Poisoned Legacy

Ten Years Later, Chemical Safety and Justice for DuPont’s Teflon Victims Remain Elusive

May 1, 2015

Poisoned Legacy: From Lab Accident to Global Pollutant

In 1938, Roy J. Plunkett, a chemist at E. I. du Pont de Nemours and Company, accidentally invented “the most slippery substance on Earth” – PTFE,[1] the first compound in the family of perfluorinated chemicals, or PFCs, to be marketed commercially. (Lyons 2007) Patented as Teflon, it was ultimately used in more than 3,000 products – nonstick cookware, waterproof clothing, camping gear, even dental floss. At their peak, Teflon sales reached $1 billion a year. (Haber 2005) In 2008, the United States alone used 100 million pounds of PTFE, about one-fourth the worldwide total. (EPA 2009)

An essential ingredient in making Teflon was another PFC known as PFOA.[2] PFOA is often called C8 after the number of carbon atoms in its chemical chain. PFCs are made up of chains of carbon atoms of varying lengths that bond strongly to fluorine atoms, yielding chemicals that do not break down in the environment and take years to decades to pass from our bodies. (Steenland 2010) (Perfluorinated chemicals with eight or more carbon atoms are called “long-chain” PFCs; the replacements now hitting the market have shorter fluorinated carbon chains.)

C8/PFOA itself was not in finished products but was used to make Teflon and was a byproduct of the process. Until 2000, the major U.S. manufacturer of C8 was 3M Company, which also made a closely related compound called PFOS.[3] [4] PFOS was a key ingredient in 3M’s stain-resistant Scotchgard, which had thousands of consumer and industrial applications from fabric sprays to fast food wrappers.

Even as Teflon and Scotchgard were earning big profits for DuPont and 3M, the companies were accumulating evidence that PFOA and PFOS were hazardous. For decades the companies kept the increasingly alarming information secret. (EWG 2002A) The truth only emerged after EPA forced 3M to phase out PFOS and lawsuits were brought against DuPont for polluting of mid-Ohio Valley water supplies with C8/PFOA. Table 1 summarizes some of these secret studies.

Table 1. Decades of Secret Studies by DuPont and 3M



A DuPont toxicologist warns that Teflon chemicals cause liver enlargement in rats and rabbits.


DuPont scientists have 40 volunteers smoke cigarettes laced with Teflon. Ninety percent of the most highly exposed group develop flu-like symptoms known as polymer fume fever.


DuPont finds there is no safe level of exposure to C8/PFOA in animals.


3M begins testing some workers’ blood for PFOA and finds it in almost every one tested.


3M finds that PFOA is “completely resistant” to breakdown in the environment.


3M finds PFOS in the blood of five workers in Alabama. Fish in the Tennessee River, where up to 1 million pounds of PFOS waste were dumped each year, are found to have significant concentrations of the chemical in their blood, evidence of bioaccumulation.


3M finds that PFOA causes birth defects in rats.


DuPont finds PFOA in umbilical cord blood from one baby and blood from a second baby born to female workers at the Washington Works plant.


Two of seven children of women working at Washington Works are found to have birth defects of the eye, tear duct or nose. DuPont transfers “all potentially exposed female employees” out of the plant but does not tell them why.


3M doctors warn that organic fluorine levels in workers’ blood are steadily rising, evidence that PFCs accumulate faster than the body can eliminate them.


DuPont finds PFOA in tap water in two mid-Ohio Valley communities. Tests continue for 17 years before DuPont informs any area water suppliers.


Data on workers at DuPont’s Washington Works plant reveal an excess of deaths from cancer and leukemia.


A 3M study of employees at a PFOA plant finds twice as many deaths from prostate cancer as in the general population.


3M looks worldwide for clean blood samples to compare to its workers’ blood but finds only one source not contaminated with PFOS – preserved blood of soldiers who died in the Korean War, before Scotchgard products spread worldwide.


3M finds that PFOS causes liver cancer in rats. Despite federal law prohibiting the use in food of any substance that causes cancer in animals, 3M continued until 2000 to petition the FDA to allow PFOS in microwave popcorn bags.


3M study in six East Coast cities finds PFCs in supermarket food, rivers and lakes, drinking water sources and tap water.

Source: Environmental Working Group, from DuPont and 3M documents in EWG’s Chemical Industry Archives, www.chemicalindustryarchives.org.


