Defining ‘forever chemicals’ is a job for science alone

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It has all the makings of a toxic controversy. Growing evidence suggests that the molecules known as forever chemicals — used in everyday items like cosmetics, non-stick pans and water-repellent clothing — can build up in the environment and in the body, to the detriment of both.

Last year, the world’s pre-eminent chemistry organisation announced a panel would look again at how the chemicals — more properly known as per- and polyfluoroalkyl substances, or PFAS — are defined. That has stoked unhappiness among some researchers, who suspect that the rethink, to be carried out by the International Union of Pure and Applied Chemistry, might end up narrowing the definition and letting some forever chemicals off the regulatory hook. The current definition, they protest, is grounded in science and works well; the new initiative, they argue, is motivated by political or economic considerations, rather than science.

Their objections deserve a hearing. In setting out its reasons for redefining a class of chemicals that have existed for decades, the chemistry union tellingly mentions European regulation and declares it is “hardly feasible” for around 9,000 PFAS to face a possible ban from 2026. That seems an odd statement: it is unclear why a chemically rigorous definition of a chemical, as newly drafted by the world’s top chemistry body, should nod to anything other than chemistry.  

Forever chemicals, featuring a backbone of carbon atoms with fluorine atoms attached, were first developed in the 1940s. Their resistance to oil, grease and water made them a commercial hit. But those same qualities allowed the molecules to linger indestructibly — in water, soil and air, in the food chain, in blood and human organs. The substances have been variously implicated in cancers, obesity and falling fertility. Manufacturers including 3M and DuPont have paid out enormous sums to settle health- and environment-related PFAS lawsuits.

The exact number of legacy and novel PFAS is uncertain because some were made but never documented; figures between 5,000 and 12,000 are often quoted. Their proliferation, along with rising health and environmental concerns, led to the OECD consulting on a peer-reviewed definition intended to capture the full range of fluorinated molecules. That concluded in 2021, with the input of chemical agencies around the world.

In the journal Environmental Science & Technology Letters, the 20 protesting academics expressed concern this month that any fresh IUPAC manoeuvring could “exclude certain fluorinated chemical subgroups from the scope of the existing definition”. Given that the union is regarded as the ultimate arbiter of all things chemical, including the names of new Periodic Table elements, its verdict will carry clout. The letter continues: “An IUPAC-endorsed and potentially narrower PFAS definition could . . . influence regulatory bodies and others to adopt less protective policies.”

The letter of protest was co-ordinated by Gabriel Sigmund, a micropollutants researcher at Wageningen University in the Netherlands. It is signed by, among others, scientists in the US, Canada, UK, Sweden and Switzerland, some of whom worked on the OECD definition. More than 200 scientists have since added their signatures, the FT has learnt. 

Alex Ford, a marine ecotoxicologist at Plymouth University in the UK, said he signed because altering definitions could “sow doubt and create confusion” and the precautionary principle should reign supreme. “We are still seeing the harmful effects in wildlife of chemicals we banned decades ago . . . they are chemically stable, very mobile and, the more we look into them, toxic.”

As is fairly common with academic researchers, at least two members of the new IUPAC panel list past or current links with industry. Co-chair Pierangelo Metrangolo, a Milan-based chemist, discloses consultancy work for the company Solvay Solexis on his publicly available CV. In 2023, its parent company Solvay paid out nearly $400mn to settle a PFAS lawsuit in New Jersey.

There is no indication that Metrangolo was involved. He has previously said the new panel “has not finalised any conclusion, yet, and there are no indications that certain subgroups of chemicals would be excluded”. The IUPAC did not respond to a request for comment.

It is tempting to gloss over the row as technical, arcane or irrelevant. But the definition of a forever chemical matters to us all: like the chemicals themselves, its influence could persist — on research, industrial practice, regulation and legal liability cases — for decades to come.

anjana.ahuja@ft.com