RALEIGH — Talk about a teachable moment.

Students at Ligon Middle School participated in a planned fire drill Wednesday afternoon. Less than an hour later, the students evacuated the building again when a stage curtain started smoldering in the auditorium.

Wake County schools spokesman Mike Charbonneau said curtains had been pulled back to the wall and that one of them came in contact with a stage light that ignited it.

“The curtain started smoking,” Charbonneau said. “That triggered an alarm.”

The school was evacuated again just after 1:30 p.m. Firefighters arrived, but did not find much in the way of flames, only smoke. They used fans to blow the smoke out of the auditorium, Charbonneau said.

The smoke was cleared by 2:35 p.m., when students were allowed to go back inside to retrieve their book bags before they were dismissed for the day.