Abstract: An employee was unloading a Case DH5 trenching machine from a trailer. The employee backed up to the edge of the trailer, set the emergency brake, and dismounted on the left side to see if the ramps were lined up properly. As he stepped onto the trailer, the machine began to move and ran up onto his right leg. This threw him against the trailer, after which the machine crawled over his body. The employee sustained several fractured ribs and a fractured foot. He was treated at a hospital and released a few days later. The vehicle had not been inspected before use, and the emergency brake was inoperable.