A volunteer firefighter was fatally injured after being thrown from a water tanker during a rollover. The victim was traveling to a wildland fire on an unpaved road within a national forest. The tanker went out of control on a curve, rolled over, left the road and rolled several more times down into a canyon. The victim was found lying unresponsive on the ground. He was pronounced dead at the scene. Investigators recommended regular vehicle maintenance, removing defective vehicles from service until they are repaired. They also recommended use of driver restraints in vehicles such as this.