40 CFR 60.28a – Plan revisions by the State
(a) Any significant revision to a State plan shall be adopted by such State after reasonable notice, public hearing, and meaningful engagement. For plan revisions required in response to a revised emission guideline, such plan revisions shall be submitted to the Administrator within fifteen months, or as determined by the Administrator, after publication in the
(b) A revision of a plan, or any portion thereof, shall not be considered part of an applicable plan until approved by the Administrator in accordance with this subpart.