Abstract: On May 10, 2007, an employee and Coworkers #1 and #2 were using air pressure to transport a light-weight rope that was attached to a 5 to 6 inch metal carrier, mouse, from one end of a conduit to the other. The origin of this maneuver was Manhole Number 444 and the destination was Manhole Number 511. The employee was located in Manhole Number 444 operating equipment manufactured and distributed by Condux International, Inc. Coworker #1 was outside and above Manhole Number 444 operating a truck-mounted air compressor and communicating with Coworker #2, who was to receive the mouse at Manhole Number 511. The truck-mounted compressor was observed to generate air pressure of approximately 150 psi. However, after the truck engine was warm and idled back, the constant pressure generated by the compressor was approximately 110 psi. The conduit between the two manholes had a second conduit, innerduct, within the original and the mouse traveled within the innerduct. The employee inserted the rope, mule tape, through the rope adapter and seal-off head and tied the mule tape to the mouse, which subsequently was inserted into the innerduct. He then inserted the seal-off head into the innerduct, hand-tightened it, and attached the hose coupling and closed the airflow valve. Finally, he attached the air hose, which was attached to the truck-mounted compressor. The employee reported turning the airflow valve slowly but noticed the mule tape was not moving. Therefore, he closed the airflow valve, disassembled the equipment to determine if the mule tape was stuck, but found no irregularities. After reassembling, the employee opened the airflow valve slowly and noticed the mule tape moving. Coworker #2 in Manhole Number 511 reported hearing air and seeing water coming out of the conduit at his end of approximately 30 seconds before it stopped. Meanwhile, in Manhole Number 444, the seal-off head popped out of the innerduct and the mouse shot out with sufficient force to hit the employee, tear through his clothing, through his skin, traveled across his body, and lodge in the right-front part of his abdomen. The employee climbed out of the manhole with the mule tape hanging out of his clothing. Coworkers #1 and #2 obtained emergency help. The employee was hospitalized and treated for puncture wounds.