At 2:47 p.m. volunteer firefighters and rescue squads responded to Oakville Elementary School for a report of a fire alarm followed by smoke filling part of the building.
Fire and rescue crews were dispatched from Mechanicsville, Hollywood and Leonardtown.
Students were evacuated, and shortly after entering the building and discovering the problem apparently originating from the heating/cooling system, the response was scaled back and extra fire crews and ambulances were put back in service.
Firefighters set up fans to ventilate the building after locating the problem in a malfunctioning fan.