Correction: This article has been updated to accurately reflect how researchers are working to remove shorter-chain PFAS and how the Johns Hopkins Applied Physics Laboratory is seeking to trap the substances.
“Forever chemicals” are everywhere — but there are significant steps consumers can take to protect themselves against the toxic substances, leading environmental engineers said.
“We are living in a mega-experiment,” Mohamed Ateia Ibrahim, an environmental engineer at the Environmental Protection Agency (EPA), told attendees Tuesday at South by Southwest.
For decades, the government has implemented few regulations on per- and polyfluoroalkyl substances, commonly known as PFAS, a vast class of degradation-resistant chemicals linked to a staggering array of health impacts, he said.
Last month, the EPA proposed designating nine PFAS as “hazardous” — but there are nearly 15,000 such chemicals in existence, and for many of the substances, there may be no safe level of exposure.
If there is a safe level, that level is very low: Many public water utilities consider the safe threshold for PFAS to be 20 parts per trillion — the equivalent of a few drops in an Olympic-sized swimming pool. The EPA suggests far lower thresholds for some common PFAS, including 0.004 parts per trillion for PFOA and 0.02 parts per trillion for PFOS.
The chemicals have become pervasive, with research finding them in many U.S. waterways and consumer products. Asked where he was surprised to find PFAS, Ibrahim laughed ruefully.
“I’d be lying if I said I get surprised anymore, because it’s everywhere,” he said. “Where you can you find PFAS? It’s there, just waiting for someone to analyze it.”
“But discovering PFAS in toilet paper — that was … unpleasant,” he added.
The ubiquity of forever chemicals makes it “hard to do something that will completely eliminate your exposure,” said Leslie Hamilton, a materials scientist at the Johns Hopkins University Applied Physics Laboratory.
But consumers “can reduce it significantly,” Hamilton said.
In particular, Hamilton and Ibrahim said that consumers could reduce their risk by checking food and clothing packaging, and by finding out if their local water utility tests for forever chemicals.
First, Hamilton said, customers can ask their municipal water treatment plants if they test for PFAS. “Local water treatment facilities tend to pick up the phone, and they’ll talk to you,” she said.
When it comes to products they buy or interact with, both scientists said that consumers should be far more cautious around anything — from furniture and carpeting to clothing — that is stain, heat or grease-resistant.
“Since I’ve been in the field, I’ve learned more about my own and my family’s exposure risk,” Hamilton said.
She noted that PFAS exposure is of particular concern for the growing bodies of babies and young children, as well as fetuses in utero who can absorb the chemicals through their mothers’ exposure.
Since learning that the lining in popcorn bags contains PFAS, “we’ve switched to an air popper, and there are other small replacements you can make, like switching from Teflon pans to cast iron,” Hamilton said.
The nonprofits GreenScreen and PFAS Central also maintain comprehensive lists of PFAS-free products, from apparel to baby goods to furniture.
“But I decided not to live in fear, because you’re never going to be able to completely eliminate your exposure,” Hamilton said.
This consumer-awareness approach has limits. Many industries use PFAS as part of the manufacturing process used to make goods ostensibly free of the chemicals, the environmental engineers noted.
Many industries “actually use it without knowing that they’re using PFAS,” Ibrahim said.
The broad question for consumers and society alike, he added, is whether the added performance benefits of PFAS justifies the risk of exposure.
“People need to think. Our society is relying on chemicals, but we have to understand it’s a risky business — and to get to something that will replace PFAS will take time.”
The difficulty of replacing PFAS stems not just from their usefulness but their ubiquity — a market share that was enabled in large part by the industry’s reluctance over the past 70 years to share the growing evidence that the compounds were dangerous, according to research from the University of California, San Francisco (UCSF).
Documents uncovered by UCSF show “that the chemical industry knew about the dangers of PFAS and failed to let the public, regulators, and even their own employees know the risks,” Tracey Woodruff, a former EPA scientist and UCSF professor of reproductive sciences, said in a statement.
The understanding of PFAS risks has grown in tandem with the chemicals themselves, according to an Environmental Working Group timeline.
The first of the now-ubiquitous class of fluorinated compounds was invented by DuPont chemist Roy Plunkett in 1938. Teflon, the first commercial PFAS product, came to market in 1946.
By 1950, chemical giant 3M found that PFAS chemicals were toxic to mice. In 1956, Stanford researchers found that they also bound themselves to human blood proteins.
But even as this internal knowledge grew, reports have found, companies suppressed it.
The UCSF meta-analysis published in 2023 in the Annals of Global Health went through decades of internal industry documents to show “that companies knew PFAS was ‘highly toxic when inhaled and moderately toxic when ingested’ by 1970, forty years before the public health community.”
One decisive event that broke through that wall of silence was the 2017 settlement by DuPont of a massive class-action suit brought by West Virginia residents poisoned by the thousands of pounds of PFAS-like chemicals dumped into rural waterways.
