Argued on Apr 27 2026.

For petitioner: Paul D. Clement, Alexandria, Va.; and Sarah M. Harris, Principal Deputy Solicitor General, Department of Justice, Washington, D. C. (for United States, as amicus curiae.) For respondent: Ashley C. Keller, Chicago, Ill.

Question Presented:

The Federal Insecticide, Fungicide, and Rodenticide Act ("FIFRA'') creates a comprehensive regulatory scheme governing the use, sale, and labeling of pesticides. The Act preempts any state "requirement[] for labeling or packaging in addition to or different from those required under" FIFRA. 7 U.S.C. §136v(b). For decades, EPA has exercised its authority under FIFRA to find that Monsanto's Roundup product line and its active ingredient, glyphosate, do not cause cancer in humans. Consistent with that understanding, EPA has repeatedly approved Roundup's label without a cancer warning. FIFRA prohibits Monsanto from making any substantive change to an EPA-approved label unless it first obtains EPA's permission. Respondent is one of more than 100,000 plaintiffs across the country that nonetheless seek to hold Monsanto liable for not warning users that glyphosate, the active ingredient in Roundup, causes cancer. The federal courts of appeals and state appellate courts are divided over whether FIFRA preempts such claims. The Third Circuit has held that it does. In the decision below, the Missouri Court of Appeals joined the Ninth and Eleventh Circuits and state appellate courts in California and Oregon in holding that it does not. The question presented is: Whether FIFRA preempts a state-law failure-to- warn claim where EPA has repeatedly concluded that the warning is not required and the warning cannot be added to a product without EPA approval.

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