Abstract: At approximately 8:25 a.m. on September 1, 2003, an employee of Western States Engineering and Construction was operating Ditchwitch trencher Model 3700DD, Serial Number 3R0703. He was sitting at the controls and digging trenches for electrical conduit in a parking lot area of a convenience gas station that was under construction. While digging the trench the chain of the Ditch-Witch trencher came off the drive sprocket. When the chain came off the sprocket, it started a sequence of events, which resulted in the operator being struck in the head by a personnel restraint bar, guarding device. The employee was transported to Palomar Hospital, in Escondido, and later to an extended care and rehabilitation hospital in Palm Springs. He sustained a concussion and deep laceration to the back of his scalp. The seriousness of the head injury resulted in the employee being in a comatose state for several weeks. He never regained any memory of the accident or the events, which led up to it.