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Creators of forever chemicals covered up the toxic dangers for decades

In an echo of strategies employed by the tobacco industry, the chemical sector has been implicated in concealing vital information about the detrimental health effects linked to PFAS (per- and polyfluoroalkyl substances) exposure. 

This finding emerges from an examination of previously confidential industry papers by a team of researchers at UC San Francisco (UCSF).

Published in the journal Annals of Global Health, a shocking paper casts light on how companies like DuPont and 3M, the largest PFAS manufacturers, employed various tactics to delay the public awareness of PFAS toxicity. This deliberate stalling strategy further slowed the formulation of regulations governing the use of these chemicals.

PFAS, notoriously known as “forever chemicals,” are extensively used in various household goods, clothing, and food products. Their resistance to degradation has not only resulted in their prevalence in our environment but also in their omnipresence in human bodies.

Tracey J. Woodruff, PhD, professor and director of the UCSF Program on Reproductive Health and the Environment (PRHE), and senior author of the paper, said: “These documents reveal clear evidence 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.”

Woodruff, a former senior scientist and policy advisor at the Environmental Protection Agency (EPA), used this opportunity to analyze the PFAS industry documents for the first time through the lens of exposing tobacco industry tactics.

Harmful and toxic effects had been known for decades

The concealed industry documents were unearthed during a lawsuit launched by attorney Robert Bilott, known for successfully suing DuPont over PFAS contamination, and whose story inspired the film “Dark Waters.” 

Bilott forwarded these documents, spanning from 1961 to 2006, to the creators of the documentary, “The Devil We Know.” They, in turn, contributed them to the UCSF Chemical Industry Documents Library.

“Having access to these documents allows us to see what the manufacturers knew and when, but also how polluting industries keep critical public health information private,” said lead researcher Dr. Nadia Gaber.

She also stressed the importance of this research in informing policy decisions and pushing towards a precautionary principle in chemical regulation.

The researchers emphasized that public knowledge regarding PFAS toxicity remained minimal during the first five decades of their usage. This lack of transparency persisted despite industry having numerous studies showing adverse health effects at least 21 years before these were made public.

The paper reports that DuPont suppressed evidence from internal animal and occupational studies demonstrating PFAS toxicity. Instead of sharing these results with the EPA as required by TSCA, they were marked “confidential.” The paper further indicates instances where industry executives explicitly expressed their desire to have such incriminating memos destroyed.

Borrowing the suppression strategy from the tobacco industry

The paper lays out a timeline of the chemical industry’s knowledge of PFAS risks versus public awareness. It uncovers strategies used by the chemical industry to suppress vital information and protect their harmful products. 

In 1961, a company report revealed that Teflon’s Chief of Toxicology discovered that Teflon materials had “the ability to increase the size of the liver of rats at low doses,” and warned that the chemicals “be handled ‘with extreme care’ and that ‘contact with the skin should be strictly avoided.’”

A 1970 internal memo from DuPont-funded Haskell Laboratory declared C8 (one of thousands of PFAS) as “highly toxic when inhaled and moderately toxic when ingested.” By 1979, Haskell labs found that dogs exposed to a single dose of PFOA “died two days after ingestion.”

In 1980, DuPont and 3M discovered two birth defects among eight pregnant employees working in C8 manufacturing. However, they failed to disclose this finding or inform their employees about it. In a contradictory move, an internal memo in the following year claimed, “We know of no evidence of birth defects caused by C-8 at DuPont.”

Yet, DuPont reassured its employees in 1980, comparing the toxicity of C8 to that of table salt. They further downplayed reports of PFAS groundwater contamination near one of their plants in a 1991 press release, stating, “C-8 has no known toxic or ill health effects in humans at concentration levels detected.”

As lawsuits in 1998 and 2002 raised media attention to PFAS contamination, DuPont contacted the EPA, pushing for a swift public statement. They urged, “We need EPA to quickly (like first thing tomorrow) say the following: That consumer products sold under the Teflon brand are safe and to date there are no human health effects known to be caused by PFOA.”

In 2004, the EPA penalized DuPont for withholding their findings on PFOA. Despite the $16.45 million settlement being the largest civil penalty under U.S. environmental statutes at the time, it constituted a mere fraction of DuPont’s $1 billion annual revenues from PFOA and C8 in 2005.

Reflecting on the implications of the paper, Woodruff said, “As many countries pursue legal and legislative action to curb PFAS production, we hope they are aided by the timeline of evidence presented in this paper.” She noted that this timeline reveals significant flaws in the existing U.S. regulations on harmful chemicals.

More about forever chemicals 

PFAS, or per- and polyfluoroalkyl substances, are a group of human-made chemicals that have been manufactured and used in a variety of industries around the world since the 1940s. They are used in a wide range of products because of their unique properties, such as their resistance to heat, water, and oil.

PFAS can be found in:

  • Food packaging materials, such as microwave popcorn bags and pizza boxes
  • Stain- and water-repellent fabrics
  • Nonstick products, such as Teflon
  • Polishes, waxes, paints, and cleaning products
  • Fire-fighting foams (a major source of groundwater contamination at airports and military bases where firefighting training occurs)

PFAS are known as “forever chemicals” because they are extremely resistant to breaking down in the environment. They are stable, persistent, and bioaccumulate, meaning their concentration can increase over time in the environment and in organisms.

Studies have indicated that exposure to certain PFAS may lead to adverse human health effects. Some of the health effects linked with PFAS exposure include:

  • Effects on growth, learning, and behavior of infants and older children
  • Lower fertility and interference with the body’s natural hormones
  • Increased cholesterol levels
  • Elevated risk of cancer, particularly kidney and testicular cancers
  • Impact on the immune system
  • Increased risk of thyroid disease

The most studied PFAS chemicals are PFOA (perfluorooctanoic acid) and PFOS (perfluorooctanesulfonic acid). Both of these are no longer manufactured in the United States, but they are still produced internationally and can be imported into the US in consumer goods.

Due to their widespread use and persistence in the environment, most people in the US have been exposed to PFAS. They can be detected in blood, and in certain cases, in drinking water supplies.

There’s increasing concern about the health effects of PFAS exposure, and a growing push for stricter regulation of these chemicals. Various states in the US have enacted legislation or issued guidance regarding PFAS, and there is ongoing research to better understand the impacts of these substances on human health and the environment.


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