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
What causes carbon monoxide poisoning?
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
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:
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
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
Other people you work or live with have the same symptoms you
How is carbon monoxide poisoning diagnosed?
It can be hard to know if you have
carbon monoxide poisoning. The same symptoms can be caused by flu or other
problems. In the winter months, doctors may suspect carbon monoxide poisoning
in people who complain of severe headache, nausea, or dizziness. This is
especially true if other household members or coworkers have the same symptoms. Even pets in the home may get sick.
your doctor suspects carbon monoxide poisoning, he or she can order a blood
test that measures the amount of carbon monoxide in your blood. You may have
other blood tests to check your overall health and to look for problems caused
by carbon monoxide.
How is it treated?
The best treatment is oxygen
therapy. Breathing pure oxygen can bring the oxygen level in the blood back to
normal. There are two kinds of oxygen therapy:
100% oxygen therapy. For this treatment, you breathe oxygen through a
mask. This is the most common treatment.
Hyperbaric oxygen therapy. For this treatment, you lie inside a
chamber that delivers oxygen under high pressure. This quickly
reduces carbon monoxide levels in the blood.
With quick treatment, most people recover within a few
days. But long-term problems can show up later. Be sure to tell your
doctor about any changes in vision, coordination, or behavior that occur in the
weeks after treatment.
How can you prevent carbon monoxide poisoning?
Many people die every year from accidental carbon monoxide poisoning.
There are some easy steps you can take to reduce your risk. One of the most important is to see a doctor right away if you think you have symptoms.
Safe use of vehicles
Do not leave your car running in the garage, even if the
garage door is open.
Do not ride in the back of a pickup truck with a camper
Do not swim behind an idling boat.
Safe use of fuel-burning tools and appliances
Have all fuel-burning appliances (such as oil or gas heaters,
stoves, water heaters, and space heaters, fireplaces, and woodstoves) inspected
Check chimneys, flues, and vents regularly to make sure they
are in good shape, properly connected, and not blocked.
Never use a kerosene or propane heater in an enclosed area,
such as a camper, motor home, trailer, or tent.
Never use a gas or charcoal grill indoors.
Never use a gas oven to heat your home.
Do not close a fireplace or stove damper before the fire is
Do not use gas-powered generators, lawn equipment, or engines
in enclosed areas.
Carbon monoxide detectors
Consider putting carbon monoxide detectors in your home
near sleeping areas. Look for ones endorsed by Underwriters Laboratory (UL).
If you install a detector, follow the directions closely. Know what to
do if the alarm sounds.
Understand that carbon monoxide detectors are a backup safety
measure. They do not replace the need to check
appliances regularly and use them safely.
Olsen KR (2012). Carbon monoxide section of
Poisoning. In SJ McPhee, MA Papadakis, eds., 2012 Current Medical Diagnosis and Treatment, 51st ed., pp. 1518–1547. New York: McGraw-Hill Medical.
Smollin C, Olson K (2010). Carbon monoxide poisoning (acute),
search date June 2010. Online version of BMJ Clinical Evidence:
Wiegand TJ, et al. (2008). Carbon monoxide section of Management of poisoning and drug overdose. In EG Nabel, ed., ACP Medicine, section 8, chap. 1. Hamilton, ON: BC Decker.
ByHealthwise Staff Primary Medical ReviewerAnne C. Poinier, MD - Internal Medicine Specialist Medical ReviewerR. Steven Tharratt, MD, MPVM, FACP, FCCP - Pulmonology, Critical Care Medicine, Medical Toxicology
How this information was developed to help you make better health decisions.