Abstract: On October 6, 2009, Employees #1 and #2 were placing items to be shredded on the inlet conveyor of a paper shredder, when an explosion occurred in the exit conveyor approximately 35 feet from them on the same machine. While escaping, Employee #1 ran into a parked forklift and bruised his chest. He was transported to Suburban Hospital, where he was treated and released. Employee suffered temporary ringing in his ears, but he was not transported to a hospital. An investigation determined that the explosion was not caused either by an employee or by mechanical failure of the machine. The employees were not doing anything that apparently contributed to the ignition source. Fire marshals investigated the explosion as well and did not make an exact determination of the cause of the explosion. They did, however, discover a match book in the paper that had been in the grinder and shredder. It might have been the source of ignition for paper dust. An OSHA inspector's investigation did not reveal that the machine had any mechanical problems or failures. The machine was fully enclosed at all points of the conveyor, with breakaway panels to displace any explosion. Housekeeping for this facility was very good, and the system's dust collection systems were functioning properly when they were tested after the explosion.