OPINION
[p300] The Environmental Protection Agency appeals from a judgment of the United States District Court for the Eastern District of Missouri which enjoined the EPA from instituting an enforcement proceeding under the Clean Air Act, 42 U.S.C. § 7401 Et seq, against the Union Electric Company or its officers while that Company is actively and in good faith pursuing a revision or variance of the sulfur dioxide (SO 2 regulations of the Missouri Implementation Plan in the administrative agencies and/or courts of the State of Missouri. We reverse the judgment of the District Court and direct that the complaint of Union Electric be dismissed.
Union Electric serves the metropolitan St. Louis area and parts of Illinois and Iowa. Its three coal-fired generating plants, Labadie, Meramec and Sioux, are subject to the SO 2 and opacity restrictions in the Missouri Implementation Plan as approved by the EPA on May 31, 1972.
Union Electric did not seek review of the approved Missouri Implementation Plan within thirty days as it was entitled to do under § 307(b)(1) of the Act, 42 U.S.C. § 1857h-5(b)(1). It did, however, obtain one-year variances from the appropriate state and county agencies which eased the emission limitations affecting its three plants. The variances for two of the three plants had expired and Union Electric was applying for extensions when, on May 31, 1974, the Administrator of the EPA notified the Company that the SO 2 emissions from its plants violated the emission limitations contained in the Missouri Implementation Plan, and advised it of the probability that enforcement proceedings would soon be instituted.
On August 18, 1974, Union Electric sought review in this Court, contending that the SO 2 emission regulations contained in the Missouri Implementation Plan were economically and technologically infeasible and that its emissions were not interfering with attainment or maintenance of the National Ambient Air Quality Standards (NAAQS). We held that the claims of infeasibility did not afford a basis for review under § 307(b)(1) of the Act, 42 U.S.C. § 1857h-5(b) (1), and dismissed Union Electric's petition for lack of jurisdiction. Union Electric Co. v. Environmental Pro. Agcy., 515 F.2d 206 (8th Cir. 1975).
Our decision was affirmed by the Supreme Court on October 6, 1975. Union Electric Co. v. EPA, 427 U.S. 246, 96 S.C.t. 2518, 49 L. Ed. 2d 474 (1976). In that opinion, the Supreme Court stated:
Claims of economic or technological infeasibility may not be considered by the Administrator in evaluating a state requirement that primary ambient air quality standards be met in the mandatory three years. * * * (T)he States may submit implementation plans more stringent than federal law requires and * * * the Administrator must approve such plans if they meet the minimum requirements of § 110(a)(2), * * * (thus) the language of § 110(a)(2)(B) provides no basis for the Administrator ever to reject a state implementation plan on the ground that it is economically or technologically infeasible. Accordingly, a court [p301] of appeals reviewing an approved plan under § 307(b)(1) cannot set it aside on those grounds, no matter when they are raised.
Our conclusion is bolstered by recognition that the Amendments do allow claims of technological and economic infeasibility to be raised in situations where consideration of such claims will not substantially interfere with the primary congressional purpose of prompt attainment of the national air quality standards. Thus, we do not hold that claims of infeasibility are never of relevance in the formulation of an implementation plan or that sources unable to comply with emission limitations must inevitably be shut down.