Abstract: Employee #1, a cement finisher at the site of a four-story parking garage under construction, was on a column completing some work when he was struck by the falling boom of a 150-ton crawler crane that was being used to hoist buckets of concrete to fill columns. He was killed. The crawler crane was equipped with a 210 ft lattice boom and a 30 ft jib, and had been filling the columns while being directed by a signalman. At times, the crane came within close tolerance of the manufacturer's load charts. The crane's boom hoist cable and load line cables had some broken wires and had not been replaced prior to the accident, and two sections of the lattice boom had bent horizontal members (picture frames). At some time during the pour that day, the crane's boom struck and rested against a section of wooden guardrails and the edge of the building's concrete surface. Shortly afterwards, the crane operator and other coworkers said they heard a loud popping sound and the boom began to fall.