WINTHROP — The middle school was evacuated this morning when an electrical short in the ventilation system sent smoke wafting into a teachers’ room.

Fire Chief Daniel Brooks said no one was hurt in the incident and students and faculty returned to the middle school by mid-morning after a technician confirmed the smoke was caused by a short in an electric motor attached to the ventilation system.

“All the kids followed the evacuation plan in an orderly way,” he said. “They did an excellent job.”

Students returned to the school as of 10:50 a.m. and school officials said some classrooms remained smoky. Students in smoky classrooms were accomodated elsewhere.

Teachers at the middle school on Rambler Road pulled the fire alarm around 8:30 a.m., after staff in a teachers’ office smelled smoke, Brooks said. A custodian removed ceiling tiles in the office and discovered even more smoke.

“It kind of filled the area with a bad smell and that room with some smoke,” Brooks said.

Middle school students and faculty evacuated to the high school, which is just a few hundred yards away. Activating the fire alarm automatically shut down the ventilation system.

Brooks, who happened to be at the high school, said he was at the middle school moments after the alarm was activated. Firefighters searched the building with heat-detecting cameras and opened up additional ceiling tiles, Brooks said.

“We pretty quickly determined there was no fire,” he said. “We were on scene for a while trying to determine exactly where the problem was.”