Abstract: On September 17, 2010, Employee #1 and two other employees, who were employed by a company that specialized in tree removal and trimming, were cutting down an evergreen tree at a private residence in San Francisco. In the typical operation, one of the employees (a "climber") climbed the tree, trimmed branches as necessary, and dropped the cut branches down to the ground. The next worker (a "floor man") picked up the branches and brought them closer to the wood chipper. A third employee stationed at the wood chipper then put the branches through the chipper. Occasionally the floor man would need to use a chain saw to cut the branches into smaller pieces to ease transport to the chipper. During that particular operation, the regular climber had left the site to attend to personal business, and Employee #1 and his coworker resumed work to keep up progress. The coworker moved to the climber position, while Employee #1 moved to the floor man position. At approximately 11:00 a.m., Employee #1 was using a Shindaiwa Model Number 488 chain saw to cut branches from a limb that was dropped to the ground by his coworker. While Employee #1 was cutting a six-inch to eight-inch branch from a limb, the chain and guide became pinched in the partially cut branch. Employee #1 pulled up on the chain saw in an effort to free the guide bar from the pinch point of the branch. In doing so, he inadvertently pressed the trigger and activated the chain. While the chain was rotating, the chain saw swung up and struck and cut Employee #1's left leg above the knee. Employee #1 sustained a serious laceration and tendon damage. He called for his coworker to come down from the tree to help him. The coworker attended to Employee #1 and telephoned their supervisor, who then called for an ambulance. Employee #1 was hospitalized. The company president reported the accident to the Division at 12:06 p.m. on September 20, 2010.