Key Points
- Thousands of former industrial sites in Wales could need further investigation, according to a 2015 Natural Resources Wales survey cited by the Welsh Government.
- The issue has received renewed attention following Buried with Michael Sheen, a BBC documentary examining allegations of historic polychlorinated biphenyl (PCB) disposal.
- Researcher Douglas Gowan identified 14 sites of concern, including 12 in Wales, before his death.
- Environmental chemist Dr David Megson said the sites featured in the programme were only “the tip of the iceberg” and estimated that around 20,000 high-concern sites could require investigation across the UK.
- Wrexham Council and Natural Resources Wales said previous assessments of the Llwyneinion Acid Tar Lagoon did not meet the legal definition of contaminated land requiring remediation.
- Public Health Wales said current evidence does not show that historical environmental pollution has caused higher cancer or illness rates in the areas discussed.
- Ruth Jones MP, chair of the Welsh Affairs Committee, has called for stronger action, funding, monitoring and a coordinated approach to contaminated land.
Wales (Wales Times) August 27, 2026 – concern over historic chemical contamination has intensified following the broadcast of Buried with Michael Sheen, which examined sites in Wales linked to allegations that industrial chemicals, including PCBs, were disposed of in former quarries, landfills and other locations decades ago.
Wales’ toxic waste legacy has returned to national attention after Michael Sheen’s BBC investigation highlighted allegations of historic PCB dumping and prompted renewed calls for more testing, monitoring and funding for former industrial sites. Welsh Government figures indicate that more than 9,000 potential sites were identified as requiring further investigation in a 2015 survey, although officials stress that not all pose a threat to people or the environment.
As reported by Rowenna Hoskin of BBC Wales, the programme continued work begun by researcher and whistleblower Douglas Gowan, a former farming consultant who spent decades urging authorities to examine sites where he believed significant quantities of industrial chemicals had been dumped. Mr Gowan identified 14 locations of concern, 12 of them in Wales, before his death.
The investigation has centred on PCBs, man-made chemicals formerly used in products including electrical equipment, plastics and paint because of their stability and insulating qualities. Their resistance to breaking down has also made them persistent in the environment. BBC Wales reported that concerns about their toxicity led to restrictions and bans from the 1970s onwards, but residues can remain in landfills and may move through soil and water over time.
What did the Michael Sheen investigation find?
The BBC documentary brought together accounts from residents, campaigners, scientists and people who worked at industrial sites. It also examined historical documents connected to Monsanto’s former operations in uk/local/newport/">Newport and allegations over the disposal of chemical waste in Wales.
As reported by Rowenna Hoskin of BBC Wales, Michael Sheen was told by Douglas Gowan that Monsanto had disposed of “huge amounts of industrial chemicals all around Wales”. Mr Gowan described PCBs as among the most serious contaminants he had encountered, while Mr Sheen said the purpose of the investigation was to ensure residents’ concerns received proper research and action.
The BBC reported that Eastman Chemical Company, which it described as responsible for Monsanto’s legacy production in the UK, did not respond to requests for comment from either the documentary team or BBC Wales.
Journalists Dan Ashby and Lucy Taylor, who worked with the documentary investigation, examined a 1972 Monsanto memo. According to BBC Wales, the document stated that PCBs posed environmental and health risks and referred to the closure of operations in the United States, while production capacity at Newport was later increased. Mr Ashby told the programme that the UK’s approach to imports had enabled hundreds of tonnes of PCBs to be brought in from around the world.
The documentary team commissioned testing at the sites identified by Mr Gowan. Dr David Megson, a reader in chemistry and environmental forensics at Manchester Metropolitan University, led the scientific data collection. BBC Wales reported that Dr Megson found the results concerning and said testing showed the sites were leaking a “chemical cocktail”, while adding that the role of PCBs alone in any health effects remained open to scientific assessment.
Dr Megson said PCBs were suspected carcinogens, meaning they are suspected of causing cancer. However, the reporting does not establish a causal link between contamination at individual sites and any particular resident’s illness.
Why is the Llwyneinion lagoon at Ruabon significant?
The Llwyneinion Acid Tar Lagoon near Ruabon, Wrexham, has become a central focus of the wider debate because of its long industrial history, its proximity to homes and the continuing disagreement over whether formal remediation is legally required.
As reported by Rowenna Hoskin of BBC Wales, a 2006 environmental engineering report viewed by the broadcaster stated that the lagoon had been known to be contaminated since at least 1979. The report recorded 93,100 tonnes of acid sludge from Burmah Castrol and barrels of unidentified substances suspected to be linked to Monsanto among the materials disposed of at the site.
The same report identified 105 potential pathways through which contaminants could affect people, wildlife, property or water supplies. These included three uncapped mine shafts beneath the lagoon, which were identified as possible routes for contaminant movement. BBC Wales reported that, by 2026, the site had undergone 18 investigations, two remediation proposals and five treatment trials over 27 years, but the lagoon remained in place.
