§51.913. How do the section 182(f) NO X exemption provisions apply for the 8-hour NAAQS? — Inbound Citations

As of revocation of the 1997 ozone NAAQS on April 6, 2015, as set forth in § 50.10(c), the provisions of subpart AA shall replace the provisions of subpart X, §§ 51.900 to 51.918, which cease to apply except for § 51.907 for the anti-backsliding purposes of § 51.1105(c)(2). See subpart X § 51.919.

As of April 6, 2015, the provisions of subpart AA shall replace the provisions of subpart X, §§ 51.900 to 51.918, which will cease to apply, with the exception of the attainment date extension provisions of § 51.907 for the anti-backsliding purposes of § 51.1105(d)(2).