On February 9, 2006, a 33-year-old field mechanic was killed while repairing a 1989 Volvo water truck at a customer's construction site. The mechanic was dispatched to diagnose and repair a malfunction of the truck's water spray system. Working underneath the truck, the mechanic discovered a kink in the water discharge hose, which he fixed. After moving his tools out of the way, he went underneath the truck again while it was running. While he was underneath the rear undercarriage of the water truck, with a 21 in. clearance, a protruding set screw on the power take-off drive shaft that runs the truck's water pump caught on the collar of his coveralls and entangled his coveralls and shirt. His head was pulled against the rapidly rotating shaft, causing massive trauma. The water truck driver and construction site supervisor heard a noise and saw the victim fall when his clothing tore free. The victim was declared dead shortly after arrival at a hospital. A field mechanic was apparently checking his repair work underneath this water truck when his collar caught and tangled in the rotating power take-off drive shaft. Cause of death: Severe head and neck trauma. Recommendations: 1. Prior to performing maintenance operations on any machine, make sure to de-energize, isolate, and block all forms of hazardous energy. 2. Do not crawl under, on, or over unguarded power take-off (PTO) drivelines while the PTO is operating. 3. Equipment should be designed or retrofitted to shield any open, unguarded power take-off drivelines. 4. Employers should develop and implement a comprehensive safety program that includes training in hazard recognition and avoidance for all tasks that may expose workers to the release of hazardous energy.