Pelch. “The EPA will help us address that.” Although the new rules don’t fully reign in the sprawling blanket of forever chemicals in our environment, every step forward matters.

Editor’s note: The Natural Resources Defense Council is an advertiser with Grist. Advertisers have no role in Grist’s editorial decisions.