Employees were pouring a concrete thrust block on a 48-inch pipe. The concrete bucket was equipped with a side chute and was lifted by a crane. The injured employee was holding onto the bucket when other employees opened the bucket to place the concrete. As the concrete began dumping out of the side chute, it caused the bucket to shift toward the injured employee and caught his right hand and wrist between the bottom rail of the bucket and the 48-inch pipe. He suffered a broken ulna that required hospitalization and surgery.