40 C.F.R. § 56.3

It is EPA's policy to:

(a) Assure fair and uniform application by all Regional Offices of the criteria, procedures, and policies employed in implementing and enforcing the act;

(b) Provide mechanisms for identifying and correcting inconsistencies by standardizing criteria, procedures, and policies being employed by Regional Office employees in implementing and enforcing the act; and

(c) Insure an adequate quality audit for each State's performance in implementing and enforcing the act.

(d) Recognize that only the decisions of the U.S. Supreme Court and decisions of the U.S. Court of Appeals for the D.C. Circuit Court that arise from challenges to “nationally applicable regulations . . . or final action,” as discussed in Clean Air Act section 307(b) (42 U.S.C. 7607(b)), shall apply uniformly, and to provide for exceptions to the general policy stated in paragraphs (a) and (b) of this section with regard to decisions of the federal courts that arise from challenges to “locally or regionally applicable” actions, as provided in Clean Air Act section 307(b) (42 U.S.C. 7607(b)).