Supreme Court Considers Preemption in Glyphosate Labeling Case

The U.S. Supreme Court heard oral arguments on April 27, 2026, in Monsanto v. Durnell, examining whether the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) preempts state failure-to-warn claims against Bayer for its Roundup weedkiller. The case stems from plaintiff John Durnell's allegation that his non-Hodgkin lymphoma resulted from glyphosate exposure, leading to a $1.25 million Missouri jury verdict in 2019, upheld on appeal.

According to EPA data cited in court filings, glyphosate is applied to approximately 300 million acres of U.S. farmland each year, with about 280 million pounds used annually. The EPA has approved Roundup labels without cancer warnings, stating in its 2020 interim decision that "glyphosate is not likely to be carcinogenic to humans" based on its review of scientific studies.

The International Agency for Research on Cancer classified glyphosate as "probably carcinogenic to humans" in 2015, though the EPA has not adopted this classification.

Paul Clement, attorney for Monsanto, argued during the hearing that FIFRA's provision prohibits states from imposing "any requirements for labeling or packaging in addition to or different from" federal standards, as stated in the statute. He cited the 2008 Supreme Court decision in Riegel v.

" Ashley Keller, representing Durnell, argued that FIFRA registration does not equate to a binding safety determination, noting a 2022 Ninth Circuit ruling that vacated portions of the EPA's glyphosate assessment for inadequate ecological analysis, though the court did not address human health findings.

Justices questioned both sides on uniformity and scientific updates. Justice Brett Kavanaugh asked about the risks of "retroactive penalties" from varying state rules. Justice Ketanji Brown Jackson inquired how new evidence might be addressed given EPA reviews occur every 15 years. No clear majority emerged from the arguments, according to observations reported in multiple outlets.