Staffers were at the De Anza Cupertino Aquatics facility late into the night trying to air the place out. The leak happened around 2 p.m. near the shallow pool where the youngest kids learn how to swim and where the investigation is now focused.
One by one, a line of ambulances left the aquatics facility as they rushed to area hospitals with precious cargo - 16 people, including several children, were exposed to chlorine minutes after a pump malfunctioned.
"There was a back up of chlorine mixed with acid which is normally poured into the pool, but with the back up once that pump turned on it created a high concentration that met that water," said San Jose Fire Captain Chuck Rangel.
But the problem wasn't in the water, it was the chlorine in the air.
"People were having a hard time breathing and kind of nauseous," said witness Judy Aslor.
"I saw a man come out coughing and hacking and kind of heaving by my truck," said witness Judy Hill.
"Chlorine is very irritating and I wanted everybody that had inhaled it to go to the hospital," said DACA swim director Pete Raykovich.
Fourteen people, mostly children, went to five hospitals where doctors were ready for the worst.
"With major exposure to chlorine, you'd have more serious symptoms like vomiting, nausea, and potential damage to the lungs," said Joy Alexiou with the Valley Medical Center.
Fortunately, the majority of patients were released after only a few hours. Everyone is supposed to be OK. Now, the swim center remains closed and parents of young swimmers admit they are concerned.
"I need to keep an eye on this to make sure that the pools are a safe place where I can take my child," said parent Rajesh Prabhu.
The pump is only about a year old and the director at the center says he's never had a problem with it.
DACA is expected to reopen Friday.
