FOREIGN TRADE ZONES.

SEC. 9002. FOREIGN TRADE ZONES. Section 3 of the Act of June 18, 1934 (48 Stat. 999, chapter 590; 19 U.S.C. 81c) is amended by adding at the end thereof the following new subsection: “(d) In regard to the calculation of relative values in the operations of petroleum refineries in a foreign trade zone, the time of separation is defined as the entire manufacturing period. The price of products required for computing relative values shall be the average per unit value of each product for the manufacturing period. Definition and attribution of products to feedstocks for petroleum manufacturing may be either in accordance with Industry Standards of Potential Production on a Practical Operating Basis as verified and adopted by the Secretary of the Treasury (known as producibility) or such other inventory control method as approved by the Secretary of the Treasury that protects the revenue.”.