Gas Heaters and Carbon Monoxide in Winter

Every winter, families close the windows, seal the gaps under the doors and turn on a gas heater. That combination is what makes carbon monoxide dangerous. The CDC describes carbon monoxide as an odourless, colourless gas that kills without warning.

Where carbon monoxide comes from

It is produced when fuel does not burn completely. The NHS lists gas boilers, gas cookers and clay ovens, gas and kerosene heaters, wood, gas and coal fires, and portable generators as sources. It also warns about barbecues and camping stoves used indoors, and vehicle or lawn mower engines running in enclosed spaces such as a garage. Blocked chimneys and flues make the problem worse by trapping the gas inside.

Symptoms to recognise

The symptoms are easy to mistake for flu or a cold, which is part of the danger. The NHS and CDC list:

• Headache
• Dizziness
• Feeling sick or vomiting
• Weakness and tiredness
• Confusion
• Chest and muscle pain
• Shortness of breath
• Loss of vision

Two clues matter most. First, the NHS notes that symptoms tend to get worse indoors and improve when you go outside. Second, if several people in the same room feel unwell at the same time, suspect the gas rather than an infection. The CDC warns that severe exposure can cause loss of consciousness or death, and that people who are asleep or intoxicated may die before they ever notice symptoms.

Who is most at risk

The CDC says everyone is at risk, but infants, older adults, and people with long-term heart disease, anaemia or breathing problems are more vulnerable. The CDC reports that more than 400 people in the United States die each year from unintentional carbon monoxide poisoning not linked to fires.

What to do if you suspect poisoning

1. Turn off the appliance you suspect, if it is safe to do so.
2. Open the doors and windows to let fresh air in.
3. Go outside and take everyone in the house with you, including children and pets.
4. Get medical advice. Do not go back inside the affected building.
5. Have the appliance checked by a qualified engineer before it is used again.

What NOT to do

• Never heat your house with a gas oven or cooker. The CDC warns against this directly.
• Never burn charcoal indoors, and never bring a barbecue or camping stove inside for warmth.
• Never run a generator inside your home or garage, even with the doors and windows open. The CDC says a generator must be more than 20 feet (about 6 metres) from any window, door or vent.
• Never run a car or other engine in a closed garage.
• Do not seal every gap and vent in a room with a gas heater. Fuel-burning appliances need ventilation.
• Do not go back inside a building you suspect until it has been checked.
• Do not ignore an alarm that keeps sounding, or remove its batteries to silence it.

When to get emergency help

Call Rescue 1122 where available, or go to the nearest hospital emergency department, if after possible exposure a person has:

• Difficulty breathing
• Sudden confusion
• Loss of consciousness, or cannot be woken
• Marked weakness
• Chest or muscle pain

Tell the medical team that carbon monoxide is suspected, so they can test for it.

Preventing it before winter starts

• Fit carbon monoxide alarms in rooms with fuel-burning appliances, and near where people sleep. The CDC advises checking the batteries when you change the clocks and replacing the alarm roughly every five years, following the manufacturer's guidance.
• Have boilers, heaters and cookers serviced regularly by a qualified, registered engineer, and heating systems checked every year.
• Keep chimneys and flues swept and inspected annually so they do not block.
• Keep rooms ventilated when a gas appliance is running.
• Avoid using oversized cooking pots that cover several gas rings at once, which the NHS warns can affect burning.