Abstract: On the day of the accident Employee #1 and two coworkers arrived on site at approximately 7:30 a.m. and proceeded to the roof of the structure to continue the placement of metal roof decking. The completed section of decking along the east wall been installed the day before. The roof opening which Employee #1 fell through was also created the previous day. Employee #1 and a coworker lifted a single sheet of decking from the bundle along the east wall parapet above turbines Number 3 and Number 2 for placement. Each sheet of decking is approximately 20-ft-long by 3-ft-wide and weighs approximately 100 pounds. Employee #1 lifted one end of the top piece of decking and the coworker lifted the other end. They moved in a northeast direction with Employee #1 walking backwards and the coworker walking forwards. After a short distance of travel the coworker reported that Employee #1, who was walking backwards, dropped through the existing 3-ft by 2-ft-8-in. opening in the roof and fell approximately 20-ft-5-in. to the concrete floor. Another coworker indicated he heard a yell and looked over at the two men in time to see Employee #1's head and feet drop through the hole. There was no covering in place for the opening and fall protection equipment was not in use by the employees working on the roof. In addition, no formal safety or hazard recognition training had been provided for the employees. The coworker also indicated the surface of the deck had been treated with an oily substance. The coworker descended from the roof to find Employee #1 in a prone position, bleeding from the skull. Emergency services were summoned, but Employee #1 was dead when they arrived.