In an effort to help dozens of Peninsula residents who say their sensitivity to chloramine has caused skin rashes and respiratory problems, Congresswoman Anna Eshoo is pulling strings to allow them to speak with the Environmental Protection Agency's state office.

"Constituents have raised their serious concerns about chloramine," said Rep. Eshoo, D-Palo Alto. "I think it's important for the EPA and the Public Utility Commission to hear directly from them and I am facilitating this. The use of chloramine as a disinfectant in public water should be guided by sound science showing that it is both safe and effective."

Chloramine replaced chlorine as the disinfectant for Hetch Hetchy tap water in 2004. The switch had been recommended by the EPA to reduce the carcinogenic byproducts of chlorine.

Since then, however, more than 400 Bay Area residents have reported allergic reactions to chloramine, including skin rashes, respiratory problems and inflamed digestive tracts, according to the Menlo Park-based Citizens Concerned About Chloramine.

That group's president, Denise Johnson-Kula, said the goal of the meeting, scheduled for Aug. 27, is to start a discussion with the EPA about providing a "waiver" to local water agencies allowing them to go back to chlorine use -- despite whatever effects that may have on byproducts in the tap water.

On the Peninsula, this could put responsibility for the problem back into the hands of the local water provider, the San Francisco Public Utilities Commission, which has said its switch to chloramine was prompted by EPA recommendations.

The group has joined forces with others from as far away as Vermont to build a national movement to stem the disinfectant's use until studies can be done on its health effects. The renewed effort came after a California bill to study chloraminated tap water, authored by Assemblymember Ira Ruskin, failed for the second year in a row this summer.

The groups celebrated one of their first victories two weeks ago, when a handful of residents in Pennsylvania were able to delay a switch to chloramine by the Pennsylvania-based American Water Company. Opponents said proper studies of its health effects had not been conducted.

One-third of the country has already converted to the disinfectant, said Ms. Johnson-Kula. Water agencies, meanwhile, say some places have used chloramine since the early 1900s with no problems.

The EPA recommended that water agencies switch to chloramine to reduce trihalomethanes, a carcinogenic byproduct of chlorine disinfection. But the byproducts of chloramine are even more dangerous, according to Dr. Michael Plewa, professor of genetics at the University of Illinois, who recently published a study on tap water disinfection byproducts.

In an e-mail to the Mountain View Voice, Dr. Plewa stated that the byproducts of chloramine are "much more toxic" than chlorine's -- and that these byproducts are found in California water supplies. He recommends that water agencies switch back to chlorine.

Whether chloramine itself can be linked to people's health problems has yet to be studied. Dr. David Ozonoff, a professor of public health at Boston University, says that question is definitely worth looking into.

"A close temporal relationship between the treatment change and the complaints of water users strongly suggests that one is the cause of the other," he wrote in a letter to Vermont-based People Concerned About Chloramine.

"Without a more detailed study of the matter it is not possible to say this definitively, but it is plausible that something about the treatment change has caused this. Water chemistry is complicated and sometimes produces unexpected and untoward results. The complaints are notice to look into the matter."

Such chemistry may have affected water supplies in Los Altos, where lead content is regularly tested. Following the introduction of chloramine, water in several homes was found to contain lead levels over the public safety limit, possibly due to the way chloraminated tap water reacts with the lead-soldered plumbing in older homes.

Greg Hosfeldt, business manager of the Mountain View Public Works Department, said 24 random water samples were taken from Mountain View homes and wells after the switch to chloramine in 2004. Lead levels were not found to be over the maximum level, he said. The city is slated to test its water again in September.

More information can be found at www.chloramine.org .

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