1986—Subsec. (a). Pub. L. 99–495, § 4(a), (b)(1), designated existing provisions as par. (1), substituted “existing” for “original” wherever appearing, and added pars. (2) and (3).

Subsecs. (b) to (f). Pub. L. 99–495, §§ 4(a), 5, added subsecs. (b) to (e) and redesignated former subsec. (b) as (f).

1968—Pub. L. 90–451 designated existing provisions as subsec. (a) and added subsec. (b).

Amendment by Pub. L. 99–495 effective with respect to each license, permit, or exemption issued under this chapter after Oct. 16, 1986, see section 18 of Pub. L. 99–495, set out as a note under section 797 of this title.