Full opinion text
WILKEY, Circuit Judge: This case arises out of the conflict posed by two provisions of the Clean Air Act, as amended in 1977, that establish inconsistent guidelines for implementation of new federal preconstruction review requirements for major pollution-emitting facilities. The Environmental Protection Agency (EPA), in an effort to resolve the statutory inconsistency, resorted to rulemaking proceedings authorized elsewhere in the Clean Air Act to establish a new timetable and procedures for implementation of the federal requirements. These rules promulgated by EPA have been challenged on both procedural and substantive grounds by a number of environmental petitioners (Environmental Groups) and industry petitioners and intervenors (Industry Groups). We believe the EPA properly and faithfully discharged its responsibility to harmonize the statutory provisions so as to implement the congressional mandate that new federal preconstruction review requirements be instituted promptly but with minimum economic dislocation. Thus we sustain those regulations against the attack by parties here. I. BACKGROUND TO THE PRESENT LITIGATION A. Statutory Inconsistency In 1963 Congress enacted the Clean Air Act (the Act) in order “to protect and enhance the quality of the Nation’s air resources so as to promote the public health and welfare and the productive capacity of its population . . . .” The Act and its subsequent Amendments, most importantly the Clean Air Act Amendments of 1977 (the Amendments), prescribe an intricate set of relationships between federal and state agencies in order to implement that goal. At issue in the present case are provisions of the Act directed toward the prevention of significant deterioration (PSD) of air quality in relatively “clean air” areas. This program is founded on a set of federal standards concerning allowances for pollution emissions in various regions and federal supervision and approval of state plans designed to implement those standards. Until Congress passed the Clean Air Act Amendments in 1977, specific PSD requirements were provided not in the Clean Air Act itself but in EPA regulations promulgated pursuant to rulemaking authority conferred by the Act. The Amendments of 1977 significantly tightened these requirements and shifted the principal burden of administration of PSD programs from the federal to state governments, while retaining substantial federal supervisory authority. The present litigation concerns just one aspect of the Act’s program: the effective date for new substantive and procedural prerequisites to the issuance of permits for the construction of major pollution-emitting facilities, and the shift of principal responsibility for the enforcement of those prerequisites from the federal Government to the states. Two contested sections of the Clean Air Act, as amended, set forth these precon-struction requirements, as well as the procedures that govern their implementation in the interim period before state agencies have gained federal approval of environmental plans drawn up to implement all new PSD requirements. Section 165 of the Act sets forth new substantive requirements for government review of applications by private parties for permits to construct new pollution-emitting facilities. Before setting forth these new substantive requirements, however, the section provides in straightforward language that: (a) No major emitting facility on which construction is commenced after Au gust 7, 1977, may be constructed in any area to which . . . [Part C of Title I of the Act] applies unless— (1) a permit has been issued for such proposed facility in accordance with this part . (2) the proposed permit has been subject to a review in accordance with this section . (3) the owner or operator of such facility demonstrates . . . that emissions from construction or operation of such facility will not cause, or contribute to, air pollution ... in excess of [applicable standards] . (4) the proposed facility is subject to the best available control technology for each pollutant subject to regulation under this chapter . Other substantive preconditions to construction of a major emitting facility follow in § 165 subsections (a)(5) through (a)(8). Section 168 of the Act, on the other hand, provides generally for the regulation of pollution-emitting sources in the interim period before approval by the EPA of revised state environmental plans and identifies certain substantive provisions of the Act that are to be of immediate effect even prior to federal approval of revised state plans: (a) Until such time as an applicable [state] implementation plan is in effect for any area, which plan meets the requirements of this part to prevent significant deterioration of air quality with respect to any air pollutant, applicable regulations under this Act prior to enactment of this part shall remain in effect to prevent significant deterioration of air quality in any such area for any such pollutant except as otherwise provided in subsection (b). (b) If any regulation in effect prior to enactment of this part to prevent significant deterioration of air quality would be inconsistent with the requirements of section 162(a), section 163(b) or section 164(a) [of the Act], then such regulations shall be deemed amended so as to conform with such requirements. . For the purposes of this litigation, it is most important to note that § 165, which sets forth new preconstruction requirements for major pollution-emitting facilities, is absent from the list in § 168(b) of substantive provisions of the Act that are specifically identified as of immediate effect. Sections 165 and 168 of the Clean Air Act, as amended, therefore, are inconsistent in the following respect: Section 165 by its terms explicitly and without qualification prohibits the construction of any major pollution-emitting facility after 7 August 1977 unless the substantive requirements of that section have been met with regard to that facility. These requirements are far more stringent than those contained in federal regulations previously in effect and thus constitute a major environmental and regulatory hurdle to the construction of many industrial facilities. Section 168, on the other hand, fails to include § 165 among those sections of that part of the Act designated as of immediate effect, and thereby suggests that the less stringent precon-struction requirements contained in state plans pursuant to pre-existing federal regulations are to remain in effect until a state plan implementing all new PSD requirements of the Act has been federally approved. Standing alone, therefore, § 168 would have the practical effect of allowing permits to be issued for the construction of many projects for which permits would be barred by the rigorous environmental standards of § 165. As suggested by EPA, “Section 165(a) . . . would appear to prohibit, until its requirements were met, most of the post-enactment construction that section 168 would permit.” As will be discussed in Part II infra, Environmental and Industry Groups have argued at length that the conflict between the two statutory sections is more apparent than real. But the two Groups are at odds in proposing how the apparent inconsistency should be reconciled. Environmental Groups argue that § 168 sets no bar to immediate enforcement of the construction prohibitions of § 165, while Industry Groups argue that the language of § 