AliExpress and eBay have removed 438 listings for killer carbon monoxide (CO) and smoke alarms that Which? tests have found will fail to sound when they need to.
The online marketplaces took the action following our investigation, which revealed that seven potentially deadly unbranded carbon monoxide alarms and four unbranded smoke alarms were available through the sites. We've made all 11 products Don't Buys.
But not all carbon monoxide and smoke alarms are dangerous. We've tested 17 CO alarms so good at detecting the deadly gas that we've made them . And two smoke alarms responded so quickly in our tests that we've made them .
We're not even at the midway point of our latest round of CO alarm tests and we've already found seven unbranded alarms listed on eBay that simply can't detect CO reliably.
Testing is ongoing, but as we went to press each of the seven Don't Buy CO alarms has failed to detect the deadly gas at least once. And four are too quiet, with two registering just 70dB rather than the required 85dB. That's the difference between the noise a shower makes and that of a passing lorry, and it's a flaw that could cost you your life.
If you have an unbranded alarm that looks like any of the seven dangerous products featured here, you will need to buy a new alarm as soon as possible.
Buy a well-known brand from a high street store or a reputable online retailer. We've only found dangerous alarms like these ones to be available through online marketplaces, such as eBay, AliExpress and Wish. Or check out our to be sure you're buying a safe model.
The smoke alarms story is just as worrying. Four unbranded alarms bought from eBay have failed to detect any smoke at all in our tests. So, whether we set fire to wood, cotton, plastics or solvents, these alarms just didn't work.
We searched eBay for CO and smoke alarms and found reams of listings for the 11 alarms mentioned above which have failed our tests and that can't be relied upon to detect smoke or CO. Since our latest investigation, eBay has now delisted all alarms we have identified as unsafe. However, while some have only recently failed our tests, we've uncovered at least five designs of alarms in previous years and these will have been known to eBay.
It's not just eBay allowing dangerous products to be listed on its site. On Wish, we found that 125 of the cheapest 200 CO alarms had failed our detection tests. And 27 of the cheapest 200 smoke alarms listed were products that had completely failed to detect smoke in our tests. Wish has known about them since at least May 2019, when we first alerted it to the problem.
AliExpress, another marketplace, was listing 134 dangerous CO alarms among the cheapest 200 on its site. And the site was just as bad for smoke alarms, having listed 163 dangerous alarms in its most affordable 200. However, like eBay, AliExpress has now removed those listings from its site as a result of our most recent investigation.
Here are our top tips to make sure your smoke and CO alarms keep you safe.
Our challenge to eBay and also to AliExpress, Wish and other online marketplaces is simple: if the safety of customers is your main priority, then prove it by only allowing alarms to be listed on your sites that you know to be safe. It shouldn't be up to Which? to do this for you. If you can't block unbranded and dangerous alarms from being listed for sale, then don't allow that kind of product to be listed in the first place.
AliExpress and eBay told us that customer safety is paramount and both have removed the listings we highlighted. eBay said it works with Trading Standards to ensure listings are legal and has asked sellers to warn buyers and issue refunds. AliExpress said it requires merchants to comply with local rules and regulations wherever it sells.
A spokesperson for Wish told us that it is working to remove the products from its platform.