Monsanto v. Durnell bars all sub-national entities, including Oklahoma, from adding health warnings to pesticide labels different from the federal government’s. Missouri farmer John Durnell said he developed cancer after using Monsanto’s Roundup and sued the company for not disclosing the pesticide’s alleged cancer risk on the product label. Missouri’s strict liability doctrine holds companies legally accountable for failing to warn about the dangerous nature of a product. While the Environmental Protection Agency and European Union agencies have stated glyphosate, a chemical ingredient in Roundup, is unlikely to be carcinogenic, the World Health Organization deemed it probably carcinogenic to humans. Oklahoma Watch partners with Gigafact to produce fact briefs — bite-sized fact checks of trending claims.