165 is subject to the “interim period” provisions in § 168. In effect, therefore, each Group argues that one of the two sections should be given full effect so as to control the other, but the two Groups disagree as to which of the two sections should control. B. Administrative Interpretation and Action The EPA, as the federal agency charged with the unenviable task of administering the two sections, finds the statutory interpretations proposed by both Environmental and Industry Groups to be untenable. EPA concedes that the two provisions are inconsistent and argues that it had no choice but to proceed by means of administrative rule-making to implement, to the fullest extent possible, the intent of Congress in passing both sections. EPA further submits that the rules it has derived by these processes strike a reasonable and responsible balance between the two sections. EPA has not always been so firm in its resolve to pursue this “harmonization” position. On 4 October 1977, less than two months after the two sections were enacted on 7 August 1977, an assistant administrator of the EPA issued a memorandum expressing the understanding of EPA that § 165 had been inadvertently omitted from inclusion in the list of sections in § 168(b) to be afforded immediate effect, and that Congress intended that the preconstruction review requirements of § 165 be given immediate effect. The EPA assistant administrator thereafter instructed regional administrators to follow § 168(b) as if that subsection made explicit reference to § 165. This interpretation was endorsed by the principal sponsors of the Clean Air Act Amendments in both Houses, but it aroused a chorus of protest from a number of other Senators and Representatives. In a series of letters to EPA, these Congressmen argued that EPA had misconstrued the intent of Congress, and that immediate enforcement of the preconstruction review requirements of § 165 would wrongfully delay construction of a wide range of industrial projects that had not commenced construction prior to the effective date of § 165. The issue became further clouded when a provision designed to relieve the inconsistency between the two sections was expressly excluded from a list of technical amendments to the Act passed by both Houses and subsequently signed into law on 16 November 1977. The record shows that the issue of new preconstruction review requirements had become politically too sensitive to be resolved by means of technical amendment following passage of the Clean Air Act Amendments. As Senator Muskie prophetically remarked on the Senate floor on 1 November 1977, “[The] issue [of the proper construction of sections 165 and 168 of the Act] appears to be headed to the courts. » In light of this failure of Congress to clarify the meaning of its statutory instructions, and possibly also in response to political pressure, EPA reevaluated its interpretation of sections 165 and 168. On 27 October 1977 a memorandum was issued by EPA to regional administrators expressing the view that § 165 “should not [be] interpreted as immediately effective.” Subsequently, on 3 November 1977, EPA issued a final rule incorporating into EPA’s PSD regulations the “immediately effective changes” required by the 1977 Amendments, not including those of § 165. EPA also promulgated two proposed rules to become effective “no later than March 1, 1978.” One of these proposed rules provided guidance to the states on how to incorporate the new PSD requirements of the 1977 Amendments into state implementation plans, and the other incorporated the pre-construction review requirements of § 165 into federal PSD regulations as of 1 March 1978. EPA explained that “In light of the drafting inconsistencies between Sections 165(a) and 168, EPA feels that the most prudent course is to implement Section 165(a) as quickly as possible, but through the rulemaking process.” The EPA’s “prudent course” was designed to minimize air pollution during the period in which states were to develop their own implementations plans, but to exempt fully from the § 165 preconstruction requirements any project that had received a final PSD permit before 1 March 1978 and had commenced construction before 1 December 1978. Thus this regulation proposed to establish a “dual-date” system to determine, with regard to each proposed new facility, whether pre-existing precon-struction requirements or the new restrictions of § 165 would govern the issuance of the construction permit: pre-existing restrictions of § 165 would continue to apply to those facilities (1) for which a construction permit had been obtained by 1 March 1978 (with the exception discussed herein, of those facilities for which a construction permit would have been obtained but for an extension in the period of public comment), and (2) on which construction had actually commenced by 1 December 1978. Thus a facility that had received its construction permit by 1 March 1978 but had not commenced construction within nine months of that date would nevertheless be subject to the more stringent PSD requirements of § 165 and would be obliged to undergo a permit review in light of those requirements. The EPA cited as authority for these proposed rules § 301(a)(1) of the Clean Air Act, which provides that “The Administrator [of EPA] is authorized to prescribe such regulations as are necessary to carry out his functions under . . . [the Clean Air] Act.” C. Litigation These notices of proposed rulemaking set in motion the train of legal petitions that has led us to the present litigation and decision. First to pass through a courthouse door was a group called Citizens to Save Spencer County (Citizens), an environmental group based in Spencer County, Indiana. Citizens filed a petition in this court on 3 January 1978 objecting to a decision by EPA to issue a PSD permit authorizing the construction of a coal-burning electric generating plant in Spencer County. The group sought from this court an injunction to set aside the “rule” that EPA had relied upon in its decision not to apply the requirements of § 165(a) to the application of that plant for a construction permit. On 15 February 1978 EPA moved to dismiss the petition for review on jurisdictional grounds, arguing that petitioners were objecting only to “notices of proposed rulemaking” and not to actual “regulations promulgated” or “final action taken” by EPA and that therefore by the terms of the Clean Air Act review could not be had in this court. By an order of 28 March 1978, this court stated that it would rule on EPA’s motion to dismiss at the time we reviewed the merits of the petition, as we do in this decision. Shortly after the filing by Citizens of their complaint in this court, the Environmental Defense Fund (EDF) commenced a similar action against EPA in the District Court, alleging that EPA was unlawfully processing PSD applications of major pollution-emitting facilities submitted after 7 August 1977 without applying the precon-struction requirements of § 165(a). EPA again moved to dismiss the action on jurisdictional grounds, and the motion was granted by the District Court on 15 March 1978. Touching also on the merits of the issue, the trial court noted in dictum that “A reading of the 1977 [Clean Air Act] Amendments as a whole demonstrates that § 165 need not be made immediately effective. . . . [T]he Administrator had to exercise his discretion to interpret the Amendments as a whole and