Abstract: At approximately 12:15 p.m. on August 22, 2013, Employee #1 and Coworker #1, employed by a construction company subcontracted to perform concrete work, were working at a multi-family residential building. Employee #1 and Coworker #1 were trying to reposition a tamper (a jackhammer with a flat attachment to compact soil) from the back to the front of a flatbed truck. Employee #1 slipped off the bed of the truck, fell, struck his head on a concrete Jersey barrier (also known as a K-rail), and landed on the ground. Emergency services were called, and the San Francisco Fire Department responded. Employee #1 was transported by ambulance to San Francisco General Hospital, where he was admitted and treated for a fractured neck vertebra, spinal injury, and a laceration on his head. He remained hospitalized for six days. On August 22, 2013, both the employer and the fire department reported this incident to Cal/OSHA. The subsequent investigation determined that Coworker #1 was the only witness. The foreman was working nearby. The investigation also determined that when Employee #1 was trying to move the tamper, he was stepping onto unstable surfaces. One foot was standing on a pile of 4-inch by 4-inch lumber. As he was walking on the pile, he slipped and fell off the truck. The investigation report indicated that Employee #1 had not been careful while stepping in unstable areas of the lumber pile on the truck bed. The employer was issued a General Citation for violation of T8 CCR Sec. 1509(a).