The U.S. Supreme Court has ruled 7-2 that federal law preempts state-law failure-to-warn claims against Monsanto regarding its Roundup weed killer, overturning a Missouri jury verdict and blocking thousands of pending lawsuits.
The decision holds that the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) prohibits state courts from imposing labeling requirements different from those approved by the U.S. Environmental Protection Agency (EPA).
The Ruling
Justice Brett Kavanaugh, writing for the majority, found that FIFRA expressly preempts any state law requiring a label "in addition to or different from" the EPA-approved label. Because the EPA determined a cancer warning was not required for glyphosate-based products, the Court ruled that John Durnell’s state tort claim—which sought to impose such a warning—was blocked by federal law.
Justice Ketanji Brown Jackson filed a dissenting opinion, joined by Justice Neil Gorsuch. She argued the majority misinterpreted FIFRA’s preemption scope, stating that adding a cancer warning does not conflict with federal law and that the ruling leaves the plaintiff without a remedy for his harms.
"The majority leaves the plaintiff without a remedy for the harms he suffered." — Justice Ketanji Brown Jackson
Case Background
The case originated in Missouri state court, where John Durnell sued Monsanto in 2019. Durnell alleged that 20 years of exposure to glyphosate in Roundup, used at a community garden in St. Louis, caused his non-Hodgkin's lymphoma. A jury awarded him over $1 million (reported as $1.25 million), finding Monsanto failed to provide adequate warnings under Missouri law.
According to multiple sources, Bayer faces approximately 100,000 to 181,000 Roundup-related claims. Bayer has proposed a $7.25 billion class-action settlement and has previously set aside $16 billion to settle cases. The company has stopped using glyphosate in Roundup sold to the U.S. residential market, though it remains in agricultural products.
Legal Arguments
Monsanto/Bayer's position: The company argued FIFRA gives the EPA sole authority to set pesticide labels, requiring national uniformity. Attorney Paul Clement argued that the EPA's expert judgment should not be second-guessed by a single state jury. Bayer stated the ruling provides "regulatory clarity" and supports "agricultural innovation."
Plaintiff's position: Attorney Ashley Keller argued that Missouri law requires adequate warnings and that juries, not federal agencies, should determine whether warnings are sufficient. Attorney Christopher Seeger said the ruling "wrongly slams the courthouse door on Americans sickened by pesticides."
Federal government's position: The U.S. Solicitor General supported Monsanto, stating that the EPA has authority to approve label changes and state law must yield.
Broader Context
The World Health Organization's International Agency for Research on Cancer classified glyphosate as "probably carcinogenic" in 2015. The U.S. EPA, however, has determined that glyphosate is not likely to cause cancer in humans when used as directed.
Glyphosate was one of the top three pesticides used in Iowa from 2010 to 2019, according to a Harkin Institute and Iowa Environmental Council report. Bayer CEO Bill Anderson stated the decision provides "regulatory clarity" and supports "agricultural innovation." Aaron Lehman, president of the Iowa Farmers Union, criticized the ruling, stating it reduces legal protections for farmers.
"The ruling wrongly slams the courthouse door on Americans sickened by pesticides." — Attorney Christopher Seeger
Market Reaction
Bayer shares rose nearly 18% following the ruling. The decision is expected to halt most pending failure-to-warn claims, though some state tort claims unrelated to health and safety may still proceed.