The US Supreme Court heard arguments on Monday. The case is called Monsanto v Durnell.

It centers on Roundup weedkiller and its chemical glyphosate. Some studies have linked glyphosate to cancer.

The key question is whether people can sue Monsanto for not warning them. Monsanto says federal law blocks those lawsuits.

But the judges appeared skeptical of Monsanto's position. The court seems divided so the outcome is not clear.

The ruling could affect tens of thousands of lawsuits against Monsanto. Monsanto makes Roundup and is now owned by German company Bayer. A decision is expected by the end of June 2026.