Abstract: At approximately 10:45 a.m. on December 24, 2010, two employees were working for a firm that operated a truck recycling and radiator repair business at a facility in San Diego, CA. The two employees were regular full-time hourly employees. They were working on a Ford F-550 flatbed truck. The two employees had jacked the vehicle up to change the rear tire. Because the hydraulic bottle jack they were using did not provide the amount of clearance required to lift the truck to a height where they could remove the tire, the employees had used a block of 4-inch by 4-inch lumber to gain more height. They placed the block of wood between the piston of the jack and the leaf springs on the rear axle. Once the truck was lifted, the two employees began removing the rear tire. The weight of the truck caused the jack's piston to split the block. The truck fell off the jack and both employees were struck in the head by the edge of the truck bed when it fell approximately 4 inches. The sudden jolt as the truck fell caused the two employees to sustain facial and head injuries. Of the two injured employees, one was admitted for over two days for facial and head injuries, including a concussion; the other was treated and released from the emergency room. The injury line mentions only the employee who sustained the concussion.