The source of the problem, which sent one youngster to the hospital for observation, remains a mystery. But the June 16 incident appears to have been triggered by the accidental shutdown and subsequent startup of the system that circulates water in the small pool.
The pool reopened within an hour after the incident occurred; both the health department and pool operator found no problem with the water.
Emergency services were called in around 3:15 p.m. that day after the eight children experienced burning eyes and throats and other symptoms, according to Tim Campbell, a battalion chief with the Menlo Park Fire Protection District.
While some at the scene, including Campbell, suspected a problem with the chlorine flow into the pool, aquatics center operator Tim Sheeper refuted such notions and asserted that panic was a more likely suspect.
At least one mother on the scene, a registered nurse who didn't want to be identified, said the children seemed to be under real physical distress. She said some of them were gasping for air, coughing and vomiting.
One little boy was lethargic and appeared to be losing consciousness, she added.
Campbell said he was told some of the children were stricken while in the pool, but Sheeper said that was not the case. He asserted the children had been taken out of the pool before any physical symptoms were reported:
The pool evacuation, he noted, was due to a child hitting an emergency stop switch that shut down a pump circulating water in the pool.
Sheeper said a likely scenario is that they were still near the pool when the pump was turned back on, allowing the water to flow again; the strong smell of chlorinated water returned to the air, causing kids and their parents to think something was amiss.
Campbell said at least one witness reported seeing a vapor cloud over the pool when the water flow resumed, a claim Sheeper again refuted.
Those people don't have an intricate understanding of the pool or the chemical content of the water," he said. "We deal with this pool 14 hours a day, and it was fine."
The incident, he said, arose "more from a sense of panic, (from) just not knowing what was actually going on.
"Parents get scared, and end up scaring their kids," he said. "On the other hand, I'm a parent of three kids, and I understand the parenting instinct (to protect one's children)."
Sheeper and Michael Taylor, the city's acting director of community services, said the chlorine level of the pool's water was manually tested immediately after the children started complaining of symptoms, and there was nothing unusual in the chemical balance.