Abstract: Employee #1, a field technician, was inspecting the steel erection of a new commercial building. He found loose bolts at the base of a column and decided to check the I-beams supporting the ceiling joist of the structure. A 16-foot aluminum extension ladder was extended to its maximum climbing height 13 feet and placed against 16 inch I-beams with a 6-inch flange. The beam was running the length of the building (north and south) and was 12 feet 6 inches above the floor. The rails on the ladder where approximately 3 inches above the flange of the beam and not secured. The steel erectors had connected another I-beam of the same size running perpendicular (east and west) across the building to the outside wall. Employee #1 climbed the ladder with a 4-foot, 20 pound torque wrench set at 355 foot pounds to check the torque on four nuts that fastened the members together. He reached across his body to connect the socket end of the wrench to one of the nuts and pulled down on the wrench. The side pressure applied caused the ladder to skid and Employee #1 dropped the torque wrench and grabbed the I-beam above. He could not hold on and fell and struck a metal job box and then fell to the concrete floor. Employee #1 stated that from where he was located on the ladder, he had fallen approximately 9 feet. He was transported to a nearby hospital with a severe contusion to his lower back and a small laceration on his left hand.