The principal of a Mississippi elementary school averted disaster when he discovered a fire in a classroom during his final walkthrough of the school before leaving for home.

WTVA in Tupelo reports that the fire inside the Grenada Elementary 4-5 classroom was extinguished in about 15 minutes after fighters were alerted and arrived at the scene,

The fire happened shortly before 4 p.m. after students had already left for the day.

The fire damaged one classroom and did not extend to other areas of the school, which still plans to open for instruction on Tuesday.

Officials say the cause of the fire appears to be electrical. The State Fire Marshal’s office will investigate the incident.