Blue Brief 2025-2026

EPA registers the product. A product may not be “ misbranded ,” which the statute defines to include labels lacking “a warning or caution statement … adequate to protect health and the environment.” Critically, FIFRA includes a “Uniformity” provision that bars states from imposing “any requirements for labeling or packaging in addition to or different from those required under” FIFRA. The case’s central question was whether a cancer warning of the sort Durnell urged would constitute a labeling requirement “in addition to or different from [requirements] under” FIFRA. To answer the question, the Court had to determine what counts as “requirements” under FIFRA. Under one interpretation, “requirements” might mean the provisions set forth in the FIFRA statute and implementing regulations . On an alternative reading, “requirements” could refer to the specific labels certified by EPA for each product. According to a dissent penned by Justice Jackson and joined by Justice Gorsuch, “requirements” are provisions set forth in FIFRA itself and implementing regulations. By that definition, FIFRA’s misbranding prohibition is one such “requirement” for herbicide labels. Because the cancer warning Durnell sought is consistent with the statutory provision not to misbrand, the Justices reasoned, the warning would not impose a requirement “in addition to or different from” those of FIFRA. Durnell’s failure-to-warn claim, therefore, was not expressly preempted in the dissenters’ view. Justice Kavanaugh , writing for the Court, disagreed. Because “manufacturers are legally required to use” the label approved by EPA at

registration, he reasoned, such labels must constitute a “requirement” under FIFRA. Any cancer warnings imposed by state tort law thus constitute “requirements … in addition to or different from” FIFRA’s requirements and are preempted by the Uniformity provision. According to the Court, this reading conforms with precedent interpreting FIFRA as well as the Medical Device Amendments of 1976 — part of the broader Federal Food, Drug, and Cosmetic Act — which contain a nearly identical preemption clause . In sum, the Court held that Durnell’s claim was expressly preempted. The opinion’s immediate effect will be to curtail lawsuits against Monsanto. Shares of Monsanto’s parent company, Bayer, jumped by roughly 16% on the day the decision was announced. But the opinion’s lone concurrence , by Justice Thomas, urges farther-reaching doctrinal transformation. Several elements of FIFRA, The opinion’s immediate effect will be to curtail lawsuits against Monsanto. Shares of Monsanto’s parent company, Bayer, jumped by roughly 16% on the day the decision was announced.

UNIVERSITY OF SAN DIEGO SCHOOL OF LAW | Faculty Review of 2025-2026 U.S. Supreme Court Term | Page 15