Opinion Summary: Monsanto v. Durnell | Court Axes Roundup Cancer Suits

Monsanto Co. v. Durnell | Case No. 24-1068 | Docket Link: Here | Argued: April 27, 2026 | Decided: June 25, 2026

Overview: Federal pesticide law blocks a Missouri cancer patient's failure-to-warn lawsuit against Monsanto after the EPA repeatedly approved Roundup's label without requiring a cancer warning, despite the patient's claims linking Roundup to his non-Hodgkin's lymphoma.

Question Presented: Whether the Federal Insecticide, Fungicide, and Rodenticide Act expressly preempts a state-law failure-to-warn claim seeking a cancer warning the EPA declined to require.

Posture: Missouri jury awarded Durnell $1.25M; Court of Appeals affirmed; Supreme Court reversed and remanded.

Main Arguments:

• Monsanto (Petitioner): (1) EPA's registration and label approval without a cancer warning creates a binding federal requirement that preempts stricter state demands; (2) Riegel v. Medtronic establishes that analogous agency approval processes create preemptive federal requirements; (3) Missouri's failure-to-warn verdict retroactively penalizes Monsanto for complying with the federal label EPA mandated.

• Durnell (Respondent): (1) FIFRA's misbranding prohibition — not EPA's specific label approval — sets the operative federal labeling requirement, and Missouri's tort mirrors it exactly; (2) FIFRA § 136a(f)(2) bars treating registration as a complete defense, stripping EPA approval of conclusive force; (3) Manufacturers can add a cancer warning through amended registration or minor modification, defeating impossibility preemption.

Holding: FIFRA's preemption clause, 7 U.S.C. § 136v(b), expressly preempts Durnell's state-law failure-to-warn claim because the claim would require Monsanto to add a cancer warning to Roundup's label in addition to or different from the label required under FIFRA. Reversed and remanded.

Voting Breakdown: 7-2. Justice Kavanaugh delivered the majority opinion joined by Chief Justice Roberts and Justices Thomas, Alito, Sotomayor, Kagan, and Barrett. Justice Thomas filed a concurring opinion. Justice Jackson filed a dissenting opinion joined by Justice Gorsuch. Reversed and remanded.

Majority Reasoning: • (1) FIFRA's registration process mandates substantive EPA label review; after approval, manufacturers must use that label and cannot change it without prior agency authorization; • (2) Riegel v. Medtronic establishes that analogous agency approval creates binding federal "requirements" — EPA pesticide registration functions identically and carries the same preemptive force; • (3) Durnell's claim imposes a labeling requirement "in addition to or different from" the EPA-approved label, triggering FIFRA's express preemption clause and its mandate for nationwide uniformity.

Separate Opinions:

• Justice Thomas (concurring): Joined the majority fully; wrote separately to flag three constitutional concerns: FIFRA may exceed Congress's Commerce Clause authority, violate the non-delegation doctrine, and rely on a form of agency preemption the Supremacy Clause may not support.