DuPont sought to dismiss the lawsuit, arguing that proof of pollution didn’t equate to proof of harm.
The lawsuit “rests on a mistaken premise: the premise that any discharge of chemicals into the environment” creates legal liability, the company said.
“To be actionable, however, a discharge of chemicals must cause the plaintiff to suffer actual harm.”
For its part, the American Chemistry Council (ACC), the industry trade group for chemicals, argues that this “diverse universe of chemistries” is “essential to modern life.”
ACC says that “forever chemicals” is a pejorative coined by activists to frame “PFAS’ primary benefits of strengthened durability and functionality as a liability.”
In 2019, DuPont announced it was “learning from the past” and scaling back, though not eliminating, its use of PFAS, according Alexa Dembek, chief technology officer at the company.
The company now says its use of PFAS “is limited. We have systems, processes and protocols in place ensuring that PFAS is used safely, controlled to the highest standards and minimized.”
And last year, 3M agreed to pay $10.3 billion over the next 10 years to help public water utilities clean up any PFAS they find. The company has also said it would stop making PFAS by 2025.
“We got here because PFAS was this miracle chemical,” Hamilton said.
She paraphrased a quote from “Dark Waters,” a movie starring Mark Ruffalo about the West Virginia suit: “People weren’t saying I want PFAS in my corn muffins, but they wanted corn muffins not to stick to the muffin pans, you know, so it was just so good. And so it got to be so prolific before we knew anything about the dangers.”
“And so regulations are catching up, but it’s always just not going to be as fast as maybe the information” getting to the public, she said.
A letter last September by the United Nations Human Rights Office suggested another possibility: that the chemical companies had used their influence with the EPA itself to head off regulation.
The companies had “impermissibly captured the U.S. Environmental Protection Agency and delayed its efforts to properly regulate PFAS chemicals,” the U.N. rapporteurs wrote.
The same letter called out the federal government for failing to criminally prosecute “massive, serious, and widespread PFAS contamination caused by DuPont.”
EPA press secretary Remington Belford said the agency would be responding to the UN shortly, and that the agency would “use every available tool to protect people from dangerous PFAS chemicals.”
But another key change is that PFAS have gotten easier to find: Over the past decades, exponential advances in chemical analysis have allowed the chemicals to be detected at far lower concentrations than before, Ibrahim noted.
That ability to find PFAS at lower and lower concentrations coincided with a growing awareness by endocrinologists that minuscule levels of PFAS were disruptive to the body’s endocrine system, Hamilton said.
“Our bodies are some of the most exquisite sensors,” she said — meaning if the endocrine system is looking for a particular hormone, it may be disrupted by even extremely low levels of a PFAS molecule that looks similar.
The same properties that make PFAS so dangerous — like their extreme reluctance to react with other chemicals — make them very hard to study, detect or remove.
That’s because every step from finding them to pulling them from water requires in some way grabbing, trapping or manipulating them with other chemicals — processes that are stymied by the same characteristics that make PFAS so useful in various industries.
Because they are so unreactive, for example, it’s hard to get them to stick to a sensor to assess how prevalent they are, or to get them to bind to a filter that can remove them.
When it comes to cleaning PFAS out of water, the first step is to pull the the chemicals out of the liquid they are dissolved in.
“And there are ways to do that now,” Hamilton said — running the contaminated water through activated carbon or ion exchange filters.
But while those are a good first step, Hamilton said, they only grab long-chain PFAS, not shorter-chain ones — a reference to the number of carbon atoms in the molecule.
To get the shorter-chain compounds, researchers are developing new filters embedded with novel molecules specifically designed to trap PFAS.
But while those can pick up the PFAS, they create a new problem: The filter itself becomes a highly concentrated reservoir of forever chemicals. Throw it in a landfill, and the PFAS leach right back into the water.
The simplest method of dispensing with the filter without releasing the chemicals is to burn it, which Hamilton said is “simple and practical” but energy intensive, as well as creating unknown off-gases and residues.
Ultimately, the Johns Hopkins Applied Physics Laboratory, where Hamilton works, is looking at using iron-containing soil minerals as an eco-friendly means to trap PFAS, “destroy it, and capture all the teeny-tiny residues of the PFAS molecules” that are left over, Hamilton said.
Because fluorine — the building block of PFAS — is itself toxic, the ultimate goal is finding biochemical processes that convert the fluorine into a stable mineral that can be easily disposed of.
Even with all its risks, Hamilton said, “there are still going to be areas where we need [PFAS] — complex industrial chemistries that rely on it, or certain protective gear where we need oil and water resistance.”
The spread of PFAS didn’t happen overnight, and their replacement won’t either, she said. “It took several decades of [research and development] work” for the current thousands of PFAS compounds to come to market, she said. “We have to give time to the replacements to go through the same journey.”
— Updated March 15 at 11:55 a.m.