London School of Hygiene & Tropical Medicine

Stricter regulation and investigation of dangerous 'forever chemicals' is needed to protect people from continued exposure, according to Dr Tony Fletcher from the London School of Hygiene & Tropical Medicine (LSHTM).

Short for per- and polyfluoroalkyl substances, PFAS can take up to 1,000 years to break down in the environment and are now commonly referred to as ‘forever chemicals’. They were once widely used in consumer manufacturing, firefighting foam and other industrial processes, and became exposed to nearby residents through ground contamination and leaks into nearby water supplies. 

Dr Fletcher has been advising the team investigating a contamination incident in a small rural town in North Yorkshire. In May 2024, a joint investigation by The Ends Report and The Guardian revealed that groundwater was contaminated with the highest level of PFAS ever known to be recorded in the UK. The land once belonged to a factory that, between 1976 and 2024, legally produced PFAS-containing firefighting foam.

Speaking recently to The Guardian, Dr Fletcher said: “The fact there were a number of people in Bentham who have high levels well above 20 ng/ml, who didn’t work at the factory, suggests they were getting exposed in the community.

“This could be possible during the testing of PFAS firefighting foams, where the chemicals could get up into the air and rain down or settle some distance from the factory. It then soaks down into the ground and you either get exposed to the water or to food grown there.”

One particular PFAS, Perfluorooctanoic acid or PFOA, is thought to be one of the most dangerous and it has been fully banned in firefighting foams in the UK since 2025. But given its widespread use in the manufacturing of everyday items such as packaging, carpets, waterproof clothing and cookware before the regulation was introduced, alongside its wider use in foam used to extinguish fuel fires since the 1970s, it’s likely that there are ongoing sources of the chemical.

In February 2026, the UK government published its first national PFAS Plan to address their persistence in the environment but experts say the plan doesn’t go far enough to support those who have already been affected.

Dr Fletcher has been studying the long-term health effects of PFAS exposure since 2005 and continues to call for stricter regulation. He has helped investigate health effects in several high-profile pollution incidents affecting communities, including: chemical pollution from a manufacturing plant in the US, depicted in the 2019 film Dark Waters; pollution in the Veneto region in Italy by another manufacturing facility; and contaminated drinking water in the town of Ronneby in Sweden, polluted by firefighting foam used at a nearby airport. 

Speaking on a new ITV documentary about his research, Dr Fletcher said: “We concluded in the US study of PFOA contamination that six diseases were probably linked to that exposure. Two cancers, kidney and testicular cancer, raised cholesterol, ulcerative colitis, thyroid disease and preeclampsia, high blood pressure in pregnancy.

“We can be certain that there are adverse health effects caused by these chemicals and therefore it’s important to phase them out. We need to investigate how people are still being exposed.”

You can find out more by watching the full ITV documentary. Please note that it contains some scenes that viewers may find distressing.