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These chemicals, known as PFAS, can be found in drinking water as well as food packaging and nonstick cooking material such as Teflon. Getty Images
  • New research finds that a wider swath of the group of chemicals known as “forever chemicals” may have cancer-causing qualities.
  • Researchers also found it surprising that there was little research on the extent of the carcinogenicity — or safety — of these chemicals.
  • The chemicals, called PFAS, are found typically in low concentrations in drinking water, food packaging, and the environment.

The potential dangers of a group of chemicals — sometimes called “forever chemicals” due to how long they last in the environment — have been long suspected.

But some of those chemicals, which come from industrial processes such as the production of nonstick coatings like Teflon for pans, have been studied more than others.

New research is shedding light on the potential health impacts of these chemicals.

They’re finding that these perfluoroalkyl and polyfluoroalkyl substances (PFAS) have at least some cancer-causing characteristics.

But researchers are also discovering that for many of these chemicals, there is surprisingly little existing research into their potential impacts.

That matters, they say, because these chemicals can be found in everything from drinking water to fast food packaging.

The latest research comes from researchers at the advocacy organization Environmental Working Group (EWG) as well as Indiana University.

Their study, published this week in the International Journal of Environmental Research and Public Health, looked at 26 PFAS.

The researchers reported that all of the substances had at least one carcinogenic characteristic, meaning they may affect the body in at least one way that could raise the risk of developing cancer.

The most well-studied chemicals in this group had several of these characteristics. Those included PFOA, which used to be used in the production of Teflon coating, and PFOS, which used to be an ingredient in Scotchgard stain repellent.

For chemicals like those, there had already been some evidence of carcinogenicity, said Alexis Temkin, PhD, a toxicologist at EWG and the primary author of the new study.

“But there are many more chemicals in this class,” Temkin told Healthline.

That was why the researchers wanted to look at a longer list of these chemicals to see if they may have cancer-causing characteristics as well.

Temkin noted that a couple of weeks ago, the Environmental Protection Agency added more than 100 PFAS to its Toxics Release Inventory list.

Chemicals on that list are there because they’ve been deemed to cause cancer, other significant impacts on human health, or significant impacts on the environment.

There appears to be some understanding that more than just the most well-studied and well-known of these PFAS chemicals may be linked to cancer.

Temkin and her colleagues had another realization when reviewing past studies about these chemicals.

It was surprising just how little is known about the potential health impacts — and by extension, Temkin said, the safety — of these chemicals.

“The lack of evidence (for the carcinogenicity of these less-studied chemicals) was almost more surprising,” she said.

That they all had at least one carcinogenic quality was one thing. However, the fact that there generally wasn’t research that found more than that was more of a surprise.

For the chemicals for which there was more research, the evidence of carcinogenicity “seemed to line up with the more studied chemicals,” Temkin said.

“It’s surprising that there is environmental contamination (by these chemicals) and human exposure occurring, but little safety data to support the levels that we find in, say, drinking water,” she said.

In 2016, the EPA issued a health advisory for some PFAS that set a lifetime exposure limit for drinking water at 70 parts per trillion (ppt). That means no negative health effects would be expected from drinking water that contains 70 ppt of those PFAS every day over a person’s lifetime.

But health advisories are just that — advice meant to inform the public and other officials, not rules to be enforced.

There isn’t a federal maximum contaminant level for PFAS under the Safe Drinking Water Act, meaning drinking water regulation of PFAS is currently left to states and local governments to set.

Those PFAS standards vary by state.

In California, for instance, if a drinking water system is found to contain a certain concentration of PFOA, PFOS, or a combination of the two, the local water agency is notified and must take the water sources out of use, treat the water, and notify customers.

That concentration had been set at 70 ppt, but last month it was lowered to 10 ppt for PFOA and 40 ppt for PFOS over concerns about pancreatic cancer and liver tumors in laboratory studies on rats.

At these levels, the state’s Office of Health Hazard and Assessment said, the concentration of the chemical’s levels would pose no more than a 1 in 1 million cancer risk.

How best to avoid these chemicals if you’re concerned about them?

Temkin recommends focusing on preventing exposure.

Reverse osmosis filters have been “extremely effective” at removing PFAS from drinking water, according to the EPA.

Avoiding fast food is another potentially simple fix since some fast food packaging has been shown to contain types of PFAS.