UNITED STATES
DEPARTMENT OF LABOR

In the afternoon of May 4, 1984, working from the second floor with a rented hydraulic crane, a four man crew set approximately 66 roof trusses on a 6-unit townhouse. They started at a fixed gable end unit and proceeded, one truss at a time, to the other end, on 24 in. centers setting the spacing with 25 1/2 in. spacer blocks on each top chord. They also installed diagonal bracing on truss webs and one run of lateral bracing on the front top chord. This arrangement fell substantially short of the recommendations of the Truss Plate Institute, a copy of which was provided with each bundle of trusses (1 bundle per townhouse unit). The foreman in charge of this crew had seen and read this paper. At about 5:45 p.m., they were about to set the prefabricated gable end unit and add more bracing for the night. There were three men in the trusswork and one on the floor 8 ft below. One of the men saw trees waving violently, and yelled "jump". All did except Employee #1. An instant later the blow hit and 21 trusses over two adjacent units at one end dominoed outward and also dropped into the second floor, pinning Employee #1 in the collapsed trusses. While the foreman called an ambulance, the crew lifted enough trusswork to extract the employee and moved him to the first floor. An ambulance arrived in minutes and took him to Holy Cross Hospital, where he was examined and released a few hours later with no apparent injuries. He said he didn't remember anything between hearing "jump" and being in the hospital. Back at the site the job was shut down by the fire department and posted "unsafe" by a county building inspector, prohibiting further work until completion of a preliminary investigation the next morning. The "unsafe" signs were removed that afternoon by the county inspector who put them up.