proceed to administer them.” EDF appealed, and by order of 27 April 1978 this court consolidated the suit brought by EDF, the action brought earlier to this court by Citizens, and actions then underway in this and other courts by other parties on questions related to the effective date of § 165. D. Continuing Administrative Action While legal action was working its way through the courts, however, EPA moved ahead with the rulemaking proceedings that it commenced with the several public notices of 3 November 1977. Though EPA had proposed in one of those notices that its regulations incorporating the Act’s new preconstruction review requirements were to be effective as of 1 March 1978, extensive public comment on the proposed regulations led EPA to extend the comment period. On 23 December 1977 EPA announced an extension of the period to 31 January 1978 and gave notice that “In light of this extension, EPA may not be able to meet the March 1 publication date” for the new rules. EPA further stated, however, that the “previously-announced ‘permit deadline’ of March 1, 1978, for determining whether sources will be subject to the new PSD rules” would not be changed. The volume of public comment caused EPA to back off slightly from this position as well, and on 8 March 1978 EPA published an additional notice stating that EPA’s precon-struction requirements in effect prior to enactment of the 1977 Amendments would continue to apply beyond 1 March 1978 to-facilities for which “by March 1, 1978, the normal comment period would have ended and EPA review of a permit would have been completed but for an extension of the public comment period in response to a valid request for additional comment time” beyond that date. Two major industrial projects were finally issued permits pursuant to pre-existing PSD requirements as a result of that special exemption, and separate legal petitions have been entered in this case in their regard, as will be discussed in Part III of this opinion. The delay in publication of EPA’s final regulations foreseen by EPA in December 1977 more than came to pass, for it was not until 19 June 1978 that EPA published its final rules seeking to harmonize sections 165 and 168. Those rules retained the “dual-date” schedule for implementation of the new preconstruction review requirements proposed by EPA in November, but changed the deadline for commencement of construction (after which a project would become subject to the PSD requirements of § 165) from 1 December 1978 to 19 March 1979. Thus the new construction deadline would coincide with the date that state implementation plans, in light of the eventual date of publication of EPA’s transition period regulations, would now be “due.” The preamble to the new rules also contained the most thorough defense of the EPA’s rulemaking process with regard to sections 165 and 168 that EPA to that date had made public. In defense of its new regulations, EPA explained that: In passing the 1977 Amendments, Congress left standing contradictory indications as to when it intended the new PSD requirements to be effective. Because of the contradiction between Section 165 and 168, EPA had no choice but to fashion a reasonable program for the transition from the old to the new requirements. . . . Three major considerations have shaped this transition program. One is that the rate of consumption of . [allowable increments in pollution in various regions] should be minimized. . . . The other two major considerations are that economic disruption should be minimized and that orderly administration of the new requirements should be maximized. . The transition program promulgated today is reasonable . . [for it] has equitably accommodated these competing considerations. . As acknowledged by EPA in its final rule, however, Industry and Environmental Groups have joined (from opposite sides) in opposing various aspects of EPA’s rule-making procedures and results. Industry petitioners have complained, both in these proceedings and in their public comments to EPA, that EPA was without legal justification in implementing any new preconstruction requirements prior to the time of approval of revised state plans, and that EPA’s actions will cause them serious and unwarranted economic harm by ensnarling numerous construction projects in the tight environmental net of § 165. Environmental petitioners, on the other hand, have argued that EPA’s proposed regulations are far too lax, and that EPA’s decision not to enforce § 165 as of 7 August 1977 has unlawfully allowed almost 100 major pollution-emitting facilities to escape the stringent preconstruction review requirements that Congress applied to them in § 165. The numerous contentions that have been raised concerning EPA’s rulemaking, and the rules themselves, are of baroque complexity. In reviewing these matters we recognize that the agency here is charged with the task of applying a new and highly complex regulatory program while being besieged on all sides by vocal private and public interest groups. The EPA argues that it sought to pursue a legally supportable “middle path” between inconsistent statutory provisions so as to harmonize to the maximum extent possible both the public policy concerns and conflicting directives of Congress. To a large extent, at least on all critical features, we think it did. We begin our review by considering in Part II of this opinion the threshold question of the proper construction of sections 165 and 168 of the Clean Air Act, as amended, and the proper role of an administrative agency in enforcing statutory provisions that, like those at issue here, are inconsistent on certain particulars but clearly aim to establish a new regulatory scheme. In Part III we will consider the source of authority for the rulemaking in which EPA engaged in order to harmonize the statutory scheme, and whether EPA followed the appropriate procedural route and complied with all necessary procedural requirements in devising a plan to carry out the contested mandate of Congress. Finally, in Part IV we will consider on substantive grounds whether EPA properly exercised its discretion in weighing various relevant factors in promulgating its rules concerning preconstruction review. II. THE FRUITLESS SEARCH FOR A HARMONIOUS CONSTRUCTION OF SECTIONS 165 AND 168 As is often the case in law, the present case turns on the question of the meaning and proper construction of a very few words. To recall, § 165 of the Clean Air Act provides explicitly that “No major emitting facility on which construction is commenced after ... [7 August 1977], may be constructed in any area to which . . . [Part C of Title I of the Act] applies unless — (1) a permit has been issued for such proposed facility in accordance with . . . [the standards of Part C]” . . . , Section 168, on the other hand, provides that “Until such time as an applicable [state] implementation plan is in effect for any area, which plan meets the [PSD] requirements of . [Part C] ., applicable regulations under this Act prior to ... [7 August 1977] shall remain in effect . . . [except for several specified sections, not including § 165].” The central question, therefore, is whether the preconstruction review requirements of § 165 are to take effect as of 7 August 1977, as provided in § 165, or only upon the approval by EPA of revised state implementation plans, which plans (in accord with the Act and present EPA regulations) need not even