Abstract: At approximately 1:55 p.m. on August 20, 1996, Employee #1, a miner/laborer, was using a high-pressure water spray wand, capable of firing water at 10,000 lb per square inch, to loosen soil that had compacted against the outer skin of a tunneling machine's shield. Openings had been made through the shield so the wand could be inserted between it and the soil. The shield's advance had been hindered by a phenomenon called "squeeze," which is the slow, inward push of the ground into an excavated tunnel following tunnel work. Squeeze is not always predictable, but it happens from time to time and may occur without warning. The amount of tunnel affected, the time period in which it occurs, and whether it even happens, are all variable depending on the ground conditions of the tunnel under construction. Employee #1 was in the process of firing water into the shield when he adjusted his work position and inadvertently passed the wand over the top of his left foot. The spray cut through the rubber of his boot and the tissue of his foot. He sustained a laceration at the joint of his big toe, but no apparent damage to the skeletal structure of the foot. At the time the accident occurred, this was only a recordable injury; it subsequently became infected, resulting in lost work time.