A student at Kellogg Middle School in Rochester was burned after his cell phone battery exploded in his pocket Thursday.
The Rochester Post Bulletin reports an audio message to parents indicates the phone caught fire and burned the boy's leg, leaving a hole in his pants. The phone also left a burn mark on the floor.
Principal Dwight Jennings says the boy received medical treatment and the remaining students in the classroom were evacuated. The small fire caused a significant amount of smoke and left a strong odor throughout the building.
After the room was aired out, the kids returned to class.
Under advisement from the Mayo Clinic, the school is recommending that parents monitor their children for any after effects of smoke inhalation.
A burning sensation in the throat can be a symptom of inhaling sulfur from the phone's battery and should be treated by a doctor.
Earlier this month, a similar incident happened in South Korea. A spare lithium-ion battery for a Samsung Galaxy Note was in a man's pocket when it exploded, leaving second-degree burns on his thigh.
It's not clear what kind of cell phone the boy in Rochester was carrying.
Lithium-ion batteries are also behind the worldwide grounding of Boeing 787s.