Firefighters have responded to an explosion that injured at least two people at an Indiana high school.

Fox 59 reports the incident occurred Wednesday night at Carmel High in Hamilton County. The city's fire department confirmed one of the victims suffered severe burns; the second victim's condition has not been reported. Officials said children who were inside the school at the time of the explosion were sent to stadium locker rooms, where they were to be picked up by parents.

The Carmel Fire Department has not identified the source of the explosion, but said they believe it originated in a mechanical room on the school's second floor. 

The explosion resulted in a small roof fire, which was marked under control at about 6:47 p.m. local time.

There are about 5,000 students enrolled at Carmel High School. According to the school's website, students are currently on winter break. However, a tweet on the Carmel wrestling team page suggests student-athletes were inside the building when the explosion occurred.

Public information officer Tim Griffin confirmed no students were injured during the incident. One of the patients was a school employee; the other was an independent contractor who was working on a heater.