Abstract: At approximately 10:15 a.m. on June 13, 2001, Employee #1 and coworker were changing the tires of a 30-ft motor home with two vehicle lift jacks. The first jack was a 20-ton bottle jack. Employee #1 placed a 2-in. by 12-in. by 12-in. board under the jack as he used the jack to lift the left front side of the vehicle. The coworker began to unscrew the bolts of this tire as Employee #1 started to setup the other jack on another side of the vehicle with another jack. As the coworker took off the last bolt and pulled the tire, the bottle jack kicked free causing the vehicle to fall. The vehicle fell and the axle landed on the tire. Employee #1 was under the vehicle as it fell, but only received minor lacerations and contusions in the popliteal and the patellar regions of his right knee. He was taken to a hospital, where he received first aid for his minor injuries. The jack had not been blocked, nor had the vehicle been otherwise supported.