Roundup Weedkiller Seeking to Block Lawsuits

By: Shelia Mader

Here is a synopsis with what’s happening with the Supreme Court and the Roundup Weedkiller litigation.

The U.S. Supreme Court has just agreed to hear an appeal from Bayer, the company that makes Roundup (after buying Monsanto). Bayer wants the Court to block or limit thousands of state-level lawsuits alleging the herbicide causes cancer, especially non-Hodgkin’s lymphoma. Those lawsuits seek damages and were based on state “failure-to-warn” claims because plaintiffs say Bayer didn’t properly warn about cancer risks.

The heart of the legal question the justices will consider is this:

Does federal pesticide law (specifically the Federal Insecticide, Fungicide, and Rodenticide Act) preempt state lawsuits claiming a company should have added cancer warnings that the Environmental Protection Agency (EPA) did not require? Bayer argues that if the EPA has approved Roundup’s label without a cancer warning, state courts shouldn’t be able to impose different requirements through damages claims.

What this means in practical terms:

If the court sides with Bayer, many, potentially thousands, of lawsuits could be curtailed or dismissed, because the central legal claim plaintiffs are making may be blocked. If the court rejects Bayer’s preemption argument, this litigation could continue in state courts with fewer limits.

Bayer is already facing huge numbers of claims (on the order of tens of thousands nationwide) and has set aside billions of dollars to resolve them.

Background context that matters:

A jury in Missouri awarded $1.25 million to a plaintiff who said his non-Hodgkin’s lymphoma was caused by Roundup, that’s the case Bayer asked the Supreme Court to review.

In past rounds of litigation, juries have issued large verdicts, and Bayer has settled many claims, but this appeal is focused on a legal rule rather than facts about whether Roundup causes cancer.

Lower appellate courts have disagreed on whether federal law preempts state lawsuits, which is one reason the Supreme Court agreed to take the case.

Why it’s a big deal for farmers and rural areas:

Roundup and other glyphosate-based herbicides are widely used in U.S. agriculture, including on crops like corn and soybeans. If Bayer eventually wins a ruling that limits state failure-to-warn claims, it could reduce legal risk for pesticide makers and potentially influence how crop protection products are regulated and labeled. If the Court rejects Bayer’s position, liability for companies could expand, but state courts would still be able to hear those claims.

How the EPA’s stance fits in:

The EPA currently does not classify glyphosate (Roundup’s active ingredient) as likely carcinogenic when used as directed, which is part of Bayer’s argument that state juries shouldn’t override federal labeling decisions.

Timing and outlook:

The Supreme Court has accepted the case, but oral arguments haven’t been scheduled yet. A decision would likely come later in the term, which could be spring through summer 2026.