Drinking water consumed by millions of Americans from hundreds of communities spread across the United States is contaminated with dangerous levels of toxic chemicals, according to testing data released on Thursday by the Environmental Protection Agency (EPA). The data shows that drinking water systems serving small towns to large cities – from tiny Collegeville, Pennsylvania, to Fresno, California – contain measurable levels of so-called “forever chemicals”, a family of durable compounds long used in a variety of commercial products but that are now known to be harmful. The water of as many as 26 million Americans is contaminated, according to an analysis of the new EPA data performed by the Environmental Working Group (EWG), a Washington DC-based non-profit. Studies have linked the chemicals to cancers, immunodeficiencies, reproductive harms and developmental effects in children. Scientists and environmental advocates have increasingly warned about the harms of chemicals like perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) in recent decades, leading to an agreement between the the EPA and chemical manufacturers such as DuPont and 3M to phase out PFOA by 2015. However, lasting pollution of the environment and human bodies with forever chemicals continues. Studies show nearly all Americans have some level of PFOA, PFOS, and similar chemicals, scientifically known as per- and polyfluoroalkyl substances (PFAS), circulating in their bodies. Additional analyses calculate that hundreds of millions of Americans are probably exposed through drinking water contamination. But, the EPA’s testing program, part of a 27-year-old effort to sample the nation’s drinking water for unregulated chemicals, offers the most robust look into exactly which communities are polluted. The data released on Thursday is the first round of a program that will test most US water systems serving more than 3,300 Americans for 29 different forever chemicals, along with the metal lithium, over the next three years. This first batch, which analyzed data from about 2,000 systems across the country, already spells trouble. According to the data, 220 water systems found some level of PFOA, PFOS, or both chemicals in their drinking water. That means about one in 10 drinking water systems contain the two most notoriously dangerous forever chemicals. When including all 29 forever chemicals, the data confirms that the drinking water of approximately 26 million Americans is contaminated, according to the EWG non-profit. The data is also “consistent” with a 2020 study from the group that calculated more than 200 million Americans could have some form of PFAS in their drinking water. “This data confirms that PFAS is a pervasive problem, and it’s going to be a massive challenge for all of these water systems to deliver safe and clean water,” said John Reeder, vice-president for federal affairs at EWG. The EPA says the testing program is part of a holistic effort to address forever chemicals. In March, the agency proposed new regulations to limit PFOA, PFOS and several other sister chemicals in drinking water. That followed updates to the agency’s scientific findings in recent years dramatically lowering the amount of the chemicals considered safe in drinking water. In a press release, agency officials said the new monitoring data will further help inform what actions to take to protect drinking water. “PFAS are an urgent public health issue facing people and communities across the nation. The latest science is clear: exposure to certain PFAS, also known as forever chemicals, over long periods of time is linked to significant health risks,” Radhika Fox, EPA assistant administrator for water, said in the release. “EPA is conducting the most comprehensive monitoring effort for PFAS ever, at every large and midsize public water system in America, and at hundreds of small water systems.” But the road ahead remains perilous, says Tracy Carluccio, deputy director of the Delaware Riverkeeper Network, a Pennsylvania-based environmental non-profit that has pressed state regulators and the EPA for nearly two decades to take decisive action on PFAS. Carluccio says that until regulations are finalized and contaminated drinking water is treated, Americans remain at risk. With the new release of data, hundreds of towns and millions of people will probably be learning for the first time that their water is contaminated with PFAS. But with the EPA admitting its testing program is just 7% complete, that means probably tens of millions more still remain in the dark. “This is explosive and is going to be a shocker for a lot of people who thought, ‘Well I don’t live near a military base, I don’t live near a factory,’” Carluccio said, naming two common sources of forever chemical pollution. “In fact, PFAS are being found in really weird places because of how thoroughly they’ve been transported into the environment.” Carluccio says she believes officials with contaminated water systems should immediately work to provide clean water, whether from another river or well, or bottled water. Experts also question how swiftly EPA has worked to regulate PFAS. The agency previously tested water systems across the country for PFOA and PFOS as part of a similar program conducted between 2013 and 2015. That study used a less accurate technology that was incapable of detecting the smallest amounts of PFOA and PFOS in water, and thus found them in only about 4% of systems. But a report by Eurofins Eaton Analytical laboratories, a California-based lab that performed some of the earlier testing for the EPA, found that by using more accurate technology available at the time, the chemicals were actually present in an estimated 28% of systems. Andrew Eaton, former technical director of the laboratory and now owner of Eaton Environmental Water Quality Consulting in South Pasadena, California, says the newly released data thus represents a “missed opportunity”. “We could have had most of this information 10 years ago,” Eaton said, adding a caveat that safe levels of PFOA and PFOS were also believed to be much higher at the time. But Reeder, with EWG, says the lost time creates all the more impetus for EPA to work as swiftly as possible to finalize its drinking water regulations for PFOA, PFOS and other chemicals, as well as crack down on polluters. “This calls for more urgency to keep the rules on time and get them out by the end of the year,” Reeder said.