Abstract: At approximately 3:30 p.m. on September 21, 1988, Employee #1, a crane operator, had just finished moving a Grove hydraulic crane to a different location at the work site. He usually operated this crane and kept his hard hat in it. Employee #1 was going to his truck to get something when his foreman requested thathe bring him a hammer. The foreman and two other iron workers were plumbing the columns in the building. One coworker was using a come-along to pull the column plumb. Another was on top of the structural steel watching the approximately 20 ft long bar joist to ensure that it didn't slip off the beam against which the column was being plumbed. Employee #1 brought the foreman the hammer and watched as they continued to plumb the column. As the column was being pulled to the south, the 100 lb bar joist slipped off the support beam at the column north of F9 and then slipped off the support beam at column F9. It struck Employee #1 on the head, killing him. The foreman stated that he did not notice that Employee #1 was not wearing his hard hat.