DETROIT — They come from everyday products ranging from nonstick pan surfaces, carpet stain-proofing and water-resistant clothing. And they’re in almost every American’s blood: highly fluorinated toxic chemicals known as perfluorochemicals, or PFCs.

They’re linked to testicular and kidney cancer and thyroid disease — and have been found to render critical childhood immunizations against communicable diseases less effective.

A new study released Thursday by the non-profit Environmental Working Group and Northeastern University in Boston shows harmful types of PFCs, known as PFOA (perfluorooctanoic acid) or PFOS (perfluorooctane sulfonate), can be found in drinking water systems in 27 U.S. states (including Illinois) and in the tap water supplies of 15 million people.

“It’s a much larger number than we thought before,” said Bill Walker, managing editor of Environmental Working Group.

The water pollution comes from former industrial sites, current and shuttered military bases, and in many cases from unknown sources. In Michigan, five water supplies have been found with PFCs, including in Ann Arbor, from an unspecified source.

Of the 47 locations nationwide where the source of PFCs contamination in drinking water supplies is known or suspected in the Environmental Working Group-Northeastern study, 21 are current or former military bases, 20 are industrial facilities and seven are from civilian firefighting sites. Some locations have multiple sources.

The U.S. Environmental Protection Agency in May 2016 set a “health advisory level” for PFOS and PFOA at 70 parts per trillion. EPA officials said they were basing the nonenforceable threshold “on the agency’s assessment of the latest peer-reviewed science.”

But a Harvard University environmental health professor, and one of the leading researchers on public health effects from PFCs, said the standard “may be 100-fold too high.”

“The so-called safe drinking water limits are not safe; they are unsafe,” said Philippe Grandjean.

In a study published in the Journal of the American Medical Association in 2013, Grandjean looked at nearly 600 children in the Faroe Islands, a tiny island nation in the North Atlantic north of the United Kingdom. The children’s diet was heavy in PFOA-contaminated fish.

The study showed PFOA contamination of the children’s blood affected their immune systems, causing routine childhood immunizations for diseases such as measles, mumps and polio to be far less effective.

“Antibody concentrations are just flat,” Grandjean said. “They don’t respond; the vaccine doesn’t take. This is really a bomb under one of the major achievements of public health. Vaccines are hugely important.”

Research by the National Toxicology Program, EPA and the University of North Carolina, in which unborn mice were dosed in the womb with very low levels of PFOA during critical development periods, could not find a level so low as to not cause harm, the Environmental Working Group-Northeastern study noted.

Used in a variety of household products since the 1950s, PFCs “have basically polluted the entire world,” Walker said.

The federal Centers for Disease Control and Prevention, in blood samples taken from about 2,000 Americans in 2003-04, found PFOS, PFOA and other PFCs in 98% of participants’ blood.

“That’s meant to be a representative sample of the whole U.S. population,” Walker said.

PFOA was for decades used to make DuPont’s Teflon coating, a nonstick surface for frying pans and other applications, and in 3M’s Scotchgard carpet protectant. The companies, under EPA pressure, agreed to phase out use of the chemicals beginning in 2000.

In February, DuPont and its spin-off Chemours agreed to pay $671 million to settle more than 3,500 lawsuits involving the leaks of PFOA from its plant in Parkersburg, W.Va., into community water supplies.

PFOA still persists in products made outside the U.S., particularly in China, the Environmental Working Group-Northeastern study notes.

EPA directed the testing of drinking water systems serving 10,000 or more people for six different PFCs, including PFOA and PFOS, from 2013-16. But there is no ongoing, national-level testing of PFCs in drinking water, and the EPA has indicated it may not make a decision on whether to set a national standard for the compounds until 2019 or later.

That’s a problem, Grandjean said.

“The time has come for us to develop a strategic plan, No. 1, to make sure these compounds are measured in drinking water systems and potable water all over the United States,” he said.

“You can filter these compounds out. We need to aim at eliminating them where this contamination has occurred, not just where we happened to discover them. Because as this study suggests, this may occur much more widely than we are thinking.”

Keith Matheny, USA Today Network