An employee was cutting grass behind the shop using a rotary mower attached to the back of a tractor. He was passing a rack that had a sputter bar when a tractor part became hooked on a pad-eye on the sputter bar, causing the rack to be pulled down onto the employee. The rack landed on his back and pinned him against the tractor steering wheel. Another employee ran over and cut the tractor off. The employee suffered six cracked ribs, a punctured lung, and broken vertebrae, requiring hospitalization.