/ Health, Home & Energy

Carbon monoxide: the cause for alarm

carbon monoxide alarm

Following the death of her daughter Katie from carbon monoxide poisoning, Avril Samuel co-founded the Katie Haines Memorial Trust. It helps raise awareness about the dangers of the deadly gas and to prevent unnecessary loss of life especially through carbon monoxide alarms.

Thursday 18 February 2010 had been a busy day at work because my husband Gordon and I were driving later that evening to our cottage in Wiltshire, en route to Cornwall for a few days.

However, while we were on the M4, we received a call that changed our lives – a parent’s worst nightmare. Our eldest daughter Katie, 31, married in a fairy-tale wedding just two months prior, had been involved in an accident and we had to get to the Royal Berkshire Hospital in Reading immediately.

While her husband Richard was on his way home from work, Katie had taken a bath, but on standing up had been poisoned by a lethal dose of carbon monoxide [CO] from a faulty boiler, causing her to fall back into the bath, hitting her head on the side. Sadly, it was too late by the time Richard returned – Katie had drowned, with 37% CO in her blood [normal levels are less than 2.3%]. Richard, who fortunately survived, incurred 20% while trying to resuscitate her.

Our home boiler was regularly serviced and when the registered engineer recommended we install a CO alarm, we did so without really thinking about it. I think I am reasonably intelligent, but I was still unaware of the dangers of carbon monoxide and never checked to see whether our children had alarms in their homes. I thought CO poisoning was something that happened elsewhere.

Ironically, Katie and Richard had bought a smoke alarm that came with a CO alarm, and although they had installed the smoke alarm, they hadn’t got round to putting up the CO alarm.

Raising awareness

Following Katie’s death, we set up the Katie Haines Memorial Trust [KHMT] with Richard to raise awareness of the dangers of CO. Sadly, there are still up to 50 deaths per year and over 200 people attending hospital with suspected CO poisoning, according to NHS figures. The symptoms of this are flu-like and people can suffer low doses of the poison for years without it being detected.

We’ve since given away thousands of carbon monoxide alarms to vulnerable people, spoken at freshers’ fayres and industry conferences and, something of which we’re most proud, made three carbon monoxide awareness films.

We were particularly concerned that there were no prime-time TV advertisements, such as those we’ve seen for drink-driving, strokes and heart attacks, and so decided to make our own YouTube films, which have now been viewed by thousands of people.

We introduced our latest film, Cause for Alarm, at the launch of the sixth annual Gas Safety Week in September.

It shows that two simple steps can protect you against this ‘silent killer’. Firstly, to have your carbon-burning appliances regularly checked by a registered professional and, secondly, to install one or more audible CO alarms in your home.

We also commissioned a YouGov survey, which found that of the 2,133 adults polled, only 40% knew that the only safe colour for a flame on a gas appliance is blue. KHMT has warned people that if flames have a slight yellow or orange tint they could be emitting CO.

Advice on carbon monoxide alarms fpr staying safe

I’m obviously very concerned that Which? found 10 dangerous CO alarms in its recent tests of them. All of these alarms claimed to have passed the relevant EU safety standard, EN 50291.

My advice would be to always purchase audible CO alarms from a reputable source and to make sure that they carry the BSI Kitemark safety certification BS 50291. Remember to test your alarm weekly and to make a note of the expiry dates — most alarms last for seven to ten years.

Never rely on the patches that change colour when they detect CO, either. I can’t actually believe these are still sold – what on earth happens when you’re asleep and unable to check for a colour change? A noisy alarm is much more effective at alerting you to a CO leak.

I’d also advise landlords to make sure tenants have sealed-unit alarms, thus ensuring that batteries aren’t taken out to replace in a remote control.

But as much as you can make your home safe with an audible alarm, what happens when you sleep away from it? That’s why our trust advocates taking an alarm with you when you go away, whether you’re staying in the UK or abroad. We’ve noticed that whenever we’ve stayed in B&Bs, they don’t seem to have them, so we talk to the owners and often by the morning they’ve ordered some on the internet.

Our trust has received many emails from people thanking us for raising awareness of CO because they had been saved by alarms they’d bought after hearing about Katie’s tragic story.

Katie’s future has been taken away, but it’s comforting to know that she has saved other people’s lives.

This is a guest contribution by Avril Samuel, co-founder of the Katie Haines Memorial Trust. All views expressed here are Avril’s own, not necessarily those shared by Which?.

Do you think more can be done to improve our safety when it comes to carbon monoxide? Do you have carbon monoxide alarms and regularly check that they work, or have you ever come across a dangerous one?


Sorry Avril, it was bad timing that I posted my funny experience with a carbon monoxide detector earlier this morning and I am sorry you lost your daughter when as you now know detectors can be life savers. I don’t think any of us appreciate their value until we hear a story like yours.

Following one of your links, I am pleased to see we have one of Which?’s recommended detectors.


Thanks very much for this Conversation, Avril. I was aware that some carbon monoxide detectors were better than others and had suggested that Which? should offer us some advice. Many years ago, the Which? magazine alerted me to the fact that I had a smoke detector that could be slow to react. All that was necessary was to swap the cover for one with larger holes.

