While the dangerous carcinogen, otherwise known as chromium-6, may sound foreign to most people, perhaps the name Erin Brockovich will ring a bell.
After chromium-6 was discovered in the Hinkley, California, Brockovich helped bring about a lawsuit that ultimately ended in 1996 with the utility company, Pacific Gas & Electric, paying more than $330 million in damages.
Norman, Oklahoma; Honolulu, Hawaii; and Riverside, California, top the non-profit organization's list of cities with water supplies contaminated by chromium-6.
The Environmental Protection Agency has classified the toxin as "likely to be carcinogenic to humans" as part of a risk assessment the agency is currently conducting on total chromium. The agency says water utilities are required to test for total chromium levels in the water but not explicitly for chromium-6. Chromium-6 is a natural byproduct of total chromium.
"In order to protect people's health, EPA has had drinking water standards for total chromium, which includes chromium-6," the agency said in a statement to CNN. "When this scientific assessment is finalized in 2011, EPA will carefully review the conclusions and consider all relevant information, including the Environmental Working Group's study, to determine if a new standard needs to be set."
"I was expecting to find hexavalent chromium in some of the cities we checked, but I didn't expect it to be so widespread," said Rebecca Sutton, a senior scientist with the
Environmental Working Group and the lead author of the study. Sutton said there is a well-documented corollary between exposure to chromium-6 and a greater risk of stomach cancer in humans. Additionally, there is ample animal evidence showing a broad risk of gastrointestinal tumors in rats and mice exposed to the toxin, she said.
To conduct its test, the organization said it recruited volunteers in 35 cities to collect tap water samples "from unfiltered taps in homes or in public buildings such as hospitals, libraries and malls," the report said.
Here are the cities:
1. Norman, Oklahoma 2. Honolulu, Hawaii 3. Riverside, California 4. Madison, Wisconsin 5. San Jose, California 6. Tallahassee, Florida 7. Omaha, Nebraska 8. Albuquerque, New Mexico 9. Pittsburgh, Pennsylvania 10. Bend, Oregon 11. Salt Lake City, Utah 12. Ann Arbor, Michigan 13. Atlanta, Georgia 14. Los Angeles, California 15. Bethesda, Maryland 16. Phoenix, Arizona 17. Washington, D.C. 18. Chicago, Illinois 19. Milwaukee, Wisconsin 20. Villanova, Pennsylvania 21. Sacramento, California 22. Louisville, Kentucky 23. Syracuse, New York 24. New Haven, Connecticut 25. Buffalo, New York 26. Las Vegas, Nevada 27. New York, New York 28. Scottsdale, Arizona 29. Miami, Florida 30. Boston, Massachusetts 31. Cincinnati, Ohio