Abstract: At approximately 11:00 a.m. on March 1, 1996, Employee #1, an 18-year-old, and a coworker were lowering and leveling a 16 ft by 46 ft modular building that weighed about 23 tons. The employees were using two 20 ton hydraulic jacks under the building to lower the front half of it to the ground. Cribbing material, such as 4 in. wide concrete blocks and old tires, was also being used. Both employees were partially under the building when it suddenly shifted. The hydraulic jacks could not support it and the front portion fell on top of Employee #1. He sustained a fractured neck and was killed. The coworker was also partially pinned under the building, but he was not seriously injured. The jacks were situated on a good surface: 4 in. by 8 in. by 3 1/2 ft long wooden blocks and a poured concrete pad in the ground. OSHA recommended that wooden blocks be used between the top of the jack and the building structure as a safety measure in case of load shifts.