Two employees were inside the top of a silo that was filled with corn silage. The employees were positioning an un-loader in the top of the silo to remove the silage. Another employee was positioned at the base of the silo. The employees heard a popping noise and the silo tipped over to the west. The two employees were free moving inside the silo cap and rode it down to the ground. The first employee suffered pelvic and rib injuries. The second employee suffered shoulder, rib, and lung injuries. Both were hospitalized.