be submitted to EPA prior to 19 March 1979. The timing, cost, and perhaps in some cases the very feasibility of construction of numerous industrial facilities, and also the rate of deterioration of air quality in various regions, will be determined by the resolution of this question. Environmental Groups, on one side, and Industrial Groups, on the other, have devised numerous ingenious arguments to support their contention that, in fact, sections 165 and 168 do not mean what they say. First, each Group emphasizes the importance of the one (or the other) statutory section that aids the environmental or industrial interests that they represent, and each Group argues that the “plain language” of the two sections must be read so as to allow the mandate of the favored section to take precedence over that of the other. Each Group then buttresses this “plain language” argument by citing various subsections of the two principal sections, as well as other sections of the Act, to reinforce its particular view. Each Group plumbs the intricacies of legislative history for further substantiating evidence. And finally, each Group argues that only one (or the other) of the proposed statutory constructions would be consistent with the overall scheme of the Clean Air Act and with the intent of Congress with regard to the implementation role of states and the balance to be struck between economic growth and environmental protection. Judge Robinson, who takes the side of Industry Groups in his thoughtful dissent, structures his argument along similar lines and adopts many, though by no means all, of the points put forward by Industry Groups to support his dissenting view. Though we are impressed by the industry and ingenuity of counsel for both Groups, we are not convinced by their arguments. Because this case finally turns on the proper construction of sections 165 and 168, however, we must consider with some care each of the principal modes of interpretation of those sections that have been urged upon this court, and explain why we find them all to be unpersuasive. A. Relative Weight to be Afforded the Two Sections: The “Plain Language” Argument Environmental Groups argue that conclusive weight should be afforded to § 165, in part because § 168 is no more than a routine “savings clause” designed, to ensure that there is no general lapse in the applicability of pre-existing federal regulations while state environmental plans undergo revision to implement the new federal regulations of 1977. Industry Groups, however, point out that § 406(b) of the Clean Air Act Amendments is specifically identified as a “Saving Provision” and amply serves the function attributed by the Environmental Groups to § 168. Section 406(b) provides that “All rules, regulations, orders ... or other actions duly . . . taken by or pursuant to the Clean Air Act, as in effect immediately prior to the date of enactment of this Act . shall continue in full force and effect after the date of enactment of this Act until modified or rescinded in accordance with the [1977 Amendments].” Though § 406(b) begs the question of the time at which any particular provision of the Amendments actually “modifies” or “rescinds” particular sections of the Act and thus sheds no new light specifically on the meaning of sections 165 and 168, § 406(b) does ably fulfill the “savings clause” function attributed by Environmental Groups to § 168. Congress is not barred from enacting statutes that are redundant (or, for that matter, inconsistent), but there is no evidence that Congress enacted redundant provisions here. Section 168, by its heading, is specifically targeted to deal with the “[p]eriod before [state] plan approval.” Regardless of whether § 168 is a “mere” savings clause, it states a rule that is specific to PSD requirements in Part C of Title 1 of the Act and provides certain enumerated exceptions to that rule. We cannot, therefore, lightly dismiss § 168 because its function is in part duplicated by another, more general section of the Act, or because it bears a resemblance to statutory provisions that are frequently enacted to ensure the continuity of programs during a period of regulatory transition. Nor are we persuaded by the counter-assertion of the Industry Groups that the first sentence of § 165, which absolutely prohibits the construction of facilities for which a permit has not been issued in accord with the requirements of that section, is merely an “introductory” phrase and a “scrap of general language” to be dismissed in favor of the assertedly more compelling language of § 168. The first sentence of § 165 establishes the general prohibition to which the subsections of § 165(a)(1) through (a)(8) provide a broad, cumulative exception. These subsections set forth the new substantive and procedural requirements provided by the 1977 Amendments for pre-construction review of new facilities. Since these requirements are essentially nullified without the rule to which they make exception, the rule itself cannot be ignored or swept away. Citing the accepted canon of statutory construction that the more specific of two statutory provisions should govern, both Environmental and Industry Groups argue that their favored section is the more specific and, therefore, should control. Environmental Groups argue that § 165 is more specific than § 168 to the issue of precon-struction review, while Industry Groups argue that § 168 is more specific than § 165 to the issue of whether the old or new PSD requirements are to govern during the “interim” period before revised state plans are approved by EPA. Both Groups, of course, are correct. Both Groups, however, are in error in failing to concede the obvious point, damaging to both of their respective positions, that the two sections are of equal relevance to the question of which set of preconstruction review requirements are to govern in the interim period. Section 165 establishes a rule prohibiting, as of 7 August 1977, the construction of certain facilities and also sets forth its own exceptions to that general rule. Likewise, § 168 establishes a rule extending the applicability of pre-existing federal regulations through the interim period, beyond 7 August 1977, also with several exceptions. Unfortunately, the various rules and exceptions of these two sections simply do not mesh. Since the matters addressed in the two sections play an equally central role in this case, and since the two sections are equally specific in seeking to resolve those matters, no resolution of the inconsistency between the two sections can be derived by quibbling over which of the two sections is the more “specific.” Industry Groups also argue that § 168 should be afforded priority over § 165 because § 168 states in commanding terms that regulations in effect prior to the 1977 Amendments “shall remain in effect . [until a revised state plan is in effect].” By such language, it is argued, EPA is not merely authorized, but is required to extend the effective date of most PSD regulations (including those pertaining to preconstruction review) beyond 7 August 1977. Despite any special role that is customarily afforded the word “shall” in legal parlance, we find that the negative command of § 165 (“No major emitting facility . may be constructed . . . .”) is no less commanding than the positive command of § 168. Neither provision makes express allowance for the exercise of discretion by the Administrator in