Crews in Bellefontaine worked for several hours Saturday to put out flames at a business on West Columbus Avenue.
A building in the 200 block of West Columbus was reported on fire before dawn.
Crews remained at the scene heading into the early afternoon as at least one large building was reported destroyed.
The site is the former Dunson Supply Co., and renovations were underway by the new owners Tom and Bruce Gates of Gates Brothers Glass, the Bellefontaine Examiner reports.