In the IU-1 district only, storage, utilization or manufacture of solid materials
or products including free-burning and intense-burning materials is permitted providing
that such materials or products shall be stored, utilized or manufactured within completely
enclosed buildings having incombustible walls and protected throughout by an automatic
fire extinguishing system. In the IU-1 district only, the storage, utilization or
manufacture of flammable liquids or materials which produce flammable or explosive
vapors is permitted if in accordance with all applicable laws and ordinances.
