Carbon monoxide – the ‘silent killer’

Dan Moore / 09 January 2014

More than 280 people were killed in fires at home in the UK last year. And it’s the fear of fire that sees smoke alarms installed in homes up and down the country. Unfortunately, far fewer of us give as much thought to the dangers of carbon monoxide (CO) poisoning, despite it being just as deadly as fire.

It’s widely believed that there are around 50 fatalities in England and Wales alone with 4,000 sufferers being admitted to A&E, of which 200 are hospitalised, but sources disagree on the exact figures – partly because of the properties of carbon monoxide.

Spotting the invisible

The problem is that carbon monoxide is incredibly hard to detect. It’s known as the ‘silent killer’ with good reason, but that description only covers one of its features, as it’s also odourless, colourless and tasteless. All fossil-fuel appliances emit CO, so if you have a gas boiler, an open fire or have a petrol or diesel car, you’re potentially at risk and should have a quality CO alarm (see below).

It’s likely that the enigmatic nature of this gas accounts for the relatively low level of public knowledge of the risk. Unlike fire, CO won’t destroy your home and your possessions - events that make a highly visual impact.

Diagnosis problems

Accurate diagnosis of CO is a nightmare, as the symptoms are so similar to other far more common ailments. Victims may feel shivery, have headaches, and be generally run down. Although these symptoms are similar to flu, CO poisoning will not result in a rise in body temperature.

Nausea, vomiting and dizziness are other symptoms, which can be confused with gastroenteritis or food poisoning. Most of us will feel some of these symptoms at some time or other (and probably ignore them), so it’s understandable why CO symptoms may be ignored or misdiagnosed: not least as most relatively-mild sufferers will start to feel better once they are out and about. A breath of fresh air really is the antidote in this case.

Anyone who is feeling under the weather to such an extent that they visit a doctor’s surgery could be told to go home and wrap-up warm. If you think about it, this is the worst thing to do; by shutting all the windows and pumping up the heating the affects of CO poisoning will be accelerated.

And, if the worst happens, some health professionals may reasonably conclude that death was as a result of natural causes or existing medical conditions. This is because of the way CO affects the body. It binds with haemogloblin, an element of blood that would otherwise carry oxygen around us. In short, deprives the brain, heart and other vital organs of the life-source we need.

However, with swift treatment the effects of mild CO poisoning can be reversed. Victims are given 100% oxygen via a mask until the level of carboxyhaemoglobin in the blood falls to less than 10%. The level of CO in the body is established via a blood test.

How to spot carbon monoxide gas

CO is almost undetectable unless you have a decent detector in place. But it is possible to spy some tell tale signs that dangerous levels of carbon monoxide may be in the atmosphere. Alarm bells should ring if you spy soot or yellowy-brown stains on or around fuel appliances.

Excessive condensation in rooms where appliances are installed is another indicator that all is not right. If you have a gas cooker, small yellow or orange-coloured flames instead of vibrant blue ones may also hint at a problem. A pilot light that frequently blows out is a further notice of possible dangerous levels of CO.

If you spot any of these signs, take immediate action to limit the potential risk of CO poisoning by opening windows and doors, switching off the suspect appliance and by calling the National Gas Emergency Service (NGES) on 0800 111 999.

The NGES advises consumers to turn off all appliances and ventilate the area by opening doors and windows. You should never leave cars and motorbikes running in closed environments, such as garages, as these emit large quantities of CO.

CO detectors

There is a vast array of carbon monoxide detectors on the market, although these can be categorised as either spot detectors or audible detectors.

Spot indicators are fixed to or near to appliances and change colour if significant levels of CO are present. They are not recommended as they do not produce an audible alarm, so unless you regularly check them (and even if you do, they won’t help when you are asleep) they are of limited value.

Audible alarms look similar to typical smoke detectors. They are battery-operated, either being fitted with a tamper-proof battery, or utilising AA batteries. These devices are available from DIY sheds, supermarkets and online. A cross section of European Standard EN 50291 audible alarms is presented in the following table. All emit an audible alarm of 75DB to 85DB.

Even with an audible alarm fitted, it’s advisable to have gas boilers and working chimneys, flues and vents serviced on a regular basis. After all, even if the stats are right and the number of people who actually die from carbon monoxide poisoning is around 50 in England and Wales, that’s too many.

Carbon monoxide alarms

The following is s a cross-section of the type of alarms available on the UK market that comply with European Standard EN 50291.

Model Battery type
Aico Ei208DW Sealed tamper-proof
5 years
Memory feature (records last CO level tested)
Aico Ei208W Sealed tamper-proof 5 years Memory feature (records last CO level tested) £26.34
B&Q First Alert CO-FA-9BQ
AA 7 years Large test button £13.78
FireAngel CO-9B AA 7 years
FireAngel CO-9D Sealed tamper-proof
7 years Digital room thermometer
FireAngel CO-9X Sealed tamper-proof 7 years Automatic self-check facility £21.54
Honeywell H450EN Sealed tamper-proof
6 years 7 year life £20.00
Kidde 7CO AA 10 years For boats, homes and caravans £20.34
Kidde 8LLDCO Sealed tamper-proof
10 years One second test cycle £32.39
Kidde 900-0122UK AA
5 years Combined Smoke/CO Detector. Voice warning system £25.14

*Prices subject to change.

Further advice

The Health and Safety Executive has advice on carbon monoxide.
The NHS has a raft of information and a video explaining the symptoms and dangers of CO.
If you believe that an appliance is leaking CO contact the National Gas Emergency Service on 0800 111 999.
Carbon Monoxide – Be Alarmed is a national campaign website focusing on all matters CO.

Saga Home Insurance
PROMOTION Saga Home Insurance
Home insurance cover that goes
further than you might expect.
Over 50? Click here to find out more or get a quote!

The opinions expressed are those of the author and are not held by Saga unless specifically stated.

The material is for general information only and does not constitute investment, tax, legal, medical or other form of advice. You should not rely on this information to make (or refrain from making) any decisions. Always obtain independent, professional advice for your own particular situation.