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By Mayo Clinic staffCarbon monoxide poisoning is caused by inhaling carbon monoxide fumes. When there's too much carbon monoxide in the air, your body replaces the oxygen in the hemoglobin of your red blood cells with carbon monoxide. This keeps life-sustaining oxygen from reaching your tissues and organs.
Various appliances fueled by wood or gas produce carbon monoxide, including:
- Fuel-burning space heaters
- Furnaces
- Charcoal grills
- Cooking ranges
- Water heaters
- Fireplaces
- Portable generators, including those often used on houseboats
- Wood-burning stoves
- Car and truck engines
Normally the amount of carbon monoxide produced by these sources isn't cause for concern. But if appliances aren't kept in good working order or if they're used in a closed or partially closed space — such as using a charcoal grill indoors or running your car in a closed garage — the carbon monoxide can build to dangerous levels. Even swimming behind a motorboat or riding in the back of an enclosed pickup truck can be dangerous.
Smoke inhalation during a fire also can cause carbon monoxide poisoning.