Amazon’s Choice CO Detector Removed From Site After Reports of Hospitalizations

The plug-in CO detector cited in the reports was sold under the brand name Hembisen and model number KH-158. The four-in-one product was marketed for general home use and claimed to measure temperature and humidity and detect CO and combustible gas.

If you own one of the detectors, you should return it to Amazon, request a refund, and replace it with a top-rated model from our ratings. (See below.)

“People rely on CO detectors for their life-saving capabilities,” says Gabe Knight, a senior safety policy analyst for Consumer Reports. “The perception, until proven otherwise, is that it’s working. That leads to a false sense of security.” 

The detector was purchased more than 4,000 times in the month prior to its removal from Amazon’s website. It had received more than 800 product reviews and was given an Amazon’s Choice designation and featured by Amazon influencers. 

At the time of publication, similar or identical-looking CO detectors remained available for sale on Amazon from both the Hembisen retailer and other third-party sellers under brand names such as KH Alert, Koabbit, Vilfet, and Yojock. 

The reports were received by the CPSC between late February and early March, and all claim the detector failed to warn residents of dangerous CO levels—leading to illness and the hospitalizations of at least four people, including two children and one senior. 

In separate incidents in February, a 15-year-old and a 14-year-old were treated for potential CO poisoning. “The device failed to sound any alarm or show any elevated readings while CO levels had reached life-threatening concentrations,” states one report filed using the CPSC’s SaferProducts.gov, a public database for reporting and searching user-submitted complaints about potentially dangerous products.

In March, a 60-year-old man was hospitalized under similar circumstances. “Family members began experiencing symptoms consistent with carbon monoxide exposure, including dizziness and difficulty breathing,” according to that report. 

“Most people don’t know to report unsafe products to SaferProducts.gov, so the fact that there are four reported incidents in a month linked to the same model indicates this may be a very widespread issue,” Knight says.

Consumers cited similar safety issues among the dozens of one-star reviews left on the product’s Amazon page. In a review posted in February, one stated that the detector, plugged in next to her home’s furnace, failed to identify a CO leak that an HVAC company later discovered. “My family had been waking up with headaches frequently and feeling tired from what we now know was chronic carbon monoxide exposure,” the review says. 

In an October 2025 review, a user complained about a false alarm that prompted a call to a local gas company. An employee of the company recognized the brand name. “Before even seeing it,” the review states, “he told me he had two false alarms within the past week in our city.”

The risk of faulty CO detectors sold on third-party retail sites such as Amazon and Walmart is a growing concern. 

In 2021, the CPSC filed an administrative complaint against Amazon, citing over 400,000 defective or noncompliant products, including 24,000 CO detectors that had failed to alarm. And the CPSC’s recalls page lists numerous actions and warnings tied to faulty CO detectors.

There is no mandatory safety standard for CO detectors, but reputable manufacturers ensure that their models are certified to meet the voluntary UL 2034 standard, which sets strict requirements for how quickly a detector sounds an alarm based on the CO concentration level. 

The models cited in the CPSC reports have not been tested by Consumer Reports.