Appalachian Power Co. v. Environmental Protection Agency , 249 F.3d 1032 ( 2001 )


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  •                   United States Court of Appeals
    FOR THE DISTRICT OF COLUMBIA CIRCUIT
    Argued December 15, 2000     Decided May 15, 2001
    No. 99-1200
    Appalachian Power Company, et al.,
    Petitioners
    v.
    Environmental Protection Agency,
    Respondent
    Commonwealth of Pennsylvania,
    Department of Environmental Protection, et al.,
    Intervenors
    Consolidated with 99-1205,
    99-1206, 99-1246, 99-1266, 99-1285, 99-1289, 99-1291,
    99-1292, 99-1293, 99-1295, 99-1299, 99-1300, 99-1301,
    99-1303, 99-1304, 99-1306, 99-1307, 00-1013, 00-1021,
    00-1022, 00-1024, 00-1038, 00-1042, 00-1050, 00-1071,
    00-1074, 00-1077, 00-1083, 00-1087, 00-1088, 00-1096,
    00-1097, 00-1098, 00-1099, 00-1102, 00-1103, 00-1105,
    00-1106, 00-1107, 00-1108, 00-1109, 00-1110, 00-1113,
    00-1114, 00-1119, 00-1122, 00-1123, 00-1125, 00-1128
    _______
    On Petitions for Review of Orders of the
    Environmental Protection Agency
    Norman W. Fichthorn, James C. Gulick, Special Deputy
    Attorney General, State of North Carolina, Lisa M. Jaeger,
    Brian J. Renaud and Anthony C. Sullivan argued the issues
    for petitioners.  Counsel appearing with them on the briefs
    were Andrea Bear Field, Mel S. Schulze, James D. Elliott,
    Allison D. Wood, Grant Crandall, Eugene M. Trisko, Jeff F.
    Cherry, Kathy G. Beckett, Scott D. Goldman, David M.
    Flannery, Jeffrey J. Lettrich, Gale R. Lea, Charles S. Carter,
    Deborah Ann Hotel, Theodore L. Garrett, Michael D. Hock-
    ley, Terry W. Schackmann, Robert M. Sussman, Claudia M.
    O'Brien, Scott H. Segal, Charles E. Dunn, Rhonda Lee Ross,
    Robert L. Brubaker, Andrew S. Bergman, Alan H. McCon-
    nell, Kurt E. Blase, J. Jeffrey McNealey, Michael F. Easley,
    Attorney General, Grayson G. Kelley, Senior Deputy Attor-
    ney General, Thomas J. Ziko and J. Allen Jernigan, Special
    Deputy Attorneys General, Marc D. Bernstein, Assistant
    Attorney General, State of North Carolina, James M. Hauck,
    Gordon Alphonso, Stuart Pierson, Geoffrey K. Barnes, Scott
    T. Kragie, Lisa G. Dowden, Matthew W. Ward, Kathy G.
    Beckett, Scott Goldman, Eliot Spitzer, Attorney General,
    Peter H. Schiff, Senior Counsel, J. Jared Snyder and Michael
    J. Myers, Assistant Attorneys General, State of New York,
    Thomas F. Reilly, Attorney General, William L. Pardee,
    Assistant Attorney General, Commonwealth of Massachu-
    setts, M. Dukes Pepper, Jr., Commonwealth of Pennsylvania,
    Jennifer M. Granholm, Attorney General, Thomas L. Casey,
    Solicitor General, Alan F. Hoffman, Assistant Attorney Gen-
    eral, State of Michigan, John G. Horne, II, Jack B. Bates,
    Susan Rose Green, Commonwealth of Kentucky, Betty D.
    Montgomery, Attorney General, Bryan F. Zima, Assistant
    Attorney General, State of Ohio, Mark L. Earley, Attorney
    General, Steward T. Leeth, Assistant Attorney General, Com-
    monwealth of Virginia, Karen M. Freeman-Wilson, Attorney
    General, Steven D. Griffin, Deputy Attorney General, State of
    Indiana, Thomas H. Zerbe, Office of Legal Services, State of
    West Virginia, Bill Pryor, Attorney General, Prudence A.
    Cash-Brown, Assistant Attorney General, State of Alabama.
    Thomas Y. Au and Gene E. Godley entered appearances.
    David J. Kaplan, Norman L. Rave, Jr. and Scott Williams,
    Attorneys, U.S. Department of Justice, argued the cause for
    respondents.  With them on the briefs were Lois J. Schiffer,
    Assistant Attorney General, Alexandra Teitz, Howard Hoff-
    man and Dwight C. Alpern, Attorneys, U.S. Environmental
    Protection Agency.  Christopher S. Vaden, Attorney, entered
    an appearance.
    William L. Pardee, Assistant Attorney General, Common-
    wealth of Massachusetts, argued the cause for intervenors
    Commonwealth of Massachusetts, et al. and amicus curiae
    State of New Jersey.  With him on the briefs were Thomas
    F. Reilly, Attorney General, Commonwealth of Massachu-
    setts, Eliot Spitzer, Attorney General, J. Jared Snyder, Assis-
    tant Attorney General, State of New York, Richard Blumen-
    thal, Attorney General, Richard F. Webb, Assistant Attorney
    General, State of Connecticut, M. Dukes Pepper, Jr., Com-
    monwealth of Pennsylvania, Philip McLaughlin, Attorney
    General, Maureen D. Smith, Assistant Attorney General,
    State of New Hampshire, William H. Sorrell, Attorney Gen-
    eral, Dianne H. Sanford, Assistant Attorney General, State
    of Vermont, Sheldon Whitehouse, Attorney General, Tricia
    Jedele, Assistant Attorney General, State of Rhode Island,
    John J. Farmer, Jr., Attorney General, Howard Geduldig,
    Deputy Attorney General, State of New Jersey.  Roger L.
    Chaffe, Senior Assistant Attorney General, Commonwealth of
    Virginia, and Ronald A. Shems, Assistant Attorney General,
    State of Vermont, entered appearances.
    Andrea Bear Field, Norman W. Fichthorn and Mel S.
    Schulze appeared on the brief of Appalachian Power Compa-
    ny, et al. as intervenors.
    David W. Marshall, Ann Brewster Weeks and David G.
    Hawkins appeared on the brief of intervenors Natural Re-
    sources Defense Council, et al.  Raissa Griffin entered an
    appearance.
    David P. Novello was on the brief of the Electric Generator
    intervenors.
    Before:  Williams, Ginsburg and Sentelle, Circuit Judges.
    Opinion for the Court filed Per Curiam.*
    TABLE OF CONTENTS
    I.   BACKGROUND                                              5
    A.   Statutory Framework                                     6
    B.   The NOx SIP Call                                        8
    C.   The Original Section 126 Rule-Conditional Findings           8
    D.   Revised Section 126 Rule-Final Findings            10
    II.  COMMON AND GENERAL ISSUES                              12
    A.   Scrivener's Error                                           12
    B.   The NOx SIP Call and s 126                                  19
    C.   Significant Contribution                               27
    D.   Emission Limitation Determinations                     32
    1.   Standard of Review                                     32
    2.   The Integrated Planning Model                          33
    3.   EGU Growth Factors                                35
    __________
    * Judge Williams wrote Parts II.C, III.B-C, and V;  Judge Gins-
    burg wrote Parts II.A-B and II.D.5;  Judge Sentelle wrote Parts
    I, II.D.1-4, II.E-F, III.A., and IV.
