WASHINGTON (DC News Now) — DC firefighters have issued safety warnings after two house fires were started by hoverboards that ignited while they charged.

The devices run on lithium batteries, which pose a threat if they are not charged properly.

“These devices are very sensitive to changes to different types of electricity that might be coming in,” said Fire Marshal Matthew Kannry. “So it’s very important to only use those chargers.”

Plus, unplug the hoverboard when the process has ended. The batteries are also used in such items as electric bikes, scooters, laptop computers, and even some toys.

“An issue that we find a lot with these lithium batteries is called ‘thermal runaway,'” said Kannry. “What happens is the batteries get warm, and it’s kind of a self-fulfilling cycle where they continuously heat up. They start to smoke and can combust very rapidly.”

Kannry also gave a reminder not to place hoverboards near escape routes while they are being charged.

A hoverboard is blamed for the January 10 fire at a home on Burns Street SE.

A similar fire happened about two miles away on 31st Street. Firefighters rescued a family and their pets from a second-floor apartment when the fire started in a downstairs apartment on December 28.

“This just a minor setback for me to come back (from),” said Darius Bolden, who lived in the apartment with his mother and sister. “You know what I’m saying. We’re going to be back soon.”

Bolden used to have a hoverboard. But he pawned it two days after the fire.