A California jury ordered chemical giant Monsanto to pay nearly $290 million for failing to warn a dying groundskeeper that its weed killer Roundup might cause cancer.

Jurors unanimously found that Monsanto - which vowed to appeal - acted with "malice" and that its weed killers Roundup and the professional grade version RangerPro contributed "substantially" to Dewayne Johnson's terminal illness. Following eight weeks of trial proceedings, the San Francisco jury ordered Monsanto to pay $250 million in punitive damages along with compensatory damages and other costs, bringing the total figure to nearly $290 million.