A string of toxic pollution hotspots has been uncovered across Cumbria and Lancashire, with high levels of the banned cancer-causing “forever chemical” Pfos detected in rivers and groundwater at 25 sites.

The contamination, spread across a large area, was uncovered by Watershed Investigations and the Guardian after a freedom of information request revealed high concentrations of Pfos in Environment Agency samples taken in January 2025.

Pfos is a type of per- and polyfluoroalkyl substance (Pfas), known as “forever chemicals” because they take hundreds or thousands of years to degrade. They are widely used in consumer products and some have been linked to a range of serious health problems.

At one site, groundwater contained Pfos at 3,840ng/l, alongside elevated levels of other banned Pfas compounds. Twenty-five sites recorded Pfos concentrations well above drinking water guideline limits of 100ng/l for the combined total of 48 Pfas compounds.

The contamination spans an area of outstanding natural beauty with multiple protections for wildlife and habitats.

A resident whose business’s private well is polluted said they found out in November 2021 after being “unofficially” informed by an individual at the Environment Agency, and stopped drinking the water immediately. According to the resident, the agency had been testing the well for about 35 years because of concerns about “chemical drift” in the groundwater.

“When I contacted the agency, they offered no help,” the resident said, adding that they were directed to Westmorland and Furness council, which “said they wished I had not been told, as they could not even test for Pfas … there was no help, no advice, no support of any kind”.

“I tried to get the council to look for the source of the pollution but no one seemed interested,” the resident said. “They said it looked like we were an outlier … nearly five years later I am still no wiser.”

Westmorland and Furness council said it was informed by the Environment Agency about the contaminated supply in late 2021 and that the business switched over to the mains water supply.

“The council has continued to support the business to ensure compliance in line with statutory requirements and the provision of a safe water supply. These arrangements remain in place and are being managed to ensure there is no risk to public safety,” said a spokesperson.

The Environment Agency said it identified elevated levels of Pfas in the area in 2022 through its national surveillance monitoring programme, but stressed that responsibility for protecting users of private water supplies lies with local authorities.

The agency said it alerted the private borehole owner after detecting Pfas above drinking water guidelines and advised them to contact the local council. It added that councils, the UK Health Security Agency, the Food Standards Agency and the Drinking Water Inspectorate (DWI) were informed in 2025.

Possible sources of Pfos contamination identified in the Environment Agency’s March 2025 report include a paper mill in Beetham, where Pfas are known to have been used. Sites where Pfas-contaminated paper pulp may have been spread on land are also flagged as potential hotspots where Pfas could contaminate soils and enter the food chain.

The mill’s operator went into administration and its assets were sold to a new operator in June 2025. Responsibility for earlier operations now sits with the former company’s administrators.

“The mill is now operated by a new legal entity,” said Robyn Khan, director of the new operator Pelta Medical Papers. “Since this acquisition, there has been no use of Pfas-based chemicals on site, and the mill does not manufacture paper containing Pfas.

“Any manufacture of Pfas-containing paper products occurred under the previous legal entity and ownership, in line with regulatory guidance and permit conditions in force at the time. We take our environmental responsibilities seriously and will continue to engage appropriately with the relevant regulatory authorities.”

The mill’s administrators, Kroll Advisory, did not respond to requests for comment.

The Environment Agency report also identified five historical landfills and one operational landfill as possible sources of Pfas, alongside sewage treatment works, fire stations and discharges from caravan parks.

The government’s new Pfas action plan, published on Tuesday, sets out proposals to tighten controls on the chemicals, including new guidance on contaminated land, a consultation on statutory limits on Pfas levels in drinking water, and potentially tougher rules for industrial sites.

But Water UK wants Pfas banned altogether. It said: “We risk falling further behind other European nations, which are increasingly banning these substances and demanding manufacturers pay for clean up.”

Chloe Alexander, the chemicals policy lead at Wildlife and Countryside Link, said the government’s plan was “a roadmap to nowhere”, warning it contained no binding phaseouts, no clear timetable, and no commitment to match the EU’s proposed Pfas ban.

There are about 33,000 private water supplies in England and “it is becoming ever clearer how vulnerable some private water supplies are as the climate changes”, a DWI report said, with more running dry during droughts and others increasingly hit by environmental pollution.

Hannah Evans from the environmental charity Fidra said: “This is yet another case demonstrating just how prevalent Pfas pollution is and the real-world consequences. Persistent chemicals should not be in our drinking water, our food, or our bodies. We urgently need to turn off the tap and transition the UK towards Pfas-free alternatives, many of which are already widely available.”