Abstract: On July 11, 1990, Employee #1, an apprentice carpenter, was preparing a pneumatic nailing gun before starting to nail off a sheer wall. He was near the job box and was holding the gun in one hand while, with the other hand, he attempted to connect the air hose to the gun fitting with a quick-connect chuck. As he made the connection and the air pressure increased inside the gun, a nail was fired into the front of his left leg above the knee. The nail lodged in his leg bone, fracturing it. The nail was surgically removed and Employee #1 was released from the hospital on July 14, 1990. He stated that the gun malfunctioned and that he did not have the muzzle resting against his leg, as indicated by a witness. The gun and air pressure system were tested on July 17, 1990.