Roundup Preemption Fight Takes New Turn After Loper Bright Ruling
Recent analysis spotlights a new approach in the Roundup preemption dispute after Loper Bright.
Why it matters: The Supreme Court’s handling of federal preemption questions post-Loper Bright could change the landscape for product liability and environmental tort litigation. This outcome directly affects corporate defendants, insurers, and the regulatory authority of federal and state governments.
- Monsanto Co. v. Durnell centers on whether FIFRA preempts state-law failure-to-warn claims over Roundup.
- The Supreme Court ended Chevron deference in Loper Bright, requiring independent judicial interpretation of statutes.
- Bayer, which owns Monsanto, has paid over $11 billion in settlements from more than 100,000 Roundup lawsuits.
- EPA maintains glyphosate is not risky to humans when used as labeled, but some agencies disagree.
The U.S. Supreme Court’s April 2026 arguments in Monsanto Co. v. Durnell shine a spotlight on whether the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) blocks state-law failure-to-warn claims about Roundup’s cancer risks. The debate follows the Supreme Court’s landmark 2024 decision in Loper Bright, which ended decades of Chevron deference—now obliging courts to interpret statutes independently rather than relying on agency expertise.
- Bayer, which acquired Monsanto in 2018, faces massive liability—over 100,000 lawsuits and more than $11 billion in settlements and verdicts—stemming from claims that Roundup causes non-Hodgkin’s lymphoma (New Lede).
- The EPA, for its part, consistently finds that glyphosate (the key ingredient in Roundup) poses no human health risk when used as directed (Washington Post), while other international agencies warn of potential carcinogenicity.
Legal experts are divided. Cory L. Andrews of the Washington Legal Foundation argues that by demanding uniform labeling, FIFRA shields manufacturers from state-tort liability: “By expressly prohibiting a State from altering the content of pesticide labeling, FIFRA not only protects pesticide manufacturers like Monsanto from state-tort liability but also promotes national labeling uniformity.”
On the other hand, attorneys general from several states contend that “state tort law is the traditional regulatory scheme for poisonous substances, and it serves vital compensatory and deterrent purposes.”
The Supreme Court’s pending decision could redefine the preemption defense for companies in regulated industries, with ripple effects across product liability, tort, and environmental law. Until the ruling, both sides wait for clarity on the future role of federal and state authority in such disputes.
By the numbers:
- 100,000+ — Lawsuits Bayer faces over Roundup’s alleged cancer risks
- $11 billion+ — Total Bayer has paid in settlements and jury verdicts related to Roundup
- 2024 — Year the Supreme Court ended Chevron deference, shifting statutory interpretation to the courts
Yes, but: The Supreme Court has not yet issued a decision in Monsanto Co. v. Durnell, leaving significant preemption questions unsettled.
What's next: A Supreme Court ruling in Monsanto Co. v. Durnell is expected later in 2026, which could clarify federal preemption standards.