Former Wrexham councillor Paul Pemberton, who has campaigned over the site for more than two decades, said the site had been used and “abused” for many years. He told BBC Wales that scientists had identified cyanide, arsenic and PCBs at the location, and that an estimated clean-up cost of around £45 million would have been beyond the council’s means.
Nation.Cymru reported that the estimated £45 million remediation figure dated from 2010 and that Councillor Pemberton believes any current cost would be higher. The publication also reported that he regarded the documentary as a possible final opportunity to secure action over the lagoon.
What do regulators and public bodies say?
Natural Resources Wales and Wrexham Council have maintained that earlier technical assessments did not find the Llwyneinion site met the statutory legal test for designation as contaminated land.
As reported by Rowenna Hoskin of BBC Wales, Natural Resources Wales said investigations by the Environment Agency, its predecessor, took place in 2006 and 2008. The regulator said the findings did not meet the legal definition of contaminated land, leaving Wrexham Council as the regulator responsible for the site.
Wrexham Council said ongoing monitoring since those investigations had not identified significant change and that there was no statutory requirement for remediation. It has said it would consider new robust and verifiable evidence.
Public Health Wales said its cancer intelligence and surveillance unit had collected and analysed cancer data since the 1970s. It stated that, based on the evidence currently available, there was no indication that historical environmental pollution had led to a higher risk of cancer, disease or illness in the areas discussed.
The Welsh Government acknowledged that historic industrial activity had left a difficult legacy. In its statement reported by BBC Wales, it said Natural Resources Wales’ 2015 local-authority survey had identified more than 9,000 potential sites requiring further investigation. The Government emphasised that the figure did not mean every site posed a risk, but said it illustrated the scale facing Welsh regulators.
It added that it intended to develop a Wales-wide strategy to progressively restore post-industrial land and reduce potential risks to communities and the natural environment.
How have MPs and campaigners responded?
The investigation has also renewed political pressure for a larger and more coordinated response across Wales and the UK.
As reported by Nation.Cymru staff, Ruth Jones, Labour MP for Newport West and Islwyn and chair of the Welsh Affairs Committee, said Buried with Michael Sheen had put on screen many of the concerns raised during the committee’s own inquiry into Wales’ industrial legacy.
Ms Jones said the documentary and parliamentary evidence had highlighted limited resources to identify, monitor and clean up sites, as well as a lack of support and information for people who may live near potentially contaminated land. She said the committee had written to Welsh Secretary Stephen Kinnock seeking funding for land clean-up, support for people at risk and a coordinated four-nation approach to testing.
Wales Environment Link has called for the UK Government to help fund work at contaminated sites while pursuing compensation from companies responsible for historic pollution, according to Nation.Cymru. The organisation argues that much of the dumping predates devolution and should not be treated solely as a Welsh Government responsibility.
Friends of the Earth Cymru’s Kirsty Luff has separately called for a public inquiry into the “scale and impact” of toxic sites in Wales. BBC Wales reported that she warned more frequent and intense flooding associated with climate change could increase the risk of contaminants being moved into fields and watercourses.
What is the background to Wales’ toxic waste legacy?
Wales’ toxic waste legacy is linked to the country’s long history of heavy industry, chemical manufacturing, mining and waste disposal practices that often pre-dated modern environmental regulation.
PCBs were widely used during the twentieth century before restrictions were introduced because evidence mounted about their potential effects on human and animal health. Their chemical persistence means that historical disposal can remain a regulatory and scientific concern long after factories have closed or sites have changed ownership.
The current scrutiny is broader than the 14 locations identified by Douglas Gowan. Dr David Megson told BBC Wales that the sites highlighted in Buried with Michael Sheen were “the tip of the iceberg”, estimating that around 20,000 high-concern sites existed across the UK. That estimate concerns the need for investigation, not a finding that all sites are contaminated or dangerous.
How could this development affect Welsh communities?
The immediate effect is likely to be increased public and political scrutiny of historical industrial land, particularly for communities near sites raised in the documentary or in local campaigners’ evidence.
For residents, further investigation could provide clearer information about site histories, environmental monitoring and the basis on which regulators assess risk. For local authorities and Natural Resources Wales, the attention may increase pressure to review evidence, publish accessible findings and identify what resources are needed for site assessment or remediation.
For the Welsh Government and UK Government, the development may intensify discussion about responsibility, funding and whether existing contaminated-land rules adequately deal with pollution dating from before modern regulation. The Welsh Affairs Committee’s continuing inquiry means the issue is likely to remain under parliamentary examination.
The evidence currently available does not establish that historic pollution has caused higher rates of cancer or illness in the affected areas, according to Public Health Wales. Future action will therefore depend on additional environmental, medical, legal and scientific evidence, alongside decisions by regulators and governments on funding and statutory thresholds.
