Class III materials or products may be stored, manufactured or utilized in manufacturing processes or other production only in accordance with the following provisions:

(a)        In M1 Districts

In M1 Districts, Class III materials or products shall not be manufactured in any event, and shall be stored or utilized subject to the following limitations:

(1)        such storage or utilization shall be carried on only within buildings or other structures which are completely enclosed by incombustible exterior walls;

(2)        such buildings or other structures shall either be set back at least 40 feet from any lot line or, in lieu thereof, all such buildings or other structures shall be protected throughout by an automatic fire extinguishing system which shall comply with the requirements set forth in the Administrative Code, and all such structures as storage tanks shall be protected by a fire extinguishing system which shall comply with the requirements set forth in the Administrative Code;

(3)        the final manufactured product shall have a rating of Class I; and

(4)        the storage of Class III materials or products shall be limited to 50,000 gallons.

(b)        In M2 Districts

In M2 Districts, Class III materials or products shall not be manufactured in any event and shall be stored or utilized subject to the following limitations:

(1)        the final manufactured product shall have a rating of Class II; and

(2)        the storage of Class III materials or products shall be limited to 100,000 gallons, except that such limitation shall not apply to storage in underground tanks and storage of finished products in original sealed containers.

(3)        In M2 Districts, and within 100 feet of the district boundary of a Residence District, a Commercial District or an M1 District, Class III materials or products shall be stored or utilized only in accordance with the provisions set forth in paragraph (a) of this Section for M1 Districts.

(c)        In M3 Districts

In M3 Districts, Class III materials or products may be stored, manufactured, or utilized without limitation.

(1)        Special provisions applying along district boundaries

In M3 Districts and within 400 feet of a Residence District, a Commercial District or an M1 District, the provisions set forth in paragraph (a) of this Section for M1 Districts shall apply. In M3 Districts and within 300 feet of the district boundary of an M2 District, no more than 200,000 gallons of Class III materials or products may be stored, except that such limitation shall not apply to storage in underground tanks or storage of finished products in original sealed containers.