A fire at the Fraser Valley Institution for Women, located on the same property as Matsqui Institution on King Road in Abbotsford, suffered about $30,000 damage from a fire on Saturday morning.
Abbotsford Fire Rescue Service crews were called just after 11:35 a.m. for a report of a kitchen fire at the facility.
Crews were escorted through heavy security to a single-story residential until with light smoke coming from the building.
Corrections staff had reported that the flames had been extinguished, but crews discovered there was still a small fire extending into the attic space.
Assistant Fire Chief Ron Hull said the cause of the fire was cooking oil left unattended on a stove.
The unit suffered smoke, fire and water damage.
Hull said the fire could have been much worse if the facility had not been equipped with a sprinkler system.
The incident was attended by 18 firefighters with five fire trucks.
Cooking oil left unattended on a stove has been the cause of a few recent fires, including one on April 14 and one in December.