THE EMPLOYEE WAS TRYING TO REMOVE A TIRE FROM A FORKLIFT. HE WAS SITTING ON A ROLLED-UP CONVEYOR BELT FACING THE REAR LEFT TIRE. HE NOTICED TWO DIFFERENT-SIZED LUG NUTS BUT DIDN'T CONSIDER THE TIRE HAVING A SPLIT RIM HELD TOGETHER BY 6 STUD NUTS. AS HE HAD 2 REMAINING STUD NUTS TO REMOVE THE TIRE RIM SHOT OUT HITTING HIS ARMS. THE TIRE HAD APPROX. 100 LBS OF PRESSURE.