DALLAS, Texas (WFAA) -- There's a safety warning spreading across the nation about what can be a hidden danger in smart phones.
Last week a Dallas girl's phone got hot under her pillow in the middle of the night and caught fire.
Three hours after falling asleep, 13-year-old Ariel Tolfree says she felt the heat and woke up. She says everything was charred and there was a hole in her mattress. Her phone was destroyed, but she wasn't injured.
Tolfree and her family suspect it was the lithium ion battery, which was a replacement and not the battery the phone came with.
At least one major phone company warns customers that leaving their smart phones under bedding may cause a fire or even an explosion.
Experts say what happened to Tolfree is rare, but can obviously happen.
Lithium ion batteries are used in many products, from phones to tablets. They can overheat, sometimes reaching 350 degrees.