Carbon monoxide is a silent killer. It has no smell, no taste, and no sound. Neither people nor animals can tell when they are breathing it, but it can be fatal.

Carbon monoxide (CO) is a by-product of combustion. Common household items, such as gas fires, oil-burning furnaces, portable generators, charcoal grills, among others, put people at risk of exposure to this poison gas.

According to the Centers for Disease Control and Prevention (CDC), over 400 Americans die every year from accidental CO poisoning that is not caused by fires. There are more than 20,000 emergency room visits, and over 4,000 hospitalizations.

Every dwelling should have a carbon monoxide alarm.

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Every house should have a carbon monoxide alarm fitted.

Hemoglobin is the molecule in red blood cells that carries oxygen from the lungs to tissues all over the body, and it brings carbon dioxide (CO2) back from the tissues.

CO binds to hemoglobin over 200 times more easily than oxygen does, so if CO is present, oxygen will not be able to find space to get into the hemoglobin. This is because the space is occupied with CO.

As a result, parts of the body will be starved of oxygen, and the affected parts will die.

The human body needs oxygen, but it has no use for CO. If we breathe in CO, it provides no benefit, but it deprives the blood of oxygen.

Vitas Gerulaitis, the tennis star, died of CO poisoning in 1994. His cottage in Long Island, NY, was filled with CO because of a fault in the swimming pool heater.

A person who is exposed to CO may notice that something is wrong, but they may not know where the symptoms are coming from.

The person may feel as if they have the flu, but without a temperature. If several people in the same building have the same symptoms, they may have CO poisoning.

If this happens, all cooking and heating appliances should be switched off, all windows opened, and the local gas safety authorities notified.

The longer an individual is exposed to CO, the more severe the symptoms will become.

Within a few hours of first being exposed, a person may experience:

  • loss of balance
  • vision problems
  • memory problems
  • eventual loss of consciousness

If the symptoms are mild, there is a very chance of a full recovery.

Other symptoms may occur later, even months after inhaling CO gas.

These include:

  • confusion
  • memory problems
  • coordination difficulties

Serious CO gas poisoning can cause long-term problems, including heart damage.

People with heart-related or breathing problems tend to be affected more quickly by CO gas poisoning. Pregnant women, babies, and small children are also more susceptible.

Pets, too, will react quickly to CO poisoning. If a family pet suddenly gets ill or unexpectedly dies, and the death cannot be linked to anything else, such as age or an existing condition, the owners should try to rule out CO poisoning as one of the possible causes.

Household appliances, such as gas fires, boilers, central heating systems, water heaters, cookers, and open fires which use gas, oil, coal and wood may be possible sources of CO gas. It happens when the fuel does not burn fully.

Running a car engine in an enclosed space can cause CO poisoning.

If household appliances are well serviced and used safely, they should produce negligible quantities of CO gas. Using old appliances, and not servicing them frequently, leads to a higher risk of CO emission.

Here are some other causes of CO gas emission and buildup:

Smoking cigarettes causes blood levels of CO to rise.

  • Leaving a car in a closed garage with its engine running can produce deadly amounts of CO within 10 minutes.
  • Burning charcoal produces CO gas.
  • Blocked flues and chimneys can stop CO from escaping.
  • Fumes from certain paint removers and cleaning fluids can cause CO poisoning.

Products that contain methylene chloride (dichloromethane) should be handled with care, because methylene chloride turns into CO when it is breathed in.

It is important to be aware of the possible signs of CO poisoning.

These include:

  • a large proportion of people in the same environment developing the same symptoms
  • symptoms improving when a person is away from that environment, and reappearing when they return
  • seasonal symptoms, which may be caused by a central heating system that is used only at certain times of the year

A physician may request a blood test to detect unusual levels of carboxyhemoglobin and perhaps an electrocardiogram (ECG) assess how well the heart is pumping blood around the body.

The first step is to move away from the possible source of CO gas, and to have symptoms assessed.

If symptoms are severe, the person may be hospitalized. Hospital treatment includes 100 percent oxygen delivered through a mask, to speed up the production of oxyhemoglobin, as this will replace the carboxyhemoglobin.

If the physician suspects nerve damage, or if exposure to CO has been extensive, hyperbaric oxygen therapy (HBOT) may be offered. This treatment floods the blood with pure oxygen, to compensate for the lack of oxygen caused by the CO gas poisoning.

HBOT may be given to patients whose oxygen supply was reduced or cut off, a patient in a coma, individuals with a history of loss of consciousness, those with an unusual ECG reading or reduced brain activity, and pregnant women.

The complications of CO poisoning can be serious and long-lasting.

Brain damage can occur, and it may cause a progressive worsening of memory and concentration. Very rarely, CO poisoning has been linked with the symptoms of Parkinson’s disease. These include stiffness, slow movements, and shaking.

Heart damage, including coronary heart disease, can result, especially if a person is exposed over a long time.

Urinary incontinence can develop in women with severe CO gas poisoning.

It is important to be aware of the dangers of CO poisoning.

To prevent leakage of CO gas, the following can help:

Keep appliances in good working order, and use them safely. Have them serviced regularly by a qualified and registered professional.

  • Do not use gas ranges or ovens for heating.
  • Make sure all rooms are well ventilated and that vents are not blocked. Be especially careful in well-insulated environments.
  • Have chimneys and flues swept thoroughly regularly by a fully-qualified sweep, at least once a year.
  • Be careful when using gas-powered tools and equipment inside rooms.
  • Wear a mask when using products that contain methylene chloride.
  • Do not leave a gasoline-powered motor running in a garage, for example, motorbikes, cars, or lawn mowers.
  • Do not use charcoal on an indoor barbecue.
  • Never use a generator within 20 feet of a window, door or vent.
  • Service the exhaust pipe in a motor vehicle every year.
  • If the tailgate of a vehicle is open and the engine is running, open the doors and windows too.

The CDC advises every household to install a CO alarm. Some detectors have a digital readout. Others give out a loud, high-pitched sound when levels of CO pass a certain limit.

According to the United States Consumer Product Safety Commission, long-term exposure to 1 to 70 ppm of CO will not normally cause any harm, but people with heart problems may have chest pain.

Levels of over 70 ppm may cause noticeable symptoms, and if they reach above 150 to 200 ppm, they may cause disorientation, unconsciousness, and death.

An alarm can be placed in every sleeping area in the house. Alarms should be checked regularly.