Abstract: Employee #1 was changing the filter elements on the smoke filters mounted on the ceilings. He was using a Hunterlift scissor lift, raised to a height of approximately 16 feet, with the guardrails raised up another 42 inches. While Employee #1 was up in the scissor lift, the bridge crane traveled north. The bottom of the bridge crane beam is approximately 16 feet 4 inches off the floor. It struck and pushed the scissor lift, causing the lift to upset. Employee #1 fell and sustained fatal skull fractures when his head struck a blunt object or the floor. The primary cause of this accident was the failure of Employee #1 to secure the electrical power to the bridge cranes prior to working on the smoke filters.