Abstract: At approximately 9:30 a.m. on April 19, 1988, Employee #1 and six coworkers were putting a 15 ft extension on a silo that was 16 ft in diameter and 45 ft high. Employee #1 was on the door side of the silo chute, standing above a barnyard on a stone wall that was 29 1/2 in. wide by 53 in. high. Two coworkers were out of the employee's sight on the ground around the base of the silo. The crew foreman was on a platform inside the silo chute. The remaining three coworkers, one of whom was a supervisor, were working on the platform inside the silo. Employee #1 had sent up all the pre-cast concrete staves for the third course of the chute and the foreman had installed them. The bottom silo hoop was around the staves and the foreman was ready to place the top hoop when the first stave in the course fell out. The foreman yelled a warning. He saw Employee #1 bend over, then straighten up and look up in response to his warning. The foreman believes he yelled at least one more warning, perhaps two, but Employee #1 did not move, although he did put his arms in front of his face. The 75 lb, 30 in. high by 11 in. wide stave struck him on the left side of his face. He was knocked from the wall to the barnyard and killed. Employee #1 and his coworkers were not wearing protective helmets. According to the foreman, protective helmets were available; the company recommends but does not require that ground workers wear them.