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Carbon Monoxide Poisoning

Carbon monoxide, or CO, is a highly toxic gas. You cannot see, smell, or taste it. Breathing high levels of carbon monoxide can cause sudden illness or death in a matter of minutes. Gas- and oil-burning furnaces produce carbon monoxide, an invisible, odorless, poison gas that kills hundreds every year and makes thousands more sick.
Carbon monoxide poisoning is preventable and there are several things you and your family can do to ensure your safety. Preventing and stopping exposure are important.

Poisoning is more commonly reported during colder months when people tend to be indoors but can happen year-round in homes, garages and cars. Doing an appliance check-up and practicing safety can reduce the risk in all seasons.
Carbon monoxide poisonings that happen in the home are often due to faulty furnaces, heaters, fireplaces, stoves and by using outdoor appliances inside the house. Poisonings that happen around the home occur when outdoor appliances such as generators and heaters are used in garages and semi-enclosed spaces or when a vehicle is operated in an enclosed space, such as garages. Away from the home, carbon monoxide poisoning happens in vehicles or when using outdoor appliances in tents or shelters. The following tips are suggested to reduce the risk of exposure.

In addition to having your furnace, heaters, fireplaces, and stoves inspected and maintained annually, it is a good idea to install carbon monoxide detectors near bedrooms and living spaces as a safety measure. (Carbon monoxide detectors are intended to complement, not replace, your prevention routine).

Although most detectors will not alarm for on-going low-levels (but still unhealthy levels), most will alarm when the level has reached a point which can be immediately deadly. An alarming detector alerts people to quickly get outside. Carbon monoxide gas (CO) can suddenly build up to a dangerous level when a furnace recently cracked or if a fireplace chimney becomes clogged, for example. These types of unexpected malfunctions can happen when your family is sleeping. For these reasons, having a detector is an important step in your prevention routine.

Carbon monoxide detectors are available from most hardware stores and department stores and often fall in the $20-$40 price range. Some models are combined with a smoke alarm.

Factors you should consider when shopping for a detector:
  • Level of Detection and Alert/Alarm
    • Most detectors alarm at 30 ppm-70 ppm of CO in the air.
      • Keep in mind that "low" levels are below 11 ppm and levels can often range between 11 and 400 ppm
      • Alarms that are under UL-2034 standards do not alert at levels of CO below 70 ppm, or above 400 ppm and do not sound an alarm when levels of CO are at 30 ppm for thirty days.
  • Type of Sensor
    • Biomimetic - Gel coated disks darken in the presense of CO. Color change sounds the alarm.
      • Benefits are: Less expensive and can be battery operated.
    • Metal Oxide Semi-Conductor (MOS) - Heated oxide reacts with CO to determine the levels of the toxic gas.
      • Must be connected to the power of the building.
      • Unit is always plugged in. Battery backup is available.
    • Electrochemical - Chemical reaction with CO creates an electrical current that sets off the alarm. Highly sensitive and accurate at all levels of CO.
      • Most of these units come with a readout memory to keep track of CO levels.
      • Many of these units will sound off alert when sensor needs to be replaced.
  • Battery Backup
    • Useful for power outages and natural disasters.
  • Memory. This can be useful for tracking lower levels, which are still unhealthy, alerting people to troubleshoot potential sources of on-going exposure such as malfunction in a household appliance.
    • Helps to keep track if there is a history of CO exposure.
    • Allows user to monitor long term low levels of CO, or high level of exposure.
  • Is the Detector Certified?
    • Many different devices are available that are certified by different companies.
    • Underwriter Laboratories (UL) - Major company that certifies equipment in the US and Canada have specific standards for CO detectors. Electrical Testing Laboratories (ETL) certification is another company.

Using and Maintaining Your Detector

After you have bought a detector:
  • Mark on it the date of purchase so you will know when to replace it. Detectors must be replaced at least every five years because after five years the sensors go bad.
  • Place the alarm in an area, where most time in the home is spent such as a bedroom.
  • As you purchase more units, place those near other bedrooms and common living areas.
  • Next, make it a point to replace the batteries twice a year: in the spring and in the fall when you change your clocks or when you are switching from using a cooling system to a heating system and vice versa.

Since alarms are meant to be an additional safety measure, it is important to practice routine protection in the home by having furnaces regularly inspected and by not allowing the use of outdoor appliances inside the home or enclosed spaces.

What to Do When the Detector Alarms

If you hear the alarm, get outside. When a carbon monoxide detector in your home has alarmed, that is a cue for you to immediately evacuate the house.

