Abstract: On December 10, 2006, Employee #1, a motorman for Company A, was cribbing under a drilling rig. The cribbing consisted of driving heavy planks under the substructure after it was jacked up to the appropriate height. Company B was called in to jack-up one side of a drilling rig to a level height to allow cribbing material to be placed under the drilling rig's substructure to keep it level after the hydraulic jacks were removed. Although this leveling work was not a routine activity for Employee #1 or his company, no safety meeting was held and the risk associated with this new hazard not adequately evaluated. A 1,000-lb metal stairway was attached to the side of the drilling rig that was to be jacked-up, but it was not considered to be a hazard because its upper end was secured to the rig. However, the lower end of the stairway was not secured, since it simply rested on the top platform of a smaller stairway. The decision was made to jack-up the drilling rig without removing the 1,000-lb stairway. After the drilling rig was raised to the necessary height, cribbing commenced and continued until the work took Employee #1 into the zone under the heavy stairway. At that point, the lower end of the 1,000-lb metal stairway slipped off its platform and swung approximately 10 ft before striking Employee #1 in the back. Employee #1's face was driven into the metal substructure of the drilling rig. Employee #1 suffered serious head, face, and back injuries. Employee #1 was hospitalized and treated for his injuries.