"It would last eight hours," Dronek said.

Unsure of what was causing his symptoms, Dronek, who works in Northrup Grumman's Sunnyvale offices, began avoiding the gym, and the reaction stopped. But when he went back, Dronek noticed the same delayed reaction. He also noticed that anytime he washed his hair at the gym, his scalp itched.

He began to suspect the water.

In fact, there was something new in a good portion of Sunnyvale's water. In February 2004, a month before Dronek began having his reactions, the San Francisco Public Utilities Commission, which handles water for much of the peninsula, began treating its water with chloramine instead of chlorine. Tim Risch, Sunnyvale's representative in the Bay Area Water Service and Conservation Agency--said close to 44 percent of Sunnyvale's water comes from the Hetch Hetchy Reservoir, which is almost 200 miles away. That percentage is much higher for cities closer to San Francisco.

Chloramine is a chemical disinfectant made of chlorine and ammonia--typically five parts of chlorine for one part of ammonia. According to the International Chemical Safety Card produced by the National Institute for Occupational Safety and Health, chloramine irritates the eyes and respiratory tract, and can cause asthmatic symptoms if inhaled.

The symptoms are typically delayed and are aggravated by physical effort.

Dronek's physician was unsure what was causing his reactions. At one point the doctor even recommended Dronek stop smoking, but Dronek has never smoked.

Similar problems with water were beginning to spring up around the peninsula. In Menlo Park, 45-year-old Dennise Kula was having problems with her showers.

At the beginning of February 2004, she stepped into her apartment's shower as she had done for 20 years, but soon after the stream of water hit her, she developed severe sinus congestion; her skin began burning, and she passed out in the shower. After recovering and kicking the shower door open to let fresh air in, she was able to get out of the bathroom and regroup from the reaction.

"My skin burned and itched for three days," Kula said. "I had the same reaction every time I stepped into the shower, the same horrific reaction. I thought 'I'm going to die.' "

After visiting her doctor--who suggested it was an allergic reaction to something in the house--she and her husband removed every scented item, all detergents and any other possible allergens from the house. They changed soap and shampoos, but every time she showered she had the same reaction.

After calling her local government and finding out about the new water treatment, Kula contacted the San Francisco Public Utilities Commission about the problem and was told that chloramine was safe and should not be causing such reactions.

To deal with the immediate problem, Kula began driving to Morgan Hill or Gilroy--where her parents own property--to shower and do her laundry in water systems that draw from underground wells.

"I look like I just climbed out of a manhole the rest of the time," Kula said.

To deal with the chloramine problem, Kula helped start Concerned Citizens Against Chloramine, a group dedicated to educating people in the area about the effects of chloramine on people, animals and the environment.

There are some 30 members of the group, although they are not always all present at meetings. Kula said a satellite group of 30 more people is also forming in Pacifica. Group members come from all cities along the peninsula, from San Francisco to Sunnyvale.

The group meets frequently--most recently on May 3--to discuss concerns and share stories. They are trying to incorporate and get nonprofit tax status to begin working with local governments and representatives to try to solve the chloramine problem.

According to Lillian Brown, spokeswoman for the public utilities commission, chloramine has been used in water systems since the early 1900s. It's recommended as an alternative to chlorine because when chlorine mixes with organic matter like algae in water, it can produce trihalomethanes, believed to be carcinogenic. Chloramine also stays in water longer as it flows from treatment plants to homes.

"You have to disinfect municipal water supplies or otherwise you'll be back in the days of cholera outbreaks," Brown said.

Brown said that since its introduction, chloramine has reduced the amount of byproducts by one-third. She added that before chloramine was used, a 10-year study was done on the effects of the chemical. The San Francisco PUC was the last major utility commission in the Bay Area to convert to chloramine.

Although Brown said the commission has received minimal complaints about chloramine, Concerned Citizens Against Chloramine members say there will be more as people come forward to talk about the reactions they're having to the water.

"Eventually it will take its toll; we're just the canaries in the coal mine right now," Kula said.

To contact Concerned Citizens Against Chloramine, call Denise Kula at 650.328.0424 or visit www.chlo ramine.org. For other concerns about chloramine issues, contact the Santa Clara County Public Health Department at 408.423.0700.