Abstract: On or about October 24, 1989, a crew of iron workers was laying decking on a second floor level approximately 18 ft above a concrete first floor. The crew laid the decking between two pieces of angle iron, with 2 1/2 in. on either edge of each sheet resting on the angle iron by on either end. These pieces were not taken down. At this time, the welder was about 50 yards away working on other pieces of decking. At break time, approximately 20 employees--concrete finishers and carpenters--walked across the unattached decking. Following their break, the employees returned to their work station not knowing about the decking. Several minutes later, Employee #1, who was working from a scissor lift installing plates on the underside of the steel beams, stood on the decking to receive a small piece of plate from an iron worker who was working below and to one side of the decking. When Employee #1 reached for the plate (which was approximately 6 in. by 12in. by 1/2in.) the decking gave way sending him through the 2 ft by 8 ft 3 in. hole it created to the concrete floor. He sustained multiple injuries to the head and right side of his body. Employee #1 was given immediate care at Good Samaritan Hospital in Corvallis, OR, and then was flown by Life Flight to Good Samaritan Hospital in Portland, OR.