Chemical industry used big tobacco’s tactics to conceal evidence of PFAS risks

DuPont or 3M scientists discovered PFAS toxicity internally, but did not publish findings or report them to the EPA, study says

In 1953, a paper developed for cigarette maker RJ Reynolds detailed possible cancer-causing agents in tobacco, but the document would remain hidden from public view for decades. In the interim, the industry told the public: "We don't accept the idea that there are harmful agents in tobacco."

The chemical industry, it seemed, took note. Just a few years later, DuPont scientists found PFAS enlarged lab rats’ livers and likely caused birth defects in workers. Still, the company told its employees the cancer-linked compounds are "about as toxic as table salt".

Like the tobacco industry before it, the chemical industry managed to keep PFAS's health risks hidden from the public for decades. A new peer-reviewed study dissecting PFAS producers’ public relations strategies provides a smoking gun timeline composed of industry studies and comments from DuPont and 3M officials showing they knew the dangers, but publicly insisted the chemicals were safe.

"The chemical industry used the tactics of the tobacco industry to delay public awareness of the toxicity of PFAS and, in turn, delayed regulations governing their use," the University of California at San Francisco authors wrote. "PFAS are now ubiquitous in the population and environment."

PFAS are a class of about 15,000 chemicals often used to make thousands of products resistant to water, stains and heat. The compounds are linked at low levels of exposure to cancer, thyroid disease, kidney dysfunction, birth defects, autoimmune disease and other serious health problems. They are called "forever chemicals" because of their longevity in the environment.

The public largely would not learn of the health threat until the aughts when subpoenaed records in a lawsuit against DuPont revealed the chemicals’ toxicity and industry cover up.

The study used scientific methodology previously developed by tobacco industry researcher Stan Glantz to analyze similar documents from cigarette makers. The authors found PFAS producers and their allies most frequently employed two tobacco strategies: withholding internal studies that revealed health risks and distorting public discourse.

"All these companies … try to prevent the development of public understanding and they’re always years ahead of the public and mainstream scientific community," Glantz said.

Between 1961 and 2006, the authors identified dozens of instances where DuPont or 3M scientists discovered or acknowledged PFAS toxicity internally, but did not publish the findings or report them to the EPA, as required under federal law.

DuPont's chief toxicologist in 1961 found rats’ livers enlarged at very low doses of exposure, a health impact recognized as "the most sensitive sign of toxicity." The report recommended PFAS be handled "with extreme care" and that "contact with the skin should be strictly avoided."

Around the same time, a DuPont worker died from PFAS inhalation, which the company on multiple occasions dismissed as a rumor. Meanwhile, workers reported an "epidemic" of flu-like symptoms from Teflon exposure.

In 1970, a DuPont-funded lab found PFAS to be "highly toxic when inhaled and moderately toxic when ingested". About a decade later, the lab killed two dogs with low doses of the chemicals. The lab also observed corneal ulcerations in newborns, and 3M, in a report shared with DuPont, "observed fetus eye changes were due to [PFAS]".

In the early 1980s, DuPont found elevated liver enzymes in 60% of workers tested, and a confidential internal report detailed birth defects among pregnant plant employees. In the years that followed, 3M and DuPont internal studies found the chemicals likely caused prostate, testicular, bladder and kidney cancers.

Virtually none of this information was shared with the public, regulators, or DuPont employees, and none of the research was published in a scientific journal. The motivation, said study co-author Tracey Woodruff, was profits.

"This is a chemical that made them a lot of money, and these studies that showed the chemicals are harmful would be threatening their profits if [the studies] came out," she added.

Instead, in a 1980 memo circulated to employees, DuPont insisted "there is no known evidence that our employees have been exposed to [PFAS] levels that pose adverse health effects."

"We know of no evidence of birth defects caused by [PFAS] at DuPont," the document continued, adding that the chemicals are "about as toxic as table salt".

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When water pollution near its Parkersburg, West Virginia, plant seemed to be sickening residents, DuPont responded in a press release that DuPont and 3M have found "no known toxic or ill health effects in humans at concentration levels detected".

As media and public scrutiny of the chemicals’ dangers increased in the 2000s, DuPont vice-president Susan Stalnecker wrote an email to the EPA in 2006 with the subject line "Urgent: EPA Action Needed".

"We need the EPA to quickly (like first thing tomorrow) say the following: 1. That ‘Consumer products sold under the Teflon brand are safe’ and 2. ‘Further, to date, there are no human health effects known to be caused by PFOA,’" the email read.

That same year, 3M funded a study that found no liver effects in men exposed to PFAS.

PFAS manufacturers have continued to conceal evidence since the conclusion of the DuPont lawsuit. The Guardian in 2021 revealed how DuPont and Japanese chemical maker Daikin hid evidence of the toxicity of 6:2 FTOH, a "new generation" of an allegedly safe PFAS compound that was approved for use in food packaging in 2009. But the companies’ testing before and after approval showed the chemicals caused kidney failure, liver damage, mammary gland problems, mottled teeth and other issues in lab rats.

It's unclear how the industry hides today, but "their history makes me think that there's always something that they aren't disclosing", said Maricel Maffini, an independent consultant who blew the whistle on 6:2 FTOH.

She said the problem is due in part to the nation's weak regulatory system, which in the case of the Food and Drug Administration does not require chemical companies to alert the agency if it finds a chemical is more dangerous than was known at the time it was approved.

Governments have begun taking only the most basic steps to protect the public from PFAS, and the federal government has yet to set any enforceable rules. The most meaningful legislation has come at the state level over the last two years, where a crop of laws now prohibit PFAS in consumer goods such as clothing, food packaging, firefighting foam and cosmetics.

The delay was a direct result of the PFAS industry's campaign, Woodruff said. Had the internal documents been released sooner, the EPA may have acted differently and independent scientists would have been studying the chemicals. That would have generated the kind of public pressure that is only now forcing governments to respond.

"This all would have occurred a lot earlier," Woodruff added.