Supreme Court Considers Granting Bayer Protection From Pesticide ‘Failure-To-Warn’ Lawsuits

The U.S. Supreme Court heard oral arguments Monday about whether Bayer can be held liable for state-level failure to warn claims when the company followed EPA labeling guidelines after the federal agency classified glyphosate as “not likely carcinogenic to humans.” The court is not considering the underlying safety profile of glyphosate or Roundup, but the legal question of whether federal preemption applies and the EPA holds supreme authority to dictate pesticide labels.

Glyphosate was last reviewed for safety by the EPA in 2020, but a federal court vacated the human health portion of the review in 2022. The updated review has not yet been completed. Prior to 2020, the last EPA review of glyphosate was in 1993. In 2015, the International Agency for Research on Cancer (IARC) concluded that glyphosate is probably carcinogenic to humans. The Supreme Court case involves arguments over whether new information about the product’s safety profile requires the company to notify the EPA and seek an updated label, or whether EPA approval of the existing label preempts state failure-to-warn claims.

Specifically, the court is considering whether the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) preempts a label-based failure-to-warn claim in which EPA has not required the warning.

The argument from the plaintiff’s attorney, Ashley Keller, is that Missouri’s law is a parallel law that mirrors FIFRA regulations and labeling requirements. FIFRA provides that registration is “prima facie evidence” of compliance, meaning it is presumed true unless there is adequate and strong counterevidence.

In Bates v. Dow Agrosciences in 2005, the Supreme Court ruled that states can impose requirements so long as they are equivalent to those under FIFRA. The plaintiffs in the Durnell case against Bayer argue that this precedent also means that states can impose liability requirements for failing to have adequate warnings or directions.

Bayer’s counsel, Paul Clement, is pointing specifically to a provision of the FIFRA that says states “shall not impose or continue in effect any requirement for labeling or packing in addition to or different from those required.” Keller argues on behalf of the plaintiffs that this provision requires uniformity in law and doesn’t prevent states from having parallel laws. Keller said that civil juries reach different conclusions, which is not the same as states having different labeling requirements than the federal government.

Bayer’s attorney also argued that FIFRA says a registrant cannot change the safety and hazard portion of the label with EPA approval. The plaintiffs cite a FIFRA provision stating that registration is not a defense to misbranding. Keller, on behalf of the plaintiffs, further argued that following the Loper Bright ruling, the EPA cannot unilaterally determine the meaning of a law written by Congress. Only the court can determine the meaning of the laws as they are written.

A ruling in this case is expected in early summer, and it is unclear which side the justices will take after oral arguments heard on Monday.

The HighWire has reported about concerns with Bayer and glyphosate safety, including a $2.1 billion liability verdict last year. President Donald Trump signed an executive order declaring glyphosate production a national security concern.

A Freedom of Information Act (FOIA) request revealed that Trump administration officials met with Bayer executives in June of 2025 to discuss legal issues. All three EPA officials who met with Bayer had ties to the agrochemical industry before working for the EPA. During the meeting, they reportedly discussed the Supreme Court case, and Bayer offered a “small thanks” for updating the glyphosate web page. The administration withdrew a 2022 letter that authorized California to require a different label for glyphosate, indicating a cancer risk, as long as it noted the EPA disagreed.

The HighWire streamed a protest outside of the Supreme Court on Monday morning called The People Vs. Poison with many speakers, including The HighWire Host and Informed Consent Action Network CEO Del Bigtree, regenerative farmer Joel Salatin, House Representative Thomas Massie, and “Food Babe” Vani Hari. Salatin made a confident statement that no pesticides are necessary for growing food, with a loud cheer of approval from attendees. Massie talked about the need to prevent immunity for pesticide manufacturers. Bigtree said that while President Donald Trump has done a lot of good things for the MAHA movement, his administration got this one wrong by supporting Bayer in a Supreme Court brief.

In December 2025, a review article that concluded that glyphosate is not a safety threat to humans was retracted. Eight years ago, court documents showed the paper was co-authored by Monsanto employees even though they were not named. This paper has been frequently cited by the EPA in its safety evaluations of glyphosate.

A 2021 analysis by The Intercept found that all seven directors of the EPA’s pesticide division since 1974 who continued working made money from the agrochemical manufacturers they were tasked with regulating after leaving the EPA.

The EPA, under Administrator Lee Zeldin, has hired several chemical industry professionals since taking office. The agency has approved the herbicide Dicamba despite serious safety concerns, despite two previous court orders that EPA approvals of Dicamba were unlawful. The EPA has continued to challenge the landmark fluoride ruling in which a federal judge determined that water fluoridation poses an unreasonable risk to human health.

The HighWire has also reported about multiple chemical disasters in which the EPA’s response has been challenged by local residents who feel their health conditions aren’t being taken seriously. This includes East Palestine, OH; Conyers, GA; and Roseland, LA. Recently, FOIA documents showed the agency secretly was concerned about a “grave threat to human health” while publicly stating “there is no indication of any imminent threat to public health from the soot or smoke residue deposited in the surrounding area.”