The Associated Press

Photo CBS4Denver.com Captain Shane Stewart.

PIERCE, Colo. — A volunteer firefighter headed to assist the victim of a medical emergency in Ault was killed this morning when his tanker-pumper rig overturned.

Captain Roger Moore of the Eaton Fire Protection District says 33-year-old Pierce firefighter Shane Stewart was alone in the truck. The Colorado State Patrol says Stewart went off the edge of a road, overcorrected and rolled the truck, which landed on its roof.

The medical emergency victim was transported to an area hospital and was in stable condition.

Stewart is survived by a wife and two children. His brother and father also are volunteers with the fire department.

Photo CBS4Denver.com Stewart was ejected from his truck when it rolled over, officials say.

A candlelight vigil for Stewart is planned tonight (7 p.m.) at the fire station in Pierce.