If your carbon monoxide (CO) alarm goes off, get everyone out of the home right away and call 911 once you're outside. Don't stop to open windows, look for the cause or turn off the furnace. If you also smell gas, call Enbridge Gas's emergency line from outside too. Stay out until the fire service or another qualified professional says the home is safe.
Safety first: If a CO alarm goes off, leave the home now and call 911 from outside. If you smell gas, leave and, from outside, call 911 and Enbridge Gas's emergency line at 1-866-763-5427. On propane, call 911 and your propane supplier. Don't stop to find out why.
What should I do the moment my CO alarm goes off?
Leave. Wake anyone who's asleep, gather children and anyone who needs help, and go outside into fresh air. Take pets with you if you can do it on the way out, but don't go searching for them. Ontario's carbon monoxide guidance says it's critical to get everyone out of the home immediately and call 911 from outside. Grab a phone only if it's in reach.
Right now, in order
- Shout to wake everyone and head for the nearest exit.
- Help children, older adults and anyone with limited mobility.
- Bring pets that are close by.
- Go outside, away from the house.
- Call 911 from outside or from a neighbour's home.
You can check Ontario's carbon monoxide safety page for the current official steps.
Should I open windows or turn off the furnace before I leave?
No. Every minute inside means breathing more CO, and you can't see, smell or taste it. Health Canada's steps for a sounding alarm are to leave immediately, move to fresh air and not try to find the source. Barrie Fire & Emergency Service also asks you to leave doors and windows closed as you go, so responders can get an accurate CO reading. Leave the furnace and other appliances as they are.
Things not to stop for
- Opening windows or doors to air the house out
- Turning off the furnace, thermostat or gas
- Looking for which appliance caused it
- Packing bags or looking for lost items
- Pressing buttons on the alarm to make it stop
The steps above come from Health Canada's carbon monoxide guidance.
Who do I call once we're outside?
Call 911, even if no one feels sick. Ontario, Health Canada, Enbridge Gas and Barrie Fire all say a sounding CO alarm means calling 911 once you're outside. Tell the dispatcher that the CO alarm went off, how many people were inside and whether anyone has symptoms. Enbridge Gas's 24/7 emergency line, 1-866-763-5427, is for gas smells. Call it too if you also smell rotten eggs, or your supplier if you're on propane.
While you wait for help
- Stay nearby until responders arrive. A neighbour's home or another warm place close by works.
- If you sit in a car to stay warm, make sure it's parked outside, not in a garage.
- Keep everyone together and count heads.
- Tell responders about anyone who still feels unwell.
What are the symptoms of carbon monoxide poisoning?
Early symptoms can feel like the flu without a fever. Ontario lists headaches, nausea, dizziness, confusion and drowsiness, and higher exposure can lead to loss of consciousness and death. Enbridge adds shortness of breath, weakness, vomiting and changes in vision or hearing. Barrie Fire & Emergency Service notes that older adults, children, people with heart or breathing conditions, and pets may feel the effects sooner.
Get medical help right away if someone
- Has a severe headache, vomiting or confusion
- Is very drowsy, weak or hard to wake
- Has fainted or collapsed
Tell the 911 dispatcher about anyone with symptoms. Barrie Fire & Emergency Service says anyone with symptoms should get medical help.
When is it safe to go back inside?
Only when the fire service or another qualified professional tells you it is. Enbridge's guidance is not to re-enter until the home is determined safe by a qualified professional, such as a firefighter. Health Canada says to return only after the problem has been fixed by a professional. An alarm that has gone quiet is not a sign that the air is safe.
Don't go back in because
- The alarm has stopped sounding
- You feel better once you're outside
- You want to grab keys, a coat or a pet that stayed behind
If a pet or a person is still inside, tell the 911 dispatcher and the firefighters. Don't go back in yourself.
Is it a real alarm or just a chirp?
A sounding CO alarm is an emergency, and Barrie Fire & Emergency Service says alarms are rarely faulty. A chirp is usually the alarm telling you about itself, such as a low battery or that it has reached the end of its life. Ontario's guidance is to learn your alarm's low-battery, end-of-life and emergency sounds from its manufacturer's instructions. If you're not sure which one you're hearing, treat it as an alarm: get out and call 911.
Ontario also notes that CO alarms sound different from smoke alarms. It's against the law in Ontario to remove an alarm's batteries or tamper with it. If an alarm needs a new battery or replacing, our CO alarm checklist covers testing and placement.
Was it my furnace, and when can I use it again?
It may not have been. Ontario lists furnaces, fireplaces, water heaters, stoves, portable heaters, generators and vehicles as possible CO sources. Barrie Fire & Emergency Service advises having a professional check your home whenever a CO alarm activates. Don't use the furnace again until it has been checked, even if responders say the air is clear. Leave anything they turned off for a qualified professional to restart.
After the home is cleared
- Ask the responders what they found and write it down.
- Don't relight, reset or restart anything they shut off.
- Call our 24/7 emergency furnace repair line at (249) 209-2216 to have the furnace checked before you use it.
Blocked outdoor vent pipes can also cause problems. Our guide to a furnace vent blocked by snow explains why. If you ever smell gas instead, follow our gas and burning smell guide.