Abstract: At approximately 11:45 a.m. on December 19, 2011, an employee was working as an interior carpenter at one of several custom homes under construction in St. Helena, CA. At about 11:40 a.m., he had stopped his carpentry work and gone to move a Genie S-60 boom lift down the home's driveway to a lower area of the property. He did this because the machine was scheduled to be picked up later that day. The worker was riding in the boom basket as the lift went down the paved driveway. The driveway had an approximately 20 percent grade. The boom basket was in a fully lowered boom position. He had the machine running in its forward direction, facing downhill, with the basket trailing. As he moved down the hill, the machine began to gain speed. When he tried to stop the machine, it went into a skid. He then intentionally steered the machine into a tree in order to bring it to a stop. When the machine hit the tree, it rolled over and came to a rest across the driveway. The worker was not secured to the basket by any means, but he physically held on to the basket railing as it hit the ground beside the driveway. He was thrown into the guardrail, and he sustained spinal injuries. His back strains and sprains required treatment and hospitalization of over 24 hours. The injured employee's supervisor was onsite but not in the immediate vicinity at the time of the accident. At approximately 3:45 p.m. on December 19, 2011, the Santa Rosa district office of Cal/OSHA received timely notification by the employer. On December 21, 2011, Cal/OSHA initiated an investigation.