DUBLIN — The system that pumps fluoride into Dublin drinking water has been shut down pending the results of an investigation into an incident that left 23 people sick Tuesday.
Officials at Dublin San Ramon Services District found over-fluoridated water at Zeiss Humphrey Systems Inc. in eastern Dublin, where four employees sought medical treatment after drinking the water.
Fluoride is added to water to control tooth decay, but too much can cause nausea, vomiting and diarrhea, officials say.
No other illnesses have been reported, said spokeswoman Mary Gordon. District officials went out to nearby Dougherty Elementary on Wednesday morning and didn’t find any problems, she said.
As a precaution, the district shut down the fluoride systems for the entire city, not just the affected area.
“It’s just to kind of check out the system,” Gordon said. “There’s no evidence there is any problem.”
The investigation should take a week to 10 days, she said, and the fluoride system will remain off-line the whole time.
Officials have theorized that an excess of fluoride was caused by a mechanical overfeed, when one “turnout” pipeline was shut down for maintenance but the fluoride feed continued to run, resulting in a buildup of the chemical.
The Department of Health Services requires a level of between 1 part and 2 parts fluoride per million parts of water. Samples from Humphrey Systems on Tuesday had concentrations of 250 parts per million.
The affected employees were treated and released, and aren’t expected to suffer any long-term side effects.
For more information, call (925) 828-8524.
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