Carbon Monoxide Poisoning From Heaters: Symptoms and What to Do

A cold night in Amman, and the family has gathered in one room because it's the warmest. The heater has been on for hours, and the windows are shut tight so the warmth doesn't escape. Then one of the children complains of a headache, their mother feels dizzy, and grandfather says he's tired and will turn in early. It looks like a flu that's going round the house. But when everyone falls ill together, in the same room, at the same time, the cause is often not a virus — it's the air.

What is carbon monoxide, and why is it so dangerous?

Carbon monoxide (CO) is a gas produced when any fuel burns incompletely: gas, kerosene, diesel, charcoal, wood or petrol. When you breathe it in, it binds to the haemoglobin in your blood far more strongly than oxygen does, which stops your blood carrying oxygen to the brain, heart and other organs. In effect, the body is starved of oxygen from the inside, even though breathing may look normal.

What makes it a killer is that it has no colour, smell or taste, and it doesn't irritate the eyes or throat. The smell of kerosene or gas you recognise is not carbon monoxide, and the absence of that smell doesn't mean the air is safe. That is why Jordanian households know it as "heater suffocation" (ikhtinaq al-sobba): it happens silently, and often during sleep.

Where carbon monoxide comes from in a Jordanian winter

Any appliance that burns fuel in an enclosed space can be a source. These are the most common ones in homes here, what makes each risky, and how to use them more safely:

The common thread in most cases is the same: a fuel-burning heater in a room whose windows and doors have been shut to trap the heat, so oxygen falls, combustion gets worse, and more gas is produced. Electric heaters produce no carbon monoxide at all, although they carry other risks such as fire and burns.

Carbon monoxide poisoning symptoms

Early symptoms are vague and look like flu or ordinary tiredness, which is exactly why they are so often missed:

• Headache, the most common symptom — often a dull, tension-type ache.
• Dizziness or light-headedness.
• Nausea or vomiting, sometimes with stomach pain.
• Unusual tiredness or sleepiness.
• Confusion or difficulty concentrating.
• Shortness of breath, or a racing heart.

With higher levels or longer exposure, serious signs appear: loss of balance, marked confusion, chest pain, seizures and loss of consciousness. A person can die in their sleep without ever waking.

Clues that it's carbon monoxide, not flu

• Several people in the same home or room fall ill at the same time.
• Pets seem lethargic, unwell or are vomiting too.
• Symptoms improve when you leave the house or go to work, and return when you come back.
• Symptoms get worse after the heater is switched on, or in the morning after a night with it running.
• There's no fever, aching muscles or sore throat, as there usually would be with flu.

If the household has fever, cough and other respiratory symptoms, it may well be a seasonal infection — see our guide to flu, RSV and COVID and when to see a doctor. But if you're not sure and there's a fuel-burning heater on, assume it's carbon monoxide until proven otherwise, and get into fresh air first. If headache is the main symptom, our guide on when a headache is worrying covers the other red flags.

What to do immediately if you suspect carbon monoxide

1. Get everyone into fresh air immediately, pets included. Don't stop to gather belongings.
2. Turn off the heater or generator only if you can do it quickly and safely on your way out. If it's a gas heater, close the cylinder valve if you can.
3. Open doors and windows to ventilate, but don't stay inside to do it.
4. Call 911 if anyone is unconscious or not responding normally, very drowsy or confused, struggling to breathe, or has chest pain or a seizure. If an unconscious person isn't breathing, start CPR if you know how, and follow the operator's instructions.
5. Don't go back inside until the space has been checked and the faulty appliance fixed. If a gas cylinder or leak is involved, the Civil Defence can help through 911.
6. Get checked at an emergency department even if symptoms improve outside: anyone who had symptoms needs a medical assessment the same day.

For the direct lines and what to tell the operator, see our guide to Jordan's emergency number, 911.

Why go to the ER if you already feel better?

Feeling better in fresh air is a good sign, but it doesn't mean the danger is over. Carbon monoxide stays bound to the blood for hours, and the main treatment is oxygen, which speeds its removal. A doctor may need a blood test to confirm poisoning and judge how severe it is, and a heart assessment for anyone with chest pain or heart disease. Some people develop problems with memory, concentration or mood days to weeks later, especially after heavy exposure or loss of consciousness, so any clear exposure deserves medical follow-up.

One important caution: a fingertip pulse oximeter can show a normal reading in someone who is poisoned, because it can't tell carbon monoxide from oxygen. Don't rely on one to decide whether to stay home.

Who is most at risk

• Babies and young children, who breathe faster and can't describe how they feel.
• Pregnant women — carbon monoxide reaches the unborn baby, which can be affected more than the mother.
• Older adults, and people with heart disease, lung disease or anaemia.
• Anyone who was asleep, or under the influence of sedating medicines or alcohol, because they won't notice the symptoms.

Call 911 or go to the ER?

Carbon monoxide poisoning is not something to manage at home or to wait out until morning. The only decision is how you get to care:

• Call 911 now: unconsciousness or being hard to wake, confusion or strange behaviour, difficulty breathing, chest pain, a seizure, or a pregnant woman with clear symptoms.
• Go to the emergency department the same day: headache, dizziness or nausea after exposure even if better outside, or any child, older adult or person with heart disease who was in the room.
• There's no "wait and see" at home while the source hasn't been fixed — going back into the same room means being exposed again.

How to prevent carbon monoxide poisoning at home

• Never sleep in a closed room with a fuel-burning heater on. Warm the room before bed, then turn it off, and rely on blankets or a safe electric heater.
• Always ventilate. Leave a window slightly open or the door ajar while any gas, kerosene or diesel heater is running, and never block air vents.
• Never burn charcoal indoors — no manqal, kanoun or barbecue, not on a closed balcony or in a tent, and not "just to warm the room for a bit". Be careful with charcoal argileh in closed rooms too.
• Fit a carbon monoxide alarm that is battery-operated or has battery backup, near bedrooms and on every floor; test it regularly and replace the battery and the unit as the manufacturer recommends. A smoke alarm does not detect carbon monoxide.
• Service heaters before every winter. Clean the wick and burner of kerosene heaters, check the hose and regulator on gas heaters, and use only the fuel the heater is designed for.
• Watch the flame. A healthy flame is mostly blue. A yellow or orange flame, smoke, or soot marks around the heater are signs of poor combustion — turn it off and get it checked.
• Generators go outside only, well away from doors and windows, and never run a car in a closed garage, even with the door partly open.

Heaters also cause many burns in winter, especially to young children who get too close or trip against them. See our guide to burns first aid and when to go to the ER.

Sources

• NHS — Carbon Monoxide Poisoning
• CDC — About Carbon Monoxide Poisoning
• Mayo Clinic — Carbon Monoxide Poisoning
• MedlinePlus — Carbon Monoxide Poisoning