One of the company’s yard forklifts had a flat on one of the front tires. The flat consisted of a hole in the tread of the tire. The flat tire was picked up and repaired by a local tire repair shop and put back onto the forklift by the repair shop personnel. Because the tire was repaired the Yard Supervisor had the tire swapped with one of the rear tires. The forklift had been used several times and was sitting idle and all yard personnel had left the yard except for one welder. He was preparing to leave at around 2:30 pm when he heard a loud pop. He then noticed a cloud of dust around the forklift. Inspection showed that the rear tire (the tire that had been repaired) had exploded. The tire rupturing caused considerable damage to the forklift. (As seen in the photos) The tire evidently blew upward separating the step from the mounting bracket and causing it to hit the cab. It is very fortunate that no one was in or around the forklift at the time of this failure. Had some one been near and the tire blew out to the side the results could have been catastrophic.