Five children were taken to a hospital in Tampa, Florida, after a “freak accident” caused a cloud of chlorine gas to erupt at a local indoor pool.
ABC News reports that the accident occurred after a thunderstorm on Monday had caused one of the pool’s water pumps to shut off. While the pump was off, chlorine gas built up inside — and then exploded outward into the pool area when the pump was turned back on.
The five children were taken to the hospital and were treated for respiratory burns, stomach irritation and nausea.
A crew in hazmat suits arrived to help ventilate the pool, which was deemed safe to use shortly afterward.
“We’ve trained hundreds of kids for water safety and our concern is about everyone’s safety,” the pool’s owner said. “We believe that it was a malfunction.”
Watch ABC News’ video of the incident below.