Abstract: At 2:50 a.m. on August 10, 1988, Employees #1 and #2 and coworkers at a steel mill were going to change out the entry guide box on stand #15, the last stand in the mill. The 13-in. mill took 3-in. by 4-in. or 4-in. by 5-in. steel billets heated to approximately 2200 degrees F and ran the billets through up to 15 stands. Each stand consisted of two horizontal or vertical rollers with seven to eight passes on the rollers that determined the shape (flat or round) and the size of the finished product. At each stand there was an entry guide box and a delivery guide box, which guided the billet in and out of the correct pass. Employee #1, a mill builder, took off the old entry guide box. A coworker (the #1 mill builder) put on the new entry guide box. He aligned the new entry guide box on the fourth pass from the west side, which looked rusty and used. The third and fourth passes were both capable of running the 1.375-in. plain round bars that were being produced. The mill was restarted. Employee #1 was standing near the new delivery guide box on stand #15 so that he could chalk the top side of the bar. Employee #2 was observing stand #13, which was 9 feet away from stand #15. The bar entered the guide box on stand #15, which was set up on the fourth pass from the west. When the bar exited, it struck the east side of the delivery guide box, which was set up on the third pass from the west. The bar cobbled. Employee #1 was struck by the bar and trapped by the twisted metal. He was burned over 75 percent of his body and died 16 hours later. Employee #2 sustained burns on his legs. There was no procedure for checking the proper alignment of the entry and delivery guide boxes. The special instructions for dealing with cobbles, which occurred at least once per shift per day, averaging three cobbles per shift, were to run if a cobble occurs. Employees had been injured by them before.