Sustainability Environment

Common questions about PFAS, answered

“So the [EPA] is saying ‘if you can detect PFAS in your drinking water, then that level is too high.’”
water fountain
Water flows from a water fountain at the Boys and Girls Club in Concord, N.H. The state has 469 known PFAS contamination sites. AP Photo/Jim Cole

Story at a glance


  • A group of potentially harmful chemicals called per- and polyfluoroalkyl substances (PFAS) have repeatedly cropped up in headlines. 

  • But the sheer number of chemicals in this class, along with unclear communication from federal agencies and a host of other factors might cause confusion in the average American consumer.

  • Here, we lay out common questions related to PFAS, their answers, and explain the next steps needed to address this potential pollutant, according to experts.

Per- and polyfluoroalkyl substances (PFAS) are a group of thousands of chemicals found in everything from floss, to makeup, to frying pans, to clothes — and the list goes on. 

Numerous studies have been published documenting the harmful health and environmental impacts of these chemicals, especially in water systems.

But no federal agency currently enforces PFAS regulations for drinking water, although several states have enacted local policies.

Meanwhile, reforms aimed at phasing out certain PFAS from U.S. production processes have resulted in companies substituting lesser-known — and sometimes understudied — chemicals that might be just as dangerous, researchers warn. 

A disjointed approach to regulation, the myriad health problems associated with exposure, lack of public information on private production practices and limited communications from health agencies combined can easily lead to confusion in the average consumer. 

Here are some common questions about PFAS and their answers based on research and interviews with experts.

What exactly are PFAS and can they be dangerous?

PFAS are incredibly tough substances that are difficult to break down, earning them the moniker “forever chemicals.” The bond between carbon and fluorine atoms is one of the strongest in chemistry, inhibiting PFAS’ natural environmental degradation. Along with their high physiologic activity in humans, these characteristics contribute to the chemicals’ risks.

Over time the substances build up, and experts have concluded even periodic limited exposure to PFAS can be dangerous. Toxicology signals from low, infrequent exposure have put some scientists on high alert.

Despite the ubiquitous nature of these chemicals, their presence in drinking water is a pressing concern, researchers say.

“The difference between water and cosmetics is not really a difference of the route of exposure. It’s a difference of the amount that we get,” explained Alan Ducatman in an interview with Changing America. “And we get more [PFAS] if it’s in our water than if it’s in our cosmetics. But it’s undesirable in both cases.”

Ducatman is a doctor and professor emeritus at West Virginia University. He served as a principal investigator for health communications on the C8 health project, developed in response to E.I. DuPont de Nemours & Co’s contamination of drinking water in West Virginia with certain PFAS. 

DuPont has since merged with Dow Chemical and subsequently broken into Dow Inc., which specializes in material science; Corteva, which focuses on agriculture; and DuPont de Nemours, Inc., commonly referred to as DuPont, which focuses on specialty products. 

Chemours, another spinoff of DuPont established prior to the Dow merger, has come under fire for its use of GenX, a replacement PFAS manufactured without PFOA, though company efforts are underway to trap the pollutant before it enters the environment. An EPA toxicity assessment for GenX found the chemical has harmful effects on animals’ liver, kidneys, immune system and offspring development.

Unlike other toxic chemicals, the threat of PFAS exposure lies in their ability to result in chronic disease, said Jaime DeWitt, a professor of pharmacology and toxicology at East Carolina University.

“In some ways that makes them worse than acutely toxic chemicals because once you develop a chronic disease, you’re probably not going to get cured,” DeWitt said in an interview. “If you develop something like an immune suppressive disorder, you may have other diseases as you progress through life.”

Why is public attention swelling now?

PFAS have been around since the 1930s, but some might credit the highly publicized court case brought against DuPont in the early 2000s for the increased attention paid to these chemicals throughout the past few decades. 

However, Ducatman would like to think it’s more “about the symphony crescendo of increasing evidence that” points to the chemicals’ harmful effects on humans.

“We now have very good evidence that the bio accumulative chemicals are problems from multiple perspectives including for the liver and the kidney, and the immune system, and for at least two cancer outcomes, [and] preeclampsia in women,” Ducatman said. 

Recent research has also prompted responses from state governments and the Environmental Protection Agency (EPA), with particular focus on water contamination. 

EPA recommendations are just that, though: Recommendations absent any enforcement. These advisories also only pertain to four PFAS, including perfluorooctanoic acid (PFOA) and perfluorooctyl sulfonate (PFOS).

“If and when EPA will establish maximum contaminant levels (MCLs) for PFOA and PFOS it will take into account both technological feasibility and economic cost,” said Rainer Lohmann, a professor of oceanography and director of the University of Rhode Island Superfund Research Center, ‘STEEP,’ in a statement to Changing America. But removing PFAS from drinking water is a very pricey endeavor, underscoring the importance of preventing contamination in the first place.

U.S. production of PFOA and PFOS, two common PFAS, was phased out in 2016, but their effects linger in the environment, while products that were developed prior to 2016 still in circulation pose risks, as do products imported from other countries.

Under the new EPA health advisory, acceptable levels of PFOA in drinking water were set to .004 ng/l parts per trillion (PPT), and .02 ng/l ppt for PFOS – minuscule amounts that are effectively below limits of detection with current analytical technologies, DeWitt said.

