Hexavalent chromium is the pollutant at the heart of 'Erin Brockovich.' The movie recounts the legal battle waged by residents of Hinkley, Calif., who blamed exposure to the chemical for high rates of diseases.
The findings were released Monday by the Environmental Working Group, which used laboratory tests. It found the highest concentrations of hexavalent chromium, also known as chromium 6, in the drinking water in Norman, Okla.; Honolulu; and Riverside, Calif. Levels ranged from 12.9 parts per billion in Norman to 0.03 ppb in Cincinnati and Boston.
For the 35 cities surveyed the average was .18 ppb. That's three times the “public health goal,” or ideal standard, under consideration by California's Office of Environmental Health Hazard Assessment. [Editor's note: The original version of this paragraph overstated the average concentration and the degree to which it overshot the public health goal.]
Scientific and legal debate has raged over the risk posed by hexavalent chromium in drinking water since the 1990s, when the then-obscure legal file clerk Erin Brockovich unearthed evidence that the substance had leaked from a Pacific Gas & Electric natural-gas plant into the groundwater in Hinkley, Calif.
Residents sued, and in 1996 PG&E paid a $333 million settlement to about 600 people who blamed exposure to the chromium 6 for high rates of cancer and other diseases.