    4.   Non-EGU Budget Determinations                     38
    5.   Local Regulation and Permit Trading               39
    E.   Regulation of "Future" Sources                         40
    F.   The Dorris Report                                           44
    III. NON-ELECTRIC GENERATING UNIT ISSUES           47
    A.   Alleged Budget Allocation Errors                       47
    B.   Treatment of Cogenerators                                   48
    C.   Source-Specific Issues                                      53
    1.   AK Steel Corporation                                   53
    2.   New Boston Coke Corporation                       54
    IV.  FACILITY-SPECIFIC ISSUES                               55
    A.   Midland Cogeneration Venture                           55
    B.   Indiana Municipal Power Agency                         56
    V.   PITTSBURGH                                                  57
    VI.  CONCLUSION                                             60
    PER CURIAM.
    In response to petitions from several northeastern states
    that alleged that nitrogen oxide emitted in neighboring states
    was harming their local air quality, the Environmental Pro-
    tection Agency promulgated a rule that requires many NOx-
    emitting facilities in several midwestern and southeastern
    states to conform to emission limits set by the EPA and to
    participate in an emissions trading program.  Numerous peti-
    tioners challenge the rule as inconsistent with the Clean Air
    Act, arbitrary and capricious, and technically deficient.  We
    uphold most aspects of the rule but remand several particu-
    lars to the Agency for reconsideration.
    I. BACKGROUND
    On January 18, 2000, the Environmental Protection Agency
    ("EPA") issued its final rule to control emissions of nitrogen
    oxide ("NOx") under section 126 of the Clean Air Act
    ("CAA").  42 U.S.C. s 7426.  Under certain conditions, NOx
    combines with hydrocarbons in the atmosphere to create
    ozone, commonly known as "smog."  In the January rule, the
    EPA made final its findings that stationary sources of NOx
    emissions in twelve upwind states and the District of Colum-
    bia contribute significantly to ozone nonattainment in north-
    eastern states.  This finding triggers direct federal regulation
    of stationary sources of NOx in the upwind states.  The rule
    further established a "cap and trade" system for NOx emis-
    sions within each upwind jurisdiction.  Covered sources must
    obtain NOx emission allowances to cover their emissions,
    adopt additional emission controls, or cease operations.  Nu-
    merous petitions for review challenge various aspects of the
    rule.
    A.   Statutory Framework
    Under the Clean Air Act, the EPA promulgates national
    ambient air quality standards ("NAAQS") for criteria air
    pollutants, including tropospheric ozone.  See 42 U.S.C.
    s 7409.  The EPA then designates those areas of the United
    States that fail to meet the various NAAQS.  42 U.S.C.
    s 7407(d).  States, in turn, are required to adopt state imple-
    mentation plans ("SIPs") providing for the attainment of the
    NAAQS.  42 U.S.C. s 7410.  The SIPs are submitted to the
    EPA for approval, and may be revised at the EPA's insis-
    tence if found to be inadequate to ensure maintenance of the
    NAAQS or public health.  States that fail to comply with
    these requirements are subject to various sanctions and the
    imposition of a Federal Implementation Plan ("FIP").  42
    U.S.C. s 7509.
    Much air pollution is a local or regional problem.  Some
    pollution, however, is caused or augmented by emissions from
    other states.  Emissions from "upwind" regions may pollute
    "downwind" regions.  Several provisions of the CAA are
    designed to address such transboundary air pollution.  In
    particular, section 110(a)(2)(D)(i)(I) of the Act requires states
    to prohibit emissions within the state in amounts that will
    "contribute significantly to nonattainment in, or interfere with
    maintenance by, any other State" of the NAAQS.  42 U.S.C.
    s 7410(a)(2)(D)(i)(I).
    CAA section 126 provides a mechanism whereby downwind
    states may petition the EPA to directly regulate upwind
    sources of pollution.  Under section 126(b), 42 U.S.C.
    s 7426(b), a downwind state "may petition the Administrator
    for a finding that any major source or group of stationary
    sources emits or would emit any air pollutant in violation" of
    CAA section 110(a)(2)(D).  Once the EPA makes a section
    126(b) finding, section 126(c) provides that:
    it shall be a violation of this section and the applicable
    implementation plan in such State--
    (1) for any major proposed new (or modified) source
    with respect to which a finding has been made under
    subsection (b) of this section to be constructed or to
    operate in violation [of this section or section 110], or
    (2) for any major existing source to operate more than
    three months after such finding has been made with
    respect to it.
    42 U.S.C. s 7426(c).  The Administrator may allow the con-
    tinued operation of existing sources beyond three months
    provided such sources comply with emission limitations and
    compliance schedules provided by the Administrator which
    "bring about compliance ... as expeditiously as practicable,
    but in no case later than three years after the date of such
    finding."  
    Id. At issue
    in this case is the extent of the EPA's authority to
    make findings and directly regulate sources in upwind states
    under section 126, and whether the EPA's section 126 rule
    was arbitrary and capricious or contrary to law.
    B.   The NOx SIP Call
    In October 1998, the EPA issued a final rule calling upon
    twenty two states1 and the District of Columbia to revise
    their ozone SIPs to address interstate air pollution (aka
    "interstate transport").  See Finding of Significant Contribu-
    tion and Rulemaking for Certain States in the Ozone Trans-
    port Assessment Group Region for Purposes of Reducing
    Regional Transport of Ozone, 63 Fed. Reg. 57,356 (1998)
    ("NOx SIP Call").  Concluding that upwind states contribute
    significantly to ozone nonattainment problems in downwind
    states, the EPA required each jurisdiction to promulgate a
    new SIP to reduce NOx emissions.  This "NOx SIP call"
    required states to reduce NOx emissions by the amount that
    could be accomplished by emission controls capable of reduc-
    ing emissions at a cost of $2,000 or less per ton.  Under the
    rule, revised SIPs were due by September 30, 1999, and SIP
    provisions covering stationary sources had to be implemented
    by May 1, 2003.  Failure to submit an adequate NOx SIP by
    the deadline would result in implementation of a FIP by the
    EPA.  In other words, if the states do not submit a plan for
    meeting their CAA obligations, the EPA will impose one of its
    own.
    C.   The Original Section 126 Rule-Conditional Findings
    In August 1997, eight states submitted petitions requesting
    that the EPA find that stationary sources in upwind states
    contribute significantly to downwind air pollution.  Specifical-
    ly, the petitioning states sought findings pursuant to CAA
    section 126(b), 42 U.S.C. s 7426(b), that specified sources or
    categories thereof are the source of NOx emissions that
    __________
    1  The states are Alabama, Connecticut, Delaware, Georgia,
    Illinois, Indiana, Kentucky, Maryland, Massachusetts, Michigan,
    Missouri, New Jersey, New York, North Carolina, Ohio, Pennsylva-
    nia, Rhode Island, South Carolina, Tennessee, Virginia, West Virgi-
    nia, and Wisconsin.
    contribute significantly to ozone nonattainment in the peti-
    tioning states in violation of CAA section 110(a)(2)(D).  42
    U.S.C. s 7410(a)(2)(D).  Each petition further sought to have
    the EPA implement direct federal regulation of stationary
    sources in upwind states, primarily electric generating facili-
    ties and fossil-fuel fired industrial boilers and turbines.  Be-
    cause the section 126 petitions raised many of the same issues
    as the NOx SIP call, and would require comparable emission
    reductions, the EPA coordinated its response to the section
    126 petitions with the NOx SIP call rulemaking.