“So the agency is saying, ‘if you can detect PFAS in your drinking water, then that level is too high.’”

How concerned should the average consumer be?

“Maybe best described as concerned but not panicked,” Lohmann said. 

“Having access to ‘clean’ drinking water is most important, as it is relatively easy to obtain (and to identify PFAS in it). It is far more difficult to know which of your cosmetics, outdoor gear or dental floss contains PFAS, to name a few,” he continued. Mandatory product labeling could better aid consumers looking to avoid these chemicals.

For Ducatman, given the choice between being a pack-a-day smoker and being exposed to 2005 levels of PFAS — the year DuPont settled with the EPA over the West Virginia contamination — he would choose PFAS exposure. 

“But that is not really very comforting, that’s the opposite of comforting,” he said, adding existing evidence puts this class of chemicals on par with other biopersistent organic chemicals like dioxins — substances that are regulated due to their health risks.

More research is needed to fully understand the effects of PFAS as a whole and exposure to individual chemicals. But ultimately, “I don’t think we have to wait for more instances of proving that yet another organ system is harmed before we get serious about them,” Ducatman said. 

Threats can also vary depending on where someone lives and their socioeconomic status.

“We know that some people are exposed to greater amounts of PFAS because of the water contamination in their area,” DeWitt explained. 

“And if you can’t afford to put in a whole house or even under the sink filtration system, then your exposure is going to be higher than somebody who can afford to pay for those things.”

What is being done to address this issue?

Addressing PFAS contamination is an expensive undertaking, due in part to the large number of chemicals included in this class. Although many studies have been conducted on PFOA and PFOS, relatively less is known about other PFAS. 

“The consumer can play a role in making sure that they don’t get these things if they don’t want them,” said Ducatman. Looking for the chemicals on product labels could be one way to mitigate exposure.

But private companies could also be more open and communicative with the federal government with regards to replacement PFAS used, Ducatman added. 

“Some of the replacement chemicals have remarkably active toxicology – whether they’re going to be as big a problem as their predecessors, I think it’s an open question because they may not be as bio accumulative in some circumstances,” Ducatman said. 

These replacements can also be more physiologically active, “and we’re just hoping against hope that their lack of bioaccumulation is going to protect us and other species,” he said. “I don’t think hope is a very good federal policy.”

However, some experts argue the burden of vetting products should not fall on consumers and that state and federal regulators need to step up to address the problem.

“I’m not suggesting that our state and federal agencies aren’t doing their jobs. I am suggesting though, that we have a system that makes it especially difficult for our state and federal agencies to do their jobs,” DeWitt said, citing the recent Supreme Court decision that stripped EPA of some of its regulatory powers

Being proactive in addressing the problem instead of retroactive might also ease burdens put on regulators’ shoulders. 

Currently, the EPA acts on a single PFAS at a time, usually examining the risks of compounds already on the market, explained Lohmann.

“This perpetuates EPA having to react to bad chemicals, rather than prevent their production in the first place.”

Lohmann and his team at the University of Rhode Island are working to identify the transport of PFAS away from contaminated sites. They are also working to establish detection tools for PFAS assessments in groundwater and better understand contamination routes in dust, indoor air or consumer products. 

More research aimed at understanding the class as a whole, or as several subclasses as opposed to individual chemicals can also help move the needle, according to DeWitt. 

“I think if we look at the common threads of concern among all PFAS, we can consider a class-based approach to their management,” DeWitt said. “So even though there’s greater than 12,000 individual chemicals, we don’t have to know everything about every single one of those 12,000 chemicals to know that as a class they pose concerns for society and for environmental health.”

Currently, Maine, Massachusetts, Michigan, New Hampshire, New Jersey, New York and Vermont enforce MCLs for drinking water, while 12 other states have issued guidance on safe PFAS levels. Local research labs are also working to study the effects of PFAS and mitigate their effects. 

“What has to come next is better health communications, and some approach to some cost effective way to cleaning up a very large mess that we haven’t completely characterized yet,” Ducatman concluded. 

What are companies saying?

3M, another manufacturing company, first developed and sold PFOA and PFOS. When asked about the company’s use of any replacement PFAS in current production processes, a spokesperson told Changing America, “Treating [PFAS] as a single group or class is not scientifically sound or appropriate.” 

This stance is in direct opposition to some of the solutions proposed by experts, as it would likely take ample time and resources to individually study each of the more than 12,000 chemicals. 

The statement continued: “In some applications, no suitable technical and/or economically feasible alternative is currently available,” and noted CDC testing for perfluorobutane sulfonic acid (PFBS), a replacement for PFOS, in the general population was halted as none of the chemical was detected. 

However, just because a chemical is not widely detected in humans does not mean it is safe. 

According to an EPA toxicity assessment of PFBS, the chemical has been found in surface water, wastewater, drinking water, dust, carpeting, carpet cleaners and floor wax, while animal studies have linked PFBS exposure with effects on the thyroid, kidney, reproductive organs and tissues, as well as fetal development. 

DuPont de Nemours, which was formed in 2019 as result of the Dow-DuPont merger and subsequent spinoff, “has never produced PFOA or PFOS,” the company said in a statement to Changing America when asked about any replacement PFAS currently in use.

“The company has established a set of commitments to take responsible action related to PFAS, and also supports sensible, science-based regulatory standards on PFAS that will provide clear, uniform guidance for all,” the statement continued.