A fire alarm during lunchtime interrupted plans for an afternoon fire drill at South Bosque Elementary School on Thursday.
An exit sign shorted out and produced noticeable smoke, Midway Independent School District officials wrote in an update sent to parents and media outlets.
School officials escorted students outside to a playground area while fire officials investigated the smoke, according to the update.
Students and faculty were allowed to return inside by about 1 p.m., spokeswoman Traci Marlin said. No one was hurt.