waiving or adding new exceptions to the rules set forth, and both provisions provide in clear and unequivocal terms that certain action is (or is not) to take place. It is indisputable that the one section allows what the other prohibits. Similarly, we must rebuff the contention of Industry Groups that the plain language of § 165 delimits its own effective date, in conformity with § 168, by confining its prohibition of construction to “any area to which [Part C of Title I of the Clean Air Act] applies . . . .” Industry Groups note that under § 107(d)(1) of the Act, “clean air” areas are to be identified by the states in accord with federal ambient air quality standards within 120 days after the enactment of the Amendments, and that therefore the prohibition of § 165 (which applies to those areas) could not possibly take effect as early as 7 August 1977. But we believe Environmental Groups are on firmer ground in pointing out that the phrase “any area to which . . . [Part C] applies” was intended solely to define the geographic scope of the section’s application and not to postpone its effective date. Section 165 does not suggest that the list of geographic areas to which its requirements apply must have been fully promulgated by the first date on which the precon-struction requirements in § 165(a) are to take effect. Furthermore, § 163(b)(1) of the Act, like § 165, applies by its terms to designated “clean air” areas, and yet Congress directed specifically in § 168(b) that § 163(b) was to take effect on 7 August 1977. Finally, if the contested phrase in § 165 were given the import urged by Industry Groups, that phrase would undermine entirely the more explicit prescription of the immediately preceding phrase, which provides that no nonconforming facility may be constructed after 7 August 1977 unless the requirements set forth are met. Though we are constrained by all logic to find inconsistent language in two different sections of the same Act, we are reluctant, unless so compelled, to find such incongruities within the same sentence of a single section of that Act. Debate has also focused on the proper interpretation of § 165(e). Subsections 165(e)(1) and (e)(2) provide that, as of 7 August 1978, an analysis of ambient air quality at the site of any proposed facility must have been gathered “over a period of one calendar year preceding the date of application for a [construction] permit . .” It follows from this, according to Environmental Groups, that all of the requirements of § 165 must take effect by 7 August 1977 (when air quality analysis must begin for a permit proposal to be made by 7 August 1978), or be in place at least by 7 August 1978, which is the date cited by § 165(e)(1), since there is no indication in § 165 that the various subsections of that section are to be effective on different dates. Industry Groups, however, argue that § 165(e) proves just the opposite: that Congress, to ensure that the preconstruction review program of § 165 would bring about no delay in the issuance of construction permits, gave early notice in § 165(e) that a lengthy period of air quality monitoring would be required before permits would be issued under § 165. Industry Groups argue that § 165(e) does not suggest that the requirements of other subsections of § 165 must take effect on 7 August 1977, or even before 7 August 1978. They also suggest that subsection (e) demonstrates generally that the requirements of § 165 may be implemented in phases, rather than simultaneously on the date of enactment of the 1977 Amendments — an argument buttressed by time schedules provided in other sections of the Act. Unfortunately, these various arguments do little to lift the fog of ambiguity surrounding the effective date of § 165. Even if Environmental Groups are correct in their interpretation of § 165(e), their argument does nothing to relieve the inconsistency between sections 165 and 168, which is at the center of the present controversy. Likewise, the argument of Industry Groups is seriously undermined by the explicit language of subsection § 165(a), which sets forth both its own effective date and (in § 165(a)(2)) the requirement of air quality review for which further amplification is provided in § 165(e)(1) and (e)(2). We see no reason why the effective date in § 165(e) should control the effective date provided in § 165(a). Thus the two contending Groups have failed in yet another place to move the harmonization of sections 165 and 168 past their facial contradiction. In summary, the “plain language” arguments concerning sections 165 and 168 fail to convince us that one or the other of the two sections should control. Instead, we can only conclude that the “plain language” of each of the sections 165 and 168 means what it says and that the two sections are inconsistent. B. Other Sections of the Act Cited in Support of “Plain Language” Contentions Environmental and Industry Groups have also engaged in an analytical tour de force of other sections of the Clean Air Act and its Amendments to buttress their “plain language” contentions. Though we cannot respond to each point raised, we will consider those that seem most credible. To defeat the potentially corrosive effect of § 168 on the environmental protections afforded by § 165, Environmental Groups have argued that the effective date contained in § 165 makes that section self-executing and therefore immune from the conflicting effective date prescription of § 168. These Groups argue that there was thus no need to list § 165 among the various sections cited in § 168(b) that are to be afforded immediate effect. The counterargument is raised, however, that § 162(a), which is included among the sections cited in § 168(b), also provides its own effective date. It is asked, therefore, why Congress in § 168 would specifically cite one self-executing section as immediately effective but not another, if it intended for both to be immediately effective? The elaborate attempts of Environmental Groups to distinguish § 165 from § 162(a) in this regard are scarcely comprehensible, let alone credible, and we need not attempt to review their arguments here. But we are also not persuaded by the argument of Industry Groups that because Congress in its wisdom decided to cite § 162(a) in § 168(b), it intended by omitting § 165 from § 168(b) to negate entirely the self-executing language of § 165. If Congress intended to negate the effective-date provision of § 165, why would it have included that effective-date provision at all in § 165? Once again, like the search of Ponce de Leon for the fountain of youth, the search for perfect logic fails, and we recognize again an imperfect statute that gives inconsistent instructions to its administering agency. The Groups have also fallen hungrily upon various provisions of § 406 of the Amendments to support their contentions concerning sections 165 and 168. Subsection 406(d)(1), for example, provides that “Except as otherwise expressly provided, the amendments made by this Act shall be effective on date of enactment.” Environmental Groups cite the second portion of this sentence as confirmation that the requirements of § 165 are to be effective immediately. Industry Groups, on the other hand, cite the first phrase of the sentence and argue that § 168 is a section that “otherwise expressly providers] . . . .” We believe, however, that § 406(d)(1) contributes essentially nothing to the present debate, for