Performed gas line leak search on all reachable gas appliances and fittings. No indication of leaks in furnaces or in furnace room. Inspected reachable gas line in shop area. No indications of leaks. Walked around to look for any other propane powered equipment. Leaks detected on the propane powered forklift at the connection joint, and on one other forklift propane tank. Uncertain if this is the reason for the propane smell throughout the building, but no leaks were found on the main propane lines.