A BBC documentary, Buried with Michael Sheen, investigating chemical dumping in Wales has prompted a former Monsanto worker to come forward, describing "cheap" protective equipment and staff who were never told what they were burying. Scientists involved in the programme say the 14 contaminated sites it identified are only "the tip of the iceberg", with an estimated 20,000 high-concern sites across the UK, raising fresh concerns about the scale of Britain's toxic waste legacy and the health risks it poses.

Stephen Constance, 61, spent three years in the 1990s helping seal buried waste at Monsanto's Newport factory and is now in remission from lymphoma, saying he cannot rule out a link to his exposure. The documentary features whistleblower Douglas Gowan, who spent 50 years raising concerns about dumped polychlorinated biphenyls (PCBs) — banned in the UK since the 1970s — and uncovers a 1972 Monsanto memo showing the company knew of the health dangers yet expanded its Newport operations. Dr David Megson of Manchester Metropolitan University, who led the documentary's scientific data collection, said some tested sites showed the highest contamination levels he had ever recorded, and warned that only public pressure is likely to force government action. Eastman Chemical Company, which now holds responsibility for Monsanto's UK legacy production, did not respond to requests for comment.