A modular building at the Mendocino County Administration Center was burned in a fire Tuesday evening along Low Gap Road. The Ukiah Valley Fire Authority says a man driving by saw the fire and alerted someone in one of the buildings. They used a fire extinguisher to put out the flames and reported the fire to UVFA. While crews were responding, the fire re-ignited and by the time they arrived, one of the modular buildings was fully involved in flames. That building was empty, and no injuries were reported. The cause of the fire is undetermined.