Abstract: At 9:08 a.m. on April 9, 2007, Employee #1 was working at the Youngstown-Warren Regional Airport, between Youngstown and Warren, Ohio. He was working alone, when he was notified that Hangar 2 North needed to be opened up for an inbound flight. The hangar is equipped with two personnel access doors mounted in the aircraft hangar doors for employee access. Although both doors were locked, Employee #1 did not get the keys from the land shack. When the 19 foot 7 inch-wide aircraft hangar doors were in their closed position, the door frame was 3 inches from the hangar frame. This 3 inch space was taken up by a flexible rubber weather seal. The doors were operated using constant pressure control buttons mounted on the inside of the hangar door, 11.75 inches from the leading edge. The door controls consisted of two buttons, "open" and "close," that required the operator to maintain constant pressure and accompany the door as it was being opened or closed to ensure that the door pathway was clear of obstructions. The lead door was motorized, and it moved the other doors through a cascading-type opening and closing process. The lead door had two limit switches installed, one for the "doors open" position and another for the "doors closed" position. Anyone moving the doors ran them until the open or closed limit switch was activated, stopping the door movement, or until he released the control button prior to activation of the limit switches. The control buttons were recessed in a ring guard to prevent inadvertent activation, but approximately two years ago, the controls had been modified by a previous tenant. Holes had been drilled through the ring guards to allow the insertion of a 2.5-inch-long nail that was kept suspended by a chain next to the controls. The nail could be inserted through the holes in the ring guard to hold constant pressure on the buttons. This modification allowed the doors to open and close until the limit switch was reached without having an operator accompany them. On the day of the accident, it appears that the doors had been previously closed by use of the nail. Employee #1 arrived outside the hangar door and stuck his arm around the door and through the rubber seal to the control buttons on the inside of the hangar. At this time, the nail was still holding the "close" button switch depressed. When Employee #1 pressed the "open" button, the door started to open, and he started through the gap between the door and the door frame. When he released the "open" button, however, the "close door" circuit was energized, as the nail was holding the "close" button depressed. The door immediately started to close, catching Employee #1 between the door and the frame, and crushing his head, chest, and body. He was found pinned in the door, with the door motor deenergized through activation of the motor's overheat thermal disconnect switch. He had been killed.