3M Knew that PFAS Was Hazardous to Humans in 1950. It Is Still Being Produced.

Should 3M be required to pay for cleaning up the evironmental disaster created by its products?


In 1947, 3M began producing perfluorooctanoic acid (PFOA) by electrochemical fluorination.

In 1951, DuPont purchased PFOA from then-Minnesota Mining and Manufacturing Company for use in the manufacturing of teflon, a product that brought DuPont a billion-dollar-a-year profit by the 1990s. DuPont referred to PFOA as C8. The original formula for Scotchgard, a water repellent applied to fabrics, was discovered accidentally in 1952 by 3M chemists Patsy Sherman and Samuel Smith. Sales began in 1956, and in 1973 the two chemists received a patent for the formula. As far back as 1950, studies conducted by 3M showed that the family of toxic fluorinated chemicals now known as PFAS could build up in our blood. By the 1960s, animal studies conducted by 3M and DuPont revealed that PFAS chemicals could pose health risks. But the companies kept the studies secret from their employees and the public for decades.


Here is a timeline of some important events.


1950 – 3M mice study reveals that PFAS builds up in blood.

1956 – Stanford University study finds that PFAS binds to proteins in human blood.

1961 – DuPont toxicologist warns that PFAS chemicals enlarge rat and rabbit livers.
1962 – Volunteers who smoke PFAS-laced cigarettes get “polymer fume fever.”

1963 – 3M technical manual deems PFAS toxic.

1965 – DuPont rat study shows liver damage and increased spleen size.

1966 – The Food and Drug Administration rejects a DuPont petition to use PFAS chemicals as a food additive, citing liver studies. 1966 – 3M study finds that PFAS causes “acute oral toxicity” in rats.

1970 – 3M warns Fire Journal, the magazine of the National Fire Protection Association, that PFAS is toxic to fish. 1970 – DuPont scientists say PFAS is “highly toxic when inhaled.”

1973 – DuPont finds there is no safe level of exposure to PFAS in food packaging. 1975 – 3M is informed that PFAS builds up in human blood samples. 1975 – DuPont warns 3M about “toxic effects” of PFAS in food packaging.

1977 – 3M tests workers and animals to measure PFAS in blood. 1977 – 3M finds PFOS, the PFAS chemical in the company’s Scotchgard fabric treatment, “more toxic than anticipated.”

1978 – 3M animal tests find lesions on spleen, lymph nodes and bone marrow.

1978 – 3M concludes that PFOS and PFOA, a PFAS chemical used to make DuPont’s Teflon, “should be regarded as toxic.”

1979 – DuPont survey of employees in its Parkersburg, W.Va., Teflon plant finds possible evidence of liver damage.

1981 – 3M and DuPont reassign female workers after animal studies reveal PFAS damages the eyes of the developing fetus.

1983 – 3M identifies PFAS’ potential harm to the immune system as a cause for concern.

1984 – 3M documents rising fluorine levels in workers’ blood.

1984 – DuPont detects PFAS in the tap water in Little Hocking, Ohio, but does not alert the local water utility.

1987 – 3M PFOA animal study finds tumors.

1989 – 3M study finds elevated cancer rates among PFAS workers.

1990 – 3M study finds risk of testicular cancer from exposure to PFOA, also known as C8.

1992 – DuPont study finds elevated cancer rates among workers.

1992 – Former 3M scientist finds male PFOA workers more likely to die from prostate cancer.

1995 – DuPont scientist expresses concern over long-term PFAS health effects.

1997 – DuPont study finds heightened cancer rates among workers at the Parkersburg plant.

1998 – 3M scientists report that PFAS moves through the food chain.

1998 – 3M provides EPA evidence that PFAS accumulates in blood.

1998 – 3M animal study finds liver damage from PFAS exposure.

1999 – 3M scientist describes PFOS as “the most insidious pollutant since PCB.”

2000 – 3M animal study finds liver damage from PFOS exposure


Information Sources


Wisconsin Dept. of Health Services