The head of the U.S. Environmental Protection Agency said she will be working with local and state officials to determine the amount of a toxic chemical found in a single sample of drinking water in Honolulu as well as in water in dozens of mainland cities.

Lisa P. Jackson yesterday said her agency will also be providing officials with guidance to help them develop monitoring and sampling programs for the chemical hexavalent chromium, also known as chromium-6.

The EPA action follows disclosure by the nonprofit Environmental Working Group (EWG) that tests it had conducted showed the presence of chromium-6 in drinking water systems in dozens of cities.

EPA has no maximum contaminant level for hexavalent chromium in water. The group compares levels it found to with California’s proposed public health goal level of .06 parts per billion, which it supports.

"It is clear that the first step is to understand the prevalence of this problem," Jackson said. "We will also offer significant technical assistance to the communities cited in the EWG report with the highest levels of chromium-6 to help ensure they quickly develop an effective chromium-6-specific monitoring program."

In Honolulu, the group found that a water sample taken from the Wilhelmina Rise area showed a level of 2 ppb parts per billion for hexavalent chromium.

The EPA establishes national guidelines for safe drinking water. Critics say the agency has been operating under a outmoded standard — a maximum contaminant level of 100 parts per billion for chromium that includes hexavalent chromium and the less toxic trivalent chromium.

California is reviewing a proposed public health goal level of .06 parts per billion for hexavalent chromium.

In reaction to EWG’s study, Jackson met with Hawaii’s U.S. Sen. Daniel Akaka and a number of other senators Tuesday to brief them on the issue.

Akaka spokesman Jesse Broder Van Dyke said the senators received assurances that EPA would develop guidelines for hexavalent chromium within a year.

In a telephone conference call yesterday, state Department of Health spokesman Janice Okubo said EPA officials pledged its assistance in analyzing more water samples.

"We’re thinking this work will probably be under way shortly after the New Year’s," Okubo said.

Asked if whether residents should be worried, Okubo said, "For our department, it’s just too early to make any definite statement or findings from the EWG (tests)," she said.

Chromium-6 was the chemical in drinking water that led to a $333 million legal settlement between residents of Hinkley, Calif., and Pacific Gas & Electric described in the movie "Erin Brockovich." In Hinkley, contaminant levels reached 500 ppb parts per billion, the group said.

Federal officials are in the process of evaluating studies of hexavalent chromium, including peer review comments. California health officials are also undergoing a similar review process for its proposed .06 ppb parts per billion level for hexavalent chromium.

The group said tests show clear evidence that chromium-6 in drinking water causes cancer in laboratory animals. Other health risks associated with exposure include liver and kidney damage, anemia and ulcers, it said.