    In a final rule published on May 25, 1999, the EPA
    determined that NOx emissions in twelve states and the
    District of Columbia contribute significantly to non-
    attainment of the one-hour ozone NAAQS in Connecticut,
    Massachusetts, New York, and Pennsylvania.  Findings of
    Significant Contribution and Rulemaking on Section 126 Peti-
    tions for Purposes of Reducing Interstate Ozone Transport,
    64 Fed. Reg. 28,250 (May 25, 1999) ("May 1999 Rule").  The
    twelve states are Delaware, Indiana, Kentucky, Maryland,
    Michigan, New Jersey, New York, North Carolina, Ohio,
    Pennsylvania, Virginia, and West Virginia.
    Rather than make section 126 findings at that time, howev-
    er, the EPA determined that it was appropriate to postpone
    such findings pending the resolution of the NOx SIP call
    process.  Accordingly, the EPA issued a rule providing that
    the findings would automatically be deemed made with re-
    gard to sources from a given state should that state fail to
    comply with a NOx SIP call deadline.  The EPA based this
    decision on the judgment that full compliance with the NOx
    SIP call would obviate the need for section 126 findings.
    Once made, the section 126 findings would require covered
    sources to come into compliance no later than May 1, 2003.
    Sources that failed to comply by that date would be required
    to cease operations.
    D.   Revised Section 126 Rule-Final Findings
    Subsequent to the completion of the section 126 rulemak-
    ing,2 this court issued two orders which caused the EPA to
    change course.  First, on May 14, 1999 this court remanded
    the EPA's proposed revisions to the ozone NAAQS.  Ameri-
    can Trucking Ass'ns v. EPA, 
    175 F.3d 1027
    , reh'g granted in
    part and denied in part, 
    195 F.3d 4
    (D.C. Cir. 1999), rev'd in
    part sub nom. Whitman v. American Trucking Ass'ns, 121 S.
    Ct. 903 (2001).  Second, this court issued an order staying the
    NOx SIP call deadline.  Michigan v. EPA, No. 98-1497 (D.C.
    Cir. May 25, 1999) (order granting stay in part).
    In response to these orders, the EPA revised the section
    126 rule.  Findings of Significant Contribution and Rulemak-
    ing on Section 126 Petitions for Purposes of Reducing Inter-
    state Ozone Transport, 65 Fed. Reg. 2674 (Jan. 18, 2000)
    ("Jan. 2000 Rule").  In particular, the EPA made the re-
    quested findings of significant contributions, granting the
    relevant portions of the section 126 petitions and delinking
    the section 126 findings from compliance with the NOx SIP
    call.  The EPA explained that it was "implementing the
    requirements of section 126 of the CAA in the absence of any
    currently effective requirement for upwind States to address
    the interstate pollution transport problems themselves."  
    Id. at 2683.
     Instead, the EPA's new rule contained a provision
    to withdraw the relevant findings upon approval of a NOx SIP
    in accordance with the October 1998 NOx SIP call.
    As with the NOx SIP call, the EPA considered both NOx
    emissions and the cost of control in determining which
    sources contribute significantly to downwind ozone nonattain-
    ment.  Based upon its analysis of the cost of emissions
    controls, the EPA concluded that measures which can reduce
    NOx emissions for $2,000 or less per ton are highly cost-
    __________
    2  Although published on May 25, the initial section 126 rule was
    signed by the Administrator on April 30, 1999.  See May 1999 Rule,
    65 Fed. Reg. at 28,318.
    effective.  May 1999 Rule, 64 Fed. Reg. at 28,299.  The EPA
    then divided NOx emission sources into various categories and
    determined the level of emission reduction that would be
    highly cost-effective for each category.  
    Id. at 28,300-01.
    The section 126 rule also established an emission allowance
    "cap and trade" program, known as the Federal NOx Budget
    Trading Program.  Under this program, originally outlined in
    the May 1999 rule, regulated sources are allocated tradeable
    NOx emission allowances and are prohibited from emitting
    more NOx than the amount of allowances held.  If a facility
    emits more than its initial allowance allocation, it must pur-
    chase additional allowances from another facility, reduce its
    emissions, or cease operations.  Jan. 2000 Rule, 65 Fed. Reg.
    at 2733.
    To determine the initial allocations, the EPA established a
    NOx emission cap for each upwind state.  Each state's cap is
    based upon expected emission reductions from highly cost-
    effective controls in that state as of 2007.  
    Id. at 2698.
    Ninety-five percent of each state's cap is allocated proportion-
    ally among existing sources based upon each facility's heat
    input.  Five percent of the cap is set aside for future, as-yet-
    unproposed sources.  
    Id. at 2698-99.
     These initial allocations
    will apply for the 2003-07 time period.  
    Id. at 2700.
     The
    EPA will issue revised allocations for the 2008-12 time peri-
    od, and every five years thereafter.  
    Id. Since the
    issuance of the final section 126 rule, this Court
    has ruled on various challenges to the EPA's NOx SIP call.
    In Michigan v. EPA, 
    213 F.3d 663
    (D.C. Cir. 2000), we
    upheld the SIP call in most respects, remanding portions of
    the rule to the EPA.  Of greatest relevance to these proceed-
    ings, we upheld the EPA's analyses of interstate transport of
    NOx emissions and its use of cost-effectiveness criteria in
    determining which upwind sources "contribute significantly"
    to nonattainment in downwind states.  Subsequently, we en-
    tered an order amending the deadline for full implementation
    of NOx SIP revisions from May 1, 2003 to May 31, 2004.
    Michigan v. EPA, No. 98-1497, 
    2000 WL 1341477
    (D.C. Cir.
    Aug. 30, 2000) (order denying motion to stay mandate pend-
    ing petition for certiorari).
    After the EPA published the final section 126 rule in
    January 2000, numerous groups petitioned this Court for
    review.  Among the petitioners are a group of upwind states
    from the midwestern and southeastern United States ("MW
    & SE State Petitioners");  utilities and other operators of
    electric generating facilities ("Non-State Petitioners");  com-
    panies that operate non-electric generating/industrial facilities
    ("Non-EGU Petitioners");  and several individual companies
    that have facility-specific concerns ("Facility-Specific Peti-
    tioners").  A group of northeastern states ("NE State Peti-
    tioners") also petitioned for review alleging that the EPA's
    rule did not go far enough in controlling upwind NOx emis-
    sions.  The northeastern states otherwise intervened in sup-
    port of the EPA, as did a group of environmental organiza-
    tions.  The various petitions for review were consolidated into
    this case.
