Dangerous carbon monoxide (CO) alarms are being sold on popular retailers such as eBay, Amazon, AliExpress and Wish, new research has found.

The devices are used to detect high levels of lethal gas around a person’s home which can be fatal.

Consumer group Which? said it discovered 149 listings for unsafe CO alarms across the four online marketplaces, which have all now been removed.

Just one of the models which is a battery-operated CO alarm, was first reported to eBay by Which? seven years ago.

One model of a carbon monoxide alarm sold on eBay "failed to respond" to the high level of gas

Bournemouth Echo: Have you ever bought a dangerous carbon monoxide alarm from eBay?Have you ever bought a dangerous carbon monoxide alarm from eBay? (Image: Which?/PA)

This year’s tests found the model failed to respond to carbon monoxide 10 times out of 28 tests and was “too quiet” when it did sound.

The research also revealed five of the cheapest 10 carbon monoxide alarms on eBay were for this model.

Additionally, another unbranded CO and smoke alarm that failed to trigger 22 times when CO was in the air was listed by 22 eBay sellers, with more than 700 sales recorded.

Which? claims the government is “failing to take the urgent action needed” to hold online marketplaces “legally accountable”.

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.

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“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.”

The five unsafe CO alarm models, all unbranded and made in China, featured on the online marketplaces when product listings were filtered by “cheapest first”, in some cases being sold for as little as £5.

Within the selection, another unbranded alarm which failed to sound in 15 carbon monoxide detection tests was available for sale from six sellers on Amazon and eBay.

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eBay is the only online retailer to disclose sales figures for dangerous carbon monoxide alarms

eBay is the only online marketplace that disclosed sales figures, which said that it had sold at least 1,311 of the alarms.

An eBay spokesman said: “We take the safety of our users very seriously and immediately removed the listings reported to us by Which?

“We prohibit unbranded and unsafe brands of smoke or carbon monoxide detectors. We only allow sellers to list approved brands of carbon monoxide detectors and have taken action against the sellers who breached this policy.

Bournemouth Echo: eBay said they take the safety of their users 'very seriously' and immediately removed the listings reported to them by Which?'eBay said they take the safety of their users 'very seriously' and immediately removed the listings reported to them by Which?' (Image: Getty)

“We continuously review and update the measures in place to prevent the sale of unsafe products. We have also conducted further sweeps of our site to remove any similar listings.”

An Amazon spokesman added: “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.”

Responding to Which?, a Department for Business and Trade spokesman said the government take “public safety extremely seriously”.

They continued: “Which is why we are consulting on modernising our product safety framework to hold online marketplaces to account, ensuring items sold online meet the same standards as on the high street.

“If businesses don’t comply with product safety regulations, the Office for Product Safety and Standards will take appropriate enforcement action such as ordering the removal of the product from the market.”

In total, across the five alarms, Which? found 46 listings on AliExpress, 42 on eBay, 41 on Wish and 20 on Amazon.

Newsquest has contacted AliExpress and Wish for comment.