Abstract: At approximately 1:00 p.m. on July 16, 1991, a 25 ft tall base section of a transmission tower was being dismantled at fly yard #2. Leg #4 had been removed; a crane was attached to leg #3 and a boom truck was attached to leg #2. Four employees were on the structure. Four rope guys were also securing the structure. The knee brace bolts between legs #1 and # 2 were inadvertently removed from the top level. The foreman told Employee #1 that the knee brace bolts between legs #2 and #3 were to be taken off. Employee #1 went to remove the bolts, leaving legs #1 and # 2 unbolted. As the knee braces were unbolted at legs #2 and #3, leg #1 began to rock and sway. It eventually fell to the ground toward leg #2. Employee #1, who was standing 18 ft above the ground on leg #1, fell with the leg and hit the ground. He was taken to Chico's Enloe Hospital for treatment of a fractured hip, shoulder blade, and ruptured spleen.