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The silent killer

Posted by Be Well

Carbon monoxide is a poisonous gas that has no smell, no taste and no sound, and so often goes undetected. You can breathe it in without even knowing it.

It may be invisible, but it is lethal.

Do you know how to protect yourself and your family from this hidden danger? Read on and find out how to make your home safe from the threat of carbon monoxide poisoning.

What is carbon monoxide?

Carbon monoxide gas is produced when fuels such as gas, coal, oil and wood don't burn fully.

When a fire burns in an enclosed space (such as a room in your house, or a garage) all the oxygen is used up, and replaced with carbon dioxide.

Carbon dioxide builds in the air, which stops the fuel from burning properly. It then releases carbon monoxide.

People tend to think that carbon monoxide poisoning happens only in homes such as council housing and student accommodation. This is a myth. Carbon monoxide leaks can happen in any home or enclosed space, at any time. You need to make sure you know the dangers.

Killing me softly

When you breathe in carbon monoxide it gets into your blood stream. It mixes with the hemoglobin (part of the red blood cells that carry oxygen around your body).

When carbon monoxide mixes with hemoglobin, it stops your blood from carrying oxygen. This is why carbon monoxide poisoning is fatal - the lack of oxygen it causes means that your body cells and tissues eventually die.

When carbon monoxide and hemoglobin mix together, carboxyhemoglobin is formed. This affects blood vessels in the body, making them leak. This in turn leads to swelling of the brain, causing unconsciousness and neurological (nerve) damage.

The smaller the person or animal, the quicker the carbon monoxide takes effect. Elderly people are also particularly at risk, as are those with heart and lung problems.

Know the signs

The initial symptoms of carbon monoxide poisoning are similar to cold and flu symptoms. They can occur a few days, or even a few months after exposure to carbon monoxide.

The symptoms of mild carbon monoxide poisoning include:

  • headache,
  • feeling sick (nausea),
  • tiredness, and
  • dizziness.

In children, symptoms are similar to those of a stomach upset with feeling and being sick.

Because of the similarity of the symptoms to other conditions, carbon monoxide poisoning is often missed.

Severe carbon monoxide poisoning may cause a fast and irregular heart beat, hyperventilation (quick, shallow breathing), confusion, drowsiness and difficulty breathing. It can result in seizures, loss of consciousness and in the worst case, death.

It is important that you know how to spot the more specific signs of poisoning, as catching it early could save your life and the lives of the people you live with.

  • Unlike flu, carbon monoxide poisoning does not cause a high temperature.
  • If more than one person in your household has the symptoms, it could be a sign of a carbon monoxide leak.
  • If you go away (for example on holiday) and your symptoms get better, only to worsen upon your return, this could be a sign of a carbon monoxide leak.
  • If a pet becomes ill and dies unexpectedly (not relating to old age or an existing condition), it could be caused by carbon monoxide poisoning.
  • If your symptoms are seasonal, for example worse in winter when the heating is on, you should have your appliances and carbon monoxide levels in your home checked.


Your doctor can test for carbon monoxide poisoning by checking the levels in your blood. If you have been poisoned, you need to get away from the source of the gas. Treatment usually includes basic life support, and oxygen replacement.

Those who have mild poisoning generally make a full recovery. In cases of more severe carbon monoxide poisoning, between 10% and 50% of people go on to experience long term health problems such as poor memory and concentration, urinary incontinence (this means that you are sometimes unable to control when you urinate) and in some cases, after years of exposure to carbon monoxide, coronary heart disease.

How to save a life

Protect your family from carbon monoxide poisoning by taking steps to reduce the risk of a leak.

  • Make sure all your household appliances are safe, and well maintained.
  • Ensure all boilers, heating systems and appliances are installed and serviced regularly.
  • Never use ovens or gas taps to heat your home.
  • Make sure rooms are ventilated and air vents aren't blocked.
  • Sweep chimneys and flues regularly and keep them clear.
  • Do not leave petrol fuelled lawn mowers or cars running in a garage.
  • Do not burn charcoal in an enclosed space.
  • If you are using chemicals containing methylene chloride, always use a safety mask.
  • Do not use gas-powered equipment or tools inside your home. Only use them in a well ventilated area and put the engine unit and exhaust outside.

Warning bells

The best way to keep an eye out for carbon monoxide is to install a carbon monoxide alarm in your home. They are available in most DIY and hardware stores.

Some let off a pitched alarm when carbon monoxide is present, others give a visual reading of the level of carbon monoxide in the air. Make sure you know how your alarm works.

Do not rely on them entirely, they provide a warning of carbon monoxide, but you still need to make sure your appliances are regularly serviced.

Get a carbon monoxide alarm that is approved to the latest standard.

Further information:

Carbon monoxide poisoning

Carbon monoxide kills (CORGI website)

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