Abstract: On April 29, 2002, an employee was involved in troubleshooting a dock garage door opener. The door opener was mounted above the garage door and was not functioning. The employee, along with an assistant, obtained a scissors lift and parked it parallel to the dock door. The employee first verified electrical voltage at the dock door disconnect box. The employee and the assistant then raised the scissors lift up to the garage door opener. After verifying voltage at the door opener, the employee reset a motor thermal overload breaker. Without locking and tagging out the electrical power, the employee continued to troubleshoot the door opener in an effort to identify what was causing the motor thermal overload breaker to trip. In the course of trouble shooting, the employee caused the open door relay to close, this caused the dock door to start moving to the full open position. The dock door is mounted on a track that directs the door to a horizontal position when open. The scissors lift was positioned higher than the door track allowing the dock door to come into contact with the scissors lift. The contact caused the scissors lift, elevated to approximately 16 feet high, to topple over with the employee. The employee received a severe head injury which killed him.