The study found measurable hexavalent chromium in the tap water of 31 of the cities sampled, with Norman, Oklahoma, at the top of list ; 25 cities had levels that exceeded California's proposed limit.

The study found measurable hexavalent chromium in the tap water of 31 of the cities sampled, with Norman, Oklahoma, at the top of list ; 25 cities had levels that exceeded California's proposed limit. VI and less toxic forms.

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