LINCOLN, Neb. (DTN) -- Justices on the U.S. Supreme Court seemed to struggle Monday with a question that could determine whether product liability cases like the cancer lawsuits filed against Bayer's Roundup herbicide will be allowed to continue. At issue is whether a U.S. Environmental Protection Agency stamp of approval on a pesticide label is enough to shield Bayer from thousands of state warning label lawsuits against glyphosate-based Roundup, or if individual juries still get to decide whether the chemical causes non-Hodgkin's lymphoma. Justices hearing oral arguments in the case, Monsanto v Durnell, spent nearly 90 minutes wrestling with a fundamental conflict in federal law. The Federal Insecticide, Fungicide and Rodenticide Act's express preemption clause says states cannot impose labeling requirements that go beyond what federal law demands. Another provision of FIFRA says EPA's findings at registration are not a binding legal command. Which provision controls could ...