Roundup verdicts have long dominated Monsanto's legal problems, but $269 million in jury awards in the past year tied to a different toxic chemical are creating another headache for parent corporation Bayer AG.

The verdicts all involve a school in Monroe, Washington, that allegedly exposed students, teachers and parents to polychlorinated biphenyls, or PCB, which for decades was inside fluorescent light fixtures and the caulking in window sills. More than 200 plaintiffs who attended the school and their spouses have sued PCB-manufacturer Monsanto.