Abstract: Two power line workers (Employees #1 and #2) were in a 45.7-meter Condor aerial lift transferring insulated conductors and replacing horizontal support arms on 38.1-meter-tall steel towers supporting a 230-kilovolt overhead power line along a 37-kilometer right-of-way. Another crew, working from a similar aerial lift, was assisting the employees. The employees were using full body harnesses connected by lanyards to the aerial lift platform. Both platforms were about 24 meters above the ground so that the employees could work on the insulator and lower support arm, which were located on the west side of a tower. As employees #1 and #2 started to elevate and extend their platform, a pop was heard, originating from where the upper jib was attached to the vertical frame of the main boom assembly. The upper jib boom and the platform, with the two employees still tied off, fell to the ground. The two employees were taken to a hospital, where employee #1 was pronounced dead on arrival. Employee #2 was airlifted to a shock-trauma center, where he died of his injuries 6 days after the accident.