When reporters Dan Ashby and Lucy Taylor are handed a box of unseen evidence, they begin a new investigation - into a chemical secret. A witness says he found deformed cows, and worried a toxic chemical had entered the food chain. But the witness had a warning for the future: "It's buried, isn't it? But it's going to come back."

Buried is the award-winning true-crime series digging into some of the most disturbing environmental stories in history. In this series, Dan and Lucy team up with the film star Michael Sheen, who recorded the witness before he died. Was the witness right?

Produced and presented by Dan Ashby and Lucy Taylor
Research by Georgie Styles
Sound design and mixing by Jarek Zaba
Original music and sounds by Phil Channell
Executive Producers: Philip Abrams and Anita Elash
Commissioning Editor: Dan Clarke

A Smoke Trail production for BBC Radio 4