Abstract: Employee #1, a derrickman, was on the pipe racking board, preparing to fish for the bottom hole assembly downhole. He put a drill string of 4 in. drill pipe in the hole. The drill string had another stand of 4 in. drill pipe connected to it, so the slips were removed and the drill string was lowered into the well bore until the upper tool joint of the drill pipe was approximately waist high on Employee #1. The drill string was stopped, and slips were put into the rotary table. The derrickman then moved the 17 lb sub from in back of the elevators and threaded it into the tool joint. The drill string was again lowered into the well bore until it was necessary to add another stand of 4 in. drill pipe. After the next stand of drill pipe was in the elevators, it was raised up and, for some reason, the bleed-off valve was flipped. The wire rope opened the spring-loaded latch on the safety hook, which allowed the sub to be released from the safety hook. It fell to the drill rig floor, striking Employee #1 on his safety hard hat and head. He was killed.