The US supreme court has found in favor of the former Monsanto company in a ruling that is expected to block thousands of lawsuits filed by people alleging the key ingredient in the weed killer Roundup causes cancer.

The decision was made in a 7-2 vote, with Justice Brett Kavanaugh offering the majority opinion and justice Ketanji Brown Jackson writing the dissenting opinion, joined by justice Neil Gorsuch.

The case, Monsanto v Durnell, specifically dealt with the question of whether a federal law that gives the Environmental Protection Agency (EPA) regulatory authority over pesticides preempts state claims that a company failed to warn users of certain product risks when the EPA itself has not required such warnings.