California, often an environmental trendsetter, is proposing a strict public health goal to reduce chromium-6, a probable carcinogen, in tap water following a recent report about its prevalence in 31 U.S. cities.

The state, which proposed an initial goal in late 2009, issued a draft version last week of a much stricter voluntary standard for the chemical that was made famous in the 2000 Hollywood movie Erin Brockovich. It's now seeking public comment before finalizing its goal.

The U.S. Environmental Protection Agency is considering whether to set a limit for chromium-6, also known as hexavalent chromium, in tap water. In 2007, the National Institutes of Health reported strong evidence that the chemical caused cancer in laboratory animals when consumed in drinking water.

"EPA will likely revise drinking water standards for chromium-6" once its scientific review of the chemical is done, the agency's administrator Lisa P. Jackson said last month. Currently, EPA restricts the amount of "total chromium" in drinking water, which contains both the hexavalent and the mostly benign trivalent forms, to 100 parts per billion.

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Jackson said EPA would also help local governments test for chromium-6, which a study last month by the Washington-based Environmental Working Group (EWG) found in the tap water of 31 of 35 U.S. cities. Two of the five cities with the highest levels -- Riverside and San Jose -- are in California as was the town, Hinkley, where Erin Brockovich found particularly high levels of chromium-6.

California's Environmental Protection Agency is now seeking a voluntary chromium-6 limit of 0.02 parts per billion (ppb), which is considerably stricter than its prior 0.06 ppb goal.

"One day soon, as a result of this action, California's families could find their drinking water with far less of this dangerous carcinogen," said Ken Cook, EWG's president and co-founder, in a statement "Industry influence has allowed this contaminant to remain in much of the state's water for years, endangering millions, especially infants fed powdered formula mixed with tap water."

Industry groups argue chromium-6 in tap water does not necessarily pose a human health threat. "It has been well-known for years that low levels of hexavalent chromium exist naturally in groundwater in certain geological formations," Ann Mason of the American Chemistry Council said in a statement.

Gina Solomon, a senior scientist with the Natural Resources Defense Council, an environmental group, welcomed California's proposal but noted how long it took the state to issue its draft. She wrote on her blog: See this aricle