Abstract: At approximately noon on October 25, 2002, an employee, of Utility Conduit Systems, (USC) Corona, California, suffered a fracture to his left leg while working on a residential construction project. The employee was using a blowgun to "shoot" a "bullet" and mandrel with rope attached down a 5 ft-diameter underground utility conduit pipeline, that was 300 feet in length. The bullet and mandrel stopped short of the exit because of water blockage. The employee shut off the air pressure to the pipe and did not remove the blowgun from the pipe before air pressure bled off. Employee removed the blowgun from the pipe; backpressure blew the blowgun off the pipe. The blowgun struck the employee in his left leg above his knee. Paramedics transported the injured employee to Menifee Valley Medical Center in Wildomar, California where he was treated and hospitalized for his injuries.