When Erin Brockovich went after PG&E for poisoning groundwater in the desert town of Hinkley, California — a campaign that later became a film starring Julia Roberts — the toxic chemical was a heavy metal called hexavalent chromium. Also known as chromium 6, the chemical is listed under California’s Prop 65 as causing cancer, developmental harm and reproductive harmin both men and women. A new report out today finds Hinkley isn’t the only California city with chromium 6 contamination. The report found 11 water districts serving some 400,000 Californians had hexavalent chromium in their tap water at levels above the state’s legal limit.