After her parents decide to cover their Long Island home with blue vinyl siding, filmmaker and organizer Judith Helfand sets out to verify the hazards of polyvinyl chloride, or PVC. She and codirector Daniel B. Gold travel to Louisiana, Florida, and Italy, where veterans of the vinyl industry blame their cancers on dioxin released by PVC, and to the Bay Area, where green activists talk about alternative building materials. With only a layman's knowledge of chemistry, Helfand seems to be in way over her head, and when she finally buttonholes a spokesperson for the Vinyl Institute, he deflects her questions like he's brushing away a fly. Yet the anecdotal evidence alone is damning, and when Helfand talks her parents into re-siding their home with wood, her narrative strategy drives home the real point: in a world of corporate irresponsibility toward the earth, personal responsibility is our last defense. 100 min.