    II. COMMON AND GENERAL ISSUES
    A.   Scrivener's Error
    The Clean Air Act Amendments of 1990 eliminated a
    subsection of s 110 of the Clean Air Act ("CAA"), causing
    s 110(a)(2)(E) to be renumbered as s 110(a)(2)(D).  See
    Clean Air Act, Pub. L. No. 101-549, sec. 101(b),
    s 110(a)(2)(D), 104 Stat. 2399, 2404 (1990) (codified at 42
    U.S.C. s 7410(a)(2)(D)).  The Amendments correspondingly
    updated several references to s 110(a)(2)(E)(i) that had ap-
    peared in s 126 of the Clean Air Act, but changed them to
    read "section 110(a)(2)(D)(ii)."  See Clean Air Act, Pub. L.
    No. 101-549, sec. 109(a), s 126(b)-(c), 104 Stat. at 2469-70
    (codified at 42 U.S.C. s 7426).  The 1990 Amendments thus
    not only substituted "(D)" for "(E)" in s 126, as necessitated
    by the renumbering, but also substituted "(ii)" for "(i)."  The
    EPA, which contends that the Congress amended s 126 only
    in order to update the cross-references so as to preserve the
    status quo ante, claims that this substitution of "(ii)" for "(i)"
    was "inadvertent[ ]."  May 1999 Rule, 64 Fed. Reg. at
    28,267/3.  The agency therefore construes s 126 as if this
    "inadvertence" had not occurred, i.e., as if that section re-
    ferred to s 110(a)(2)(D)(i).  See 
    id. The Non-State
    Petition-
    ers, by contrast, argue that s 126 should be read as written,
    that is, to refer to s 110(a)(2)(D)(ii).
    Section 126 gives a state the right to petition the EPA to
    find "that any major source or group of stationary sources [in
    another state] emits or would emit any air pollutant in
    violation of the prohibition of" a subsection of s 110(a)(2)(D),
    the subsection here at issue.  42 U.S.C. s 7426(b).  As we
    have noted, the ability of such a source or group of sources to
    operate is severely constrained once such a finding is made.
    42 U.S.C. s 7426(c).  The constraints in s 126(c) are trig-
    gered by the "prohibition" in whichever subsection of
    s 110(a)(2)(D) it is that s 126 cross-references.  Section
    110(a)(2)(D) provides that a state implementation plan
    ("SIP"), which describes how a state plans to comply with the
    National Ambient Air Quality Standards ("NAAQS"), must
    (D) contain adequate provisions--
    (i) prohibiting ... any source or other type of emissions
    activity within the State from emitting any air pollutant
    in amounts which will--
    (I) contribute significantly to nonattainment in, or in-
    terfere with maintenance by, any other State with
    respect [to the NAAQS] or
    (II) interfere with [various other] measures.
    (ii) insuring compliance with the applicable requirements
    of sections 7426 [CAA s 126] and 7415 [CAA s 115] of
    this title (relating to interstate and international pollution
    abatement).
    42 U.S.C. s 7410(a)(2)(D).  Thus, prior to the 1990 Amend-
    ments, s 126 provided an avenue by which a state could
    compel the EPA to enforce emissions limitations upon a
    neighboring state the emissions from which contributed to its
    own nonattainment of the NAAQS.  The EPA argues that
    s 126 should still be read to have this effect, notwithstanding
    the substitution of "(ii)" for "(i)" therein.
    Reading a statute contrary to its seemingly clear meaning
    is permissible "[i]f 'the literal application of a statute will
    produce a result demonstrably at odds with the intentions of
    its drafters.' "  Mova Pharm. Corp. v. Shalala, 
    140 F.3d 1060
    ,
    1068 (D.C. Cir. 1998) (quoting United States v. Ron Pair
    Enterprises, 
    489 U.S. 235
    , 242 (1989)).  We will not, however,
    invoke this rule to ratify an interpretation that abrogates the
    enacted statutory text absent an extraordinarily convincing
    justification:
    [T]he court's role is not to "correct" the text so that it
    better serves the statute's purposes, for it is the function
    of the political branches not only to define the goals but
    also to choose the means for reaching them....  There-
    fore, for the EPA to avoid a literal interpretation at
    Chevron step one, it must show either that, as a matter
    of historical fact, Congress did not mean what it appears
    to have said, or that, as a matter of logic and statutory
    structure, it almost surely could not have meant it.
    Engine Mfrs. Ass'n v. EPA, 
    88 F.3d 1075
    , 1089 (D.C. Cir.
    1996).  The EPA's reading of the reference in s 126 to
    s 110(a)(2)(D)(ii) to mean s 110(a)(2)(D)(i) meets this test.
    The cross-references to s 110(a)(2)(D)(ii) that appear in s 126
    clearly do not reflect the intent of the Congress.  Although
    the cross-references as written "point[ ] in one direction, all
    the other evidence from the statute points the other way,"
    United States Nat'l Bank of Oregon v. Independent Ins.
    Agents of America, Inc., 
    508 U.S. 439
    , 455 (1993).  See
    Thomas W. Merrill, Golden Rules for Transboundary Pollu-
    tion, 46 Duke L.J. 931, 955 n.124 (1997) ("[S]ection 126(b)
    contains what appears to be a typographical error which, if
    read literally, would render the EPA's obligation to make [a
    s 126] finding meaningless").
    For example, although s 126 twice refers to the "prohibi-
    tion of section 7410(a)(2)(D)(ii) [CAA s 110(a)(2)(D)(ii)],"
    there is no literal "prohibition" in that section--whereas there
    is in s 110(a)(2)(D)(i) ("prohibiting ... any source").  The
    petitioners dismiss this point, arguing that "prohibition" is not
    a term of art and that it easily embraces the directive of
    s 110(a)(2)(D)(ii) to "insur[e] compliance with the applicable
    requirements of sections 7426 [CAA s 126] and 7415 [CAA
    s 115]."  For support, the petitioners note that the third and
    final reference to s 110 in s 126 refers to the "requirements
    contained in section 7410(a)(2)(D)(ii) [CAA s 110(a)(2)(D)(ii)]."
    42 U.S.C. s 7426(c).  Although the "requirements" of these
    sections certainly include some "prohibitions," the petitioners'
    argument that the two terms are "interchangeabl[e]"
    stretches the ordinary meaning of the term "prohibition."  It
    does not, however, stretch that meaning beyond recognition.
    Taken alone, therefore, the usage is insufficient to prove the
    agency's claim of scrivener's error;  in conjunction with the
    other evidence described below, however, it lends credence to
    the view that such an error indeed was made.
    A similar analysis applies to the observation that s 126 as
    written creates a circular cross-reference:  both s 126(b) and
    s 126(c) refer to the "prohibition" or "requirements" of
    s 110(a)(2)(d)(ii), which in turn mandates compliance with
    "the applicable requirements of [CAA s 126]."  Although a
    fully circular cross-reference would be absurd, the petitioners
    note that s 110(a)(2)(d)(ii) refers to s 126 in its entirety,
    rather than to ss 126(b) and (c) alone;  it thus includes the
    requirement of s 126(a) that a state's SIP provide for notify-
    ing its neighbors of any major proposed new source that
    might affect their air quality adversely, see 42 U.S.C.
    s 7426(a).  This reading is not unreasonable.  Cf. Connecticut
    v. EPA, 
    656 F.2d 902
    , 907 (2d Cir. 1981) ("When [CAA
    s 110(a)(2)(D)(ii)] requires an SIP to insure compliance with
    s 126, it clearly refers to subsection (a) [of s 126] only and
    not to the petition procedure set forth in subsection (b)").  A
    statute that incorporates a cross-reference that is only par-
    tially circular is not for that reason absurd, although--as in
    this case--such a reference may make the statute sufficiently
    convoluted to warrant searching for a less infelicitous con-
    struction.
