Council ‘must carry out own tests’ on site labelled toxic in Michael Sheen documentary

Martin Shipton

Two campaigning councillors who appeared in Michael Sheen’s documentary about toxic land contamination in Wales have urged their local authority to carry out tests on a site highlighted in the programme.

The Ty Llwyd quarry in the village of Ynysddu, Caerphilly county borough, was used in the 1960s and 1970s as a dump site by the now-defunct chemicals manufacturer Monsanto.

According to tests undertaken for the programme, which was screened in August 2026, the levels of toxic PCBs found in samples taken at a nearby lay-by were 140 times higher than the background level.

Independent councillors Janine Reed and Jan Jones say tests should be undertaken at the lay-by, which is adjacent to a well-used local footpath.

In a statement, they said: “Why won’t Caerphilly County Borough Council (CCBC) test the layby at Ty Llwyd? That is the simple question residents in Ynysddu are asking.

“Dr David Megson, an esteemed scientist specialising in chemistry and environmental forensics, was approached by the Royal Society of Chemistry to provide scientific expertise to the production team of the BBC’s Buried with Michael Sheen. As part of that work, he carried out sampling around Ty Llwyd and reported elevated levels of PCBs. His findings have raised serious questions about contamination in an area already known to have a history of pollution concerns.

“We are not saying a television programme should replace proper council investigation. Quite the opposite. If there is nothing to worry about, surely the answer is simple: test the layby.

“CCBC has confirmed that this particular area, beside the entrance to Pantyffynnon Community Woodland and next to a council-maintained public footpath, was not sampled as part of its Ty Llwyd ‘not contaminated’ assessment.

“Dr Megson’s reported results therefore cannot simply be compared with council results for the layby — because there aren’t any.

“That leaves residents asking why.

“There is also a wider point about local democracy. We have heard repeatedly from residents who believe there is a perception of a difficult or politically hostile relationship between CCBC and the two Ynysddu councillors whenever we raise environmental concerns.

“Whether that perception is fair or not, it is something we cannot simply ignore. Our responsibility is to represent residents, ask difficult questions and pursue answers — whether those questions concern Ty Llwyd or the proposed ERI Ltd opencast development on Mynydd y Grug.

“We make no apology for doing that.

“This is not about whether the council agrees with us, or whether we agree with the council. It is about whether elected representatives can raise legitimate concerns on behalf of their communities and receive proper, evidence-based responses.

“On Ty Llwyd, one question remains particularly straightforward: if CCBC is confident there is no risk associated with the layby, why not test it?

“Test it. Publish the results. Let the evidence speak for itself — and give residents the reassurance they so badly deserve.”

Soil sampling

A senior council official wrote to the two councillors stating: “As you are aware, we have undertaken soil sampling in the woodland area and on private land where the surface water flows and where water containing leachate flows from the aeration chamber during prolonged wet periods. The PCB sampling results were compared to a conservative risk-based screening value. The PCB screening value used in the Part 2A report was for a residential land use, which is based on a young child potentially coming into contact with the soil 365 days of the year.

“The woodland and private land where the soil sampling was undertaken is more akin to public open space and grazing land and this is why the risk-based screening value for PCBs were conservative. The sum PCB results were found to be below the conservative residential land use screening value and therefore were not considered to pose an unacceptable risk to human health.

“We understand your statement that ‘there are no safe levels of PCB contamination’ but in terms of exposure to contaminants, including PCBs, we have to take a risk-based approach. This is a common approach, not just in contaminated land, but it is also used in health and safety workplace exposure limits for example.

“It is important that any further investigation is reasonable, evidence-based, and proportionate. In carrying out our duties under Part 2A of the Environmental Protection Act 1990, the council is required to focus investigations where there is a reasonable possibility of significant harm occurring and to ensure that any further investigation is proportionate to the level of risk identified. Taking into account the sampling undertaken to date, the analytical results obtained, the risk assessments completed and the nature of the layby location, Environmental Health does not consider additional soil sampling within the layby area adjacent to Twyn Gwyn Road to be necessary at this time.”

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