Abstract: On February 12, 1999, Employee #1 and coworker were washing the exterior windows of a building using a counterweight outrigger beam and a controlled descent apparatus (cda). They were on a rooftop approximately 150-ft by 75-ft and a height of 51 ft in the northeast corner. The equipment used by Employee #1 and the coworker consisted of a counterweight outrigger system, with no visible markings indicating manufacturer, serial number, name of equipment or model number. Additional equipment included a single length of rope, cda, sky genie, a bucket with rags and squeegees for cleaning the windows. Employee #1 washing the windows was suspended from the counterweight portable outrigger beam and cda. He sustained a broken back when the counterweight outrigger beam separated, causing him to fall 30 to 40 ft. Two bolts were missing from the beam at the point of separation. The bolts were found after the accident 25 ft from the area where the counterweight outrigger beam separated. The equipment was not tied back to any approved anchorage and Employee #1 was not attached to independent line and safety harness and lanyard.