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what causes carbon monoxide

Carbon monoxide is mainly caused by incomplete burning of fuels that contain carbon, especially in enclosed or poorly ventilated spaces. It is a colorless, odorless gas produced whenever something burns without enough oxygen for full combustion to carbon dioxide.

What carbon monoxide is

  • Carbon monoxide (CO) is a toxic gas that has no smell, color, or taste, which makes it hard to detect without an alarm.
  • It forms when carbon-containing fuels (gas, oil, wood, coal, petrol, charcoal, biomass) burn without enough oxygen for complete combustion.

Main causes in homes

  • Faulty or poorly maintained gas boilers, furnaces, and water heaters.
  • Gas cookers, ovens, and stoves, especially in small or badly ventilated kitchens.
  • Wood, coal, or gas fireplaces and wood‑burning stoves with blocked, leaking, or damaged flues/chimneys.
  • Portable gas or paraffin/kerosene space heaters used without proper ventilation.
  • Portable generators or petrol equipment (pressure washers, pumps, tools) used indoors, in garages, or near open windows.
  • Barbecues, charcoal grills, and camping stoves used inside tents, garages, vehicles, or indoors.

Vehicle and outdoor sources

  • Exhaust from cars, motorbikes, and trucks, especially in attached or enclosed garages.
  • Idle vehicles running with doors open into basements or living areas can allow CO to seep inside.
  • Petrol- or diesel-powered tools like lawn mowers, leaf blowers, concrete saws, and generators used in semi-enclosed spaces.

Industrial and other sources

  • Industrial furnaces, steel works, and other high‑temperature processes that partially burn carbon-based materials.
  • Some chemical production processes where CO is formed as an off‑gas byproduct and must be captured or treated.
  • Cigarette and tobacco smoke, which adds low levels of CO to indoor air, especially in closed rooms.

When carbon monoxide builds up

  • Any fuel-burning appliance can produce CO if:
    • It is faulty, badly installed, or poorly adjusted.
    • It is not regularly serviced and maintained.
    • Its flue, vent, or chimney is blocked, undersized, disconnected, or leaking.
  • Risk is highest in enclosed or poorly ventilated spaces, particularly in colder months when heating and generators are used more.

Bottom note: Information gathered from public forums or data available on the internet and portrayed here.