The Supreme Court heard arguments in Monsanto v. Durnell on April 27, with a FIFRA preemption ruling that could eliminate more than 100,000 Roundup cancer lawsuits expected by July.
The Supreme Court heard oral arguments April 27 in *Monsanto Co. v. Durnell*, a case that could extinguish more than 100,000 pending state-court lawsuits alleging Bayer's Roundup herbicide caused cancer without adequate warning [1]. Bayer, which acquired Monsanto in 2018, contends that EPA's approval of Roundup's label under the Federal Insecticide, Fungicide, and Rodenticide Act, known as FIFRA, preempts any state-law failure-to-warn claim that would impose a different or additional requirement [2]. A ruling is expected by late June or early July [1].
The case reaches the Court from federal litigation consolidating claims by cancer patients, most diagnosed with non-Hodgkin lymphoma, who argue that Monsanto knew of risks associated with glyphosate, the active ingredient in Roundup, and failed to warn consumers [3]. Bayer is represented by Paul Clement, and plaintiffs' counsel includes Ashley Keller [2]. The justices' questioning exposed a divided bench. Justice Ketanji Brown Jackson pressed Bayer's position, asking why a product would not become misbranded under FIFRA if new scientific evidence emerges after initial label approval [2]. Other justices signaled sympathy for Bayer's argument that federal uniformity in pesticide labeling would be undermined if each state's tort system could effectively mandate different warnings [1].
The doctrinal stakes turn on a narrow but consequential reading of FIFRA's preemption clause, which bars states from imposing requirements "in addition to or different from" federally approved label requirements [2]. Plaintiffs argue that state tort suits do not impose affirmative labeling mandates but instead hold manufacturers accountable for knowing concealment of risk, a distinction the Court has preserved in analogous drug-labeling preemption cases [3]. A ruling for Bayer would likely end not only the Roundup litigation but could also provide preemption cover for other pesticide manufacturers facing comparable mass-tort exposure [3]. A ruling for plaintiffs would reaffirm state tort law as an independent check on products that carry federal regulatory approval.
The political backdrop is not neutral. The EPA under prior administrations declined to classify glyphosate as a probable carcinogen, a position at odds with a 2015 assessment by the International Agency for Research on Cancer [3]. Conflict-of-interest reporting has examined the relationship between industry-funded science and the agency's labeling decisions, a dynamic plaintiffs' counsel is expected to press should the case return to lower courts [3]. The Court's decision, when issued, will set the governing standard for FIFRA preemption and reshape the litigation posture of the entire Roundup docket.