pliance schedules appear in the emergence of § 118 from the House bill and Senate amendment from which it was derived.

49

The House bill provided that federal installations "shall comply with applicable Federal, State, interstate, and local emission standards." The House Report stated that this "legislation directs Federal agencies in the executive, legislative, and judicial branches to comply with applicable Federal, State, interstate, and local emission standards." 50 The Senate amendment provided that federal agencies "shall provide leadership in carrying out the policy and purposes of this Act and shall comply with the requirements of this Act in the same manner as any person The Senate Report stated that this provision "requires that Federal facilities meet the emission standards necessary to achieve ambient air quality standards as well as those established in other sections of Title I." 52

99 51

Thus while the House bill spoke of "emission standards," the Senate amendment, like § 118 as enacted, spoke of "requirements." In accommodating the different language in the two bills and formulating what is now § 118, the Conference Committee simply combined the House and Senate provisions. If, as Kentucky ar

49 H. R. 17255, 91st Cong., 2d Sess., § 10 (§ 111) (1970), 2 Leg. Hist. 938 (emphasis added).

50 H. R. Rep. No. 91-1146, supra, n. 11, at 4, 2 Leg. Hist. 894 (emphasis added).

51 S. 4358, 91st Cong., 2d Sess., §7 (§ 118 (a)) (1970), 1 Leg. Hist. 573 (emphasis added).

52 S. Rep. No. 91-1196, supra, n. 12, at 23, 1 Leg. Hist. 423 (emphasis added). Throughout the Senate amendment and in the Report the terms "requirements," "emission requirements," and "emission standards" were used interchangeably. Compare proposed § 118 (a) ("requirements") and the Report ("emission standards") with proposed § 111 (a) (2) (D) ("emission requirements"), 1 Leg. Hist. 545.

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gues, the Conference Committee in taking the Senate language of "requirements" meant thereby to subject federal facilities to enforcement measures obviously not embraced in the language of the House bill, it is remarkable that it made no reference to its having reconciled this difference in favor of extending state regulation over federal installations. Given the interchangeable use of "emission standards" and "emission requirements" in the Senate amendment, see n. 52, supra, the predominance of the language of the Senate version in § 118 as enacted," and the absence of any mention of disagreement between the two bills, it is more probable that the Conference Committee intended only that federal installations comply with emission standards and compliance schedules than that its intention was to empower a State to require federal installations to comply with every measure in its implementation plan. See Alabama v. Seeber, 502 F. 2d, at 1247.

53

The impression that Congress intended only that federal agencies comply with emission limitations and standards is strengthened by the Conference Report, which stated in full:

"The House bill and the Senate amendment declared that Federal departments and agencies should comply with applicable standards of air quality and emissions.

"The conference substitute modifies the House

53 For example, only the Senate amendment equated the federal installation's duty to comply with "requirements" to any person's duty, a feature of § 118 as enacted. Similarly, only the Senate amendment, in § 118 (b) (1 Leg. Hist. 574), provided that a State might sue in federal court to enforce the provisions of § 118 (a). H. R. Conf. Rep. No. 91-1783, supra, at 55, 1 Leg. Hist. 205. That provision was incorporated in the Amendments in § 304 (a), through the definition of "person" retained in § 302 (e), as added, 77 Stat. 400, 42 U. S. C. § 1857h (e).

provision to require that the President rather than the Administrator be responsible for assuring compliance by Federal agencies." 54

This examination of § 118 and the central phrase "requirements respecting control or abatement of air pollution," discloses a regime of divided responsibility for the mobilization of federal installations in the effort to abate air pollution. Kentucky agrees but persists in its contention that existing federal sources have been subjected to state regulation by differing on where that division places authority to enforce compliance by existing federal facilities-" sources with respect to which state implementation plans establish the criteria for enforcement.'" 55 For such existing-sources, Kentucky maintains, the States are granted primary enforcement authority while "the responsibility and authority for

