Unsafe smoke alarms rife across eBay and Wish

Four smoke alarms widely available online have completely failed to detect smoke in Which? tests, underlining concerns about how easy it is to unknowingly buy unsafe products through online marketplaces.

The alarms were purchased from eBay and Wish. Each one was tested in fire settings involving wood, cotton, plastics and solvents.

All of the alarms were unbranded, made in China and sold through Chinese re-sellers. Two came with instructions that were not in English, meaning that the product cannot lawfully be sold in the UK.

All four failed to sound in every test conducted and have been made Which? Don’t Buys. Disturbingly, three of the alarms had a CE mark, suggesting to consumers that they are legal to sell in the UK and meet all safety standards, but based on the evidence of our testing they would be useless in a real fire and could put lives at risk.

Which? found that listings for the products are rife on eBay. In a snapshot study, the consumer champion found the four alarms that failed its testing accounted for 171 of the cheapest 500 listings for smoke detectors on its site.

On Wish, 28 out of 200 listings were for three of the alarms that completely failed to detect smoke in Which?’s tests.

Following pressure from Which?, eBay has removed the listings for the alarms that failed to detect smoke in its tests. However, this is not the first time that Which? has uncovered dangerous smoke alarms on the site.

In 2018, the online marketplace removed 100 listings for smoke alarms which appeared identical to a product that failed seven out of eight fire tests conducted by Which?. But when Which? checked eBay in May of this year, it found 60 listings for what appeared to be the same alarm among the cheapest 500 listings on its site.

By continually failing to prevent unsafe products from being listed on its site, and then not managing to stop them from reappearing once they are flagged as unsafe, Which? believes that eBay is not taking the safety of its customers seriously.

Which? is passing on the findings of its investigation to the Office for Product Safety & Standards (OPSS), as the latest example of the widespread availability of unsafe products on online market places.

Working with Trading Standards, the OPSS must ensure that online marketplaces do not become an unpoliced wild west for rogue businesses and unsafe products. It is of particular concern that some of the products tested by Which? bore CE safety markings that were not justified by their performance in tests.

Due to the risk the unsafe smoke alarms pose, people who think they have one of these in their home should stop using it immediately. Which? is calling on eBay and Wish to contact everyone who has purchased one of these products to alert them and to explain how they can get their money back.

Natalie Hitchins, Which? Head of Home Products and Services, said:

“It’s extremely concerning that eBay and Wish are listing smoke alarms that simply do not work, which could put people’s lives at risk in the event of a fire. Anyone who has one of the products highlighted should stop using it immediately.

“eBay and Wish must take the safety of their customers more seriously and stop these alarms from getting on to their sites in the first place. eBay customers will be shocked to find that listings for some unsafe alarms simply reappear on the site after being removed.

“The safety of products bought on some online marketplaces is becoming an increasing concern. The OPSS and Trading Standards need to take a more proactive approach to ensure that potentially lethal products don’t enter people’s homes through the back door.”


Smoke alarm tips


  • Buy a Best Buy-rated smoke alarm which has passed Which? tests – this is the only way to guarantee that you’ll end up with an alarm that’s quickest to sound in an emergency.
  • If you can’t find a Best Buy, look for an alarm from a recognised brand and retailer.
  • Avoid cheap imported alarms – though they may be marked to indicate they are safe, our tests have shown this is often not the case.
  • Write on the smoke alarm itself the day that it was installed, and the date that it, or the battery, should be replaced.
  • Follow the manufacturer’s guidance on the installation, location and maintenance of the alarm.
  • Test your alarm every week and, unless it has a 10-year integrated battery, change the battery annually.
  • Replace your smoke alarm after 10 years.



  1. How we test: we test each alarm in a fire chamber with smoke from four separate fires. The fires are made up of wood, cotton, plastics and solvents, the kind of things that would be present in a house fire. We record how quickly they sound and how dense the smoke is at that point. And we test two samples of each product, which means that every brand on test is given eight opportunities to detect smoke.
  2. eBay said: “The listings flagged by Which? have been removed and the sellers informed. The safety of customers is our number one priority and we work closely with bodies such as Trading Standards to ensure listings sold on our marketplace comply with the law.”
  3. Wish said: “As a marketplace with more than 2 billion products, we look to our community to help us ensure that our products are up to the standard that customers expect. We are grateful to Which? for alerting us to this issue and looking out for the needs of the consumer. We are working to remove these products from the platform and are following up with the merchants in question to ensure they are adhering to local laws and regulations.”
  4. Alarms and packaging

Press Release