An employee was working with a crew on the rig floor tripping pipe into the hole. They applied the manual tongs as and the line that supplied air to the clutch froze. When the driller started the draw works forward, the rotary turned unexpectedly. One of the snub lines, which anchor the tongs in place, was secured to the rig but not to the tongs. The tongs turned and struck the worker in the chest and the employee sustained collapsed lungs, a bruised liver and kidneys, a damaged spleen, and broken ribs.