Abstract: Employees #1 and #2 worked for a company that operates a service exchanging old barbecue-size propane bottles. Cylinders are first checked for leaks, and those with rust are cleaned by abrasive blasting before being repainted. The abrasive blasting unit holds three LP bottles at a time. One of the bottles apparently began to leak while it was being cleaned. A household-type propane detector plugged into a nearby electrical outlet went off, but Employees #1 and #2 did not know what to do. A coworker went to the alarm and unplugged it. After several seconds, he plugged it back in. The unit continued to sound, and he was beginning to unplug it again when an explosion occurred. The blast sheered off one of the steel pins that held the door closed, allowing it to swing open with great force. The door struck Employee #1, who sustained chest injuries. Employee #2, age 16, suffered burns from the flaming gas expelled when the door flew open. Both employees were hospitalized. The abrasive used is steel shot, and a spark from any number of possible sources apparently ignited the propane.