David Schnaffer developed non-Hodgkins lymphoma after years of heavy exposure to the pesticide Roundup as a landscape worker. Mr. Schaffner and his wife sued Roundup’s manufacturer, Monsanto, alleging, among other things, that Monsanto failed to provide adequate warnings of the dangerous risks associated with exposure to Roundup. The case was transferred to a multi-district litigation court in California, which rejected Monsanto’s argument that the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) preempts the Schaffners’ failure-to-warn claims. The case then returned to a district court in Pennsylvania, and Monsanto appealed the preemption ruling to the Court of Appeals for the Third Circuit. In April 2023, Public Citizen filed an amicus brief in support of the Schaffners in the court of appeals, explaining that FIFRA neither expressly nor impliedly preempts their failure-to-warn claim.