We speak with a University of California scientist Tyrone Hayes, who discovered a widely used herbicide may have harmful effects on the endocrine system. But when he tried to publish the results, the chemical’s manufacturer launched a campaign to discredit his work. Hayes was first hired in 1997 by a company, which later became agribusiness giant Syngenta, to study their product, Atrazine, a pesticide that is applied to more than half the corn crops in the United States, and widely used on golf courses and Christmas tree farms.