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 chromium-polluted 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 water 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.