How PFAS Can Harm Your Health

One of the main concerns about PFAS is how long they last. In fact, they are often called “forever chemicals” because they break down extremely slowly, if ever.

That persistence, combined with the many products that now contain PFAS, means that there are many ways the chemicals can enter the environment and eventually reach humans, too. 

For decades, PFAS manufacturers have had information indicating that the chemicals may harm human health, according to reporting from the Environmental Working Group. But for the first 60 or so years that PFAS were in production, many people thought that potential harms were specific to workers exposed to the chemicals at an industrial scale, not the general public.

Then, in 1998, a West Virginia farmer named Wilbur Tennant started raising concerns about the effects that pollution from a nearby DuPont factory had on his cattle. This helped lead to a class-action lawsuit alleging that this contamination—with the PFAS chemical PFOA, also known as C8—could be affecting the approximately 70,000 people who got water from the same polluted source.

The resulting settlement led to the creation of the C8 science panel, which between 2005 and 2013 assessed links between exposure to PFOA and a number of diseases, and found probable links between exposure and thyroid disease, higher cholesterol levels, kidney and testicular cancer, ulcerative colitis, and pregnancy-induced hypertension. Other research on various PFAS has found links to liver damage and kidney disease.

Growing research has also shown that health risks can occur even at very low levels. Some of the clearest evidence about that risk comes from an unexpected place: the seemingly pristine Faroe Islands, a group of 18 small, rocky islands midway between Iceland and Norway in the North Atlantic. 

In 2010 and 2011, Philippe Grandjean, PhD, a professor of environmental medicine at the University of Southern Denmark, had been studying children in the Faroes to see whether certain chemicals in the environment could dampen the immune system’s response to childhood vaccines. When he saw a study showing that PFAS could affect animal immune systems, he and colleagues decided to see whether PFAS also affected how children responded to the vaccines.

The results were dramatic. “I fell off my chair,” Grandjean says. “It was very clear these compounds were inhibiting the immune system.”

In 2012, Grandjean and colleagues first published their research showing that higher levels of PFAS in blood samples taken from the children were associated with less effective protection after being vaccinated. 

The findings were alarming not just for the Faroes. Blood PFAS levels among children in the U.S. are comparable, Grandjean says. Follow-up research in other countries has confirmed this effect, and has also shown that children with higher blood levels of PFAS have more infections, he says.

Still, calculating the exact level of PFAS exposure that causes harm isn’t straightforward, especially since there are thousands of different PFAS, some more toxic than others. Manufacturers have stopped producing a couple of these chemicals in the U.S., as concerns about their impact on health have become more widely known. As that has happened, however, they’ve been replaced by newer chemicals that have not been as thoroughly studied by independent researchers.

Both the Food and Drug Administration and the American Chemistry Council, which represents PFAS manufacturers, argue that we don’t know for sure that newer PFAS are as unsafe as the ones they are replacing. But a growing body of research suggests that many do pose risks, says Miriam Rotkin-Ellman, a senior scientist at the Natural Resources Defense Council. A database of research on more than two dozen different PFAS compiled by a group of scientists who study the chemicals suggests harmful effects associated with many of them.

“There are consistent patterns across these chemicals,” she says, “and the most consistent pattern is that they’re toxic.”