Abstract: Employee #1, of American Wrecking, Inc., was using an oxygen/acetylene torch to cut metal from a galvanized steel corrugated building. He was near the last remaining wall, where two coworkers were in a telescoping boom basket, when two 6 in. by 10 in. by 16 to 8 ft tall steel I-beams fell and struck the cylinder shaft of the boom basket. The basket tipped forward and onto the steel; the mobile boom teetered on its front wheels, leaving the back end approximately 5 in. off the ground. Employee #1 was struck by the falling beams and by the boom basket, sustaining two fractured ribs and a punctured lung. One of the beams had a floor plate on which the mounting bolts had been cut off; the other beam, which was back-to-back to the first, was not bolted to the floor. Failure to recognize these hazards was the probable cause of this accident.