What material is allowed for a furnace room ceiling material?
Definitely don't use WOOD as suggested by DMoore! Yes, consult your local Ohio codes. 

A new material, probably not rated or considered in Ohio code, but used extensively outside the US, is MGO board, which is fireproof, waterproof, mold proof... I wish this would get certified, as it's a much better idea than drywall in the first place! This is NOT Chinese drywall, which is just poor quality unregulated imported garbage. A reputable MGO board company will probably have certifications soon for this type of installation. 

At least be glad that the old asbestos board, which was used extensively decades ago, is gone, after the medical concerns surrounding that material arose.