the section fails to specify which of the various other sections of the Act should be construed so as to “expressly pro-vid[e]” for a later effective date and which do not, and we are thus thrown back on the internal construction of those sections. Similarly, § 406(c) provides that “Nothing in this Act . . . shall in any way affect any requirement of an approved [state] implementation plan in effect . before ... [7 August 1977] until modified or rescinded in accordance with the Clean Air Act as amended by this Act.” Though this subsection plays a useful function in ensuring that programs and regulations in effect before enactment of the Amendments are to continue until changed, it in no way indicates which regulations are to continue and which are deemed, by the Amendments, to be changed. Yet this very question is central to the present case. Thus § 406(c) leaves our analysis where it began. The contending Groups also find support in § 110 of the Act, which provides for the promulgation of state implementation plans in accord with federal air quality standards and for the review of such plans by EPA. Predictably, Industry Groups cite § 110(a)(1), which allows each state nine months to incorporate into its implementation plan certain new federal air quality standards promulgated by EPA, and § 110(a)(2)(B) and (D), which require the EPA Administrator to ensure that a state plan complies with federal standards for preconstruction review of new pollution-emitting sources. Industry Groups argue that it follows from these sections that implementation of the requirements of § 165 must await the promulgation and approval of new state plans. Environmental Groups, on the other hand, note that § 110 nowhere provides that federal requirements for preconstruction review may not take effect before the expiration of the nine-month period allowed a state to revise its plan. In support of this contention, Environmental Groups cite § 110(c)(1), which instructs the Administrator at any time to “prepare and publish proposed regulations setting forth an implementation plan . for a State if — . . . (B) the plan . is determined by the Administrator not to be in accordance with the requirements of [§ 110].” This authority, they argue, allows the Administrator at any time to suspend a state plan that is not in accord with new statutory requirements and to promulgate new regulations that are to be directly and immediately applicable in such state. This procedure was followed in implementing the new-' PSD requirements made effective as of 7 August 1977, in accord with § 168(b) and arguably could also have been followed in the case of pre-construction requirements of § 165. Environmental Groups are on even firmer ground in finding “interim period” authority for the EPA to enforce new, immediately-effective federal preconstruction requirements in § 167 of the Act, which provides that the “[EPA] Administrator shall . take such measures, including issuance of any order, or seeking injunctive relief, as necessary to prevent the construction of a major emitting facility which does not conform to the requirements of [§§ 160-169A of the Act].” Section 167, however, nowhere specifies which requirements of sections 160—169A are to be held up as the conforming standards in any particular period: those of § 165 or of § 168? There is merit in the interpretations by both sides of sections 110 and 167, but the arguments all tend to be circular in their logical effect and provide no more than the most circumstantial support for the opposing contentions concerning sections 165 and 168. Sections 110 and 167 provide ample authority for state and federal action to implement and enforce new regulations, but neither section specifies which level of government is to take the lead in implementing particular other sections, or on what date those other sections are to take effect. Section 110 merely sets forth steps to be taken by state and federal agencies in the implementation of new federal air quality standards promulgated by regulation, but the section does not prohibit (and in subsection (c) may even facilitate) the direct amendment of federal air quality standards, and thereby also of state implementation plans, by federal regulation. Similarly, § 167 provides for new federal enforcement authority but points to both 165 and 168 as sections to be enforced. Sections 110 and 167, therefore, are vehicles on which all the parties can ride, but the journey takes them (and also this court) no closer to a resolution of the present question. C. Legislative History of Sections 165 and 168 An examination of legislative history adds strength to our conclusion that Congress wrote inconsistent instructions into sections 165 and 168 and that the two sections cannot be resolved by favoring one of them above the other. The present controversy can be traced directly back to the fact that sections 165 and 168 were conceived in separate Houses and their provisions never reconciled when the Act as a whole was given birth in Conference. The Act’s eventual § 165 originated in a Senate bill, S. 252. Section 6 of that bill unmistakably aimed to give immediate effect to the preconstruction review requirements eventually set forth in § 165, and there was no provision parallel to the present Act’s § 168, arguably postponing the effective date of those requirements until approval of state implementation plans. As conceded by Industry Groups, S. 252 “would have made all the new PSD requirements immediately applicable.” The House bill, H.R. 6161, however, was silent on the question of the effective date for the preconstruction requirements set forth in that bill. Instead, in a section that is the direct precursor to the present Act’s § 168, the bill provided generally that pre-existing PSD regulations were to remain in effect until revised state implementation plans were approved. In great haste, at the close of the first session of the 95th Congress, the Conference Committee accepted key provisions of both bills. As reported later by Senator Muskie, who was a principal sponsor of the Clean Air Act Amendments and a member of the Conference Committee, the Committee worked very fast and without the usual attention to coordinating all provisions fully. The pace of events also was swift thereafter. On 3 August 1977 the bill was reported out of conference, on 4 August it was passed by both Houses, and on 7 August it was signed into law. It may never be known whether the members of the Conference Committee, while at conference, were aware of the inconsistencies they were writing into law, and what they would (or could) have done if they had known. But the conferees, and pther Members of Congress, certainly became aware of the issue shortly thereafter. On 4 October 1977, EPA issued a memorandum pointing out the inconsistencies in the language of the two sections and expressing the view that the inconsistency was “inadvertent” and would shortly be corrected by technical amendment. On 1 November, in introducing a bill of technical amendments to the Act, Congressman Rogers (a principal sponsor of the earlier Amendments and a member of the Conference Committee) conceded that there was an “apparent conflict between section 165 and 168” and that “considerable controversy [had] developed” on whether the conflict should be resolved by technical amendment. Though Rogers stated that he believed it to be the “intent of the conferees” that the