42 U.S.C. § 7514 – Plan submission deadlines

(a) Submission Any State containing an area designated or redesignated under section 7407(d) of this title as nonattainment with respect to the national primary ambient air quality standards for sulfur oxides, nitrogen dioxide, or lead subsequent to November 15, 1990, shall submit to the Administrator, within 18 months of the designation, an applicable implementation plan meeting the requirements of this part.
(b) States lacking fully approved State implementation plans Any State containing an area designated nonattainment with respect to national primary ambient air quality standards for sulfur oxides or nitrogen dioxide under section 7407(d)(1)(C)(i) of this title, but lacking a fully approved implementation plan complying with the requirements of this chapter (including this part) as in effect immediately before November 15, 1990, shall submit to the Administrator, within 18 months of November 15, 1990, an implementation plan meeting the requirements of subpart 1 (except as otherwise prescribed by section 7514a of this title).