The herbicide glyphosate, the active ingredient in Monsanto’s Roundup, has been added to California’s list of chemicals known to cause cancer. The listing, which goes into effect on July 7, will require manufacturers to add package warning labels and similar warnings to be places around certain sites where large quantities of the weed killer have been applied. The World Health Organization had previous labeled glyphosate as a “probable” human carcinogen. The chemical is the most widely used pesticide in California – and in the entire world. Monsanto has said it will fight California’s designation in court.

John R. Platt

is the editor of The Revelator. An award-winning environmental journalist, his work has appeared in Scientific American, Audubon, Motherboard, and numerous other magazines and publications. His “Extinction Countdown” column has run continuously since 2004 and has covered news and science related to more than 1,000 endangered species. He is a member of the Society of Environmental Journalists and the National Association of Science Writers. John lives on the outskirts of Portland, Ore., where he finds himself surrounded by animals and cartoonists.