In a thick, almost unintelligible Appalachian accent, Wilbur Tennant described how everyone else in his West Virginia town had ostracised him after he’d pointed the finger of blame at DuPont, the chemical giant whose huge plant dominated the town.

Rob Bilott, the lawyer he’d rung in desperation, was so confused he was about to hang up — when the farmer said he knew Bilott’s grandmother. As a favour to her, he agreed to meet the aggrieved cattleman.

His spur-of-the-moment decision would lead, after a dogged investigation stretching into years, to Bilott uncovering one of the biggest industrial scandals in U.S. history.