U.S. Supreme Court ruling narrows some “cancer warning” lawsuits over Roundup label claims

On June 25, 2026, the U.S. Supreme Court in Monsanto Co. v. Durnell (No. 24-1068) reversed a Missouri decision and sent the case back after holding that the pesticide law FIFRA can preempt a state “failure-to-warn” claim aimed at adding a cancer warning to a Roundup label.

Durnell sued Monsanto in Missouri state court, arguing that long-term use of Monsanto’s glyphosate-based herbicide Roundup caused his non-Hodgkin’s lymphoma—and that Monsanto should have included a cancer warning on the product label. A jury found for Durnell on the failure-to-warn theory and awarded him more than $1 million.

What the Court decided

The Supreme Court’s central point was that FIFRA expressly preempts a state-law labeling theory when it would require a manufacturer to add warnings that are “in addition to or different from” what FIFRA’s labeling system requires under federal law.

In this case, the Court concluded the claim would effectively force Monsanto to add a cancer warning that EPA had not required for glyphosate-based pesticide labels like Roundup.

The narrow question the justices took

According to the Supreme Court’s docket, the Court granted review limited to whether FIFRA preempts a label-based failure-to-warn claim where EPA has not required the warning.

What this could change for other lawsuits

The ruling is most likely to matter in cases where a plaintiff’s “label” theory depends on court-ordered or legally compelled label language that goes beyond what EPA required for that pesticide’s registered label. In those situations, defendants will likely argue the claim is barred under FIFRA’s express preemption framework.

What the ruling does not automatically decide

The Court’s decision focused on the specific label-based failure-to-warn claim at issue. Other claims may still proceed if they don’t require a result that effectively imposes labeling requirements “in addition to or different from” the federal requirements.

What to watch next

Lower courts will likely apply Monsanto v. Durnell case-by-case, analyzing how each plaintiff’s alleged duty-to-warn theory would interact with what EPA required on the product label. Plaintiffs may also reshape how they plead future claims to avoid requiring label changes that conflict with FIFRA’s express preemption rule.

Sources: Supreme Court slip opinion and syllabus in Monsanto Co. v. Durnell (No. 24-1068). ([supremecourt.gov](Supremecourt)) Supreme Court docket for No. 24-1068. ([supremecourt.gov](Supremecourt)) DOJ Office of the Solicitor General case page (background materials). ([justice.gov](Justice)) The Guardian reporting for additional context.

Sources

• U.S. Supreme Court slip opinion (Monsanto Co. v. Durnell, No. 24-1068)
• U.S. Department of Justice (Office of the Solicitor General) brief—Monsanto Co. v. Durnell
• The Guardian coverage translating the ruling into litigation impact