An employee was using a crane to move a large steel plate in a choke with two chains. When the plate was set down, he unhooked the chains while between the plate and a steel beam (weighing 16,000 pounds). When he engaged the hoist to lift the chains away from the plate, one of the hooks caught the steel beam and caused it to roll into him, catching him between the beam and the frame of the crane with the beam trapping his left leg. This resulted in a leg fracture requiring surgery and hospitalization.