Section 231 of Pub. L. 101–336 provided that:

“(a) General Rule.—Except as provided in subsection (b), this part [part I (§§ 221–231) of subtitle B of title II of Pub. L. 101–336, enacting this subpart] shall become effective 18 months after the date of enactment of this Act [July 26, 1990].

“(b) Exception.—Sections 222, 223 (other than subsection (a)), 224, 225, 227(b), 228(b), and 229 [sections 12142, 12143 (b) to (f), 12144, 12145, 12147 (b), 12148 (b), and 12149 of this title] shall become effective on the date of enactment of this Act.”