The discovery of PFOS in blood samples worldwide in 1997 must have spooked 3M. It started submitting selected studies to the EPA while arguing for the right to continue using the chemical in some applications even as it reformulated Scotchgard and related products. Documents in EPA’s files made public by EWG don’t give details of the agency’s negotiations with 3M, but the end came quickly after April 2000, 3M submitted a study showing deaths among monkeys exposed to low levels of PFOS. (EWG 2002B)

The next month 3M issued a vague one-page press release saying it would end production and use of PFOS by the end of 2002. Continuing to hide the truth, 3M cited concerns over what it said was new information that the chemical had been “detected broadly at extremely low levels in the environment and people. All existing scientific knowledge indicates that the presence of these materials at these very low levels does not pose a human health or environmental risk.” (3M 2000) Two days later, The New York Times reported that EPA had forced 3M’s hand: “Agency officials said that if 3M had not acted they would have taken steps to remove the product from the market.” (Barboza 2000)

As 3M phased out PFOS, it also stopped making PFOA, but DuPont started making its own at a Fayetteville, N.C., plant. Since 1951 it had been using the chemical at the Washington Works plant and disposing of it in area waterways, landfills and unlined pits, as well as polluting the air with it through the plant’s smokestacks.

In 1984, secret tests by DuPont found C8/PFOA in the drinking water of two nearby communities on either side of the Ohio River. An internal DuPont memo recommended elimination of “all C8 emissions at our manufacturing sites in a way … which does not economically penalize the business.” Instead, DuPont chose to significantly increase production and keep quiet about the water pollution and health hazards (Lyons 2007)

Then cattle started dying on the Tennant family farm.

In the early 1980s the Tennants had sold some land south of the Washington Works plant to DuPont for what they thought would be a non-hazardous landfill. A creek ran through the landfill and into the Tennants’ pasture, and the water soon ran black and bubbly. By 1998 they had lost several hundred cows. They hired Robert Bilott, a Cincinnati attorney with roots in the area, to sue DuPont.

In a DuPont document Bilott found a reference to a chemical he knew nothing of: PFOA. He went to court to get more documents, which revealed the secret water tests. The Tennants settled out of court and the terms were sealed. But with the knowledge that public water supplies had been contaminated, in 2001 Bilott brought a class-action suit against DuPont on behalf of more than 50,000 area residents. (Lyons 2007)

As he pursued the case, Bilott obtained tens of thousands of damning documents. He alerted local and state authorities but got little response. He wrote to the EPA, detailing numerous violations of the Safe Drinking Water Act, the Toxic Substances Control Act and other laws. EPA did nothing. EWG then obtained many of the same documents from public court files, published the documents online in a series of reports that brought the case to national attention and pressured EPA to act. In 2003 the agency opened an emergency review of PFOA, including possible regulatory action under the Toxic Substances Control Act.

Over the next three years, the secret studies continued to surface, but each time DuPont insisted that PFOA posed no health threat. But Robert Bilott, EWG and others kept the pressure on EPA to act. After intense negotiations that included the prospect of criminal charges by the Justice Department, DuPont agreed in 2006 to “voluntarily” phase out the chemical by 2015. EPA assessed a record $16.5 million fine against the company for not disclosing the health studies on PFOA as required by the Toxic Substances Control Act, although DuPont maintained that it had not broken the law. And in 2006 EPA’s Science Advisory Panel classified PFOA as “likely to be carcinogenic to humans.” (EPA 2006)

In 2005, DuPont settled the class-action suit by the residents under a unique agreement, with provisions not previously seen in chemical pollution cases. DuPont paid $70 million in damages upfront and promised to pay for a state-of-the-art cleanup of the Parkersburg area’s water supplies. DuPont also agreed to fund an independent panel of scientists – the C8 Science Panel – to study the links between C8 and various diseases. Under the settlement, if the science panel found probable links between C8 exposure to residents and disease, those residents could pursue damage claims against DuPont. If such links were found, DuPont would pay up to $235 million to provide medical monitoring for the exposed residents.  

[1] Polytetrafluoroethylene.

[2] Perfluorooctanoic acid.

[3] Perfluorooctanesulfonic acid.

[4] The Appendix provides a fuller explanation of the chemical structure of PFOA, PFOS and other PFCs.