Poisoning
Carbon Monoxide Poisoning
If you suspect carbon monoxide poisoning, get everyone out into fresh air immediately, do not use switches or flames, and call 999.
When to call 999. Call 999 if anyone is unresponsive, drowsy, breathless or having a fit. Get fresh air first. Carbon monoxide is a colourless, odourless gas, so suspect it if several people or pets in the same building have headaches, dizziness or nausea that improve when they leave.
What to do
- Get everyone out of the building into fresh air straight away.
- Turn off any suspected appliance (such as a boiler or fire) if you can do so safely on your way out, and open doors and windows.
- Do not use light switches, matches or anything that could cause a spark or flame.
- Call 999 if anyone is seriously unwell, and the gas emergency line or your provider about the suspected source.
- If someone is unresponsive and not breathing normally, once in fresh air, start CPR.
- Do not go back inside until it has been declared safe.
Avoid
What not to do
Do not stay in or re-enter the building, do not use flames or electrical switches that could ignite gas, and do not dismiss vague symptoms shared by several people or pets — these are a warning sign of carbon monoxide.
Afterwards and while you wait
Everyone exposed should be checked by medical staff, as carbon monoxide can cause delayed effects. Have gas appliances, boilers and flues checked by a registered engineer, and fit an audible carbon monoxide alarm to prevent it happening again.
Education and reference only. This is general first-aid information aligned with UK guidance, not a substitute for a hands-on first-aid course or professional emergency care. In a life-threatening emergency, call 999 straight away.
Answers
Carbon Monoxide Poisoning: frequently asked questions
How can I tell if it is carbon monoxide?
You cannot see or smell it, so suspect it if several people or pets in the same place have headaches, dizziness, nausea or tiredness that ease when they leave the building, especially near faulty fuel-burning appliances.
How can carbon monoxide poisoning be prevented?
Have gas and other fuel-burning appliances serviced regularly by a registered engineer, keep flues and chimneys clear, and fit an audible carbon monoxide alarm.
Related
Other poisoning first aid
Sources
Where this is drawn from
- NHS — first aid
- St John Ambulance / British Red Cross first-aid guidance
- Resuscitation Council UK (where relevant)
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