    It is impossible to accept, however, that the Congress
    intended simultaneously to repeal the regulatory regime that
    had existed before the 1990 Amendments and to replace it
    with the one that the petitioners describe.  See Nat'l Bank of
    
    Oregon, 508 U.S. at 454
    (eschewing "purported plain-meaning
    analysis" of statute as written when scrivener's error has
    "distort[ed] a statute's true meaning");  
    id. at 461
    n.10 (hold-
    ing theory of scrivener's error constituted "best reading" of
    statute notwithstanding that statute as written could be co-
    herently explained).  Before the 1990 Amendments--and still
    today, under the EPA's reading--s 126 provided a mecha-
    nism by which a state could compel the EPA to control
    emissions from sources in a neighboring state that contribut-
    ed to the complaining state's nonattainment of the NAAQS.
    See 42 U.S.C. s 7426(b)-(c).  The petitioners argue that, by
    substituting "(ii)" for "(i)" in the cross-references of s 126,
    the Congress intended to withdraw the state's right to force
    the hand of the EPA when emissions from a neighboring
    state contributed to its own violation of the NAAQS, and
    simultaneously to create a right by which a state may compel
    such enforcement when a neighboring state fails to meet "the
    requirements of [42 U.S.C. ss ] 7426 and 7415 of this title
    [CAA ss 126 and 115] (relating to interstate and international
    pollution abatement)."  42 U.S.C. s 7410(a)(2)(D)(ii).
    This reading makes no sense of either s 126 or s 115.  As
    we have noted, in order to avoid circularity, the petitioners
    suggest that the reference to s 126 in s 110(a)(2)(d)(ii) refers
    only to the notification requirements of s 126(a).  According
    to the petitioners' reading, the 1990 amendment of ss 126(b)
    and (c) gave each state the right to compel enforcement
    against another state that fails to provide notice of new
    sources and took away their right to compel enforcement
    against a state that actually pollutes the complaining state's
    air.  Even were we to assume that such a counterintuitive
    switch from substantive to procedural compliance could plau-
    sibly reflect congressional policy, the petitioners' reading
    would still be flawed.  Section 126(b) permits a state to
    petition the EPA to find that "any major source or group of
    stationary sources emits or would emit any air pollutant in
    violation of the prohibition of section 7410(a)(2)(D)(ii) [CAA
    s 110(a)(2)(D)(ii)]."  42 U.S.C. s 7426(b).  The notice require-
    ment of s 126(a), to which the petitioners claim this reference
    ultimately points, binds states only to warn their neighbors of
    proposed new and modified sources;  it does not restrict the
    behavior of sources or groups of sources, whose "violation" of
    s 110(a)(2)(D) is the predicate for a s 126(b) finding.  See 
    id. s 7426(a).
    For s 126 to incorporate the reference of s 110(a)(2)(d)(ii)
    to s 115 is similarly anomalous.  Section 115 allows a foreign
    nation affected by a state's emissions to complain to the EPA,
    which can then require the state to revise its SIP.  42 U.S.C.
    s 7415.  According to the petitioners, the 1990 Amendments
    created a new right whereby a state may compel enforcement
    against a neighboring state polluting a foreign country, while
    simultaneously abrogating that state's preexisting right to
    compel enforcement against a neighboring state polluting the
    complaining state.  That any state would be empowered to
    trump the EPA's discretion in an international dispute to
    which it is not a party--even as it lost the power to address
    another state's pollution of its own air--cannot be taken to
    express congressional intent if there is any plausible alterna-
    tive reading of the statute.
    The petitioners' suggestion that the enactment of ss 176A
    and 184, 42 U.S.C. ss 7506a, 7511c, as part of the 1990
    Amendments somehow mitigates these problems is without
    foundation.  Those sections authorize the EPA to designate a
    multistate "transport region" in a case where one state's
    emissions affect another state's attainment of the NAAQS;
    for each such region, the EPA must convene a "transport
    commission," including officials from each state within the
    region, to advise the EPA Administrator.  
    Id. The petition-
    ers correctly describe these new sections as establishing, at
    least in part, a new approach to interstate air pollution.
    Because the Congress did not repeal s 126, however, this new
    approach was clearly not meant to be exclusive;  and neither
    s 176A nor s 184 renders the change in s 126 from "(i)" to
    "(ii)" any less linguistically or substantively anomalous.
    Even if the Congress had simultaneously enacted ss 176A,
    184 and 126 as written, we might not embrace the petitioners'
    reading.  See Environmental Defense Fund, Inc. v. EPA, 
    82 F.3d 451
    , 468 (D.C. Cir. 1996) (refusing to construe a statute
    literally in order to avoid "absurd and futile results").  This
    case, however, is much clearer:  the EPA has demonstrated
    not only that s 126 as written is at odds with congressional
    intent;  it also offers a convincing account of how it came to be
    enacted nevertheless.  We find it quite plausible that the
    Congress substituted "(ii)" for "(i)" in s 126 inadvertently in
    the course of a routine renumbering of statutory cross-
    references.  Cf.  In re Chateaugay Corp., 
    89 F.3d 942
    , 953-54
    (2d Cir. 1996) (accord regarding a post-amendment renum-
    bering of the bankruptcy code).
    Because the EPA has established that the "seemingly clear
    statutory language does not reflect the 'unambiguously ex-
    pressed intent of Congress,' " 
    Mova, 140 F.3d at 1068
    (quot-
    ing Chevron U.S.A. Inc. v. Natural Resources Defense Coun-
    cil, Inc., 
    467 U.S. 837
    , 842 (1984)), we proceed under Chevron
    step two to consider whether the EPA's construction of s 126
    is reasonable.  Lest it "obtain a license to rewrite the stat-
    ute," 
    id., however, we
    do not give an agency alleging a
    scrivener's error the benefit of Chevron step two deference,
    by which the court credits any reasonable construction of an
    ambiguous statute.  Rather, the agency "may deviate no
    further from the statute than is needed to protect congres-
    sional intent."  
    Id. By reading
    s 126 to refer to
    s 110(a)(2)(D)(i)--thus restoring it to the meaning it had
    before the 1990 Amendments, as the Congress almost certain-
    ly intended--the EPA in no way overreaches;  we therefore
    accept its reading.3
    __________
    3  In the alternative, the petitioners suggest that the reference
    in s 126 to s 110(a)(2)(D)(ii) may have stemmed from a different
    error than that posited by the EPA;  perhaps, they argue, the
    Congress intended to refer not to s 110(a)(2)(D)(i) but to
    s 110(a)(2)(D)(i)(II).  This construction is less plausible than the
    B.   The NOx SIP Call and s 126
    The Administrator of the EPA must require a state to
    revise its SIP "as necessary" whenever she finds such a plan
    "substantially inadequate to ... comply" with various re-
    quirements of the Act, including the requirement that the
    plan "contain adequate provisions" to prevent sources within
    a state from contributing significantly to any other state's
    nonattainment or nonmaintenance of the NAAQS.  