requirements of § 165 be effective as of 7 August 1977, he urged that because of the risk of “significant controversy” no attempt be made to clarify the matter by means of technical amendment. Likewise, Senator Muskie, in introducing the bill of technical amendments before the Senate, stated that EPA’s memorandum of 4 October contained the “correct interpretation” of the two sections, but he implied that because of controversy that had arisen no technical amendment would address the issue. Though these post hoc interpretations by the principal sponsors of the 1977 Amendments are entitled to some consideration, the statements themselves — and also the barrage of letters of protest directed to EPA by other Congressmen — reflect the fact that many divergent views were held in Congress on the proper interpretation of the two sections. All post hoc interpretations by the sponsors of the 1977 Amendments and their opponents, therefore, truly cancel each other out on the matter of “congressional intent.” We are left only to surmise about the cause of the drafting inconsistency. It may have been merely “inadvertent,” as first noted by EPA. Or, the conferees may have found that it was politically necessary to accept both sections 165 and 168 in order to speed the Clean Air Act Amendments back to the House and Senate for passage before the end of the session. The circumstances of the passage through Congress of the Clean Air Act Amendments, and the statements of various Congressmen after enactment, indicate convincingly that Congress did not clearly resolve the issue of the effective date for the new preconstruction review requirements; this history provides no justification for implementation of only one of the two statutory sections to the exclusion of the other. D. The Overall Scheme of the Clean Air Act and the Amendments of 1977 As a “last resort” line of argument, Environmental and Industry Groups contend that EPA’s final resolution of the conflict between sections 165 and 168 is inconsistent with the policy concerns and overall intent of Congress in enacting the Clean Air Act and its Amendments. Industry Groups argue that only the implementation scheme prescribed in § 168 is consistent with the congressional goal of enhancing the role of states in implementing new federal ambient air quality standards. Not surprisingly, these Groups find the clearest support for their position in statements issued by committees of the House, which sponsored the predecessor version to § 168 and which was apparently more hostile than the Senate to federal enforcement .of new PSD requirements. Even the Senate committee responsible for passing on the Amendments supported the general shift in emphasis from federal to state enforcement of PSD requirements. That general shift of responsibility, however, is not at issue in this case, but only the time of applicability and level of government responsible for implementation of the early stages of just one aspect of the PSD program: that pertaining to precon-struction review. Furthermore, Congress clearly prescribed a somewhat larger role for the federal government in the formulation of PSD requirements than in some other aspects of the Act, and even under the scheme prescribed in § 168 the EPA would be obliged to administer the PSD program, including requirements for pre-construction review, under pre-existing federal regulations until state plans are revised to incorporate all new PSD requirements. Also, Congress in § 168(b) of the Clean Air Act demonstrated its willingness to amend state plans directly in certain respects, and thus to provide for only ultimate state administrative authority. If Congress followed this route in § 168(b), it may also have chosen to do so in § 165. It has also been argued that literal application of § 165, and even the administrative scheme devised by EPA, runs counter to the intent of Congress that implementation of new PSD requirements not disrupt industrial construction by suspending the process of granting permits for construction of new industrial facilities. This argument, however, is undermined by the fact that both the House and Senate committees responsible for the Clean Air Act Amendments were concerned about the possibility of economic disruption from implementation of new PSD requirements and took measures to reduce such disruption, and thus presumably were prepared to assume such disruption as was inherent in § 165. In consolidating various portions of House and Senate bills, the conferees rejected a number of key House provisions designed to prevent a “moratorium on growth” and accepted a number of comparable provisions proposed by the Senate. It cannot be said, therefore, that the Conference “leaned” either toward the Senate or House proposals on the matter of economic disruption, or that the EPA in pursuing a middle course between sections 165 and 168, originating in provisions passed by the two Houses, in any sense violated the intent of Congress. Furthermore, Congress demonstrated by enacting the Clean Air Act itself, and again in enacting the Act’s strengthening Amendments in 1977, that it considered the task of protecting the quality of the nation’s air to be of key importance. The intent of Congress thus compels a balancing of the need for air quality protection against any economic loss or delay that may result from enforcement of the Amendments’ strengthened environmental standards — a balancing which Congress did not clearly effect. Thus an examination of the intent of Congress in enacting the Act and its Amendments lends little strength to the contentions of either of the opposing Groups. Instead, the various policy objectives melded by Congress into the Act provide a standard by which to judge the reasonableness of the administrative actions taken by EPA. As we discuss later, EPA was on solid ground in resorting to rule-making to balance the various goals of Congress and the statutory instructions expressed in sections 165 and 168 and elsewhere in the Act; EPA would have been subject to even sharper legal attack if it had opted for one-sided enforcement of only § 165 or § 168, or chosen to abandon precon-struction review requirements altogether, for reason of statutory conflict concerning principally the time and authority by which those requirements were to take effect. E. Applicable Rules of Statutory Construction As we have seen, petitioners and intervenors have resorted to numerous constructional devices to prove that either § 165 or § 168 of the Act should control, and that the two provisions should not both be construed to mean what they say. It is a cardinal rule of statutory construction, however, that ambiguities should not be found where statutes are clear on their face. In the present case, each of the two sections of the statute at issue is clear, and it is equally clear that their provisions do not coincide. The only arguable “ambiguity” in the two sections is the lack of consistency between the two. There is thus no plain direction as to which plain provision shall prevail. Courts have frequently pointed out that statutory provisions, whenever possible, should be construed so as to be consistent with each other. But it is apparent, in all honesty and candor, that such harmonious construction is not always possible. It is not the task of a reviewing court or administering agency in the case of statutory inconsistency to distort the words of the contested provisions so as to