GRAVENHURST — A carbon monoxide (CO) alarm appears to have saved the lives of home owners here yesterday.

Gravenhurst Fire officials say they got a call at 2:15 a.m. Wednesday, Sept. 11, from a homeowner on Fernwood Drive in Gravenhurst reporting a CO alarm.

Firefighters from Station 1 found 600 ppm (parts per million) of CO, a level that is lethal if exposed to for a short period of time, they said in a release.

The two occupants were outside when firefighters arrived.

The gas line was shut off and firefighters quickly ventilated the home.

Then it was determined that the source of the CO was a blocked exterior furnace vent, forcing all the output of CO to remain in the home.

“This is an example of why CO alarms are law, said Breyan Sinnott, fire prevention officer.

“Without one, the likely result would have been fatal come morning, with the amount of CO in the home,” she said.

“This emergency underscores the importance of immediate evacuation when your CO alarm enters full activation and to call 911 from outside the home,” said Sinnott.

There were no injuries and crews left the scene at approximately 4 a.m.


Exposure to CO can cause flu-like symptoms such as headaches, nausea, dizziness, as well as confusion, drowsiness, loss of consciousness and death.

In Ontario, 65% of injuries and deaths from CO occur in the home. It is required you install CO alarms adjacent to each sleeping area if you have a fuel burning appliance, a fireplace, or an attached garage.

To prevent CO in your home:

  • Ensure fuel burning appliances, chimneys and vents are cleaned and inspected annually by a licensed contractor.
  • Check that all outside appliance vents are not blocked. Ensure portable fuel-burning heaters are vented according to manufacturer’s instructions. Never use the stove or oven to heat your home.
  • Always use gas and charcoal barbecues outdoors and away from all doors, windows, and vents.
  • Open the flu before using a fireplace for adequate ventilation. Never run a vehicle, generator, or other fueled engine, inside a garage, even with the doors open. Always remove the vehicle from the garage immediately after starting it.
  • Consult for more information on the prevention of CO poisoning.
Firefighters found a blocked gas vent that caus carbon monoxide to backup into a Gravenhurst home just after 2 a.m. Sept. 11.