Industry knew about risks of PFAS ‘forever chemicals’ for decades before push to restrict them, study says

Makers of PFAS, a class of chemicals used in everything from cookware to food containers and makeup, had evidence the substances were toxic as early as the 1970s and obscured the danger, according to a new study based on industry archives held at the University of California.

Governments in Canada and the U.S. are now cracking down on per- and polyfluoroalkyl substances (PFAS), a class of more than 9,000 human-made chemicals produced since the 1940s. They have unique properties that make them heat-resistant, oil- and water-repellent and friction-resistant, and are found in products from cosmetics and take-out boxes to non-stick cookware and fire suppressants.

Because they're hard to break down, contamination from the long-lived substances — sometimes called "forever chemicals" — is extensive all over North America.

"It's really very sad, actually, how people were harmed by this chemical while the industry knew — had documents that showed they knew — it was toxic," said Tracey Woodruff, professor of reproductive health and the environment at the University of California, San Francisco, and an author on the study published Thursday in Annals of Global Health.

The study examined 39 internal industry documents currently held at the university's Chemical Industry Documents Library, dating from 1961 to 2006. The documents come from a lawyer who led a class action lawsuit in the early 2000s against chemical manufacturer DuPont on behalf of about 70,000 people in West Virginia and Ohio over exposure to PFOA, a form of PFAS.

The internal industry documents came from the discovery process and were related to DuPont and 3M, two major PFAS manufacturers. The documents were given to the makers of a 2018 documentary film called The Devil We Know, which was about the health hazards of PFOA and its use in Teflon cookwear.

Woodruff and her team's analysis found that the companies had evidence by the 1970s —decades before public health and government authorities turned their attention to the chemicals — that some PFAS were toxic to humans, based on lab reports and health impacts on employees, but downplayed those impacts in public messaging or obscured what they had found.

"I think it really reinforces why we have to hold these industries accountable because they're clearly, as you read the documents, concerned about the profits for this chemical and not about the health of their employees nor of the public," Woodruff said.

Industry tactics

Until around 2000, the public health community considered PFAS to be inert and not something that would cause health problems, the study notes.

However, the chemicals can enter our blood and bodies from non-stick Teflon pans, fire retardant, food wrappers, cosmetics, and even the environment. In studies, they have been found in the bodies of most people tested in the U.S., Canada and other countries, and have been detected in major bodies of water.

Today, PFAS have been linked to liver problems, pregnancy issues, immune problems and some cancers. These health effects have mostly been observed in animal testing; the exact impact on human health remains unclear and is difficult to study as it would involve exposing people to suspected toxins.

The study highlighted examples of company documents mentioning toxic effects:

• As early as 1970, a DuPont memo said PFOA, a type of PFAS, was "highly toxic when inhaled and moderately toxic when ingested."
• In 1980, DuPont and 3M learned that two pregnant employees involved in PFOA manufacturing had given birth to children with birth defects. Neither company released that information or told employees.
• In 1981, DuPont workers showed elevated levels of liver enzymes.
• In 1994, 3M knew of links of PFAS to prostate cancer that it shared with DuPont, a competitor.

Woodruff's research also examined tactics the industry used to obscure and delay research into PFAS and regulations restricting their use. The study used research methods previously used to examine the tactics of the tobacco industry.

In an email statement to CBC News, 3M said "3M has previously addressed many of the mischaracterizations of these documents in previous reporting." They did not include any specific responses to the study.

In December 2022, 3M announced it was going to exit PFAS manufacturing altogether by the end of 2025, partly due to regulations coming in around the world to restrict the chemicals.

Comment was also requested from two companies resulting from DuPont's split in 2019, but both said they were not involved.

Governments step in

Human health studies that do exist mostly focus on two types of PFAS — PFOS and PFOA. There's evidence linking them to liver disease, adverse pregnancy outcomes like preterm birth and cancer, and both have been banned in Canada.

Other PFAS chemicals are not as well studied but could cause similar health problems. Because there are hundreds of different PFAS chemicals, and it would be difficult to study all of them, the Canadian government is considering regulating all PFAS rather than specific chemicals.

The government released a draft "State of PFAS" report in May, inviting public comment. The report will inform eventual policies to regulate PFAS, the government said.

South of the border, the U.S. Environmental Protection Agency is set to finalize new rules on PFAS. Several U.S. states have moved on their own to restrict the use of PFAS and keep them out of their water supply.

Fe de Leon, researcher at the Canadian Environmental Law Association, says it's difficult to keep up with PFAS regulations, because the chemicals keep changing.

For example, PFOA was replaced with another PFAS chemical called GenX, which has also been linked to liver-related health issues.

"You go one chemical at a time, and it doesn't work because those chemicals are replaced most of the time," she said.

"We have to do a better job, right, asking for more information before these chemicals are allowed in the market."

De Leon says Canada's legislative framework is not reactive enough when new information about a chemical's hazards becomes available. She hopes the "State of PFAS" report will lead to government action soon.

"The cost of doing nothing is so significant, and it affects generations," she said.

"It's not just the immediate people who are affected. The next generation could be equally affected by these types of chemicals being in people's bodies."