Abstract: Employee #1 was using a pneumatic nailer to fasten the bottom of 2 by 6 wooden studs to the outside wall of a building under construction. It was his third day on the job. His foreman was standing on a ladder above him, nailing the tops of the studs by hand. As Employee #1 attempted to nail a stud, the nose of the nailer came in contact with his left knee and a 3 in. long 16D nail was driven into his leg. His foreman was unable to extract the nail with his claw hammer, and left the employee standing adjacent to an open-sided floor to get a pair of pliers. As the foreman was returning, Employee #1 either lost consciousness or went into shock and fell 24 ft to the ground. He struck his head against a stack of 2 by 4 lumber on the ground and was killed. Neither Employee #1 nor the foreman was wearing a safety belt or was attached to a lifeline.