Carbon Monoxide and Gas Leaks
Carbon monoxide (CO) is the hidden killer of every emergency. It has no smell, colour or taste, and it comes from anything that burns: generators, grills, camping stoves, gas heaters, fireplaces and car engines. Poisonings rise sharply during blackouts and winter storms, when people bring these things indoors to keep warm or cook.
1. Before
- Install carbon monoxide alarms on every floor and near bedrooms. Test them and change batteries as the maker recommends.
- Have boilers, chimneys, gas appliances and wood stoves checked regularly by a professional.
- If you own a generator, decide now where it will stand: outdoors, at least 6 metres (20 feet) from windows, doors and vents.
- Know where the gas shut-off valve is and how to close it.
- Keep a flashlight by the bed. Never look for a gas leak with a flame.
2. Carbon monoxide
Never do this
- Never run a generator, grill, camping stove or charcoal burner indoors, in a garage, a basement, a tent or a boat cabin, even with the door open.
- Never heat your home with a gas oven or hob.
- Never leave a car running in a garage, or in snow with a blocked exhaust pipe.
Symptoms
- Headache, dizziness, weakness, nausea, vomiting, chest pain and confusion. It can feel like flu without fever.
- People who are asleep can die without waking up.
- Suspect it when several people, or pets, feel ill at the same time and feel better outside.
If the alarm sounds or you suspect CO
- Get everyone out into fresh air at once.
- Call the emergency number from outside.
- Do not go back in until the fire service says it is safe.
3. Gas leak
- Signs: a smell of rotten eggs, a hissing sound near a pipe or appliance, dead plants over a buried pipe.
- Do not switch lights or appliances on or off. Do not use a phone, lighter or matches inside.
- Open doors and windows if you can do it on your way out. Close the gas valve if it is safe and easy to reach.
- Leave the building and warn neighbours.
- Call the gas company's emergency line or the fire service from outside, at a distance.
4. After
- Anyone with symptoms should see a doctor, even if they feel better.
- Have the appliance or installation checked before using it again.
- Let a professional turn the gas back on.
Quick checklist
- CO alarms on every floor, tested
- Appliances and chimney serviced
- Generator spot outdoors, 6 metres from openings
- Gas valve located
- Family knows the symptoms and the rule: get out first, call second
See also Power Outages, Losing heat in winter, Fires and all risks.
Sources
Educational material. Always follow instructions from your local authorities. Last reviewed: November 2026.