3M Invented the Chemical Behind Scotchgard, Sold It to DuPont as a Raw Material for Fifty Years, and Found It in Its Own Workers' Blood by 1976. It Kept Selling It Anyway, Until Its Own Liability Made It Stop in 2000.
In 1953, a 3M lab assistant named Patsy Sherman spilled a fluorochemical compound on a tennis shoe and couldn't get it off. The stain resisted everything, and 3M turned the accident into Scotchgard. It was a good story, and 3M told it often. What 3M told far less often was where the underlying chemistry actually came from, and where it went next: by 1950, three years before the spill, 3M was already manufacturing PFOA — the "C8" compound — using the Simons electrochemical fluorination process, and selling it as a raw material to DuPont for Teflon production.
That supply relationship ran for fifty-two years, from 1950 to 2002. For most of it, 3M was not merely a company that happened to make the same class of toxic, non-degrading chemical as DuPont — it was DuPont's vendor. And by 1976, 3M's own toxicologists had already found PFOS and PFOA accumulating in the blood of the workers making it. The company kept selling the compound to itself and to DuPont for another twenty-four years, and only stopped when its own legal exposure made stopping the cheaper option.
The supplier nobody mentions
3M's fluorochemical program dates to the late 1940s, built on chemist Joseph Simons's electrochemical fluorination process, which let 3M attach fluorine atoms to carbon chains to make compounds that shed water, oil, and stains. PFOA — perfluorooctanoic acid, also known as C8 — was one of the byproducts and building blocks of that chemistry. DuPont needed a form of C8 as a processing aid for Teflon, and rather than build its own production line, it bought the chemical from 3M.
- 1950: 3M begins supplying PFOA to DuPont's Teflon manufacturing operations.
- ~1953: Scotchgard is reportedly discovered after a lab spill, and 3M builds a consumer brand on the same underlying fluorochemistry.
- 1950–2002: DuPont's Washington Works plant in Parkersburg, West Virginia — the site of DuPont's own long-running C8 contamination scandal — runs on 3M-supplied PFOA for the great majority of that period.
The Parkersburg story has been told elsewhere as a DuPont story. It is only half the story. The chemical DuPont dumped into the Ohio River watershed for decades was, for most of that time, not something DuPont made — it was something DuPont bought from 3M.
The blood tests
3M did not need outside whistleblowers to learn its chemical was accumulating in human tissue. Its own scientists found that out first, and sat on it.
- 1976: 3M toxicologists detect PFOS and PFOA building up in the blood of the company's own factory workers.
- Late 1970s: academic researchers Donald Taves and Warren Guy independently detect an unidentified fluorochemical in the blood of the general population and approach 3M for help identifying it.
- 1997–1998: 3M chemist Kris Hansen tests blood-bank samples collected from across the country and finds PFOS in every single one, including in decades-old archived samples.
- Hansen's colleague, scientist Richard Newmark, later told her that 3M's lawyers had blocked the lab from formally confirming the compound was PFOS — the very finding Hansen's tests already supported.
- December 1998 / March 1999: 3M toxicologist Dr. Richard Purdy resigns and separately warns the EPA that PFOS levels were rising in eagles and other wildlife, and that 3M had not disclosed this.
By the company's own internal timeline, roughly twenty years passed between 3M first detecting PFOS/PFOA in human blood and the EPA learning anything about it from 3M.
The phase-out
3M did not choose to stop making C8 because the science had changed. The science had been sitting in its own files since 1976. What changed was that regulators were now asking questions 3M could no longer deflect.
- May 16, 2000: 3M CEO Livio "Desi" DeSimone announces a voluntary phase-out of PFOS-based chemistry under mounting EPA pressure.
- The affected product lines represented roughly 2% of 3M's $16 billion in annual sales; the company took a charge of about $200 million to wind them down.
- By the end of 2002, the global phase-out is complete, and 3M exits the C8 supply business entirely.
That exit had a direct consequence for the company 3M had been supplying for half a century. With 3M gone from the C8 market, DuPont began manufacturing its own C8 in-house at Fayetteville, North Carolina, in 2002 — taking over a production step it had outsourced to 3M since 1950. 3M's decision to walk away from its own liability expanded DuPont's.
The bill comes due
Walking away from the C8 business in 2002 did not make the contamination already in the ground, the water, or the workers disappear. It surfaced on a schedule of its own.
- 2010: Minnesota's Attorney General sues 3M over PFOS and PFOA contamination of the Twin Cities east-metro groundwater aquifer, traced to 3M's Cottage Grove plant.
- February 20, 2018: 3M settles with Minnesota for $850 million; about $720 million funds Twin Cities water and natural-resource projects serving roughly 174,000 affected residents.
- 2021: excavation for Antwerp's Oosterweel road project uncovers severe PFOS contamination at 3M's manufacturing site in Zwijndrecht, Belgium.
- July 2022: 3M commits €571 million to remediation in Flanders.
- June 22, 2023: 3M agrees to a nationwide settlement worth roughly $10.3 billion, potentially up to $12.5 billion over 13 years, with more than 11,000 U.S. public water utilities — the largest environmental-contamination settlement in U.S. history. A federal judge approves it in March 2024.
- February 24, 2026: a lawsuit brought by 1,400 Belgian residents against 3M's Zwijndrecht operations opens in Antwerp, seeking roughly €30 million.
For fifty-two years, DuPont's Teflon line ran on a chemical it bought from 3M, made using a process 3M had confirmed by 1976 was building up inside the bodies of the people who worked with it. 3M kept selling it for another quarter-century, disclosed nothing to federal regulators for roughly twenty years after its own scientists found the problem, and then, in 2000, stopped selling it for reasons of its own liability — a decision that forced its former customer to start manufacturing the same chemical itself. The supplier got out first. The customer inherited the rest.
Filed from public reporting:
- The Intercept — "3M Knew About the Dangers of PFOA and PFOS Decades Ago"
- ProPublica — "Toxic Gaslighting: How 3M Executives Convinced a Scientist the Forever Chemicals She Found in Human Blood Were Safe"
- EPA Archive — "EPA and 3M Announce Phase Out of PFOS"
- EHS Today — "3M to Phase Out Chemicals Used in Scotchgard Line"
- NPR — "3M Reaches $10.3 Billion Settlement Over Contamination of Water Systems"
- Star Tribune — "State Finalizes Payouts From Minnesota's $850 Million Forever Chemicals Settlement With 3M"
- Wikipedia — "3M Contamination of Minnesota Groundwater"
- Bloomberg — "3M Hid Its Toxic Chemical Contamination in Belgium for Over a Decade"
- Courthouse News Service — "Post-it Maker 3M on Trial in Belgium Over 'Forever' Chemicals"
- Minnesota Reformer — "Toxic: 3M Knew Its Chemicals Were Harmful Decades Ago But Didn't Tell the Public, Government"