The multibillion-dollar chemicals company 3M told customers its firefighting foams were harmless and biodegradable when it knew they contained toxic substances so persistent they are now known as “forever chemicals” and banned in many countries including the UK, newly uncovered documents show.
From the 1960s until 2003, 3M made foams containing PFOS and PFOA (perfluorooctane sulfonate and perfluorooctanoic acid), synthetic chemicals that can take tens of thousands of years to degrade in the environment and have been linked to cancers and a range of other health problems such as thyroid disease, high cholesterol, hormonal problems and fertility issues.
Pollution from these substances in soils and water is now widespread across the globe, and has been detected in animals, human organs and blood. They are part of a wider family of more than 15,000 chemicals known as per- and polyfluoroalkyl substances (PFAS) but popularly called “forever chemicals”.
Experts have described PFAS pollution as “one of the greatest threats facing mankind”. Last year, 59 leading scientists signed an open letter to the UK government urging it to impose stricter regulations on the substances.
Documents uncovered by Watershed Investigations and the Guardian reveal that evidence showing PFOS does not biodegrade had begun to appear as early as 1949. However, until the 1990s 3M continued to produce information and brochures for customers stating that natural processes would break down the foams.
3M made the claims despite evidence of PFAS’ nonbiodegradable properties having grown since 1949, when an article in Scientific American noted that fluorocarbons, which include all PFAS chemicals, “do not burn, corrode, mold or decay. Neither rodents nor insects nor fungi can find any nourishment in them.”
In 1964, 3M employee HG Bryce authored a chapter of a book called Fluorine Chemistry in which he said the fluorocarbon portions of substances were “physiologically inert” – in other words, they do not biodegrade.
A 3M document dated 1983 showed that PFAS did not degrade in lab tests and said this demonstrated that biodegradation “cannot be depended on to occur in an aquatic environment”.
3M announced in 2022 it “would exit all PFAS manufacturing globally by the end of 2025 and are on schedule to do so. We will continue working to innovate new solutions for our customers. We have engaged in site remediation at our facilities and have invested in state-of-the-art water treatment technologies at sites where we have historically manufactured PFAS.”
Despite 3M’s actions and the widespread concern over PFAS, the use of foams containing PFOS was not banned in the UK until 2011, and foams containing PFOA will not be fully restricted until July 2025. Foams containing other types of PFAS are still in use.