Carbon monoxide or gas leak: what to do, step by step
Headache, smell of gas. Below: what to do right away, what next, when to call 112 and what to avoid. The same instructions are in the free SurvivalZone app and work without internet.
First, right now
- Several people with a headache, dizziness, nausea or drowsiness, or the CO alarm is beeping? Open the windows and get everyone outside now.
- Smell gas? Do not switch lights or appliances on or off and do not light anything. Close the gas valve if it is within reach.
- From outside, call 112 or your gas emergency line.
Then
- Warn neighbours by knocking on doors, not by ringing doorbells.
- Carry an unconscious person into fresh air only if you can do it quickly. Check breathing; if they are not breathing, start CPR.
- Even if symptoms go away in fresh air, anyone exposed to carbon monoxide needs to see a doctor.
- Go back inside only when the fire service or gas engineers say it is safe.
- For the future: fit a CO alarm near the boiler, stove or fireplace and in bedrooms, and have the chimney and boiler checked every year.
When to call 112
Always when you suspect carbon monoxide or smell gas. Immediately if someone is unconscious, confused or having a seizure.
What not to do
- Do not use your phone, a doorbell or a torch in a room with gas. A spark can cause an explosion.
- Do not look for a leak with a match or lighter.
- Do not go back in for belongings or pets.
- Never heat your home with a gas cooker, barbecue or generator indoors.
See also
Keep it on your phone
SurvivalZone is a free app for every emergency, with no account and no app store. It works without internet and shows the nearest shelters and help points, local radio, a 72-hour plan and a mountain trip planner.
Other scenarios
- ⚡ Power cut
- 🥶 Cold, no heating
- 🚱 No water or unsafe tap water
- 🌊 Flood, water coming in
- 🎒 Evacuation in 10 minutes
- 🔥 Fire in the building
- 🌡️ Heatwave
- 🌪️ Storm, strong wind
- 🚀 Air attack: missiles, drones, bombs
- 📢 Sirens, alarm, air contamination
- 📵 No signal, no internet
- ❤️ Someone is unconscious
- 🌍 Earthquake
- ⛵ Storm at sea, no internet
- 🚗 Road accident
- ❄️ Stuck in a car in a snowstorm
- 🌩️ Thunderstorm outdoors
- 🫀 Heart attack or stroke
- 🏊 Someone is drowning
- 🌲 Forest or grass fire
- 💳 Cards and cash machines not working
- 🦠 Epidemic, dangerous infectious disease
- 🧒 A child is missing
Sources
- Polish State Fire Service
- ERC first aid and resuscitation guidelines (European Resuscitation Council)
- BBK guide "Vorsorgen für Krisen und Katastrophen" (Germany)
Official sources are checked automatically every day. Last check: 2026-10-18.
General guidance only; it does not replace the emergency services. If a life is in danger, call 112.