(Also see our Alarms page)

How to Protect Against Carbon Monoxide Poisoning and other toxins in the products of combustion.

Summary on prevention – Emergency re gas – ring 0800 111999

Basically any appliance powered by any carbon based fuel (gas, coal, oil, diesel, petrol, wood etc.) can emit CO, especially if faulty. So to avoid this:-

  1. Make sure appliances are properly installed by qualified people according to manufacturer’s instructions. With gas this means finding a Gas Safe Registered installer qualified to work on that appliance.
  2. Appliances must be maintained regularly (refer to manufacturer’s instructions). Again with gas this means finding a Gas Safe Registered installer qualified to work on that appliance.
  3. Ensure adequate ventilation so there is enough oxygen at the flame to produce CO2 not CO.
  4. Make sure chimneys and flues are swept and checked by a sweep belonging to a recognised trade association. Unflued appliances can be extremely dangerous.
  5. As an extra safeguard buy and fit a CO alarm to EN50291. Please make sure you purchase your alarm purchased direct from a reputable supplier (e.g. DIY shop or supermarket) NOT the Internet. Please note that substandard alarms have had to be recalled and removed from the Internet
    Please make sure you get the alarm out of the package and pull the tab to connect the battery. We know of at least one death where the deceased had a CO alarm but hadn’t got it out of the package and got it going.

Please note CO alarms are very good at preventing death or serious injury but are NOT health monitors.

Summer is an excellent time to have a service of appliance and chimney sweeping because gas installers and sweeps are not as busy as they are in the winter.

Sadly installers of appliance burning other fuels such as gas, oil and wood are not required to be registered by law but the risks of CO are in our opinion, worse with regard to the other fuels. Prevention is much the same but it’s up to the consumer to find an expert.

What the public should know:

  • National Gas Emergency Services Helpline (National Grid plc) Tel 0800 111999 – But please note that the National Gas Emergency Service does not test for carbon monoxide poisoning as standard.  So if you suspect carbon monoxide poisoning you really need help and advice.
  • Please note that Northern Gas Networks undertook some research using flue gas analysers as a trial during 18 November 2011 – 22nd November 2012 – see page 4 of  However, this has raised more questions than answers and we have asked these questions by email 10.08.16 and asked for a meeting to discuss these issues.
  • However thanks to Ofgem providing funding on a Use It Or Lose It (UIOLI) basis to the four companies that together provide the gas emergency service, three of the four companies have now started to turn the gas appliances back on and undertake a sweep test for CO (please see If CO is found then Registered Gas Safe Engineers with a qualification called CMDDA1 are sent in to test gas appliances for CO. However this Ofgem funding is only for customers in vulnerable situations which we understand means those on or eligible for the Priority Services Register e.g. basically the old, disabled, poor, sick and those with young children.  We argue that this should happen to every customer however healthy, wealthy or wise. This is because CO can affect the higher intellectual functions which makes it extremely difficult for anyone to organise a Gas Safe Registered Engineer to visit and test for CO or even to service appliances. Also finding someone to test for CO is almost impossible, even for CO-Gas Safety and can cost hundreds to thousands of pounds. Why does testing matter? Because without the proof of Parts Per Million of CO found by a Registered Gas Safe Engineer, medics usually think survivors have not been exposed to CO.
  • Have your appliances properly installed and regularly serviced by qualified installers. With gas this means Gas Safe Registered. Ask about training and experience – it’s YOUR money and YOUR life and you are the person who will otherwise suffer from carbon monoxide poisoning. Ensure that your gas fitter is  not only Gas Safe Registered but also qualified to work on that appliance and uses a flue gas analyser to check for the silent killer, carbon monoxide poisoning. You can check the individual’s ID number with the Gas Safe Register ( to make sure he or she is qualified to undertake work on particular appliances (e.g. gas fires not just boilers).
  • Chimneys and flues must be swept regularly and appliances checked once a year by a fully qualified engineer/sweep.
  • ChimneysDo not block vents. Make sure you have some ventilation and wear extra clothes/ bedclothes to keep warm.
  • Portable heaters using combustible fuels have been responsible for some recent deaths from carbon monoxide poisoning. We urge that if there is no other alternative and a portable appliances has to be used, the greatest care is taken to ensure the following:
    • Adequate ventilation.
    • A CO detector with an audible alarm to EN50291is used in the same room.
    • Children or vulnerable people are never let alone with such an appliance.
    • The appliance is never left on while anyone is sleeping in the room or house or etc. where the portable appliance is present.
  • Electric fan heaters are safer with regard to Carbon Monoxide poisoning.
  • As an extra safeguard buy a Carbon Monoxide alarm to European Standards EN50291. A battery operated CO alarm to European Standards is especially useful to take with you abroad. Alarms can be purchased for about £20 or less from most DIY stores, some supermarkets or from professional merchants, engineers and energy companies.
  • Beware that low levels of CO exposure over a long period can cause carbon monoxide poisoning resulting in brain damage. Doctors can mistake CO symptoms for ‘flu or other common conditions so insist on a test for CO. Please note that some doctors’ surgeries have equipment, (sometimes called a Smokelysler or ToxCo), to analyse breath for CO. This is easy, painless and gives an instant result. If this shows CO, a blood test may be required. However, there are also other toxins in the products of combustion (see ‘Other toxins’ on the left hand side of this page) and a CO alarm will not protect you from these nor will the NHS generally test for them.

But remember that fresh air quickly reduces CO in a live body so, unless breath or blood is taken at the scene, in the ambulance or within 24 hours or so, a test may not show CO, even when carbon monoxide has poisoned. However, the other toxins stay in the body for days, weeks, months and possibly years so see under ‘Other Toxins’ for more information. Doctor John Henry, then Consultant Physician at the National Poisons Units, surveyed 200 General Practitioners. He sent them symptoms of carbon monoxide poisoning. Although many sensible suggestions were made, not one GP suggested CO as a cause of these symptoms. Hyperbaric Oxygen, (i.e. Under pressure) can prevent lasting damage.

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