The Consumer Product Safety Commission [cpsc.gov] has recalled more than 500,000 hoverboards after many months of safety warnings and reports of fires [mashable.com]:
The recall impacts the biggest hoverboard brands on the market, including Swagway (the Swagway X1 model [mashable.com]), the Hovertrax from Razor, the Airwalk Self Balancing Electric Scooter, the iMoto, the Hype Roam, the Wheeli, 2Wheelz, Back to the Future, Mobile Tech, Hover Shark, NWS, X Glider and X Rider.
Additionally, retailer Overstock.com is recalling all hoverboards sold on its website, which amounts to 4,300 in all. Similarly, Boscov's, a retailer based in Reading, Pennsylvania, is recalling 1,300 Orbit hoverboards.
The hazard described by the CPSC specifically cites risks associated with lithium-ion battery packs used in the hoverboards that may "overheat, posing a risk of the products smoking, catching fire and/or exploding."
[...] Consumers in the U.S. unsure whether or not their hoverboard is part of the recall can call the CPSC consumer hotline at (800) 638-2772.