A fire at Tempe's Kyrene Middle School caused the evacuation of about 1,300 students and 80 staff members on Thursday morning.
A teacher noticed smoke coming out of a classroom at the school, 1050 E. Carver Road, moments before the sprinkler system was activated.
One student complained about breathing problems, but no other injuries were reported, according to the city of Tempe.
Parents were notified and the students later were permitted to return to class.
According to the city of Tempe, the fire started about 11:45 a.m. and was caused by an electrical motor failure in the skylight system.