Abstract: At approximately 7:30 a.m. on February 15, 2002, Employee #1 inadvertently shot a 3.25-in. nail into his brain while using a pneumatic nail gun. There were no eyewitnesses and Employee #1 could not remember parts of the accident. The most plausible cause of the accident is as follows. The gun recoiled due to the nail hitting a hard surface such as a knot in the wood or a nail-head located beneath the plywood Employee #1 was nailing. When the nail hit a hard spot, the force of the nail gun could not drive the nail all the way, and this resulted in more pneumatic pressure to remaining in the gun. This extra pressure caused a kickback. Employee #1's hand that was holding the gun also kicked back and it may have bent his arm inward from the body's natural reflex, which resulted the gun to point at Employee #1's face. Because the recoil occurred in a couple of seconds, Employee #1 probably could not remove his finger off the trigger during the recoiling and the muzzle of the gun may have hit his cheek from the jolt caused by the recoil. Pulling the trigger and hitting the muzzle engaged the gun and may have released a nail. The nail entered through Employee #1's lower right cheek and embedded in the middle of the brain. Employee #1 was hospitalized.