EMPLOYEE HAD STARTED REPLACING A HYDRAULIC HOSE WHEN FLUID BEGAN TO SPRAY OUT FROM THE COUPLING.THE COUPLING BLEW APART SPARYING FLUID ALL OVER AND THE HOSE BOUNCING AROUND. THE HOSE STRUCK EM PLOYEE ON HIS LEFT ELBOW AS THE PRESSURE BEGAN TO DROP. THE HYDRAULIC SPRING SYSTEM HAS TWO RELIEF VALVES, TO RELEIVE THE PRESSURE. HE RECEIVED A BROKEN ARM.