An employee was greasing a pipe at the bottom of the hill to prepare it to be placed inside another PVC pipe. An excavator was working at the top of the hill about 10 feet away from a pile of 30-inch PVC pipes placed behind a berm. The vibration caused the pipes to dislodge from the berm and a pipe rolled down the 8-10-foot slope. The employee's right leg was caught between the fixed pipe he was working on and the pipe that rolled down the slope and fractured.