Abstract: Employee #1 and a coworker were instructed to climb to the top of a 150 ft high steel monopole radio transmission tower to retrieve a hoist line and pulley from the antenna platform. Although the employees had installed a ladder safety device up the side of the tower, they did not use it. The employees also were not wearing safety belts with lanyards attached to lifelines; however, they both were wearing tree trimmer saddle belts with lanyards, which are positioning or suspension belts, not safety belts. They could hook these off at approximately the 50 and 100 ft levels. At the top of the tower, the coworker took the hoist line out of the pulley and handed it to Employee #1, who was still standing on the bolt steps used to climb to the top of the tower. Employee #1 snapped the hoist line hook onto a ring on his tree trimmer belt. The coworker looked away to unfasten the pulley, then heard Employee #1 cry out and looked back to see him falling. Employee #1 was killed. He may have unhooked his lanyard from the bolt step, or may not have been hooked up to begin with, and lost his balance or slipped as he began to descend.