Two employees were working on the roof of a two-story residential home. They were aligning sun trusses. They had a ladder on each end and were on the ladders holding the bottoms of the trusses, about 3-4 feet high. The trusses began to shift and several fell, creating a domino effect. The employees were knocked to the ground, together suffering a dislocated/fractured elbow, a forehead laceration, and a dislocated/fractured toe. They were hospitalized.