New testing by the Environmental Working Group has identified the presence of toxic fluorinated chemicals, broadly known as PFAS, in the tap water of dozens of cities across the U.S. where contamination was not previously known.

EWG, an advocacy organization that tracks environmental pollutants in consumer products, sampled water in 44 places between May and December 2019. The testing revealed the presence of so-called “forever chemicals” in 34 water systems, including in the Ohio cities of Columbus and Cincinnati, as well as in Pittsburgh, Pennsylvania. Previous testing from the group found 10 PFAS compounds in tap water in Louisville, Kentucky.

The so-called “forever chemicals” persist in the environment and in the human body and have been found in numerous water systems in the Ohio Valley. PFAS chemicals were used in flame-retardant foam sprays and in the manufacture of nonstick and stain-resistant products.

David Andrews, a senior scientist with EWG, said the new testing shows how frequently PFAS chemicals are found in water systems across the country.

“I think what really struck out to me is that we know these chemicals are widespread in blood, but it’s still shocking to see that many of these major cities across the across the country, at least all the ones we tested, had so many different compounds in their water,” he said. “And at levels that were somewhat striking in terms of their potential for impacting health.”

Two per- and polyfluoroalkyl chemicals — PFOA and PFOS — have been linked to negative health effects. A medical study of more than 70,000 people exposed to PFOA, or C8, dumped by DuPont’s Washington Works plant near Parkersburg, West Virginia, linked exposure to the chemical with multiple health problems from cancer to reduced immune function.

All of the newly-tested systems reported levels of PFAS chemicals lower than the U.S. Environmental Protection Agency’s health advisory of 70 parts per trillion, with the exception of Quad Cities, Iowa. The EWG report says water tested there showed 109.8 ppt of PFAS.

Some researchers believe EPA’s health advisory is not protective of human health. A recent study by the National Institute of Environmental Health Sciences suggests that safe levels of PFAS chemicals are as low as .1 to 1 parts per trillion.

The EPA is currently debating whether and how to set legally-enforceable drinking water limits for some PFAS chemicals. Meanwhile, a handful of states have taken action to set more protective drinking water standards.

Last fall, Ohio announced it will begin testing some public and private water systems for the presence of PFAS chemicals. A recent report by the Kentucky Energy and Environment Cabinet found half of all water systems tested in Kentucky had PFAS contamination.