    Id. ss 7410(a)(2)(D)(i)(I),
    7410(k)(5).  Pursuant to this authority,
    in October 1998 the EPA issued a request for SIP revisions,
    or a "SIP call," that required 22 states and the District of
    Columbia to revise their SIPs in order to mitigate the inter-
    state transport of ozone.  Michigan v. EPA, 
    213 F.3d 663
    ,
    669 (D.C. Cir. 2000) (explicating NOx SIP Call, 63 Fed. Reg.
    at 57,358-59).  This court upheld the essential elements of the
    NOx SIP call in March 2000, although we remanded the rule
    for further proceedings with regard to three states and to
    certain types of sources.  
    Id. at 695.
    In August 1997, during the preparation of the NOx SIP call,
    eight states petitioned the EPA to find, pursuant to CAA
    s 126(b), that "major stationary sources or groups of sources"
    in specified states were contributing to the petitioning states'
    failure to meet the NAAQS for ozone.  42 U.S.C. s 7426(b).
    In the first of the two rules challenged here, the EPA
    announced that because it was "operating on basically the
    same set of facts" in making determinations under s 126 as it
    had when it issued the NOx SIP call--that is, facts showing
    __________
    EPA's for the simple reason that the EPA's reading restores the
    statute to its unarguably coherent, pre-Amendment form.  In any
    event, when "there are multiple ways of avoiding a statutory
    anomaly, all equally consistent with the intentions of the statute's
    drafters (and equally inconsistent with the statute's text)," we
    accord standard Chevron step two deference to an agency's choice
    between such alternatives.  See 
    Mova, 140 F.3d at 1068
    .
    that upwind sources contributed to downwind nonattainment
    of the NAAQS--it would eschew making formal findings
    under s 126.  May 1999 Rule, 64 Fed. Reg at 28,274/3,
    28,275/2.  Instead, the agency made the "affirmative technical
    determination" that sources in upwind states were contribut-
    ing to nonattainment in downwind states, and provided that a
    formal finding to that effect under s 126 would be
    deemed to be made for such sources in a state if by May
    1, 2000, EPA has not either (a) approved a state's SIP
    revision to comply with the NOx SIP call or (b) promul-
    gated implementation plan provisions meeting the [CAA]
    section 110(a)(2)(D)(i) requirements.
    
    Id. at 28,275/2.
    The EPA used this "automatic trigger mechanism," Jan.
    2000 Rule, 65 Fed. Reg. at 2679/1, as part of a "coordinated
    approach" to the SIP call and the s 126 petitions, May 1999
    Rule, 64 Fed. Reg. at 28,275/3:  s 126 findings would be
    withheld until the conclusion of the SIP call, but would be
    entered automatically should a state's response to the SIP
    call be either unsatisfactory or untimely.  May 1, 2000 was
    chosen as the date for triggering the s 126 finding because
    s 126(c) allows the EPA to permit sources found to contrib-
    ute to another state's nonattainment to continue to operate
    for no more than three years after the date of such a finding.
    42 U.S.C. s 7426(c).  For findings made on May 1, 2000, the
    three-year clock would expire on May 1, 2003--the same date
    by which states were required to have implemented controls
    over sources of interstate ozone under the original NOx SIP
    call.  See NOx SIP Call, 63 Fed. Reg. at 57,308/1.
    The congruence between the two schedules was disrupted
    by an order of this court staying the EPA's original SIP call
    deadline.  See Michigan v. EPA, No. 98-1497 (D.C. Cir. May
    25, 1999);  see also Michigan v. EPA, No. 98-1497, 
    2000 WL 1341477
    (D.C. Cir. Aug. 30, 2000) (ordering new deadline of
    May 31, 2004 for implementation of SIPs that are revised
    pursuant to the SIP call).  The extended timetable for the
    SIP call led the EPA to determine that "the circumstances
    under which the linkage between action on the section 126
    petitions and the NOx SIP call was appropriate are no longer
    present."  Jan. 2000 Rule, 65 Fed. Reg. at 2680/1;  see also
    
    id. at 2676/2.
     The EPA therefore abandoned the automatic
    trigger mechanism and instead simply made the s 126 find-
    ings.  See 
    id. at 2679/1.
    The EPA maintains that its approach is necessitated by the
    "language and purposes of section 126" and that it is consis-
    tent with "the language of section 110, the cooperative feder-
    alism structure of title I of the CAA, [and this] court's
    decision to stay the deadlines for States to submit SIP
    revisions under the NOx SIP call."  
    Id. at 2680/1.
     The MW &
    SE State and Non-State Petitioners disagree.  They argue
    that ss 110 and 126 require the agency to refrain from
    making any s 126 findings while the NOx SIP call is ongoing,
    and that a similar constraint is imposed by the doctrine of
    "cooperative federalism" that this court has recognized as
    being embodied in the Act.
    Once the "prohibition" to which s 126 refers is understood
    as the "functional prohibition" upon emissions of pollutants
    that subsequently cross state lines, the petitioners can find
    little support for their position by parsing ss 110 and 126.4
    The Non-State Petitioners argue that
    __________
    4  The EPA may make findings under s 126 only if a major
    source or group of sources is in "violation of the prohibition of
    [s 110(a)(2)(D)(i)]."  42 U.S.C. s 7426(b).  The petitioners might
    have argued, therefore, that because s 110(a)(2)(D) requires a SIP
    to "contain adequate provisions prohibiting" interstate emissions,
    [a]t a time when the relevant States were under a legal
    obligation to adopt "adequate [SIP] provisions" to control
    NOx emissions found by EPA to significantly contribute
    to ozone nonattainment--and at a time when States had
    not defaulted on that obligation--EPA lacked the author-
    ity to determine that those same States' NOx emission
    sources were "in violation" of that same prohibition.
    Non-State Petitioners Br. at 29.  This statement lacks a
    logical basis.  It is entirely reasonable for the EPA to regard
    a state that is under a legal obligation to revise its plan as
    being, in the meantime, in violation of a functional prohibition.
    The petitioners' primary argument, therefore, is that Title I
    of the Clean Air Act is animated by a commitment to "cooper-
    ative federalism" under which the EPA is to determine what
    level of air quality is required but must defer in the first
    instance to the judgments of the states regarding how to
    achieve that level.  This principle, according to the petition-
    ers, requires that a SIP call inviting states to respond to the
    problem of interstate transport be the preferred remedy,
    while direct federal regulation of sources, as authorized by
    s 126, must be a last resort reserved for cases in which states
    cannot or do not meet their SIP obligation.
