Killer carbon monoxide alarms still on sale through online marketplaces
Unbranded carbon monoxide (CO) alarms bought from sellers on eBay, Amazon, AliExpress and Wish repeatedly failed to detect the killer gas and sound the alarm in British Standard CO detection tests, new Which? research can reveal.
With more around 40 accidental deaths a year in England and Wales caused by carbon monoxide, the consequences of an alarm failing could be disastrous.
Which? notified eBay about one of the alarms and its inability to reliably detect carbon monoxide seven years ago, but when we checked earlier this year, five of the cheapest 10 alarms were this same model. Dangerous alarms were also found on Amazon, AliExpress and Wish.
Find a reliable carbon monoxide alarm for your home with our carbon monoxide alarm reviews.
Video: the dangers of unbranded alarms
CO alarms are the latest in a long list of unsafe products found on online marketplaces that are putting consumers at risk.
Why having a carbon monoxide alarm matters
Carbon monoxide is a colourless and odourless gas. You can’t see it, you can’t smell it, you can’t taste it and the effects of exposure can be deadly. Every year around 40 people in England and Wales die of accidental carbon monoxide poisoning.
The dangers are all too familiar to Avril and Gordon Samuel, who set up the Katie Haines Memorial Trust in 2010 to raise awareness about the dangers after their daughter Katie died of carbon monoxide poisoning at her home.
Avril told us: ‘Ever since Gordon appeared on BBC Fake Britain highlighting concerns about CO alarms being sold online that did not meet BS 50291 with many coming from China, the Katie Haines Memorial Trust has campaigned vigorously about the need to only buy CO alarms from reputable manufacturers and retailers.’
She added: ‘A carbon monoxide alarm forms the second line of defence against carbon monoxide poisoning - the first being that all carbon-burning appliances should be regularly maintained and serviced by a registered engineer. If the alarm is not to standard, that defence is negated and could have fatal results.’
We also asked the London Fire Brigade (LFB) about the dangers of carbon monoxide and the importance of fitting alarms you can rely on.
Assistant commissioner Charlie Pugsley said: ‘Carbon monoxide is highly poisonous and produced by the incomplete burning of fuel. This can happen when boilers, cookers or other appliances are faulty or have been incorrectly fitted. It can also occur if flues, chimneys or vents are blocked or have been poorly maintained.’
Charlie added: ‘It is really important to fit a CO alarm in all rooms containing fuel-burning appliances. And make sure you buy an alarm from a reputable supplier, and that it has been certified to British Standard EN50291.’
The dangers of unbranded alarms
We tested a selection of cheap and unbranded carbon monoxide alarms bought from online marketplaces – the kind that many might take a punt on after being tempted by the low prices.
We also tested 10 from leading brands including FireAngel, Firehawk, Kidde and Google (Nest). The difference in test results between the unbranded alarms and the well-known brands is stark. The unbranded alarms failed to detect CO between 10 and 22 times in our tests, while the alarms from well-known brands detected the killer gas every time regardless of how much of it was in the air.
The problem of potentially lethal alarms doesn’t just relate to carbon monoxide. In May 2023, Which? revealed that a dangerously unresponsive smoke alarm that eBay has known about since 2018 was being listed for sale by 20 sellers on the platform five years on from Which? first alerting eBay to the danger.
In every Which? test of CO or smoke alarms stretching back to 2016, unbranded alarms made in China and sold through online marketplaces have repeatedly failed to sound. If you have one in your home, replace it with an alarm from a well-known brand that you recognise.
Avoid these dangerous CO alarms
Across the four online marketplaces we investigated, we found 149 listings for the five alarms that failed to detect CO in our tests. Sellers on eBay recorded 1,311 sales for alarms that don’t work, across 42 listings. There were also 46 listings for dangerous CO alarms on AliExpress, 41 on Wish and 20 on Amazon. They don’t come with recognisable brands, we’ve referred to them as they are branded on the box.
Battery-operated carbon monoxide alarm
We’ve been reporting this dangerous alarm for years – we tested it in 2016 and 2018 and it repeatedly failed. Despite this, we found 88 sellers listing this dangerous alarm on AliExpress, eBay and Wish. eBay sellers alone accounting for close to 600 sales. This year’s tests continue to show it can’t be relied on to sound when you need it to – it failed to respond to carbon monoxide 10 times in our 28 detection tests, and was far too quiet when it did sound.
Household carbon monoxide detector
This unbranded carbon monoxide and smoke alarm is incredibly unimpressive at detecting danger. We found it for sale all over eBay, with the 22 sellers listing it quoting 718 sales. We also found two sellers listing it on AliExpress. It failed to trigger a terrifying 22 times in our 28 carbon monoxide tests. On the box it tells us, ‘it’s a loud 85 decibel (dB) alarm’. But it only hit 68 dB in our sound tests.
Carbon monoxide alarm
This unbranded alarm failed to sound in 15 out of 28 carbon monoxide detection tests. We found it to be equally unresponsive with low, but still dangerous, levels of carbon monoxide as it was with high and lethal concentrations of the gas. It wasn’t loud enough to pass our tests either and we found it for sale from six sellers on Amazon and eBay.
