A short in the electrical system that controls the emergency lights at the Somerville School caused the smell of smoke to fill the building around 4 p.m. on April 13.
Although firefighters responded to the school, there was no fire or damage to the building, fighters said at the scene. No children were present when the smell was discovered.
A small amount of smoke from the short got into the heating system, and spread around the school, firefighters said.
