EMPLOYEE WAS UNPLUGGING A CLEANUP PUMP, WHICH HAHAD BEEN HOSED DOWN DUE TO BEING HOT; HE STOOD BEHIND THE PUMP & BEGAN TO LOOSEN THE TOP UNTIL IT WAS REMOVED. WHEN CAP WAS SEPARATED FROM THE WATER IN DISCHARGE LINE BLEW DOWN, SPLASHING ON-TO HIS ARM, RESULTING IN A BURN INJURY. P, THE WATER IN THE DISCHARGE LINE BLOWED DOWN, SPLASHING ONTO THE ARM, RESULTING IN A BURN INJURY.