Prior to renumbering of sections 1651 to 1693 of this chapter as sections 3451 to 3493 by Pub. L. 102–83, § 5(a), Aug. 6, 1991, 105 Stat. 406, section 1675 of this chapter, added Pub. L. 89–358, § 2, Mar. 3, 1966, 80 Stat. 16, which related to period of operation for approval by Administrator, was repealed by Pub. L. 92–540, title IV, § 401(6), Oct. 24, 1972, 86 Stat. 1090.