It is important to teach your household members what to do when they hear the alarm. Have a plan for getting out of the house, waking family members, and designate meeting place outside of the home. Your priority is to get outside as soon as possible, however, if you must wake family members or assist people out of the home, open windows, if you can, to help reduce the concentration of the carbon monoxide while you guide everyone out of the house. Leave your doors open as you exit the house.

An alarming detector could be an indication of a harmful exposure and medical attention may be needed, even if symptoms are not apparent. You, the emergency responder, or your health care professional may call the New Mexico Poison and Drug Information Center at 1-800-222-1222 for guidance.

Since carbon monoxide gas is undetectable by human senses and the symptoms of carbon monoxide poisoning are shared with other seasonal illnesses, prevention and early detection of exposure to carbon monoxide gas is crucial. Exposure may be sudden and at a high concentration, which could set off an alarm. It could also be ongoing at concentrations that are not high enough to set off an alarm but can still be harmful.
The most common early symptoms of carbon monoxide poisoning are flulike symptoms and they may include:

  • Headache.
  • Irritability.
  • Dizziness, poor coordination.
  • Confusion, impaired judgment, memory loss.
  • Fatigue, weakness.
  • Nausea, vomiting, upset stomach.
  • Chest pain, rapid heartbeat.
  • Difficult or shallow breathing (shortness of breath or lack of breathing).
  • Changes in sensitivity to hearing, vision, smell, taste, or touch.

Carbon monoxide is called a "silent killer" because, if these early symptoms are ignored, a person may lose consciousness and be unable to escape from danger. People who are sleeping or who have been drinking alcohol can die from carbon monoxide poisoning before ever having or noticing symptoms.
Carbon monoxide exposure can happen at an on-going basis when the levels are not high enough to make an alarm to sound off but can still make a person sick. It can also happen when levels are suddenly high and can be urgently dangerous, sometimes setting off an alarm. This is why you should pay attention to any symptoms and seek medical attention. It is also why you should check where the exposure is coming from and stop or fix the problem. Common things to look for are small cracks in furnaces, faulty fuel-burning appliances or heating or energy sources meant for outdoor use only, such as generators or grills.

If you think that you or someone you know has been exposed to carbon monoxide gas, call the New Mexico Poison and Drug Information Center at 1-800-222-1222 for guidance which may include recommendations for seeing a healthcare provider and may include tips for finding the place where the gas is potentially coming from.

If you are already seeing a healthcare professional for symptoms, your healthcare provider may call New Mexico Poison and Drug Information Center at 1-800-222-1222 for guidance.
When a detector in your home has alarmed, that is a cue for you to immediately evacuate the house or building you are in. Teach your household members or employees what to do when they hear the alarm. Have a plan for getting out of the house or building, waking sleeping family members, and you should designate a meeting place outside of the home or building. Your priority is to get outside as soon as possible; however, if you must wake family members or assist people out of the home, open windows if you can to help reduce the concentration of the carbon monoxide. Leave your doors open as you exit. If you can, turn off all fuel-burning devices.

An alarming detector is a signal the gas has built up to a level that can be immediately harmful. Medical attention may be needed, even if symptoms are not obvious. The source of the carbon monoxide also needs to be looked for. At this point the two resources you may call are 9-1-1 and the New Mexico Poison and Drug Information Center at 1-800-222-1222 for guidance. You might also need to call your gas or propane company.

Do not go back into the home or building until the source of carbon monoxide has been found by local emergency authorities (which may be first responders or your gas company) and until the exposure has been stopped either by removal of fuels and/or repairs of appliances by a qualified technician (which could include a heating and cooling professional).

Additionally, you, the emergency responder or your health care professional may call the New Mexico Poison and Drug Information Center at 1-800-222-1222 for guidance at any time, even if symptoms appear to be mild, if carbon monoxide is the suspected source of on-going symptoms, or if there is an emergency.
If you have a gas emergency, or suspect a gas leak, contact the company that provides gas to your home. Many households, including rural areas, use propane. You should include the phone number of the company that provides your fuel with your other emergency contacts. For many New Mexicans, including the Albuquerque metro area, a common provider is the *New Mexico Gas Company at 888-644-2726. (*Inclusion of this company and number are not an endorsement. These are listed only for safety and convenience of the New Mexico public). You should also have handy the number of the company that services your furnace or that has recently installed your furnace.
Carbon monoxide gas is produced and released whenever fuel or other materials are burned. It is found in combustion fumes, such as those produced by small gasoline engines, stoves, generators, lanterns, and gas ranges or by burning charcoal and wood.

