Abstract: At approximately 8:35 a.m. on April 15, 1988, Employee #1 and coworkers were installing 8 in. sanitary sewer pipes in a 48 ft long by 50 in. wide by approximately 15 ft deep trench. Employee #1 was working from inside an 8 ft high by 16 ft long trench box that had an identical trench box stacked on top, directing the operator of a John Deere model 792 backhoe with bucket, serial #CKO7921001029. Employee #1 was standing inside the north end of the trench box, using his right hand to direct the backhoe operator so that the bucket would not strike the pipe that had already been laid. He moved backward as the bucket got closer and backed up against the bottom crossbeam. The bucket continued to move toward him and momentarily pinned him against the crossbeam, bruising his chest. He was hospitalized for observation. The main cause of this accident was human error on the part of Employee #1. He overlooked how close he was to the end of the trench box and backed himself into a corner. Because the backhoe operator's view was partially obscured, he had to act at the direction of Employee #1. The employee had been performing this job all along the trench and had experienced no problem until the accident.