State certifying authority
State certifying authority means:
(1) For water pollution control facilities, the State pollution control agency as defined in section 502 of the Act.
(2) For air pollution control facilities, the air pollution control agency designated pursuant to section 302(b)(1) of the Act; or
(3) For both air and water pollution control facilities, any interstate agency authorized to act in place of the certifying agency of a State.
40 CFR § 20.2
As used in this part, the following terms shall have the meaning indicated below: