Silent Spring Institute Archives

January 15, 2025

Millions of Americans exposed to unregulated chemicals in drinking water, study finds

By Shannon Kelleher

Almost 100 million people in the US may be exposed to unregulated industrial chemicals in their drinking water, with communities of color especially at risk, according to a new analysis of federal monitoring data for water systems across the country.

The study, published Wednesday in the journal Environmental Health Perspectives, analyzed data gathered by the US Environmental Protection Agency (EPA) from 2013 to 2015 for four types of unregulated chemicals, finding that 27% of those nearly 5,000 public water systems had detectable levels of at least one contaminant.

Overall, more than 97 million US residents were served by a public water system with detectable levels of the contaminants examined in the study.

The colorless, flammable solvent 1,4-dioxane was most pervasive, showing up in 22% of the public water systems, according to the study. The researchers also found the refrigerant HCFC-22, as well as a solvent called dichloroethane used in plastics production, and toxic per- and polyfluoroalkyl substances (PFAS) in about 4-6% of the water systems. The EPA data accounted for six types of PFAS, a category including thousands of chemicals: perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorohexane sulfonic acid (PFHxS), perfluoroheptanoic acid (PFHpA) and perfluorobutane sulfonic acid (PFBS).

Hispanic and Black populations are at especially high risk for exposure to unregulated chemicals in their drinking water, the authors reported. Public water systems with detectable levels of the contaminants served counties with higher proportions of Hispanic residents than those with no detections, for example, the authors said.

March 14, 2023

EPA announces proposed drinking water standards for six toxic PFAS chemicals

By Shannon Kelleher

The US Environmental Protection Agency (EPA) on Tuesday proposed national standards aimed at reducing levels of six harmful chemicals in drinking water. The move was applauded by health and environmental advocates who say the action is long overdue.

The agency said in a press release that if the rule is implemented it will “over time, prevent thousands of deaths and reduce tens of thousands of serious PFAS-attributable illnesses.”

The EPA action is part of a larger government move to respond to scientific evidence showing that certain types of per- and polyfluoroalkyl substances (PFAS) are associated with a range of health problems, including a heightened risk of developing cancer, birth defects, liver disease, thyroid disease, decreased immunity, hormone disruption and a range of other serious health problems. PFAS have become nearly ubiquitous in the environment, including in water sources.

The new standards target six types of PFAS. For PFOA and PFOS – types known to be particularly dangerous to human health – the agency said the new rule would require public water systems to ensure levels of PFOA and PFOS do not exceed a maximum contaminant level (MCL) of four parts per trillion (ppt). Additionally, the EPA would require public water providers to use a hazard index calculation to determine if combined levels of PFNA, PFHxS, PFBS, and GenX Chemicals pose a potential risk.

“Today we can celebrate a huge victory for public health in this country – US EPA is finally moving forward to protect drinking water across the United States by proposing federally-enforceable limits on some of the most toxic, persistent, and bioaccumulative chemicals ever found in our nation’s drinking water supply,” US attorney Rob Bilott said in a statement. Bilott has been calling for the EPA to address PFAS in US drinking water in 2001.

“It has taken far too long to get to this point, but the scientific facts and truth about the health threat posed by these man-made poisons have finally prevailed over the decades of corporate cover-ups and misinformation campaigns designed to mislead the public and delay action,” added Bilott.

If finalized, all public drinking water systems will be required to monitor for all six PFAS chemicals and to notify the public and reduce PFAS levels if they exceed the standards.

“It’s not surprising that [EPA under the Biden administration] is doing it,” said Phil Brown, co-director of the PFAS Project Lab at Northeastern University and co-principal investigator of a PFAS research and education project at the Silent Spring Institute, in response to the drinking water standards announcement. “Everyone wishes it had happened a long time ago,” he added.

The American Chemistry Council (ACC), which represents the interests of more than 190 chemical companies, called the EPA’s approach “misguided,” and said the new low limits would “likely result in billions of dollars in compliance costs.”

The ACC said it had “serious concerns with the underlying science” used to develop the proposed MCLs, and said the agency was violating its own guidance by combining substances affecting different health endpoints into a single index.