Every room with a gas or solid fuel appliance should have a working carbon monoxide detector that is within date. Unlike smoke detectors, carbon monoxide detectors must be replaced periodically.


Thank you for your comments. Just to let you know that smoke alarms not wired in also have an expiry date and should be replaced accordingly.


Hi Avril – I have moved house recently and bought some new battery operated alarms because the house has only a couple of interlinked mains alarms in the hall and on the landing. The ten year life ones with non-replaceable batteries have a place to record the installation date whereas the ones that take replaceable batteries have no expiry date. My research suggests that (ionisation type) smoke alarms with replaceable batteries can continue to work for many years, though I’m not advocating this. In my previous house I had 1980 alarms in two rooms in addition to newer ones. Out of interest, I took them into the kitchen and did a toast test and they were just as sensitive as the new ones. On the other hand, it is well documented that carbon monoxide alarms must be replaced by the expiry date.

Old carbon dioxide alarms can be disposed of as electronic waste at a recycling centre but ionisation smoke alarms contain a small amount of radioactivity and should be handed to a member of staff.

Best of luck with your campaign.


Hi again, Avril – I have now seen a battery-operated smoke alarm with an expiry date, as you mentioned. I presume this is a recent change.


I was staying with friends who have a holiday let in the next village. The oil-fired Worscester-Bosch boiler was in the locked garage of the bungalow and the guests heard an alarm before the boiler locked out. What had happened was the boiler had become blocked with soot causing carbon monoxide to escape and set off the alarm. Being in a rental property, the boiler had been serviced as required and there was no danger to the guests because the boiler was not in the house.

My friends asked me if I could let in the gas engineer, who fired up the boiler and it burned with a yellow flame. When this happens, carbon monoxide is produced. I asked why the boiler casing had not prevented it leaking out, but apparently this can happen. The boiler was full of soot, but he cleaned it out and adjusted it so that it burned with a blue flame.

As mentioned in the introduction, a yellow or orange flame in a gas or oil appliance is a warning sign not to be ignored. As my anecdote illustrates, regular servicing is not enough. It’s a pity that modern boilers often have tiny windows that make it difficult to keep a check on the colour of the flame.


Thank you for sharing your story. We’ve always had a carbon monoxide alarm in our boys room, but I hadn’t realised that they have a definitive life time, so I will be replacing ours. We’ve just moved house and now our boiler is in the kitchen, so I will get a new CO alarm fitting in there as well.

I’ve recently installed 3 Nest smoke alarms which also all have CO alarms which gives some added peace of mind as they will also give us alerts when we’re out of the house.


My First Alert carbon monoxide detectors pre-date the Which? test but in future I will buy recommended alarms.

I paid extra for detectors with digital displays but have never seen them read anything other than zero. I would be interested to know if testing detectors by pressing the button is sufficient to check their sensitivity throughout their working life. Test aerosols are available to check carbon monoxide detectors, but at a cost. Having bought calibration gases in large quantities when I was working, it seems that someone is making a large profit.

I would like Which? to make safety related reports freely available rather than restricted to members, but at least everyone can find out which are the ‘Don’t Buys’. It is commendable that Which? has pursued the companies involved in marketing poor quality detectors.


You know Wavechange I can go to American websites and US consumer associations and get highly detailed tech info on CO2 detectors with country of origin in a lot of cases -US products notably higher priced and industrial ones and yet over here its like secret service you just get sales patter as to best buys but technical details on a US scale are sadly lacking. I just dont get the secrecy here .


In the Which? report it is the cheap carbon monoxide (CO nor CO2) alarms that performed poorly, so in this case you are getting what you pay for. Nevertheless, it is unacceptable that any substandard ones are available. Independent testing is needed before safety devices are put on sale.

Hopefully Which? might consider making the report on carbon monoxide alarms publicly available. I hope that other subscribers would support this.


Hello Wavechange and Duncan, the ‘Don’t Buys’ have been named and made publicly available. We’ve also shared a lot of information from the investigation and our advice on how to buy an alarm, some of you may have seen this in the press yesterday and if you were up early enough and tuned into Good Morning Britain you may have even seen Which? Editor, Richard Headland, talking about the investigation.


I have a friend who fitted out a narrowboat a couple of years ago and he asked me for advice on smoke and carbon monoxide alarms. The boat had to comply with the Boat Safety Scheme, which is effectively an MOT for boats together plus numerous requirements for design. A modern narrowboat is effectively a metal box, narrower than a caravan, though often longer. Amazingly, many have solid fuel stoves in what is a very confined space. I understand that they can be the sole means of heating. I learned that having carbon monoxide and smoke alarms is recommended but not a requirement to achieve a certificate. I also learned that there have been numerous fatalities on boats, mainly as a result of carbon monoxide poisoning and fires, and solid fuel stoves are the usual culprit. I did fit a smoke alarm and a carbon monoxide alarm with a digital display for the chap with the boat.

I would like to see all homes, caravans and boats fitted with smoke alarms and carbon monoxide alarms wherever there is a gas or solid fuel appliance. Perhaps this could be made an insurance requirement.