It is no secret that hoverboards – two-wheeled, battery-powered, self-balancing scooters – have proved enormously popular with kids and teenagers. But allegations regarding defective battery packs have triggered recalls. The latest hoverboard incident was associated with a fatal fire in Harrisburg, Pennsylvania last March.

The U.S. Consumer Product Safety Commission (CPSC) started an investigation into the Harrisburg incident after fire officials blamed the accident on a charging hoverboard. Now, the CPSC has asked consumers to immediately stop using the brand of hoverboard used, LayZ Board. The CPSC made clear that the warning does not apply to Lazyboard scooters, which are a separate brand made by a different manufacturer.

Some 3,000 LayZ Board hoverboards have been imported into the U.S. Among the incidents the CPSC investigated were reports of burns and property damage across 20 states, allegedly causing in excess of $2 million in property damage. In September 2016, the CPSC recalled 501,000 hoverboards from eight manufacturers after documenting 99 incidents stemming from the scooters’ lithium-ion battery packs overheating and, in some instances, catching fire or exploding. Since then, the CPSC added another 500 scooters from a ninth manufacturer to the recall.

Lithium ion batteries offer manufacturers the ability to design and produce devices that can run for long period of time without recharging. But, after a series of high-profile accidents, the dangers posed by cheaper makes of the batteries have been widely publicized. In June 2016, CPSC’s then-Chair Elliot Kaye stated: “Unless the manufacturer can show that the device has been certified as safe by Underwriters Laboratories (UL), it should be considered “a fire hazard waiting to happen.” He urged consumers to return any non-certified hoverboard back to the manufacturers for a refund.

The first hoverboard certification was granted by UL in May 2016, meaning that earlier models would have been manufactured before the UL hoverboard standards were in place. That does not automatically mean that earlier models are unsafe if the manufacturer used a high degree of due diligence when choosing batteries for use in their products, but it is likely that they will have to demonstrate that level diligence if investigated. It is unlikely that retailers will now accept new models of hoverboards that are not certified.

It is worth noting that while the CPSC’s has issued a warning notice about LayZ Board rather than a recall, the Commission can still initiate a recall down the road.