EMPLOYEE WAS USING HAND WRENCH TO REMOVE BOLTS FROM RIDE STRUT ON HAUL TRUCK. COULD NOT BREAK LOOSE & HAD ANOTHER EMPLOYEE USE HYDRAULIC CRANE BOOM TO PUSH ON WRENCH, THE WRENCH CAME OFF THE BOLT HEAD & STRUCK EE IN BOTH HANDS & CUT OFF PART OF (1) FINGER & CUT/SMASHED (2)OTHER FINGERS.