Prolonged exposure to carbon monoxide can cause serious complications, including brain damage and heart problems. In very severe cases, it can result in death. 

Effects of severe carbon monoxide (CO) poisoning include breathlessness, chest pains, seizures (fits) and a loss of consciousness. The severity depends on the amount of carbon monoxide gas you have been exposed to, and how long you have been exposed to it.

Around 10-15% of people who have severe carbon monoxide poisoning develop long-term complications.

Some of the possible complications of carbon monoxide poisoning are described below.

Brain damage

Prolonged exposure to carbon monoxide can cause memory problems and difficulty concentrating. It can also cause vision loss and hearing loss.

In rare cases, it can cause Parkinsonism, which is characterised by tremors (shaking), stiffness and slow movement.

Parkinsonism is not the same as Parkinson's disease, which is a degenerative neurological (brain) condition linked to ageing.

Heart disease

Coronary heart disease is another serious condition that can develop as a result of long-term exposure to carbon monoxide.

Coronary heart disease is where the blood supply to the heart is blocked or interrupted by a build-up of fatty substances (atheroma) in the coronary arteries.

If the blood supply is restricted, it can cause angina (chest pains). If the coronary arteries become completely blocked, it can cause a heart attack.

Read more about coronary heart disease.

Harm to unborn babies

Prolonged exposure to carbon monoxide gas can also damage an unborn child. Infants exposed to carbon monoxide during pregnancy are at risk of:

• low birth weight
• perinatal death (stillbirth and death that occurs within the first four weeks of birth)
• behavioural problems