Product Liability and Mass Tort Monitor: May 2026

The Product Liability & Mass Tort Monitor is a monthly newsletter delivering critical updates, data insights and actionable strategies for navigating the complexities of product liability and mass tort litigation. This month’s issue looks at the Supreme Court’s review of FIFRA preemption and the potential implications for product liability litigation.

Advocates around agriculture, healthcare, business, state governments and federal governments, among others, are eagerly awaiting a decision by the U.S. Supreme Court in Durnell v. Monsanto Co.

On April 27, 2026, the Court heard argument in the case, which could resolve a circuit split over whether the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) preempts state law failure-to-warn claims when the EPA has declined to require the warning at issue. In addition to guiding product manufacturers on their labeling requirements and practices, the Supreme Court’s decision may shed light on preemption in the post-Chevron era of Loper Bright. A decision is expected by late June.

Arguments Before the Court

• Monsanto argued that FIFRA’s express clause, which prohibits additional or different state labeling and packaging requirements, preempts all state law failure-to-warn claims for herbicides and other products FIFRA governs, analogizing the process to FDA premarket approval.

• Monsanto also raised implied preemption, contending that federal law bars unilateral changes to EPA-approved labels, that “clear evidence” shows the EPA would reject any cancer warning, and that rejecting preemption could create piecemeal obligations nationwide.

• The EPA supported Monsanto’s position, arguing that it can adequately regulate herbicides without state law failure-to-warn claims. The EPA asserted that its evaluation process already includes registration and periodic re-registration, permits states and individuals to petition to cancel a defective registration, requires manufacturers to bring new research to the EPA’s attention and allows judicial review of registration decisions. The EPA argued that label changes resulting from individual state tort suits, as Durnell advocated, would conflict with and undermine its regulatory process.

• Durnell invoked the Supreme Court’s recent upending of Chevron deference in Loper Bright, arguing that courts, not the EPA, have the ultimate authority to interpret FIFRA’s misbranding provisions and that therefore the EPA’s determination, during registration, that Roundup was not misbranded cannot bind a later state court from reaching a different conclusion. Durnell further argued that FIFRA and its implementing regulations did not preempt the Missouri court’s determination because they did not prohibit Monsanto from adding a cancer warning to the label.

Several Justices highlighted nuanced implications of each interpretation during oral argument:

• 15-year period between reviews: Justice Ketanji Brown Jackson questioned Monsanto about whether the EPA registration decisions could keep pace with evolving science because the agency reviews herbicide safety only every 15 years. Monsanto and the EPA responded that the EPA monitors new information on an ongoing basis, not only every 15 years; manufacturers must bring new information to the agency’s attention; and any individual or state can petition the EPA to cancel a product’s registration and review its safety again. This focus on new information suggests that preemption could depend on whether new evidence emerges between registration reviews.

• Inconsistency in state authority — ban versus liability: Justice Neil Gorsuch highlighted a key ramification of Monsanto’s interpretation, noting that Congress enacted FIFRA and gave states unambiguous authority under 7 U.S.C. § 136v(a) to ban herbicides entirely, yet, under Monsanto’s construction, withheld from states the lesser power to impose tort liability. The EPA clarified, however, that Monsanto and the EPA’s preemption argument applies only to failure-to-warn claims, not defective design claims. States do retain the authority to impose tort liability on manufacturers for defective design claims — a closer parallel to banning, than failure-to-warn claims — even if the Supreme Court rules in Monsanto’s favor.

• Uniformity concerns: Justice Brett Kavanaugh questioned how Durnell’s position could coexist with FIFRA’s prohibition on states imposing labeling or packaging requirements in 7 U.S.C. § 136v(b). Durnell distinguished state-imposed distinct requirements from jury verdicts that find liability notwithstanding federal requirements, emphasizing that inconsistent jury verdicts are far from unique to FIFRA or preemption doctrine more broadly.

Potential Loper Bright Limitations?

Oral argument revealed that the Monsanto decision could have effects beyond product liability by continuing to shape post-Chevron agency interpretation. Durnell argued the EPA’s interpretation of FIFRA through regulations should not preempt state law because, under Loper Bright, the EPA lacked delegated power to “give meaning to” FIFRA’s provisions. Justice Samuel Alito’s questions revealed potential skepticism about whether Loper Bright is relevant to such preemption questions.  Loper Bright, Justice Alito suggested, addressed only the relationship among the federal legislative, executive and judicial branches rather than the relationship between the federal government and the states presented by preemption. If the Court wades into that issue, it could have wide-ranging implications across all agencies and clarify the reach of Loper Bright.

For more information on these issues, contact the authors or their colleagues at McGuireWoods’ Product Liability & Mass Tort Practice Group.