40 CFR § 60.5720a
What if I do not submit a plan, my plan is incomplete, or my plan is not approvable?
June 9, 2020
(a) If you do not submit a complete or an approvable plan the EPA will develop a Federal plan for your State according to §60.27a. The Federal plan will implement the emission guidelines contained in this subpart. Owners and operators of designated facilities not covered by an approved plan must comply with a Federal plan implemented by the EPA for the State.
(b) After a Federal plan has been implemented in your State, it will be withdrawn when your State submits, and the EPA approves, a plan.