Abstract: At approximately 1:58 p.m. on April 10, 2001, Employee #1 was nailing stiffeners onto trusses with an ITW Paslode nail gun. A fellow employee lined the trusses, stiffeners, and pieces of wood to be nailed. Employee #1 was nailing the two pieces of wood together. He had to bend to nail the trusses. He got up holding the trigger and the nail shot him on the knee. The nail was approximately 2.5 inches in length. The spring on the trigger and the safety device on the muzzle were in place. Employee #1 stated that he got careless toward the end of the day which led to the accident. He also stated that he received plenty of training from both work and school on the use of a nail gun. Employee #1 was transported to Pomona Valley Hospital. He sustained a puncture wound to his right knee and was hospitalized.