A family is alive and will be able to celebrate Christmas thanks to a working carbon monoxide detector. The Gravenhurst family was woken up early Sunday morning by the sound of their CO alarm and called the fire department. A check by fire officials discovered higher than allowable levels of the odorless gas. All the appliances were shut off and the house was vented. The source of the gas was traced back to a problem with the homes heating system. Fire officials say the family of 5 was checked and found to be in good health and did not require medical treatment.