Carbon Monoxide Poisoning is often referred to as the ‘silent killer’. It is a poisonous gas that has no colour, and is odorless and tasteless making it hard to detect. It forms from domestic fuels like gas, coal or wood not being able to burn fully in enclosed spaces, the fuel uses up all the oxygen, replacing it with carbon dioxide, which stops the fuel burning fully allowing it to release carbon Monoxide.

The most common cause of accidental carbon monoxide poisoning is from faulty household appliances either incorrectly installed, poorly maintained or poorly ventilated – such as cookers, heaters and central heating boilers. It is important to make sure these are regularly checked or a carbon monoxide alarm fitted.

You could also be exposed to carbon monoxide poisoning from blocked flumes and chimneys, faulty or blocked car exhausts, or inhaling paint fumes.

Breathing the gas in can make you unwell. Once you have breathed the gas in, it enters your bloodstream and mixes with the part of your red blood cells that carry oxygen around your body (haemoglobin), limiting the amount of oxygen the blood can carry, which therefore limits the oxygen available to the body and vital organs like the heart and brain. If exposed to high levels of the gas the brain can be totally deprived of oxygen causing anoxic brain injury or even death.


Symptoms of low level carbon monoxide poisoning aren’t always obvious and can be mistaken for flu or food poisoning. Common symptoms include:

  • Tension headache
  • Dizziness
  • Nausea and vomiting
  • Tiredness and confusion
  • Stomach pain
  • Shortness of breath

If it is a faulty appliance causing a carbon monoxide leak your symptoms will be less severe when away from the source.

The longer you are exposed the worse these symptoms get. If you are exposed to low levels of the gas over a long period of time it can also lead to a change in your behaviour, such as frequent emotional changes, being easily irritated, depressed or making irrational decision.

If you have been exposed to a high level of gas in a short period of time (can be as little as 2 hours) your symptoms will be severe and you will deteriorate quickly, possibly losing consciousness or even death. Other symptoms to look out for are: a change in personality and mental state, vertigo, lack of co-ordination and seizures.

Carbon monoxide poisoning may lead to long term neurological problems. Around 10-15% of those with severe carbon monoxide poisoning will have symptoms including memory loss, problems with speech, cognition, mood swings and behavioural changes.  In rare cases, severe carbon monoxide poisoning can cause tremors, stiffness and slow movement known as Parkinsonism.
These problems do not always develop straight after the poisoning and can occur up to 6 week after exposure.

If you think you have been exposed to low levels of carbon monoxide seek medical advice from your GP, if you have been exposed to high levels you must go to A&E immediately.

The hospital will do a blood test to determine the amount of carboxyhemoglobin in your blood. A level of 30% indicates severe exposure.

If the blood test shows you have been exposed to a high level of carbon monoxide you will most likely need Standard oxygen therapy, this is where 100% oxygen is given to you through a breathing mask, allowing your body to replace the carboxyhemoglobin with the concentrated oxygen until carboxyhemoglobin levels are down to 10%. Recovery time depends on the amount and time you were exposed to carbon dioxide for.

Ask us a Question

If you have a question for one of our experts please complete this form. We aim to respond to you within 2 hours.

Your Name (required)

Your Email (required)

Your Telephone Number (optional)

Your Question