The Biden administration on Wednesday finalized tough limits on certain so-called “forever chemicals” in drinking water that will require utilities to reduce them to the lowest levels that can be reliably measured. Officials say this will reduce the exposure of 100 million people and help prevent thousands of diseases, including cancer.

The rule is the first national limit on toxic PFAS, or per- and polyfluoroalkyl substances, which are widespread and persistent in the environment, in drinking water.

Health advocates praised the Environmental Protection Agency for not abandoning the tough restrictions it proposed last year. Water companies have challenged the rule, saying treatment systems would be expensive to install and customers would end up paying more for their water.

Water providers are entering a new era, and the EPA says the standards will make tap water safer for millions of consumers, a top priority of the Biden administration. The agency also proposed forcing utility companies to remove dangerous lead pipes.

Utility groups warn that each rule would cost tens of billions of dollars and would have the greatest impact on smaller communities with fewer resources. Legal challenges are sure to follow.

EPA Administrator Michael Regan said the rule is the most important action the agency has taken on PFAS.

“The result is a comprehensive, life-changing rule that will improve the health and vitality of many communities across our country,” Reagan said.

PFAS chemicals are dangerous because they do not degrade in the environment and have been linked to health problems such as low birth weight and kidney cancer. They are already used in everyday products including nonstick pans, firefighting foam and waterproof clothing. Although some of the most common types have been phased out in the United States, others remain. Water suppliers will now be forced to clean up environmental pollution caused by other industries.

“The problem is accumulation,” said Scott Belcher, a professor at North Carolina State University who studies the toxicity of PFAS. “Even a small, small, small amount of water you drink every time throughout your life can add up and have health consequences.”

PFAS is a broad family of chemicals, and the new rules set strict limits on two common types, known as PFOA and PFOS, at 4 parts per trillion. Three other types, including GenEx chemicals, are a major problem in North Carolina and are limited to 10 parts per trillion. Water suppliers are required to test for these PFAS chemicals and inform the public if levels are too high. Certain combinations of PFAS types will also be restricted.

Reagan will announce the rule Wednesday in Fayetteville, North Carolina.

Environmental and health advocates praised the rule but said PFAS manufacturers knew the substances were dangerous for decades but hid or downplayed the evidence. They believe the restrictions should have come sooner.

“Reducing PFAS in drinking water is the most cost-effective way to reduce our exposure to PFAS,” said Scott Faber, food and water specialist at the Environmental Working Group. “Reducing other exposures, such as PFAS in food or clothing, is more challenging. ” Or carpet. ”

Last year, the EPA regularly released batches of utility testing results for PFAS in drinking water. About 16% of utilities found at least one of two severely restricted PFAS chemicals at or above the new limits. These utilities serve tens of millions of people. However, the Biden administration expects about 6-10% of water systems to exceed the new limits.

Water suppliers typically have three years to conduct testing. EPA officials said if those tests exceed limits, they would have two years to install treatment systems.

Some funds are available to help utility companies. Manufacturer 3M recently agreed to pay more than $10 billion to drinking water suppliers to settle PFAS lawsuits. The bipartisan infrastructure deal includes billions of dollars to combat the substance. Utilities say more is needed.

For some communities, the test results were surprising. Last June, a utility company outside Philadelphia that serves nearly 9,000 people learned that one of its wells had PFOA levels of 235 parts per trillion, one of the highest results in the country at the time.

“I mean, obviously, it’s shocking,” said Joseph Hastings, director of the Joint Public Works Department of Collegeville and Trapp District, whose job includes addressing issues raised by the new regulations.

The well was quickly pulled offline, but Hastings still doesn’t know the source of the contamination. Water levels in several other wells exceeded the EPA’s new limits but were below those set earlier by Pennsylvania. Hastings said it can now cost millions of dollars to install a treatment system, a significant expense for a small customer base.

Mike McGill, president of water industry communications company WaterPIO, said the new rules “will throw public confidence in drinking water into chaos.”

The American Water Works Association, an industry group, said it supports setting standards to limit PFAS in drinking water but believes the EPA’s regulations are deeply problematic.

The association said the agency underestimated its high costs, which would be unreasonable for communities with lower PFAS levels and would increase customers’ water bills. In addition, there are insufficient experts and workers, and the supply of filter materials is also limited.

Work has already begun in some places. Veolia operates utilities serving approximately 2.3 million people in six eastern states and manages water systems for millions more. Veolia has established a PFAS treatment system for a small water system serving approximately 150,000 people. However, the company expects to have about 50 more sites to treat and is working to increase its efforts to reduce PFAS in the larger communities it serves.

In recent years, the EPA’s health guidance on PFAS has changed dramatically as more research on the health hazards of PFAS has emerged. Less than a decade ago, the EPA issued a health advisory limiting PFOA and PFOS to a combined level of 70 parts per trillion. Now, the agency says no amount is safe.

Public panic has also increased. In Minnesota, for example, Amara’s law aims to prevent avoidable use of PFAS. The law’s namesake, Amara Strande, died of a rare cancer that her family blamed on 3M PFAS contamination near her Oakdale high school, even though PFAS The link to her cancer has not yet been proven, but it has been nearly a year. Biden administration officials say communities should not suffer the way Oakdale has. 3M expresses its deepest condolences to Amara’s friends and family.

Losing Amara spurred the family toward activism. They have repeatedly testified in support of PFAS restrictions.

“Four parts per trillion, we couldn’t ask for a better standard,” said Amara’s sister Nora. “That’s a very ambitious target, but anything higher than that would be life-threatening.”