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.
Brochures for 3M firefighting foams dated 1979 described them as being “environmentally neutral” as well as “biodegradable, low in toxicity, and … can be treated in biological treatment systems”.
In a 1986 document, 3M stated that “if 3M Light Water Brand aqueous film-forming foams (AFFF) products were pure chemicals instead of mixtures, OECD guidelines would classify them as ‘readily biodegradable’”. Data sheets from 1993 still recommended that the foams be discharged to sewers because they were “treatable in a biological wastewater treatment system”, although they noted that some elements might remain in treated wastewater.
Prof Ian Cousins from Stockholm University, a leading PFAS expert, said: “Disposing of the foams in a sewer was disastrous as the PFAS went straight through the wastewater treatment process, either ending up in the effluent from the wastewater treatment plant or in the sludge. The effluent was discharged into rivers and the sludge would often be spread on agricultural land.”
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”.
Evidence came to light when 3M paid out $890m in settlements in 2018 after the former Minnesota attorney general Lori Swanson filed a lawsuit against 3M for PFAS pollution.
In testimony to the US House of Representatives, Swanson provided a fax from a fire protective equipment firm to 3M dated June 1988. In it, the firm said: “In all literature and documentation that is published by the major manufacturers of AFFFs [and verbal presentations made by manufacturer’s reps] it is claimed that these products are biodegradable … Imagine the surprise and total shock … embarrassment and credibility loss …” at being told by others that the foams were not after all biodegradable.
3M in 2023 agreed to pay settlements amounting to more than $10bn over contamination of various public drinking water systems, though it did not admit liability in these cases.
It has previously been established that 3M also knew certain PFAS were toxic early on. Company meeting minutes dated 1978, which reviewed studies on monkeys and rats, stated that PFOS and PFOA “should be regarded as toxic although the degree of toxicity was left undefined”.
As a result of 3M providing misleading information to customers, untold volumes of the foams may have been misused across the world, contaminating soils, water and people’s blood with PFAS.
In 1987, the Australian government used 3M’s information to justify spreading firefighting foams on to fields as a means of disposal. Department of Defence documents prepared for RAAF Tindal, an airbase in the Northern Territory, included 3M’s advice stating that the foams were “biodegradable and have low toxicity”. It recommended “land treatment” as an “effective and inexpensive method of stabilising AFFF wastewater”.
In 2017, it was discovered that PFOS from RAAF Tindal had contaminated a drinking water aquifer. The government had to provide a new water treatment plant capable of removing PFOS, and urged anyone reliant on private boreholes to drink bottled water. The Department of Defence said the cost to taxpayers would run into hundreds of millions of dollars. In December, the Australian government said it would “establish a national coordinating body to respond to the specific needs of communities impacted by PFAS around defence bases”.
In the UK, many PFAS pollution hotspots are linked to sites that used high volumes of PFAS foams, such as the fire training college in Moreton-in-Marsh in the Cotswolds, Angus Fire in Bentham in Yorkshire, and the Duxford airfield in Cambridgeshire, where a drinking water source was contaminated. Other hotspots include airports, military sites, manufacturers and landfills.
A spokesperson for 3M said: “AFFF was developed in the 1960s to be used by military service members and other first responders facing potentially high hazard, life-threatening challenges. As the science and technology of PFAS, and societal and regulatory expectations have evolved, so has how we manage PFAS.”
In 2000, 3M announced it would phase out certain PFAS chemistries used in the production of products such as AFFF, including PFOS and PFOA. 3M says it has “long since phased both materials out of its operations and also permanently discontinued production of AFFF”.
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.”
The company says it is “committed to these actions in partnership with leading scientists, community advisers, and government authorities”.
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.
A UK government spokesperson said: “PFAS chemicals have been used extensively for over 70 years and their persistence once in the environment unfortunately means there are no quick fixes. We have already begun investigating whether to restrict PFAS in firefighting foams and will set out more detail in due course.”
