Debate has raged about the risk posed by chromium 6 in drinking water since the 1990s, when legal clerk Erin Brockovich discovered evidence the carcinogen had leaked from a Pacific Gas & Electric natural-gas plant into the groundwater in Hinkley, Calif.
People in the Mojave Desert community reported illnesses and deaths allegedly caused from exposure to the chemical. In 1996, PG&E settled a lawsuit filed by more than 600 Hinkley residents for $333 million and a mandate to clean up the water.
The movie â€œErin Brockovichâ€ was released in 2000, Julia Roberts won an Oscar for her portrayal of the title character and a movement was mobilized over concerns about chromium 6.
â€œThere were media reports and legislators and others; in fact there was a California law passed in the early 2000s that required us to develop a goalâ€ for the amount of chromium 6 that should be found in drinking water, said Sam Delson, a spokesman for California's Office of Environmental Health Hazard Assessment.
To this day news reports still focus on Hinkley, often with what appears to be conflicting information. In November, California newspapers reported the plume of chromium 6-laced drinking water continues to spread from Hinkley, having moved more than half a mile in two years.
The highest concentration of chromium found at a Hinkley area resident's well in the past year has been about 14 parts per billion, according to news reports. The most toxic area closest to the plume's source has a chromium concentration of 9,030 parts per billion, but that measurement does not single out chromium 6 from other forms of chromium.
Officials at the California Cancer Registry conducted a survey earlier this year, finding less than expected number of cancers among residents of the census tract that includes Hinkley. From 1996 to 2008, officials identified 196 cancers â€” a slightly lower number than the 224 cancers that would have been expected given the size and population of the area, California Department of Public Health spokesman Ken August said.
â€œThey have done three assessments now of the census track that includes Hinkley and have found no excess in the number of cancers,â€ he said.
The surveys did not attempt to look at a link between chromium 6 and cancer or any other reason for the cases it detected, August said. â€œThis is just simply looking at is there an excess number of cases of cancer in Hinkley.â€
The survey, August said, doesn't change California's conclusion formed when â€œErin Brockovichâ€ was released: â€œChromium 6 is still a drinking water contaminant and should be removed.â€