EMPLOYEE WAS WORKING ON THE 3RD FLOOR OF SILO 35 AT THE SURGE BIN LEVEL. THE EMPLOYEE FINISHED HIS WORK AND HEADED TO CHECK THE INSPECTION DOOR ON THE OUTSIDE. EMPLOYEE STARTED UP THE STAIRS, HIS RIGHT FOOT GOT CAUGHT-UP BETWEEN THE GAP OF THE FIRST AND SECOND STAIRS. HE FELL FORWARD PUTTING HIS HANDS IN FRONT OF HIM, MOSTLY FALLING ON HIS RIGHT ARM.