Abstract: A three man crew was in the process of setting up a water jet for another company to operate. The water jet was capable of 10,000 pounds per square inch and was operating at approximately 500 pounds per square inch. Employee #1 and another worker set up the water jet and radioed the owner of the company. When the owner arrived he surveyed their work and began the process of purging the machine of air and engaging the clutch from the power side of the machine. Employee #1 and the other worker were on the fluid side of the machine. The owner asked for the all clear signal and both employees signaled back yes. Employee #1 walked by the fluid end of the water jet to grab a hose. The water jet was in a slow roll and the pressure gauge was oscillating between 0 and 500 pounds per square inch. This occurred two or three times in a span of a few seconds and then there was a loud retort. The owner immediately shut down the machine and ran around to the fluid side of the water jet, thinking that the hose on the fluid side of the machine had become disconnected. He saw that the hose was still connected and Employee #1 was holding his left side and turning towards his left. Employee #1 was struck in the left upper quadrant by the head of a plug, which became a projectile from the fluid end of water jet, and died two days later in the hospital.