Supreme Court Sides with Monsanto in Pesticide Warning Case
The US Supreme Court has ruled in favor of the former Monsanto company in a decision that will block thousands of lawsuits from people alleging that the key ingredient in the weedkiller Roundup causes cancer. The 7-2 ruling, issued on 27 April 2026, centered on whether federal law preempts state-level failure-to-warn claims when the Environmental Protection Agency (EPA) has not required a cancer warning on the product.
Justice Brett Kavanaugh wrote the majority opinion, stating that the Federal Insecticide, Fungicide and Rodenticide Act (Fifra) expressly preempts such state claims. Justice Ketanji Brown Jackson wrote the dissenting opinion, joined by Justice Neil Gorsuch, arguing that Fifra does not entirely eliminate state authority to regulate pesticide labels.
Case Details: Monsanto v Durnell
The case, Monsanto v Durnell, specifically addressed whether federal law preempts claims that the company failed to warn users of risks when the EPA itself has not required such warnings. The majority opinion held that Fifra preempts Durnell's state-law failure-to-warn claim.
In her dissent, Justice Jackson wrote: "Fifra expressly limits States’ authority to regulate pesticide labels, but it does not eliminate that authority. Fifra’s preemption clause does not block state-law claims where the violation of state law is also a violation of Fifra." She added that the court's decision leaves Durnell without a remedy for significant harms suffered.
Background on Glyphosate and Lawsuits
The case involves Monsanto's glyphosate, a weedkilling chemical used in Roundup and other products. The company, now owned by Germany's Bayer, has faced over 100,000 lawsuits from people who developed non-Hodgkin lymphoma, which they attribute to glyphosate exposure. The World Health Organization's cancer agency classified glyphosate as a probable human carcinogen in 2015.
Bayer has paid billions in jury awards and settlements but maintains that its products do not cause cancer. The company argues that under Fifra, the EPA is the key authority on whether a cancer warning is needed. The EPA has not required such a warning, stating that glyphosate is "unlikely" to be carcinogenic.
Impact of the Ruling
The Supreme Court's decision means thousands of pending failure-to-warn claims against Monsanto cannot proceed. Similarly, claims against pesticide maker Syngenta involving paraquat and Parkinson's disease are also blocked. Syngenta maintains that evidence linking paraquat to Parkinson's is "fragmentary" and "inconclusive."
Environmental and public health advocates expressed outrage. Tarah Heinzen, legal director of Food and Water Watch, said: "Once again, the Supreme Court has sided with big business over people and the environment." Nathan Donley of the Center for Biological Diversity called it a "Trump-blessed ruling" that underscores the need for an EPA that protects people instead of pesticide companies.
Reactions and Next Steps
Patti Goldman of Earthjustice stated: "The fact that EPA approved a pesticide label does not mean a product is safe, and it should not become a shield for companies that fail to warn about cancer risks." The farmer-led group Farm Action expressed disappointment but vowed to continue fighting. President Angela Huffman said: "No corporation should be allowed to use its market power or political influence to put itself above the law."
