Top scientists have criticized the UK government for failing to take stronger action to tackle "forever chemical" pollution and refusing to follow an EU move to ban non-essential use of the substances.

Last year, 59 per- and polyfluoroalkyl substances (PFAS) experts wrote to the Department for Environment, Food and Rural Affairs (Defra) asking it to follow science which has confirmed that PFAS do not biodegrade and despite The differences, toxicity, and persistence are enough of a concern on their own that all PFAS should be regulated as a class.

PFAS contamination is so common that nearly everyone on the planet has the chemical in their blood. Of the more than 10,000 chemicals known to exist, two are widely banned after decades of scientific research conclusively demonstrated that they are toxic and linked to cancer and a host of other serious diseases.

Given the time required to determine the toxicity of both substances, five EU member states proposed a collective ban, except for critical uses. Industry lobby groups are opposing the proposal.

Defra responded to scientists in a letter seen by Watershed Inquiry and the Guardian, setting out plans to permanently control the chemicals. The plans fell short of what scientists wanted.

"Defra has repeatedly suggested... that 'not all PFAS are harmful' - which I believe is untrue," said Professor Ian Cousins, the letter's organizer. “I agree that PFAS have multiple properties and toxicities, but their extremely high environmental persistence makes all PFAS problematic.”

Fluoropolymers are high-performance plastics that the industry has fought to gain immunity from regulation along with other PFAS. The UK government decided not to adopt the definition of PFAS used by the Organization for Economic Co-operation and Development (OECD), which includes fluoropolymers, and said it would create its own smaller group.

“The implication is that I believe Defra wants to exclude fluoropolymers from the PFAS action,” Cousins ​​said, arguing that “the industry likes (the UK’s approach) because it favors a risk-based approach rather than a hazard-based approach. EU regulation is based on problematic intrinsic properties, such as high persistence”.

He added: "My view is that a risk-based approach does not work for this extremely persistent chemical. If extremely persistent chemicals are released continuously, environmental levels will increase over time... If we "We do cross some known or unknown impact threshold before we can remove (certain types of PFAS) from drinking water."

Professor Crispin Halsall of Lancaster University wanted to understand the basis for Defra to create its own grouping of PFAS. "Is this based on science or is it political? Based on their letter, it's a pragmatism, which I can understand...but I think they should align more closely with the EU rather than create a new PFAS sub-list, but in collaboration with the OECD.”

Professor Patrick Byrne of Liverpool John Moores University said: "The lack (of toxicological evidence for most PFAS) does not mean there is no risk." He also raised questions about the government's claim that there are only "a few hundred" PFAS across the UK Objection, while "emerging evidence suggests there are many more PFAS out there, and (Defra is making this assumption) may simply be because we are only monitoring "a few".

In the letter, Defra said it would review more evidence before deciding whether to lower the limits for PFAS in drinking water to be closer to the much lower limits used in Europe and the United States.

But Dr David Megson of Manchester Metropolitan University said "Defra is avoiding the issue when it is put in front of you". He added: "We need more than just the government saying: 'We're just assessing it.'"

Halsall said the search for alternatives to PFAS would "drive innovation in the chemical industry...push the button on the growth agenda".

"I applaud the government for its response but there are some issues here and if it's a big issue and they want to put it aside for a while because they don't know what to do with it, then that's not good enough," he added .

Dr Shubhi Sharma, of the charity Chem, called Defra's "lack of urgency" shocking. "Every day of delay adds to this toxic time bomb. The UK government has all the evidence it needs to take immediate action to protect people and nature from the harmful effects of these permanent chemicals."

A Defra spokesman said the government was committed to protecting the environment from the risks posed by chemicals. "We are rapidly reviewing environmental improvement plans to achieve legally binding targets for saving nature, including how best to manage the risks posed by PFAS," they said.