derive a result consistent in logic but exotic in meaning, extreme in effect, and never contemplated or imagined by the legislature or within the range of the legislature’s intention. Statutory conflict gives no license to a court or agency to indulge in unrestrained and fanciful flights of constructional imagination to arrive at artful but artificially consistent interpretations. In the present case, therefore, we are guided by the rule that the maximum possible effect should be afforded to all statutory provisions, and, whenever possible, none of those provisions rendered null or void. We hold that this principle applies with equal strength when statutory provisions are in certain respects inconsistent; if the inconsistent provisions point generally in a common direction —as here, sections 165 and 168 of the Act both point-toward eventual implementation of new preconstruction review requirements for major pollution-emitting facilities — it is the task of an agency with the requisite authority to pursue a middle course that vitiates neither provision but implements to the fullest extent possible the directives of each, and it is the task of a reviewing court to ensure that the agency has effected an appropriate harmonization of the conflicting provisions while remaining within the bounds of that agency’s statutory authority. In devising such a course, it is appropriate for the agency, as courts have so often done, to look for guidance to the statute as a whole and to consider the underlying goals and purposes of the legislature in enacting the statute, while avoiding unnecessary hardship or surprise to affected parties and remaining within the general statutory bounds prescribed. Only by this approach can legislative purposes and statutory instructions be given the greatest possible practical effect. It is obvious, but bears repeating, that in legislative (as in judicial) affairs, allowance must be made for human error and inadvertence. In coping with such inadvertence and error, a reviewing court should eschew an overly technical view that would invalidate all facial instructions of the law that may be inconsistent in certain respects when there is an ascertainable, functionally viable, reasonable legislative purpose lying beneath which would be fundamentally disrupted or violated by any judicial command to return, for reason of the inconsistency, to any status quo ante. In the present case, Congress in great haste at the close of a legislative session drew upon two bills originating in different Houses and containing provisions that, when combined, were inconsistent in respects never reconciled in conference. The one bill proposed that certain regulations take effect immediately; the other bill proposed that those same regulations take effect at a later date, upon incorporation of those regulations into state implementation plans. But both bills — and the provisions of both bills adopted by the conferees — provided that the regulations should eventually take effect. To require that the regulations not take effect at all until the inconsistent provisions for their implementation have been reconciled by a later session of Congress would defeat the intent of both Houses and could have the practical effect of eviscerating a substantial part of a legislative plan, the substantive terms of which were not finally the subject of legislative dispute. Such a result would truly “topple the temple” to correct the lean of a single pillar; for clearly, it was of primary concern to Congress in the present case that the new preconstruction review requirements enacted in 1977 take effect, and only secondarily on what precise date and under which administering authority (i. e., the states or federal government) they initially should do so. Likewise, to give effect to just one of the contested provisions would give full rein to just one of perhaps many competing interests that in the final legislative enactment were given even weight, and would work a serious injustice to some of those interests. On the other hand, to give unlimited license to an agency to devise whatever course it pleased in the case of statutory breach or inconsistency would overreach the bounds of delegation and confer on that agency inordinate power and authority. Under the circumstances of the present case, it was the greater wisdom for the agency to devise a middle course between inconsistent statutes so as to give maximum possible effect to both. Not every administrative agency will have authority to pursue such a course; but where such authority is present, and where the agency in a reasonable and responsible manner exercises the discretion that by inadvertence or legislative impasse it has been afforded, and properly takes into account the various concerns and determinations that lay behind the legislative enactment, it is the duty of the reviewing court to sustain the agency’s result. It remains for this court, therefore, to determine whether the administering agency in the present case had authority to devise its “middle path,” whether it pursued the appropriate procedural route in so doing, and whether its results are substantively reasonable. III. THE SOURCE OF AUTHORITY AND PROCEDURES APPROPRIATE FOR PROMULGATION OF EPA’S “HARMONIZATION” REGULATIONS The interrelated questions of the source of authority and procedures to be followed by EPA in promulgating its “harmonization” rules lead to several subquestions. We will consider first whether EPA had the requisite authority to adopt the present rules, and in light of that authority and the matters contained in the rules what form of rulemaking procedure was appropriate to pursue. We will then consider whether EPA in this case properly followed the steps required to engage in that form of rulemak-ing. Specifically, we will consider whether EPA was justified in issuing final rules with allegedly “retroactive effects” and in applying pre-existing PSD regulations to two major facilities for which EPA extended the 1 March 1978 permit-issuance deadline to accommodate an extension of the public comment period. A. The Source of Authority for EPA’s Rulemaking Although EPA says nothing of it in its brief, the Agency’s notices of proposed and final rulemaking issued on 3 November 1977 cited section 301 of the Clean Air Act as one of the statutory provisions on which it relied for rulemaking authority. Section 30.1(a)(1) provides, in pertinent part, that “[t]he Administrator is authorized to prescribe such regulations as are necessary to carry out his functions under . [the Clean Air Act].” Such a provision does not provide the Administrator with carte blanche authority to promulgate any rules, on any matter relating to the Clean Air Act, in any manner that the Administrator wishes. But in light of the dilemma posed by the conflicting provisions of sections 165 and 168, and tracking the words of § 301(a)(1), it was clearly “necessary” for the Administrator in order to “carry out his functions” in administering the new precon-struction review requirements of the 1977 Amendments to employ the rulemaking authority provided in § 301(a)(1) to resolve the conflict between sections 165 and 168. Without § 301 rulemaking, EPA would have been compelled to pursue one of several equally undesirable and untenable paths of action: to enforce only section 165, in violation of section 168; to enforce only section 168, in violation of section 165; to enforce neither section, thus