‘Forever chemicals’: Everything you need to know about PFAS

The thousands of chemicals in the PFAS group are coming under increasing scientific, regulatory and legal scrutiny and are the subject of a new film starring Mark Ruffalo. Here’s what you need to know.

The PTFE (Teflon) coating of many non-stick pans is based on a polymerised form of PFAS, though exposure from this route is thought to be minimal. Photograph: The Washington Post/Getty Images

What is PFAS?

The chemicals’ useful properties, particularly in creating stain resistance, have generated a hugely valuable market that has been growing for decades.

But alarm bells were raised. An early form, PFOS (formerly the key ingredient in the Scotchgard stain resistant treatment) was not only being found in human blood, it was also toxic, persistent and bioaccumulative.

Under pressure from the US Environmental Protection Agency, producer 3M announced that it would phase out the production of PFOS and related compound perfluorooctanic acid (PFOA) in 2000. Its Scotchgard product was reformulated in 2003 to use perfluorobutanesulfonic acid (PFBS) instead. Though similar in structure, it was thought to be much safer.

In 2017, DuPont settled a lawsuit brought on behalf of people living around its factory in West Virginia for $671m, after PFOA entered the town’s drinking water and high levels of it were found in blood. The case is depicted in the recent film Dark Waters. It formerly used the substance to make non-stick coating Teflon.

The following year, the state of Minnesota obtained an €850m settlement from 3M for polluting groundwater with PFOA. DuPont spinoff Chemours estimates litigation and cleanup costs for the same chemical will come to $884m.

PFOS, PFOA and PFBS are members of the wider per- and polyfluroalkyl substances group, which has at least 4,730 members, according to the Organisation for Economic Co-operation and Development (OECD). Many have a soap-like structure, with a long chain of carbons attached to fluorine atoms, with a water-attracting head.

Due to its solubility, extreme persistence and tendency to bioaccumulate, high levels of PFAS have been found in Arctic animals such as polar bears and seals.

The health impacts of PFOA are by far the most well-studied, due to an epidemiological study undertaken as part of the DuPont litigation over 2005-13. The ‘C8 Science Panel’, named after the number of carbons in PFOA, found “probable links” with high cholesterol, chronic kidney disease, ulcerative colitis, liver disease, osteoarthritis, thyroid disease, and pregnancy-induced hypertension.

The panel also proved a link to testicular cancer and kidney cancer, though it found against links to Parkinson’s disease, asthma and diabetes.

The lawyer involved in the DuPont case, Rob Bilott, is currently pursuing a suit against 3M, DuPont and Chemours on behalf of “everyone in the United States who has a detectable level of PFAS chemicals in their blood”. 

His plan to agree funding for a major health study, “would go a long way to resolving the PFAS crisis by providing scientific answers that everybody involved would commit to,” said Bilott in an interview two years ago. “Otherwise there’s the potential for endless litigation and fighting over the meaning of the science,” he added.

Further research has also suggested an impact on the development of foetal brain tissue and low birth weight.

Where is PFAS?

European Environment Agency (EEA) has estimated that PFAS exposure costs Europe at least €52-84bn a year.

Aside from being used as monomer for non-stick coatings, it is present in products as diverse as waxes, polishes, paints, cleaning products, hydraulic fluid and formerly fire-fighting foams – leading to groundwater pollution after blazes such as the Buncefield disaster and from training exercises. At least 400 US military bases are affected, alongside civilian airports.

Individual exposure to PFAS “is very low”, according to Tony Fletcher, environmental epidemiologist at the London School of Hygiene and Tropical Medicine. Due to trace amounts in drinking water, fabric and suchlike, “there is not much you can do” about that – you can’t control it”.

He added that there is not much point in junking Teflon-coated pans for health reasons. While there may be trace amounts in new ones, it would soon be volatilised through heating. Exposure to PFAS is more likely from salmon, he suggested, so long as pans are not over-heated.

But recent research from Scottish environmental charity FIDRA has also established how common PFAS is in food packaging, being used to make paper and card-based products such as takeaway containers waterproof. It has warned that the public’s exposure could rise as regulatory and public pressure rises to stop the use of single-use plastic.

What is being done about it?

The EEA’s report into PFAS, published in December, stated that the huge number of PFAS chemicals mean that the conventional “substance-by-substance risk assessment and management approach is not adequate to efficiently prevent risk to the environment and human health.” It backed regulating them as an entire group, a measure long-advocated by chemicals campaigners.

In December, the Dutch government, backed by Denmark, Luxembourg and Sweden and European Chemicals Agency, proposed a “comprehensive” phase-out of PFAS across the EU. Its scope implies far-reaching implications for the chemical industry and manufacturers. 

EU water service association EurEau backed a broad restriction this week. “In order to maintain safe, clean, healthy and above all, affordable water services for all our consumers… it is essential to keep PFAS out of the environment. The only effective way to achieve this is a ban of all non-essential PFAS applications,” its secretary general Oliver Loebel told ENDS.

Earlier this week, an update to the 1998 Drinking Water Directive was finalised, introducing a limit for the 20 forms of the substance – though there will be no obligation for the UK to do the same due to Brexit.

In September, the Danish government said it would ban PFAS from paper-based food packaging from the middle of this year, prompting calls for the move to be reflected in EU law.

Danish food minister Mogens Jensen said the substances represent a “major health problem” because of the risk that they may migrate from paper and cardboard packaging into food.

Both European consumer group BEUC and chemical campaigners CHEM Trust have said that the situation illustrates deficiencies in the EU’s regulation of toxics in good contact materials.

“The high concerns of PFAS exposure for our health are so well documented by scientific studies that the Council of Environment Ministers recently requested a European action plan to eliminate all non-essential uses for these substances,” said Natacha Cingotti, senior policy officer at the Health and Environment Alliance (HEAL). 

Some forms of PFAS are already banned or subject to stringent control, with the UK introducing a unilateral ban on PFOS in 2005. 

PFBS – also used as a flame retardant and pesticide – turned out to be an example of ‘regrettable substitution’. It was designated as a substance of very high concern by ECHA last month, joining other forms of PFAS HPFO-DA, PFHxS, PFDA and PFNA.