'Erin Brockovich' Carcinogen in Tap Water of More than 200 Million Americans

The conflict over chromium-6 regulation stems not only from the question of how much is safe, but the staggering cost of cleaning up such a widespread contaminant that is an industrial pollutant but also occurs naturally. The California Department of Public Health estimates that treating the state's water to meet the legal limit of 10 parts per billion will cost nearly $20 million a year,[20] so the cost of meeting the much more stringent public health goal would be far higher.