THE EMPLOYEE WAS CLEAINING DIRT OFF AROUND THE TAIL PULLEY OF A CONVERYOR BELT. THE PLANT WAS POWERED OFF, LOCKED OUT AND TAGGED OUT. THE BELT UNEXPECTEDLY ROLLED BACKWARD, CAUGHT THE EMPLOYEES GLOVE WHICH PULLED THEIR HAND AND ARM UNDER AND AROUND THE TAIL PULLEY. ANOTHER EMPLOYEE WAS ABLE TO GET A WRENCH AND ROLL THE TAIL PULLEY FORWARD AND RELEASE THE HAND AND ARM.