Bayer Wins Major Supreme Court Victory on Roundup, But Doors Remain Open for Lawsuits

Bayer secured a Supreme Court victory last week that will provide a liability shield against failure-to-warn lawsuits for harms caused by pesticides, including Roundup and its active ingredient, glyphosate. The company has been paying out large lawsuit settlements with 65,000 pending cases. Many of the cases allege an association between glyphosate and Non-Hodgkin’s Lymphoma. While there is a liability-shield effect from this court ruling, it doesn’t rule out other methods of bringing lawsuits against pesticide manufacturers for harm caused by products determined safe by the EPA.

Carl Tobias, a law professor at the University of Richmond who teaches about mass-tort cases, told Claims Journal that there are still negligence and marketing claims that can be brought against Bayer and other pesticide manufacturers.

“Juries can still hand down billion-dollar verdicts against Bayer on grounds other than failure-to-warn,” Tobias said. “This is not the silver bullet Bayer was looking for to end all Roundup litigation.”

Bates v Dow Agrosciences LLC, a 2005 Supreme Court case, actually set a precedent that other types of cases do not fall under federal preemption the way failure-to-warn claims do. This includes claims for defective design, defective manufacturing, negligent testing, and breach of express warranty.

Last week’s case only determined that in the case of failure-to-warn claims, federal preemption laws prevent states from bringing these types of claims against manufacturers. The EPA is responsible for testing the chemicals to determine whether they are safe, and they determine the warnings that need to appear on labels. For this reason, the Supreme Court justices ruled 7-2 in favor of Bayer, with Justices Neil Gorsuch and Ketanji Brown Jackson as the only dissenters.

“Durnell’s state tort claim would require Monsanto to add a cancer warning to Roundup’s label even though federal law requires Monsanto to use the EPA-approved label without a cancer warning,” wrote Justice Brett Kavanaugh in the majority opinion. “Because Durnell’s state tort claim would impose a pesticide labeling requirement ‘in addition to or different from’ the label required by EPA, FIFRA expressly preempts Durnell’s claim.”

Jackson and Gorsuch disagreed on the grounds that states were not creating new laws or labeling requirements, but rather allowing lawsuits based on state laws that parallel federal lawsuits. For this reason, they argued that federal preemption doesn’t apply.

“Durnell’s failure-to-warn claim is not ‘in addition to or different from’ FIFRA’s mandates; it is equivalent to FIFRA’s key labeling requirement—the misbranding prohibition,” Justice Jackson wrote. “And Durnell’s claim does not conflict with any other FIFRA ‘requirement’ for §136v(b) purposes because the EPA’s registration of a pesticide and approval of its label do not create a labeling requirement under FIFRA.”

“Ultimately, the effect of the majority’s interpretation is both remarkable and regrettable, for it unjustifiably closes the courthouse doors to state tort plaintiffs like Durnell,” Jackson added.

The EPA has long determined that glyphosate is “not likely to be carcinogenic to humans,” a conclusion that relied heavily on the results of a now-retracted paper ghostwritten by Monsanto executives. Following the latest Supreme Court ruling, failure-to-warn claims are generally barred unless the company violates the EPA-approved label.

Bayer executives had a private meeting with EPA officials in the Trump administration last year to give a small thanks for updating the glyphosate website. Specifically, the website included an EPA letter reaffirming the safety of glyphosate and an official letter stating that the agency would not approve a label that includes a cancer warning.

The private meeting included EPA officials who have ties to the agrochemical industry, and they discussed the Supreme Court case. The Trump administration also wrote a brief to the Supreme Court to support Bayer in the case.

EPA administrator Lee Zeldin was pressed in an April Congressional hearing by Representative Alexandria Ocasio-Cortez. In that exchange, Zeldin initially denied meeting with Bayer, but then explained he had only a brief meeting that didn’t involve discussions about the Supreme Court case. Zeldin was not one of the named individuals who were involved in the June 2025 private meeting.

The EPA’s ongoing review of glyphosate is expected to be completed in 2026, after a court vacated the human health portion of the agency’s 2020 review. The EPA’s cancer paper said a conclusion could not be determined regarding an association between glyphosate exposure and Non-Hodgkin’s Lymphoma. The court ruled that the EPA could not reasonably conclude that glyphosate is not likely to cause cancer while not being able to reach a conclusion on NHL. The human health portion was vacated in 2022 as a result of this internal inconsistency, and the review has subsequently been pushed back until 2026.

Bayer CEO Bill Anderson celebrated the Supreme Court decision. “This litigation has enormous costs for the company and has impacted public trust,” he said. “The decision brings overdue justice on an issue that should have been clarified much earlier. It’s time to put it behind us. Strengthened by this ruling, we continue to pursue our multi-pronged containment strategy, which includes the previously announced class settlement.”

Days after the ruling, Bayer filed a petition with the U.S. Department of Commerce and International Trade Commission seeking antidumping and countervailing duties on glyphosate imported from China. Bayer is the only US producer of glyphosate and stands to have a stronger market share with President Trump’s February executive order invoking the Defense Production Act to manufacture glyphosate domestically.