Abstract: Employee #1 and three coworkers were raising the two 16 ft tall by 4 ft wide end frames of a storage rack system. Three of the four workers raised the first end frame, after which one of them held it in place. The remaining three workers raised the second frame, and one of them remained in place to hold it up. This left two workers to secure the horizontal bracing that would attach the two end frames. One of the workers supporting an end frame lost control of it, and the approximately 150 lb unit fell over. Employee #1 continued to work and the coworker was taken to the hospital as a precautionary measure. None of the four workers were wearing hard hats as they raised the unbraced rack system. No information on Employee injuries was provided.