The Zanesville Fire department is issuing a warning to people who use alternate heating sources during the cold winter weather. It could turn into a serious problem. Assistant fire chief Dave Lacy says his department sees 12 to 20 fires each year that originate with a heating source like a fireplace or a kerosene heater. Lacy says those items must be maintained correctly if used. Lacy also discourages people from using their kitchen ovens as a heating source. Lacy says if you have a gas range and use it for heat it can cause a fire or give off carbon monoxide.