One of the hot gifts this year–the hover board–may be too hot for some people. It’s even got the Wilton Fire Department‘s fire chief suggesting people think twice about giving one of the scooters as a gift.

“If it was me, I would not buy my kid one,” says Chief Ronald Kanterman. “And my advice is if they are going to buy one, and take a chance, don’t keep them in the house. And if it’s a wooden porch, don’t leave them on the porch either.”

Strong words from Wilton’s top safety officer. They come after several reports have hit national news about incidents where these hover boards have suddenly exploded or burst into flames.

The term “hover board” is sort of a misnomer, as they don’t really hover. They’re self-balancing, battery-powered, motorized scooters, and some carry well-known brand names, from Swagway to Razor, and they can be found on Amazon as well as in big-box stores.

As news reports started running about incidents, Kanterman did some research of his own. He says most of the problems are being traced back to bad rechargeable batteries.

“One of the professors of engineering science at Carnegie Mellon University got it whittled down to a really cheap brand of lithium ion batteries. Almost everything uses lithium ion batteries these days–cell phones, electronics–but it’s such a cheap brand that they’re overheating quickly. You’ve got more of a shot [for overheating] if it’s charging but the famous pictures you saw a few days ago of one burning in the mall, that was not on charge, it just broke into flames,” Kanterman says.

The scooters burst onto the consumer scene relatively quickly this year. They’re so new, and the problems so recent, that there hasn’t been a lot of research done into their safety.

“The Consumer Product Safety Commission has nothing on their website–they say they’re looking at it, that’s all. They have to get a certain number of complaints before opening an investigation,” Kanterman says. But, he adds, the handful of incidents that have occurred are alarming enough. They’ve been banned by several airlines and the biggest consumer electronics show as well, he says. “They don’t want them in the convention center.”

Some reports say the problems is only with the cheaper, knock-off models made in China, and many articles suggest it’s safe to stick with American-made models. But Kanterman is even more cautious.

“Not until it’s perfected or someone of authority, like CPSC or Underwriters Lab comes out and says, ‘We tracked it down, here’s the problem, and the manufacturer said they’re going to start making changes.’ It’s like buying a brand new model of a car, they have to get the kinks out of it. This was the first shot out the door and I think they rushed it,” he says.

Part of the problem, says Wired magazine, which talked to that same professor Kanterman referenced, is that not only are mass-produced, low quality lithium ion batteries at higher risk for becoming compromised while charging, any battery of this type can malfunction if damaged in the exact way in which the scooter boards are used:

“For one, the nature of a scooterboard—it can bang into stuff, smash into things at high speeds, and be abused by bros—makes the batteries susceptible to damage. It’s not just the nature of a cheap battery, it’s the nature of any lithium-ion battery. And when one of these batteries punctures, this is what happens:”