Edwin Hardeman sued Monsanto, alleging that he had developed non-Hodgkin’s lymphoma as a result of exposure to the Monsanto pesticide Roundup. The case went to trial, where the jury found that Mr. Hardeman proved that his exposure to Roundup was a substantial factor in causing his cancer, that Roundup’s design was defective, that Roundup lacked sufficient warnings of the risk of non-Hodgkin’s lymphoma, and that Monsanto was negligent by not using reasonable care to warn about Roundup’s non-Hodgkin’s lymphoma risk. Monsanto appealed to the U.S. Court of Appeals to the Ninth Circuit, arguing, among other things, that Mr. Hardeman’s claims are preempted by the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), 7 U.S.C. § 136 et seq. Public Citizen filed an amicus brief in support of Mr. Hardeman in the Ninth Circuit, explaining that FIFRA neither expressly nor impliedly preempts Mr. Hardeman’s claims. The Ninth Circuit affirmed, holding that FIFRA does not preempt Mr. Hardeman’s claims. The Supreme Court later denied Monsanto’s petition for certiorari, ending the case.