Carbon monoxide poisoning

Over four in ten UK households don't have a carbon monoxide detector. Carbon monoxide detectors reduce the risk of carbon monoxide poisoning.

What is carbon monoxide poisoning?

When carbon monoxide is present, it competes with oxygen to be carried around the body in our red blood cells. However, because it's much more efficient than oxygen at attaching to the cells, even small amounts can deprive our bodies of vital oxygen. In severe cases, it can cause irreversible brain damage by starving the brain of oxygen.

• Carbon monoxide is produced when fuels (gas, coal, charcoal, wood, oil) don't combust fully. Poorly fitted or un-serviced cookers, boilers and gas fires are the main sources.

• The risk of carbon monoxide poisoning is much lower than it was in the days when gas was mostly produced from coal. When gas was produced by coal, large amounts of carbon monoxide was given off as a by-product. In those days, thousands died in the annual London smogs produced by wood and coal-burning fires in the inner cities. These days, most of our gas comes from North Sea gas. Blocked gas flues or vents, poorly serviced gas fires or ovens, and any solid fuel stove are the main current causes of carbon monoxide poisoning.

• Car exhausts give off carbon monoxide if the engine is left running in a confined space such as a garage. Paraffin camping stove or disposable barbecues left burning overnight (or even if they seem to have gone out) in an unventilated tent or other indoor space can cause carbon monoxide poisoning.

Milder symptoms of carbon monoxide poisoning include:

• Headache.

• Feeling sick (nausea) or being sick.

• Dizziness.

• Flushing.

• Feeling weak.

• Abdominal pain.

• Difficulty in concentrating.

These can be mistaken for flu or tummy bugs, with occasionally fatal consequences. With vague symptoms, it is more likely that carbon monoxide poisoning is the cause if:

• Other people in the house have the same symptoms; or

• Your symptoms are worse at home and better when you're outside.

Exposure to low levels of carbon monoxide over long periods can result in developing any of these symptoms along with:

• Memory problems.

• Flu-like symptoms.

• Tiredness.

• Loss of vision.

• Problems with sleep, smell or balance.

• Anxiety.

More severe cases of carbon monoxide poisoning can lead to:

• Palpitations.

• Breathlessness.

• Personality change.

• Confusion.

• Heart attack.

• Convulsions and loss of consciousness.

Carbon monoxide poisoning can cause serious symptoms weeks after apparently recovering from an acute poisoning episode. Confusion, personality changes and symptoms similar to those of Parkinson's disease can all occur.

Diagnosis

Anyone who thinks they may have carbon monoxide poisoning, should attend the emergency department of their nearest hospital immediately.

Doctors will perform a blood test which will confirm the amount of carboxyhaemoglobin - a chemical formed when carbon monoxide binds to red blood cells. A reading of over 30% indicates a severe case. Smokers will already have a higher level of this chemical in their blood, which can make it more difficult to interpret the results.

Mild poisoning won't usually require hospital treatment, but it's still important to seek advice from the emergency department as blood tests can only be offered in this setting. GP surgeries are unable to offer the correct testing or assessments.

Standard oxygen therapy

Standard oxygen therapy may be given to people who have been exposed to a high level of carbon monoxide or who have severe symptoms of poisoning. In this type of treatment, 100% oxygen is given through a tight-fitting mask. It will allow the body to replace the carboxyhaemoglobin with normal haemoglobin.

There are around 30 deaths from accidental carbon monoxide poisoning in England and Wales every year. About 200 people a year need emergency treatment for carbon monoxide poisoning and another 200 a year have mild carbon monoxide poisoning which does not need hospital treatment.

Anyone can be affected by carbon monoxide poisoning. However, the risks are higher if:

• Gas kitchen and heating appliances (such as boilers) are not serviced regularly.

• Gas appliances are fitted by anyone who is not a Gas Safe registered engineer.

• Ventilation changes have recently been made to a home (eg, installation of double glazing) - this does not increase carbon monoxide production but may reduce the escape of carbon monoxide through poorly fitting windows.

• A wood or coal fire is used in the home and the and the chimney is not swept regularly (at least twice a year if you are burning wood or coal).

• A new cooking or heating appliance has recently been installed.

• There is no carbon monoxide alarm in the house.

• There has been an increase in condensation or sooty marks around any of the household appliances.

• A gas stove or oven is used to heat a room as well as to cook.

• A barbeque has been brought inside a room or a tent.

It is important to remember that even if you have your appliances serviced regularly, your neighbours may not. Living in any accommodation that is not a detached house means there is a risk of carbon monoxide from neighbouring properties.

How to protect yourself

Ideally everyone should take simple steps to stop carbon monoxide poisoning happening in the first place. While it costs money to action these steps, failure to do so increases the risk of carbon monoxide poisoning.

Carbon monoxide has no smell, no taste and no colour so is hard to detect without an alarm. The symptoms of mild poisoning - poor concentration, feeling sick, general weakness - are very nonspecific. Various medical issues, including viral infections and dehydration, can give rise to the same clinical picture.

But the messages for prevention are clear:

• Always fit a carbon monoxide monitor in your home.

• Make sure your carbon monoxide monitor shows a British Standards Kitemark or Loss Prevention Certification Board logo.

• Have gas fires fitted by a qualified, registered engineer. The same goes for boilers and cookers.

• Get flues and chimneys checked and cleared regularly.

• Service your boiler and cooker regularly.

• Never use barbecues in garages or tents.