A Sunday night fire of undetermined origin destroyed two unoccupied buildings on the grounds of Walden Correctional Institution off Broad River Road.
The fire will be investigated by SLED, which has an arson team, said Columbia Fire Department spokesman Brick Lewis.
There were no people in there apparently it started in the upper part of one of the buildings, said S.C. Department of Corrections spokesman Clark Newson.
More than 30 firefighters and eight fire engines from Columbia and Irmo were on the scene.
Waldon Correctional Institution is a mimimum security facility on the grounds of a large prison complex outside Columbia that houses a number of state prisons.
One building was a barn that housed farm equipment; the other was a one-story office.