Abstract: At approximately 1:30 a.m. on July 7, 1984, the crew on an oil and gas drilling well was nippling up a blowout preventer stack. On the surface casing, Employee #1, part of a two-man specialty service company, was torquing the blowout preventer bolts. The bell nipple atop the blowout preventer stack had to removed and placed on the ground. A winch hoist line through a rotary table was secured to the top of bell nipple. A cathead actuated boom line was lowered below and outside the rig floor near, extended generally horizontally toward and then secured to the lower flange on the bell nipple off-stack. The boom line pulled the bell nipple horizontally to the door side of the substructure. Both lines were then played out to lower the nipple to the ground. Apparently unknown to the rig crew, Employee #1 and his coworker returned to the blowout preventer to resume their work. As the nipple was being lowered, the boom line became temporarily hung up on the rig floor. The crew did not realize this and the cathead operator continued to play out the line, thinking the nipple he could not see was on the ground. The boom line came free as the wire line clamps slipped. With the slack in the boom line, the bell nipple swung toward the blowout preventer stack, fatally crushing Employee #1 between them.