Carbon monoxide alarm
This alarm simply couldn’t detect carbon monoxide in the air reliably. We found it being sold by seven sellers on AliExpress and Wish. From low but still dangerous levels of the killer gas right up to catastrophically high concentrations, it repeatedly failed to sound and missing the presence of CO in the air 17 out of 28 times. Like others we tested it was too quiet despite claims to the contrary on the box.
Carbon monoxide alarm
With nine CO detection failures registered in our tests, this tiny octagonal carbon monoxide alarm – 5.5cms across – is just as bad as the others we’ve tested. It wasn’t able to detect the deadly gas reliably at a variety of concentrations and failed to sound the alarm 15 times in 28 CO tests. And when it did go off, it was far too quiet. We found this dangerous alarm being stocked by 25 sellers on AliExpress, Amazon, eBay and Wish.
What to do if you’ve bought an unsafe CO alarm
If you own an alarm that’s identical to any of those featured here, you should replace it with an alarm from a recognised brand as soon as you can. Contact the seller and the online marketplace you bought the alarm from and request a refund based on the fact that the alarm shouldn’t have been sold to you because it’s dangerous.
Check out how to install and test carbon monoxide (CO) alarms.
How we test carbon monoxide (CO) alarms
We test CO alarms with increasing concentrations of the gas from low but still dangerous to high and life-threatening. Each of the alarms featured here failed to detect both low and high levels of the gas.
We ran multiple tests on more than one sample and all unbranded models we tested failed to sound over and over when CO was present. Occasionally they would detect the gas and sound but they need to sound every time to meet the requirements of the British Standard tests, and for owners to be able to rely on them. Along with being unresponsive to carbon monoxide in our lab tests, none were loud enough when they did sound. We also found that the instructions were often misleading. The guidance given with four of the five alarms was to not install them in the kitchen, which is where you’ll find gas or oil-fired cookers and boilers – a potential source of CO – in many UK homes.
More unsafe products found on online marketplaces
Carbon monoxide alarms aren’t the only dangerous products we’ve found being sold through sellers on eBay, Amazon, AliExpress and Wish.
- Child car seats - We found dangerous child car seats made of nothing more than fabric and illegal to use in the UK being sold for as little as £8 through online marketplaces.
- Christmas lights - Our testing found dodgy Christmas lights on online marketplaces that could give you a shock and posed a fire hazard.
- Energy-saving plugs - We shone a light on the ‘energy-saving’ plugs that fail to save energy and that pose a serious risk of fire and electric shock.
- Plug-in heaters - We revealed the dangerous electric plug-in heaters on online marketplaces that melt when in use.
- Power banks and USB chargers - Which? tests revealed the unsafe USB chargers and power banks that could give you a shock and that melted in our tests.
- Smoke alarms - Since 2018 Which? research has highlighted the danger posed by unbranded smoke alarms bought from online marketplaces that don’t detect smoke.
Which? calls for new regulations to protect consumers
Which? believes online marketplaces need to do much more to prevent unsafe product listings appearing in the first place, rather than removing them reactively – especially since they appear to be unable to prevent them being easily relisted for sale.
The government is consulting on potentially positive measures as part of its long-delayed product safety review. However, Which? believes it must move faster to establish new regulations that put consumer safety first and enable tough enforcement action, including heavy fines, against online marketplaces that break the rules.
Sue Davies, Which? head of consumer protection policy, said: 'Which? has been raising concerns about dangerous CO alarms for years, yet online marketplaces continue to allow them on their sites and into people’s homes, despite the potentially fatal consequences.
'This is the latest in a long line of examples of unsafe products being readily available on online marketplaces, with far too little action taken by the platforms to prevent them being allowed for sale.
'The government cannot delay any longer. It must move at pace to establish new regulations that put consumer safety first and enable tough enforcement action against online marketplaces that break the rules.'
What the online marketplaces told us
We shared our findings with AliExpress, Amazon, eBay and Wish directing them to the 149 listings we found on their platforms for alarms that our tests have shown are dangerously unresponsive.
As we went to press, all 149 listings had been removed.
AliExpress told us: ‘We take product safety very seriously and work hard to create a safe shopping environment. The items identified as part of the investigation by Which? have been removed. As a third-party marketplace, AliExpress does not take custody of the goods being sold. We have very clear rules and policies in place that must be adhered to by all the sellers on our platform.’
Amazon said: 'Safety is a top priority at Amazon. We require all products to comply with applicable laws and regulations and have developed industry-leading tools to prevent unsafe or non-compliant products from being listed in our stores. We have removed these products pending further investigation.'
eBay told us: 'We take the safety of our users very seriously and immediately removed the listings reported to us by Which? We only allow sellers to list approved brands of carbon monoxide detectors and can confirm that action has been taken against the sellers. We continuously review and update our safety measures which aim to prevent the sale of unbranded carbon monoxide detectors and have conducted further sweeps of our site to remove any similar listings.'
Wish said: 'All of our merchants are required to adhere to local laws and safety standards wherever their goods are sold. It’s clear that the products identified by Which? do not comply with those standards, so we have acted quickly to remove them, along with any similar and identical items. Meanwhile we are contacting the merchants responsible for listing those items to remind them of the importance of complying with product safety rules.'
