Abstract: On September 10, 1992, Employees #1 and #2 and a coworker were preparing to jack up and level a single residential structure to place it onto new interior piers. Other workers had already built a full perimeter foundation. The entire structure was supported by vertical 4 by 6 wood members on top of the foundation and the existing internal piers. The only shear bracing around the perimeter was plywood sheeting, which had been removed, and 1 by 6 diagonal bracing on the interior supports. The employees placed three jacks on top of the front perimeter foundation and snugged them up against the bottom plate of the floor joists. They then moved to the center of the building and placed a 4 by 12 wood girder across the house. Employees #1 and #2 had set the girder on top of 4 by 6s and were about to place it against the floor joists when the structure started to crack. The employees moved to get out from under the structure when it fell off its supports toward the rear. The structure landed on Employees #1 and #2. They were hospitalized. No cribbing structure had been used to prevent unexpected movement.