Abstract: On September 2, 1998, Employee #1 and Employee #2 were working on opposite sides of a wall in two different rooms. Between the rooms there was a plexi-glass separation with a vertical opening to allow a pallet of discs to pass from one room to the other. An emergency stop button was located on each side of the wall near the plexi-glass separation which would prevent the door from opening, or closing, if items needed to be passed from one room to the other. Employee #1 pushed the emergency stop button to pass paperwork to Employee #2. Employee #2 received the paperwork and turned to walk away. Employee #2 dropped the paperwork, pushed his emergency stop, and stopped to pick it up. Employee #1, not knowing that Employee #2 had dropped the paperwork pulled her emergency stop button allowing the door to close on the arm of Employee #2. The emergency stop buttons had been improperly installed allowing either button to override the other. The arm of Employee #2 was crushed.