    In Michigan this court assessed the legality of the emis-
    sions budgets that the EPA assigned to each state as part of
    __________
    the "prohibition of [CAA s 110(a)(2)(D)(i)]" in s 126 refers only to
    restrictions upon emissions incorporated into state or federal imple-
    mentation plans prepared pursuant to s 110(a)(2)(D).  When this
    argument was raised during the rulemaking, the EPA rejected it in
    favor of the view that "prohibition" means "the actual functional
    prohibition of section 110(a)(2)(D)(i), which bars impermissible state
    transport, rather than the specific provisions through which states
    implement that prohibition ... in an approved SIP."  May 1999
    Rule, 64 Fed. Reg. at 28,272/2.  No petitioner, however, argued the
    former view in its opening brief, and we therefore need not decide
    it.
    the NOx SIP call with respect to what we called the "Train-
    Virginia federalism 
    bar." 213 F.3d at 687
    .  We referred
    there to our holding in Virginia v. EPA, 
    108 F.3d 1397
    , 1408,
    modified on other grounds, 
    116 F.3d 499
    (1997), that under
    s 110 each state retains the power, in its SIP, to determine
    how it will achieve the NAAQS, and that the EPA may not
    dictate to a state a particular "source-specific means" to that
    end, a proposition for which we relied upon Train v. Natural
    Resources Defense Council, Inc., 
    421 U.S. 60
    , 79 (1975).  This
    principle, of course, cannot be absolute in the face of s 126,
    which contemplates that in at least some circumstances the
    EPA will directly regulate sources within a state.  See 42
    U.S.C. s 7426(c).  Neither Train and Virginia nor Michigan
    considered the interaction of their holdings with s 126,5 but in
    its 1999 rule the EPA noticed the tension between s 126 and
    the Train-Virginia line of cases, and properly sought to
    accommodate the two:
    Section 126 is somewhat unusual in Title I [of the CAA]
    in that it authorizes EPA to control sources directly,
    rather than providing a means for EPA to encourage
    states to control those sources.  In that sense, it is
    similar to the provisions for federal implementation plans
    in section 110(c).  With both of these provisions, Con-
    gress provided tools for direct federal action to address
    serious failures of state action.  Nevertheless, Congress'
    clear preference throughout Title I is that states are to
    decide and plan how they will control their sources of air
    pollution.
    May 1999 Rule, 64 Fed. Reg. at 28,273/2.  This analysis led
    the EPA to adopt the automatic trigger approach during the
    pendency of the NOx SIP call.
    The petitioners contend that the delay in the NOx SIP call
    deadline, because it did not affect the "Congress' clear prefer-
    ence" for state implementation decisions, should not have
    __________
    5  Train, of course, was decided before s 126 was enacted.
    altered the EPA's determination that the SIP call takes
    precedence over s 126.  The EPA, however, is obligated not
    only to give to s 110 a meaning that is consistent with Train
    and Virginia, but also reasonably to construe s 126.  The
    EPA, which considers the two provisions to be "independent
    statutory tools to address the problem of interstate pollution
    transport" that the EPA may deploy either singly or in
    tandem, Jan. 2000 Rule, 65 Fed. Reg. at 2680/1, reasonably
    construes both provisions.
    The EPA's view accords with the position of the Second
    Circuit which, in Connecticut v. EPA, was presented with the
    converse of the question before us:  Do ss 110 and 126
    require the EPA to postpone its approval of SIP revisions
    pending its final action upon petitions for findings under
    s 
    126(b)? 656 F.2d at 906-08
    .  Although the Connecticut
    court suggested that "s 126(b) appears to have been primari-
    ly designed as a means for resolving interstate pollution
    disputes in situations where an SIP is not being revised," 
    id. at 907--a
    dictum in some tension with the EPA's view that
    s 126 is "independent" of the SIP revision process--the
    Second Circuit's point was only that the EPA need not, upon
    receipt of a s 126 petition, suspend the SIP revision process.
    The court therefore concluded, properly we think, that "[a]s
    the substantive inquiry for decision is the same in both [s 110
    and s 126] proceedings, an argument that one proceeding
    must be completed as a prerequisite to a final decision in the
    other makes no sense."  
    Id. at 907;
     see also 
    id. at 908
    n.4
    (quoting statement of H.R. Rep. No. 95-249, at 331, reprinted
    in 4 A Legislative History of the Clean Air Act Amendments
    of 1977, at 2798 (1978), that "the s 126(b) process is designed
    to provide an 'entirely alternative method and basis for
    preventing and abating interstate pollution' ") (emphasis omit-
    ted).
    By contrast, three critical provisions of s 126 would lose
    their force if, as the petitioners suggest, the lengthened
    timetable of the NOx SIP call were to suspend the s 126
    process.  First, s 126 emphatically requires that any source
    found to contribute to downwind nonattainment may in no
    event be permitted to operate for more than three years after
    such finding.  See 42 U.S.C. s 7426(c).  Second, under s 126
    "[r]elief does not depend upon any action by the upwind
    states, as is necessary for a SIP revision."  May 1999 Rule,
    64 Fed. Reg. at 28,264/2.  Third, relief under s 126 is inde-
    pendent also of the discretionary policy preferences of the
    EPA;  the agency must act upon a request for a s 126 finding
    within 60 days.  See 42 U.S.C. s 7426(b).  Under the EPA's
    approach, of course, s 126 retains each of these features.
    See, e.g., Jan. 2000 Rule, 65 Fed. Reg. at 2681/1 ("Congress
    provided section 126 to downwind states as a critical remedy
    to address pollution problems ... otherwise beyond their
    control, and EPA has no authority to refuse to act under this
    section").
    The petitioners argue, however, that the EPA's construc-
    tion deprives s 110 of its force because it constrains the
    development of the SIP:  sources subject to a s 126 finding
    will be bound by emissions limitations set by the agency, see
    42 U.S.C. s 7426(c), and by the emissions trading program,
    see Part II.D below, even if the state in which they are
    located prefers to regulate different sources or to use differ-
    ent methods to mitigate downwind nonattainment.  The peti-
    tioners argue that such constraints violate s 110 as interpret-
    ed in Virginia, but they plainly do not.  In Virginia, this
    court disapproved the EPA's plan to reject SIPs that did not
    incorporate particular limits upon emissions from new cars;
    we held that the EPA may not, as part of the "section 110
    process," intervene in a state's choice of how to reach the
    
    NAAQS. 108 F.3d at 1410
    ;  cf. 
    id. at 1406
    (question is what is
    permissible "under section 110").  We did not suggest that
    under s 110 states may develop their plans free of extrinsic
    legal constraints.  Indeed, SIP development, like any environ-
    mental planning process, commonly involves decisionmaking
    subject to various legal constraints.  That s 126 imposes one
    such limitation--and it is surely not the only independent
    provision of federal law to do so--does not affect a state's
    discretion under s 110.
    The MW & SE State Petitioners argue in the alternative
    that, if ss 110 and 126 are independent, then the EPA may
    select either one but cannot impose s 126 findings and a SIP
    call simultaneously.  Neither the statute nor the states' brief
    offers support for this suggestion, and the states' suggestion
    that the EPA embraced it in the preamble to its second rule
    is without foundation.  Because it is reasonable, and because
    the "Congress provided both [ss 110 and 126] without indi-
    cating any preference for one over the other," Jan. 2000 Rule,
    65 Fed. Reg. at 2680/1, the EPA's conclusion that these two
    provisions operate independently merits our deference under
    Chevron step two.  See 
    Chevron, 467 U.S. at 843
    .
