WHILE DOING MAINTENANCE WORK ON THE BOOSTER, EE HAD CLIMBED OVER A V-BELT GUARD. AFTER DOING SO HIS RIGHT FOOT STEPPED ON A SHORT PIECE OF ANGLE IRON THAT WAS WELDED TO THE BARGE. UPON PUTTING HIS FULL WEIGHT ON THE IRON ANGLE, HIS RIGHT FOOT TURNED OVER ON ITS SIDE. EE WASN'T IN PAIN RIGHT AWAY BUT AS THE DAY WENT ON, THE PAIN INCREASE. AREA WAS LOCKED OUT PRIOR TO MAINTENANCE.