Abstract: Employee #1, a 19-year-old lifeguard, went into the pump house of rooftop swimming pool that had a closed cold water cleaning system. The pump house smelled strongly of chlorine and she saw hot water leaking from the hair lint filter onto the floor. She shut off the water pump and left to call the office. She returned to the pump house to shut off the entire system when the 40 lb PVC piping containing water and chlorine exploded. Employee #1 sustained broken bones in her right leg and the loss of upward flexibility in her right foot. Chlorine tablets had been added to the hair and lint filter the night before the explosion because of a broken feeder on the automatic chlorinator. Employee #1 was not certified as a pool operator or manager.