Associated Press

SAN FRANCISCO (AP) – International agencies, U.S. and foreign regulators and agribusiness giant Monsanto have already evaluated claims that the active ingredient in Monsanto’s widely used weed killer Roundup can cause cancer.

Now, a federal judge in San Francisco will conduct his own review during an unusual set of court hearings starting Monday.

The case has big stakes for Monsanto and hundreds of farmers and others who have sued the company.

U.S. District Judge Vince Chhabria will spend a week hearing from experts to help decide whether there is valid scientific evidence to support the claim that exposure to Roundup can cause non-Hodgkin’s lymphoma.

Chhabria is presiding over more than 300 lawsuits against Monsanto by cancer victims and their families who say the company knew about Roundup’s cancer risk but failed to warn them