Parents of students in Malibu are suing the Santa Monica-Malibu Unified School District, saying that schools like Malibu High are too dangerous for their kids. The parents are protesting the presence of PCBs, a substance that was widely used in construction materials before 1980. PCBs are banned today, but two older Malibu schools have elevated levels of PCBs in their buildings’ window caulking. The school district and the Environmental Protection Agency have said that the schools are safe, but parents and some experts disagree. We look for clarity with an expert.