Abstract: On April 2, 2006, Employee #1, an ironworker, was attaching open web joists onto girders from a boom- supported aerial lift on the site of a large retail store under construction. He noticed that the girt line at Grid Line D Grid Line 1 did not appear to be straight and then informed the foreman that the column was plumbed up. While the foreman and another coworker were looking at the girder connection at the tilt wall panel, he exited the elevated platform of the (JLG Model 460SJ, Serial Number 030081611) and climbed onto the girder. He walked approximately 110 ft on the steel girder to inspect the bolted connection of the girder to the tilt wall panel, when he lost his balance and fell 21.25 ft onto the concrete slab below. He was either not wearing his combination fall protection harness/tool belt or had not connected the lanyard to the structural steel, as he fell.