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Carbon Monoxide Poisoning: What You Need to Know

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Carbon monoxide, also known as CO, is a colorless, odorless gas that is poisonous to humans. Its toxic effects have been known since prehistoric times and, according to the CDC, more than 400 Americans die every year from unintentional CO poisoning. And that’s not even counting the 100k+ annual visits to the emergency room, and over 14k hospitalizations.

Although the dangers of carbon monoxide exposure are real and can be life-threatening, CO poisoning is preventable. Recognizing potential risk factors and symptoms can help you catch it in time. Read on to learn what carbon monoxide poisoning is and how long you need to be exposed to its effects for its toxic properties to affect you. For more information on CO detectors, which can save you from a potential leak, take a look at our list for the best home security systems.

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How does carbon monoxide poisoning happen?

Carbon monoxide poisoning occurs when humans breathe in large amounts of said gas, usually in poorly ventilated spaces. In these conditions, the CO bonds with hemoglobin and prevents oxygen from being absorbed, causing asphyxiation and oxygen deprivation. This process can occur slowly or all at once, depending on the carbon monoxide concentration in the air.

CO is produced by combustion reactions, which is why prehistoric humans learned not to start fires in enclosed spaces, as the fumes proved toxic. In modern society, the most common producers of CO are cars and fuel-powered machines such as generators, water heaters, space heaters, power washers and lawnmowers. Using a generator or a charcoal grill indoors can also cause dangerous levels of CO to build up.

Carbon monoxide leaks usually take place when one of these machines malfunctions in an enclosed space, which is why some require CO detectors and are installed in well-ventilated areas. Even using a gas stove for too long, for example, to try to warm a room, increases your risk of carbon monoxide poisoning.

Symptoms of carbon monoxide poisoning

As we mentioned above, this gas enters the body by breathing, and the most common symptoms of CO poisoning are often confused with other illnesses, like food poisoning or the flu. Common side effects include dizziness, shortness of breath, nausea, light-headedness and headaches. At its worst, it can cause anoxic brain damage if the brain is deprived of oxygen for 4 minutes or longer.

How dangerous CO exposure may be depends on several factors, including your health and activity level. Infants, pregnant people and anybody with a physical condition that limits their ability to use oxygen (such as asthma, heart disease, or emphysema) are at higher risk of being affected by lower concentrations of CO than a healthy adult.

How long does it take to get carbon monoxide poisoning?

The amount of time it takes to get carbon monoxide poisoning varies based on the concentration of CO in the air. CO concentration is measured in part per million (ppm), and any quantity above 70 ppm (part per million) can produce symptoms that may require medical attention.

In high concentrations, it can take fewer than five minutes to feel the effects of carbon monoxide poisoning. Under lower concentrations, it can take hours for you to notice any significant discomfort. The World Health Organization recommends that indoor air level for CO be below an average of 9 ppm for any eight-hour period and 225 ppm for any one hour period. Bear in mind that you can be poisoned both by a small amount of CO over a long period of time and by a larger amount over a shorter period.

According to the National Fire Protection Agency’s Fire Protection Handbook, 20th Edition, the symptoms of carbon monoxide poisoning are as follows, by concentration:

Concentration measured in parts per million (ppm)

Effects

Exposure time

50

None

8 hours

200

Mild headache

2-3 hours

800

Headache, nausea, dizziness

45 minutes

800

Collapse and unconsciousness

1 hour

1,000

Loss of consciousness

1 hour

1,600

Headache, nausea, dizziness

20 minutes

3,200

Headache, nausea, dizziness

5-10 minutes

3,200

Collapse and unconsciousness

30 minutes

6,400

Headache and dizziness

1-2 minutes

6,400

Loss of consciousness, danger of death

10-15 minutes

12,800

Immediate physiological effects

0 minutes

12,800

Loss of consciousness, danger of death

1-3 minutes

What to do if you get carbon monoxide poisoning

It’s important to react quickly if you feel you have been intoxicated by carbon monoxide, immediately moving to a fresh air location outdoors. Make sure everyone in the home is accounted for and outside with you, and call for help from the outdoor location. Wait there until emergency personnel arrive.

CO poisoning is treatable if caught quickly enough, but the danger of losing consciousness in a CO-filled environment is serious and can be fatal.

Treatment for carbon monoxide poisoning is usually administered in the form of concentrated doses of oxygen. This helps your body get rid of the CO in your bloodstream more quickly. Exposure can be fully reverted with treatment if caught in time.

If you and the people you are sharing an enclosed space with start feeling flu-like symptoms, consider the possibility of a carbon monoxide leak. If you feel you have been exposed to CO poisoning, contact a healthcare professional immediately.

How to prevent carbon monoxide poisoning

48 states require that carbon monoxide detectors are installed in homes. Some require them for all new single- and multi-family dwellings, while others limit the requirement to buildings that have fossil-fuel burning devices. Ideally, they should be installed within 10-15 feet of sleeping rooms and in every level of the home, as well as other locations as required by the applicable state laws, codes or standards.

When you’re looking into purchasing a carbon monoxide detector, the U.S. Consumer Product Safety Commission (CPSC) recommends looking for ones that meet the most current Underwriters Laboratories (UL) 2034 standard or International Approval Services 6-96 standard. The Commission also recommends having any fuel-burning appliances in the home — such as furnaces, stoves, fireplaces, clothes dryers, water heaters, and space heaters — inspected professionally for leaks. And, like any other appliance, detectors themselves should be verified periodically (about once a month) to make sure they’re working properly.

When you’re installing a CO detector, make sure to follow the manufacturer’s instructions for both placement and mounting height. Another good preventative measure is to find out your local fire department’s number to call in case of a CO leak. If the alarm sounds, make sure to check for low batteries. If that’s not the issue, call the fire department.

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Carbon monoxide poisoning FAQs
What are two warning signs of carbon monoxide poisoning?
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The two most common symptoms of carbon monoxide poisoning are headaches and shortness of breath.
What are the 3 steps in treating someone who is suffering from carbon monoxide poisoning?
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The first thing to do if you suspect you or someone else has carbon monoxide poisoning is get into fresh air immediately and call emergency services. At the hospital, treatment may include using an oxygen mask or ventilator to deliver pure oxygen to the body. Severe CO poisoning may require the use of hyperbaric oxygen therapy, which consists of being placed in an oxygen chamber with 2-3 times higher than normal air pressure for a set amount of time. 
What condition is often confused with the early stages of carbon monoxide poisoning?
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Since the early symptoms of CO poisoning can be so broad, it can be confused with intoxication, the flu, or even seasickness.
How long does it take to get carbon monoxide poisoning?
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How long it takes to get carbon monoxide poisoning depends on a number of factors, including the CO concentration, the length of your exposure, and whether you have any underlying conditions.