Abstract: At approximately 4:30 p.m. on September 29, 1995, Employee #1, a cement truck driver for Swift Concrete Transportation in Riverside, CA, had finished cement delivery and was cleaning the barrel and rear of the truck. He had driven the truck close to a water island to load water into the barrel and lowered the booster wheels in order to hose off the back of the truck. The ground near the water island had a slight slope to allow the water to drain. Employee #1 did not disengage the truck's power take-off. The engine was idling and caused the power take-off to apply pressure to the cylinder of the booster wheels. As pressure increased, the wheels of the truck were lifted off the ground. The truck rolled backward, pinning Employee #1 between its booster wheel and the water island. He suffered a fractured left leg and was hospitalized.