The smoke that prompted evacuation of Heritage Middle School just before classes were to begin Monday morning was caused by a short in an electrical connection to a fan in ductwork, West Ada School District spokesman Eric Exline said.
The problem was discovered in the area of the south-wing drama room at the school, 4990 Meridian Road, Exline said.
The school’s 1,150 students in grades 6 through 8 were evacuated as a precaution shortly after 8 a.m. and were allowed to return to the building at 9:20 a.m. after investigators identified the problem, he said.
“Anytime you have smoke or the smell of something burning, it’s typical to pull the fire alarm and evacuate the building,” Exline said.
Nothing caught fire, and the fan was removed from the ductwork, he said. It was unclear Monday afternoon whether the fan can be repaired or must be replaced, he said.