Abstract: At 1:20 p.m. on November 8, 2021, an employee was topping a 40-foot cypress tree. His right hand was holding a running chain saw, Stihl Model 201, to cut the tree limb that was being held with his left hand. The employee's operation of the chain saw with only one hand was not in accordance with the manufacturer's instructions to always hold a running chain saw with both hands. The chain saw kicked back into the employee's left forearm just below the elbow, cutting it to the bone. The employee was transported to and underwent initial treatment and surgery at Mercy San Juan Medical Center for 2 days. He was then transferred to the California Pacific Medical Center for 2 follow-up nerve surgeries over 4 days.