Friday, June 26, 2026

Supreme Court Ruling Deals Major Blow to Roundup Cancer Lawsuits

By ANDRÈ COLEMAN, Managing Editor

Cancer patients seeking to sue a pesticide company whose product may be linked to cancer suffered a major setback when the U.S. Supreme Court ruled this week that federal law shields manufacturers from certain state failure-to-warn claims involving Roundup weed killer.

In a 7-2 ruling, the court held that the Federal Insecticide, Fungicide, and Rodenticide Act preempts state-law failure-to-warn claims seeking to require cancer warnings on Environmental Protection Agency (EPA)-approved Roundup labels, handing Monsanto parent company Bayer a significant legal victory.

The city of Pasadena stopped using Roundup on city property in 2018.

The following year, the Los Angeles County Board of Supervisors banned its use after it was discovered the herbicide had been sprayed near a heliport in unincorporated Pasadena.

Roundup also was used during sediment removal work at Devil’s Gate Dam before county officials discontinued its use.

In 2019, Caltech prohibited the use of glyphosate-based herbicides at its student housing facilities after a landscaper applied a generic version of the chemical in playground and courtyard areas.

The decision could reshape thousands of pending lawsuits alleging that Roundup’s active ingredient, glyphosate, caused non-Hodgkin lymphoma and that the company failed to adequately warn consumers about the potential risk.

“The courtroom has historically been one of the few places where evidence and truth can outweigh corporate power. This decision is a severe blow to holding corporations accountable,” said Brent Wisner, managing partner at Wisner Baum LLP, who successfully tried the first Roundup cases against Monsanto in 2018.

According to Wisner, Bayer has already paid more than $10 billion to resolve claims involving Roundup and more than 60,000 cases remained pending in U.S. courts when the Supreme Court agreed to hear the case.

“Now the fate of those cases remains to be seen,” Wisner said.

“This is not the outcome we wanted from the Supreme Court, but it means there is more work to be done,” he added.

The case centered on whether federal pesticide labeling requirements override state laws allowing juries to find pesticide manufacturers liable for failing to include additional cancer warnings. Bayer argued that because the EPA has repeatedly approved Roundup’s label and concluded glyphosate is not likely to cause cancer when used as directed, state courts cannot impose different warning requirements.

Plaintiffs argued that federal approval should not insulate manufacturers from liability when evidence presented in court suggests additional warnings are warranted.

Federal regulators continue to maintain that glyphosate does not pose a cancer risk when used according to label directions, while California lists the chemical as a carcinogen under Proposition 65, reflecting the continuing disagreement among scientific and regulatory bodies over the herbicide’s safety.

Although the ruling significantly limits one of the primary legal theories used by plaintiffs, attorneys representing cancer patients are expected to continue evaluating other avenues for pursuing claims against Bayer.