‘Our Land Is Leaking’: Michael Sheen’s Damning BBC Documentary Uncovers the Poisonous Legacy Hidden in the Welsh Earth

Decades after industrial giants buried hundreds of thousands of tonnes of carcinogenic ‘forever chemicals’ across Wales, actor Michael Sheen and top forensic scientists have exposed a cover-up that hits horrifyingly close to home—revealing that the toxic threat is far from history.

In the lush, rolling hills of South Wales, where livestock graze and children play, a lethal secret lies buried.

It is a story of corporate greed, political complicity, and decades of systemic denial. But following the broadcast of the explosive two-part BBC investigation Buried with Michael Sheen, the true, terrifying scale of Wales’s toxic legacy can no longer be swept under the rug.

Fronted by the Port Talbot-born Hollywood actor, the groundbreaking documentary picks up the mantle of environmental campaigner and whistleblower Douglas Gowan. Before his death in 2018, Gowan recorded his final testimony with Sheen, desperate to warn the public that dangerous chemicals dumped in quarry sites half a century ago were still actively poisoning the Welsh soil and water table.

What Sheen and a team of forensic scientists uncovered over the course of their investigation has sent shockwaves through our nation—and directly into the homes of ordinary Welsh families.

The Newport Factory and the Toxic Miracle

At the heart of the scandal lies Monsanto, the American chemical conglomerate whose plant in Newport, South Wales, manufactured roughly one-third of the world’s supply of Polychlorinated Biphenyls (PCBs) between the 1940s and late 1970s.

Marketed as industrial “miracle compounds” for their flame-retardant and insulating qualities, PCBs are now universally recognized as Group 1 carcinogens and non-biodegradable “forever chemicals.” They do not break down in nature; instead, they bioaccumulate in animal tissue, human organs, and food chains, causing cancers, immune disorders, and severe birth defects.

               HOW "FOREVER CHEMICALS" (PCBs) TRAVERSE WALES

       [ Monsanto Plant, Newport ]  ──► Industrial Production (1940s-1970s)
                                                 │
                                                 ▼
             [ Night Tankers ] ──────► Unregulated Dumping
                                                 │
      ┌──────────────────────────────────────────┴──────────────────────────────────────────┐
      ▼                                          ▼                                          ▼
 [Ty Llwyd Quarry]                        [Brofiscin Quarry]                   [Llwyneinion Acid Lagoon]
  (Ynysddu, Caerphilly)                 (Groesfaen, RCT)                           (Rhosllanerchrugog, Wrexham)
      │                                          │                                          │
      ▼                                          ▼                                          ▼
 Toxic Leachate Seeps                  Infiltration of Deep                  Over 90,000 Tonnes
 Into Rivers & Soil                   Groundwater Reserves                  Acid Sludge Leaching
      │                                          │                                          │
      └──────────────────────────────────────────┼──────────────────────────────────────────┘
                                                 ▼
                             [ Modern Testing: 13 of 14 Sites Active ]
                                                 │
                                                 ▼
                            [ Widespread Human & Animal Contamination ]

When Monsanto’s operations in Anniston, Alabama, faced lawsuits over severe public health crises, internal corporate memos uncovered by journalists Dan Ashby and Lucy Taylor show the company knew as early as the mid-20th century how deadly PCBs were.

Yet, while production stalled in North America, imports and manufacturing surged in South Wales. By-products and toxic sludge were routinely tankered off in the dead of night, dumped untreated into unlined quarries, fields, and pits across South and North Wales.

“A Chemical Cocktail”: The Scientific Evidence

Working alongside Dr Dave Megson, a reader in environmental forensics at Manchester Metropolitan University, the documentary team conducted independent testing across suspect sites.

The results were damning:

• 13 of 14 Sites Leaking: Environmental testing revealed elevated, dangerous levels of PCBs escaping from almost every location tested.

• Shocking Concentrations: In woodland surrounding the Ty Llwyd quarry above Ynysddu, soil samples showed PCB levels up to 140 times higher than average, with toxic “leachate” liquid actively seeping through fences into public walking areas.

• Contaminated Food Chains: Earlier testing carried out for the project found banned PCBs in shop-bought fish at levels so high they breached official health advice—and, in one case, broke UK safety laws.

“What our data shows is those sites are leaking and those sites are a chemical cocktail… Some of these readings were pretty much the highest I’ve ever seen in anything we’ve tested. The country is in a really dire place.”

— Dr Dave Megson, Environmental Scientist

For Sheen, the investigation turned terrifyingly personal. When he agreed to have his own blood tested as a baseline control subject, laboratory tests revealed he carried detectable levels of toxic “forever chemicals” in his bloodstream.

Human Cost in the Valleys

Across the communities featured in Buried, residents recalled decades of strange industrial practices. In Ynysddu, elders remembered lorries dumping black, jelly-like sludge into local quarries that spilled out onto public roads. Today, families report unusually high clusters of cancer, while dog owners recount pet after pet dying from rare pancreatic diseases after walking in nearby woods.

Farther north at the Llwyneinion Acid Tar Lagoon near Wrexham, over 93,000 tonnes of chemical waste—including barrels suspected to originate from Monsanto—sit behind flimsy security fences. Despite 18 separate state investigations since 1979, the site remains un-remediated, posing a continuous threat to local water tables.

“They Wouldn’t Be Able to Fight Back”

Throughout the documentary, a dark thematic thread emerges: working-class communities were deliberately targeted as sacrifice zones. When Sheen traveled to Alabama to speak with US attorney Donald Stewart—who successfully sued Monsanto on behalf of local residents—the veteran lawyer broke down in tears when asking why industrial magnates chose these regions:

“If you look at this area, they’re working people… They wouldn’t be able to fight back.”

In Westminster, historic parliamentary records show that rather than investigating Douglas Gowan’s warnings in the 1970s, government ministers attacked his credibility from the dispatch box to shield lucrative chemical manufacturing.

The Political Reckoning: What Happens Now?

In the days since Buried with Michael Sheen aired, thousands of former industrial areas across Wales have come under scrutiny.

• Calls for Health Studies: Local politicians, environmental organizations like Friends of the Earth Cymru, and the Royal Society of Chemistry are demanding an immediate, comprehensive epidemiological health survey of communities living near historic dump sites.

• Enforcing ‘Polluter Pays’: Campaigners are calling on both the Welsh Government and Westminster to institute a legally binding “polluter pays” model. Currently, corporate entities avoid liabilities while local councils—strapped for cash—claim sites “do not meet the statutory definition of contaminated land” due to restrictive testing criteria.

• Regulating PFAS: The Royal Society of Chemistry is leveraging the film’s momentum to push for new, strict drinking water standards for modern PFAS chemicals, warning that history is repeating itself.

Wales was once the powerhouse of the Industrial Revolution, but its people are still paying the price in blood, soil, and water. As Michael Sheen’s crusade makes clear: the truth can no longer stay buried.