Abstract: Employees #1 and #2 were setting up roof trusses on a two story split-foyer house. Employee #1 was working on the floor and handing the roof trusses to Employee #2 and a coworker. They were standing on the third roof truss, which they had just set and braced with a 2 by 4 and a 1 by 10. The combined weight of the two employees was 385 lb and the wind was gusting to 28 mph out of the west. The roof truss that Employee #2 and the coworker were standing on began to twist and break away from the gusset plate that held the bottom of the truss together. The truss broke up and Employee #2 fell 8 ft to the 2nd floor of the house, injuring his lower back. He required hospitalization. The coworker jumped off the roof truss and was not injured. Employee #1, who was struck in the left arm by the falling truss, suffered minor injuries. Neither Employee #2 or the coworker, who were standing on the roof truss, was wearing any type of fall protection. Job tasks had been assigned by the working partners, who were at the job site working with the employees.