EMPLOYEE WAS USING THE FIRE HOSE FROM THE WATER TRUCK, TO WASH OUT THE MUD FROM THE TRANSMISSION BELLY PANS OF TWO HAUL TRUCKS. THE NOZZLE END WAS HELD IN PLACE BY A HOSE CLAMP. THE HOSE BECAM E SEPARATED FROM THE NOZZLE. THE HOSE SLIPPED THROUGH HIS HAND AND THE HOSE CLAMP CUT HIS THUMB.