Laboratory tests commissioned by Environmental Working Group (EWG) have detected hexavalent chromium, the
carcinogenic “Erin Brockovich chemical,” in tap water from 31 of 35 American cities. The highest levels were
in Norman, Okla.; Honolulu, Hawaii; and Riverside, Calif. In all, water samples from 25 cities contained the
toxic metal at concentrations above the safe maximum recently proposed by California regulators.
The National Toxicology Program has concluded that hexavalent chromium (also called chromium-6) in drinking
water shows “clear evidence of carcinogenic activity” in laboratory animals, increasing the risk of gastrointestinal
tumors. In September 2010, a draft toxicological review by the U.S. Environmental Protection Agency (EPA) similarly
found that hexavalent chromium in tap water is “likely to be carcinogenic to humans.”
In 2009, California officials proposed setting a “public health goal” for hexavalent chromium in drinking
water of 0.06 parts per billion (ppb) to reduce cancer risk. This was the first step toward establishing a statewide
enforceable limit. Despite mounting evidence of its toxic effects, the EPA has not set a legal limit for hexavalent
chromium in tap water nationally and does not require water utilities to test for it. In 25 cities where EWG’s testing
detected chromium-6 — in the first publicly available national survey for the contaminant — it was found in
concentrations exceeding California’s proposed maximum, in one case at a level more than 200 times higher.
At least 74 million Americans in 42 states drink chromium-polluted tap water, much of it likely in the cancer-causing
hexavalent form. Given the scope of exposure and the magnitude of the potential risk, EWG believes the EPA should move
expeditiously to establish a legal limit for chromium-6 and require public water suppliers to test for it.