A cellphone caught on fire early Friday afternoon at a Texas junior high school, causing at least one student to suffer thermal burns and sending 10 other people to the hospital for smoke inhalation.

The explosion happened at Mayde Creek Junior High School in Houston, according to the Harris County Fire Marshal’s Office, which is investigating the incident.

Between 25 and 40 students were reportedly being evaluated for injuries after the explosion.

The explosion happened inside the school’s chemical lab.

More details as they become available.