NACo Legal Advocacy: Monsanto Company v. Durnell

County Nexus

Monsanto v. Durnell considers a preemption issue that carries substantial implications for counties. The legal doctrine implicated is federal preemption, which comes from the Supremacy Clause of the United States Constitution that outlines that federal law is the 'supreme law of the land' and that state laws that conflict with federal law are not law. A ruling in favor of the petitioner in this case could harm counties’ ability to protect public health and safety by weakening counties’ ability to take legal action against bad actors.

Background

In 2019 John Durnell filed suit against Monsanto in Missouri state court, alleging that exposure to Roundup caused him to develop lymphoma. He argued a strict liability failure to warn claim, which is a traditional state claim asserting that a manufacturer failed to provide adequate warnings about known or reasonably knowable risks associated with its product. Monsanto was found liable, but appealed the decision to federal court, asserting that the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) preempted the failure to warn claim.  

Monsanto argues primarily that FIFRA’s express preemption (a type of preemption where federal law explicitly states its supremacy over state and local law) clause, bars state-law labeling requirements 'in addition to or different from federal requirements.’ Monsanto also asserts implied conflict preemption (a type of preemption where it is impossible to comply with both state and federal law or where state law stands as an in the way of federal objectives) on the grounds that EPA regulations require agency approval before adding new health warnings to a pesticide label, making compliance with state-imposed warning duties allegedly impossible.

The Missouri Court of Appeals ruled with the state court, holding that the state-law duty to warn was not 'in addition to or different from' FIFRA’s requirements. Monsanto filed a petition for writ of certiorari in 2025. The Solicitor General submitted a brief recommending that the Court grant review. On January 16, 2026, the Supreme Court granted certiorari to determine whether the FIFRA preempts state level tort claims.

NACo Advocacy

Counties rely on state tort law, public nuisance doctrines, and consumer protection statutes as complementary tools to federal enforcement; because of this NACo supports the respondent’s position. NACo will be joining the Local Government Legal Center in filing an amicus brief in support of the respondent. The brief will emphasize the need to preserve state power, maintain limits on preemption of counties, and proper use of federal laws. Clarifying these limits is critical to protecting federalism and preserving counties’ ability to protect their residents.

Current Status

Currently oral arguments are scheduled for April 27, 2026 and a ruling is expected at the end of the court’s term.