CSG Law Environmental Blog: Supreme Court Ruling Closes the Door on Roundup Failure to Warn Claims
On June 25, 2026, the U.S. Supreme Court in Monsanto Company v. Durnell, issued a decision holding that the producer of Roundup weedkiller cannot be sued in state courts for failure to warn. The Court found that state law and court rulings cannot impose labeling requirements that differ from those approved under the Federal Insecticide, Fungicide, and Rodenticide Act (“FIFRA”), which preempts state-law failure to warn claims. Because federal regulators have determined that a link between cancer and the weedkiller is unlikely, and therefore Roundup does not require a warning label, the Court in a 7-2 ruling sided with Bayer, who acquired Monsanto, Roundup’s original producer, in 2018.
Over the past decade, tens of thousands of lawsuits have been brought against Monsanto and Bayer over Roundup’s labeling, alleging a failure to warn consumers of the link between glyphosate and cancer. The Court’s decision has far-reaching implications for all pending failure to warn lawsuits against the company over the weedkiller.
Roundup’s key ingredient, glyphosate, and its links to cancer are the subject of ongoing debate. The World Health Organization’s International Agency for Research on Cancer found that glyphosate is “probably carcinogenic” in 2015. Notwithstanding this, the U.S. Environmental Protection Agency (“EPA”) has determined that glyphosate is unlikely to cause cancer when used as directed and therefore has repeatedly determined that glyphosate-based products do not require a cancer warning.
Accordingly, as a matter of federal law, and as per the Court’s decision, companies producing glyphosate-based products “legally must use a label without a cancer warning unless and until EPA approves or requires a change.” While the Court determined that third parties can bring new research to the EPA’s attention, they cannot use state lawsuits to impose different labeling requirements than the EPA.
Justice Ketanji Brown Jackson wrote a dissenting opinion, joined by Justice Neil Gorsuch, where she asserted that the Court’s ruling and interpretation of the law is “both remarkable and regrettable.” Jackson stated that FIFRA “expressly limits States’ authority to regulate pesticide labels, but it does not eliminate that authority.”
Separate from the Supreme Court’s ruling, Bayer has indicated that it plans to proceed with a $7.25 billion class action settlement intended to resolve current and future Roundup claims alleging non-Hodgkin lymphoma injuries.
For more information or updates, please contact the author of this post or the CSG Law Environmental Group.