54 H. R. Conf. Rep. 91-1783, supra, at 48, 1 Leg. Hist. 198. We are not persuaded by the argument that reference to the President's replacing the EPA Administrator as the one "responsible for assuring compliance by Federal agencies" only implicates the President's power to "exempt any emission source of any department, agency, or instrumentality in the executive branch from compliance with . . . a requirement." 42 U. S. C. § 1857f. Both the House and Senate Reports referred quite plainly to the power to exempt and to make exceptions when referring to the President's (or the Administrator's) power to act in the paramount interest of the United States on a case-by-case basis. S. Rep. No. 91-1196, supra, at 23, 1 Leg. Hist. 423; H. R. Rep. No. 91-1146, supra, at 15, 2 Leg. Hist. 905. Thus, reference in the Conference Report to the President's authority to assure compliance merely expresses what is implied by the very grant of authority to exempt some federal sources the authority, as to those installations subject to Presidential control, to enforce in the first instance the new regimen of federal compliance with primarily state formulated and administered implementation plans rests in the Federal Government, not in the States.

55 Brief for Petitioner 33, quoting Alabama v. Seeber, 502 F. 2d, at 1244.

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56

enforcement is granted to EPA in those instances (i. e., new sources and hazardous pollutants) where EPA establishes the criteria.'" 5 Perhaps we could agree if the issue were not whether there is a clear and unambiguous congressional authorization for the regulatory authority petitioner seeks, for as the Fifth Circuit has said, such a "scheme is a reasonable one." Alabama v. Seeber, supra, at 1244. But that is the issue, and the implications Kentucky draws from its evaluation of the manner in which the Congress divided responsibility for regulation of new sources and of hazardous air pollutants do not persuade us.

In drawing on the manner in which the Clean Air Act has divided the authority to regulate new sources of air pollutants" and the emission of hazardous air pollutants 58 in comparison with existing air pollutant sources, Kentucky makes two separate though related arguments. The first is that when Congress wanted to exempt federal facilities from compliance with a state requirement, it did so by express exclusionary language. Thus § 111 (c) (1) authorizes the Administrator to delegate to a State "any authority he has under this Act to implement and enforce" new-source standards of performance-with which new sources owned or operated by the United States must comply (§ 111 (b)(4))—"except with respect to new sources owned or operated by the United States." 42 U. S. C. § 1857c-6 (c)(1). Section 114 (b)(1) of the Clean Air Act, as added, 84 Stat. 1688, is to the same

56 Ibid.

57 Regulation of "new sources" of air pollutants, by EPA-promulgated "standards of performance" (see infra, n. 59), is provided for in § 111 of the Clean Air Act, as added, 84 Stat. 1683, 42 U. S. C. 18570-6.

58 Regulation of "hazardous air pollutants" is provided for in § 112 of the Clean Air Act, as added, 84 Stat. 1685, 42 U. S. C. § 1857c-7.

effect respecting inspections, monitoring, and entry of an emission source. 42 U. S. C. § 1857c-9 (b)(1). Similarly, § 112 (d) (1) authorizes the Administrator, upon finding that a State's plan to enforce emission standards for hazardous pollutants is adequate to the task, to delegate to that State "any authority he has under this Act to implement and enforce such standards (except with respect to stationary sources owned or operated by the United States)." 42 U. S. C. § 1857c-7 (d)(1). The argument that these specific exemptions of federal facilities from state enforcement and implementation methods are necessary only because § 118 has, as a general matter, subjected federal installations to all state requirements fails on several counts. First, as we have demonstrated, by itself § 118 does not have the effect petitioner claims. Second, the relevant portions of §§ 111, 112, and 114 assume that the Administrator possesses the authority to enforce and implement the respective requirements against sources owned or operated by the United States. See §§ 111 (c) (2), 112 (d) (2), and 114 (b)(2). Third, just as in providing for Presidential exemptions in § 118 Congress separated the requirements of §§ 111 and 112 from other requirements, Congress naturally treated the submission of federal installations to state regulation under §§ 111, 112, and 114 separately from general provisions for meeting ambient air quality standards under § 110 implementation plans devised by the States and approved by the EPA. A State must promulgate an implementation plan. § 110 (a). The delegation provisions of §§ 111, 112, and 114, on the other hand, are permissive, providing that "[e]ach State may develop and submit to the Administrator a procedure" to carry out the section. (Emphasis added.)

Kentucky's second argument is that the manner in which Congress differentiated treatment of new sources