Topic Overview

What is carbon monoxide poisoning?

Carbon monoxide poisoning happens when you breathe too much carbon monoxide. Carbon monoxide is a gas produced by burning any type of fuel—gas, oil, kerosene, wood, or charcoal. What makes this gas so dangerous is that when you breathe it, it replaces the oxygen in your blood. Without oxygen, cells throughout the body die, and the organs stop working.

You can't see, smell, or taste carbon monoxide. But if you breathe too much of it, it can become deadly within minutes. So be sure you know the signs of carbon monoxide poisoning, what to do if you have the symptoms, and how to keep it from happening.

What causes carbon monoxide poisoning?

Carbon monoxide can come from any source that burns fuel. Common sources are cars, fireplaces, powerboats, woodstoves, kerosene space heaters, charcoal grills, and gas appliances such as water heaters, ovens, and dryers. Usually they cause no problems. Trouble comes when:

• Cars, trucks, or other engines are left running in enclosed spaces, such as garages. Carbon monoxide can build up in a garage and leak back into the house. Even sitting in an idling car in an open garage or swimming behind an idling boat can be dangerous.
• Fuel-burning appliances are not installed or used properly. Dangerous levels of carbon monoxide can build up inside houses and other buildings.
• Fuel-burning heating systems and appliances are used during cold weather, when doors and windows are closed. Chimneys in older buildings become blocked and release fumes into the homes or offices. Newer houses that are well insulated and tightly sealed can trap carbon monoxide inside.

What are the symptoms?

Early symptoms of carbon monoxide poisoning include:

• Headache.
• Dizziness.
• Nausea.

As carbon monoxide builds up in your blood, symptoms get worse and may include:

• Confusion and drowsiness.
• Fast breathing, fast heartbeat, or chest pain.
• Vision problems.
• Seizures.

If you have symptoms that you think could be caused by carbon monoxide poisoning, leave the area right away, and call 911 or go to the emergency room. If you keep breathing the fumes, you may pass out and die.

Carbon monoxide poisoning can occur suddenly or over a long period of time. Breathing low levels of carbon monoxide over a long period can cause severe heart problems and brain damage. See a doctor if:

• You often are short of breath and have mild nausea and headaches when you are indoors.
• You feel better when you leave the building and worse when you return.
• Other people you work or live with have the same symptoms you do.