It can build up and concentrate in enclosed or partially enclosed spaces. The build-up of carbon monoxide in an enclosed space is not easily detected because it cannot be seen or smelled.
Common ways people are exposed to carbon monoxide is when it builds up:

  • In homes, often due to faulty furnaces, heaters, fireplaces, and stoves.
  • In homes, garages, campers or tents when outdoor appliances are used an enclosed space.
  • Inside a garage or shed due to a vehicle engine running.
  • In your car, truck, or SUV, if the tailpipe gets clogged with mud or snow.

It is important to practice safety in the home by having furnaces regularly inspected and by not allowing the use of outdoor appliances inside the home or enclosed spaces.
Since carbon monoxide gas is undetectable by human senses, (it is colorless and odorless), prevention and early detection of exposure are crucial.

Around the House

According to the U.S. Consumer and Product Safety Commission, the common carbon monoxide clues you can see around the home are:
  • Rusting or water streaking on vent/chimney
  • Loose or missing furnace panel
  • Debris or soot falling from chimney, fireplace, or appliances
  • Loose or disconnected vent/chimney for a fireplace or appliance
  • Loose masonry on chimney
  • Moisture inside of windows

Carbon monoxide clues you cannot see are:

  • Internal appliance damage or malfunctioning components
  • Improper burner adjustments
  • Hidden blockage or damage in chimneys

Only a trained service technician can detect hidden problems and correct these conditions which is why it is important to have these inspected annually as part of prevention regime. It is best if these are inspected by a professional.

Since heating systems and appliances can malfunction or become faulty at any time, it is essential to also have a carbon monoxide detector in the home as an added safety measure to your prevention regime.

Click to Download a PDF: Sources and Clues to a Possible CO Problem

Click to Download a PDF: Portable Generator Safety Guide

Learn more about sources and appliance safety at:

Health symptoms as clues

Other clues about carbon monoxide exposure include health symptoms. If you are regularly experiencing flu-like symptoms but do not have the flu:
  • Ask your healthcare provider if your symptoms could be related to CO exposure,
  • Consult with the New Mexico Poison and Drug Information Center at 1-800-222-1222, and,
  • Install a carbon monoxide detector in case the gas builds up to reach deadly levels.
Although unintentional CO poisoning can almost always be prevented, CO is the most common cause of poisoning deaths in the United States and every year more than 20 New Mexicans die as a result of accidental or unintentional exposure to this toxic gas. Patients who survive are likely to develop long-term neurological problems.
People of all ages are at risk for carbon monoxide poisoning. Carbon monoxide is most harmful to:
  • Pregnant women and children; carbon monoxide poisoning can be highly dangerous for unborn children, because it greatly increases the risk of fetal death and developmental disorders.
  • People of all ages living with a chronic disorder of the blood (such as anemia), brain (such as seizures or stroke), heart (such as angina or heart failure), or lungs (such as asthma, bronchitis, emphysema).
  • The elderly; older adults more frequently have chronic diseases which lower their tolerance and increase the risk a fatal exposure.
According to a study conducted in the state of Washington, carbon monoxide poisoning has been found to be more common among minorities:
  • Hispanic populations had a three-time greater risk than White populations for carbon monoxide poisoning.
  • 67 percent of Hispanic populations and 40 percent of Black populations became poisoned due to the indoor burning of charcoal briquettes.
Check your home heating sources such as furnaces, water heaters, wood stoves, and portable heaters for leaks, cracks and proper function every year. Many people have this done by professionals during the spring or autumn when the cooling systems (evaporative coolers, swamp coolers, air conditioning) are being set up for the summer or closed up for the winter.
Stop using broken and faulty heaters, furnaces, stoves and heating appliances. Get major heating systems repaired by a professional, such as your furnace or stoves, or replaced. Do not run a car engine in a garage or shed even if the doors are open. Do not use fuel burners inside garages, sheds, or tents, even if the doors or flaps are open. If your truck or car gets stuck in the mud or the snow, avoid running it if the exhaust pipes are clogged or blocked by the mud or snow. Install battery-operated carbon monoxide detectors near every sleeping area in your home.
  • Train your family what to do if the detector alerts you of dangerous gas build-up.
  • Check your detector monthly to make sure it is working.
  • If you have a monitor that tracks multi-day exposure at lower levels, check it regularly to make sure you are not having on-going exposure at lower levels.
For an explanation of how carbon monoxide poisoning works, visit CDC Carbon Monoxide Fact Sheet.


Learn more about carbon monoxide poisoning and your home appliances, boating, after a disaster, and small gasoline-powered tools at CDC Carbon Monoxide and the CDC Carbon Monoxide Prevention Guidelines. Also check out:
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Content updated: Thu, 4 Jun 2020 16:26:03 MDT