40 CFR § 61.358
Delegation of authority
June 9, 2020
(a) In delegating implementation and enforcement authority to a State under section 112(d) of the Clean Air Act, the authorities contained in paragraph (b) of this section shall be retained by the Administrator and not transferred to a State.
(b) Alternative means of emission limitation under §61.353 of this subpart will not be delegated to States.