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.

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:

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.