In all Manufacturing Districts, the Board of Standards and Appeals may permit the utilization of Class IV explosives, as defined in Section 42-272 (Classifications), in manufacturing processes or other production and storage accessory thereto, provided that the following findings are made:

(a)        that such manufacture is carried on within completely enclosed buildings or other structures whose exterior walls are of incombustible materials;

(b)        that such buildings or other structures are protected throughout by an automatic fire extinguishing system which meets all requirements set forth in the Administrative Code of the City of New York; and

(c)        that such utilization and the storage accessory thereto complies with all additional applicable provisions of the Administrative Code and all rules and regulations of the Fire Department.

The Board may prescribe appropriate conditions and safeguards to minimize adverse effects on the character of the surrounding area.