Hillsborough County Fire Rescue officials tell news outlets it happened Monday evening at Calypso Swim Center in Tampa.
Fire rescue officials say the storm caused the breaker to shut off one of the two pumps, which caused the water in the pool to stop circulating. That led to a buildup of chlorine in one of the pipes. When the pump came back on, it pushed the chemical mix into the pool, causing the cloud of gas.
A hazmat crew helped ventilate the building. The pool owner called it a “freak accident.”
The children complained of stomach discomfort and were treated and released.