Lawrence-Douglas County firefighters determined a fire in a vacant apartment building Tuesday in the 1900 block of West 24th Street was accidentally set.

Fire and Medical Division Chief Eve Tolefree said improper use of a propane torch was to blame for the blaze.

Crews were called to the scene around 7:30 p.m. Tuesday, where smoke was coming from the northeast corner of the building.

Three units of the 12-unit apartment building were damaged.

A damage estimate has not yet been determined.