    Finally, we note that the MW & SE State Petitioners
    object to the EPA's construction of 40 C.F.R. s 52.34(i),
    which provides that s 126 findings will be withdrawn if the
    EPA takes "final action" to approve a SIP or impose a FIP
    that will control NOx emissions that contribute to downwind
    nonattainment.  See 40 C.F.R. s 52.34(i) (2000), promulgated
    at 65 Fed. Reg. at 2727.  Although the rule contains no date,
    the agency avers that it will apply the rule only to SIPs or
    FIPs adopted before May 1, 2003, the s 126 deadline.
    The Supreme Court recently held that we should not defer
    to an agency's interpretation imputing a limiting provision to
    a rule that is silent on the subject, lest we "permit the
    agency, under the guise of interpreting a regulation, to create
    de facto a new regulation."  Christensen v. Harris County,
    
    529 U.S. 576
    , 588 (2000).  The Court, however, carefully
    limited this principle to cases in which the agency's interpre-
    tation postdated its adoption of the rule and was not itself
    "subject to the rigors of ... notice and comment."  
    Id. (citing Reno
    v. Koray, 
    515 U.S. 50
    , 61 (1995)).  We therefore contin-
    ue to grant "a high degree of deference" to an interpretation
    that the agency promulgates contemporaneously with its own
    regulation, affirming it "unless it is plainly erroneous or
    inconsistent with the regulation."  Jersey Shore Broad. Corp.
    v. FCC, 
    37 F.3d 1531
    , 1536 (D.C. Cir. 1994).
    Here the agency contends that it imputed a date to
    s 52.34(i) not post hoc but "[t]hroughout the Section 126
    rulemaking."  Although the date might better have been
    made explicit in the preamble to the rule, the agency did
    clearly, albeit implicitly, assume that s 52.34(i) would apply
    only to SIPs promulgated before the s 126 deadline.  This is
    evident from the agency's express reservation for another
    rulemaking of the question whether it would "automatically
    withdraw the section 126 findings upon EPA approval of a
    later SIP revision."  Jan. 2000 Rule, 65 Fed. Reg. at 2683/2.
    A contrary interpretation, moreover, would apparently create
    a conflict between s 52.34(i) and the s 126 deadlines, the
    sanctity of which the EPA emphasized throughout its rule-
    making.  Because the EPA appears ever since the rule was
    promulgated to have interpreted s 52.34(i) to apply only to
    SIPs approved before May 1, 2003, and because this interpre-
    tation is not "plainly erroneous or inconsistent with the
    regulation," Jersey 
    Shore, 37 F.3d at 1536
    , we defer to the
    agency's view.
    C.   Significant Contribution
    Non-State Petitioners challenge the methodology by which
    EPA reached its findings of "significant contribution" to
    nonattainment of the "1-hour" ozone rule under s 126, 42
    U.S.C. s 7426.  EPA started with the two-step method that it
    had used in issuing the SIP call and that we upheld in
    Michigan v. EPA, 
    213 F.3d 663
    , 674-80 (D.C. Cir. 2000).  As
    we explained there, EPA first performed computer modeling
    to determine whether a state's manmade NOx emissions
    perceptibly hindered a downwind state's attainment.  
    Id. at 675.
     For any state exceeding EPA's threshold criteria, EPA
    then defined as "significant" those emissions that could be
    eliminated through application of "highly cost-effective" con-
    trols, namely measures costing no more than $2,000 per ton of
    NOx removed.  
    Id. Similarly, EPA
    relied here on the state-
    wide threshold findings made in the SIP call and then applied
    the same cost-effectiveness criterion to determine which
    sources to include.  See Findings of Significant Contribution
    and Rulemaking on Section 126 Petitions for Purposes of
    Reducing Interstate Ozone Transport, 63 Fed. Reg. 56,292,
    56,301/3 (proposed Oct. 21, 1998) ("Oct. 1998 Rule").
    As discussed above, 
    see supra
    Part II.B, both the SIP call
    and the s 126 rulemaking are directly linked to the require-
    ment under s 110(a)(2)(D)(i) that SIPs contain provisions
    prohibiting "any source or other type of emissions activity
    within the State from emitting any air pollutant in amounts
    which will ... contribute significantly to nonattainment...."
    s 110(a)(2)(D)(i), 42 U.S.C. s 7410(a)(2)(D)(i).  But the neces-
    sary determinations are different in at least two material
    respects.  First, whereas the SIP call exercise yielded a total
    amount of NOx cutback for each state, which the state was
    then free to achieve however it might, see 
    Michigan, 213 F.3d at 687-88
    , here the mandate applies directly to sources.
    Second, whereas s 110(a)(2)(D)'s broad reference to "any
    source or other type of emissions activity" supported SIP call
    findings based on aggregate emissions from within each
    regulated state, s 126 demands that the significant contribu-
    tion come from a "major source or group of stationary
    sources."  42 U.S.C. s 7426(b) (emphasis added).
    The Non-State Petitioners argue that this latter distinction
    renders EPA's reliance on the SIP call findings inadequate;
    the findings based on all emissions can't determine whether
    stationary source emissions are sufficient.  Instead of using
    those findings, petitioners argue, EPA needed first to make
    the more rigorous finding that the specified stationary
    sources within a given state independently met its threshold
    test for effect on downwind nonattainment.
    Petitioners find support for their view of the statute in
    Michigan, where we said that the first step in EPA's
    s 110(a)(2)(D)(i) finding must show a "measurable contribu-
    tion" to downwind 
    nonattainment. 213 F.3d at 683-84
    .
    Here, EPA did not purport to satisfy such a standard on the
    basis of the covered stationary sources alone.  Rather, it
    conceded, "[i]t is conceivable that modeling only the emissions
    from the section 126 sources would result in smaller ambient
    impacts downwind [compared to total man-made emissions],
    and....  those smaller impacts, if analyzed on the basis of
    the metrics and thresholds developed for State-wide [total
    man-made] emissions, may not exceed those thresholds."
    May 1999 Rule, 64 Fed. Reg. at 28,283/1.
    EPA defended its approach both as a recognition of the fact
    that the ozone problem is due to the accumulation of emis-
    sions and as a sensible reconciliation of s 110(a)(2)(D)(i) and
    s 126.  See 
    id. at 28,282-83.
     On the need for some aggrega-
    tion, of course, there can be no quarrel.  Congress's use of
    the phrase "group of ... sources" plainly reflected a decision
    to act against sources whose emissions, while harmless indi-
    vidually, could become harmful when combined with others.
    And, given the relevant statutory provisions, it was reason-
    able for EPA to link its stationary source findings to the
    significance of a state's total NOx emissions.  By speaking of
    stationary sources that emit pollutants "in violation of the
    prohibition of [s 110(a)(2)(D)(i)]," Congress clearly hinged the
    meaning of s 126 on that of s 110(a)(2)(D)(i).  EPA reasoned
    that if it treated any state's entire manmade emissions as the
    controlling aggregate for both purposes and found a "signifi-
    cant contribution," "then the State's section 126 sources may
    be subject to SIP controls."  
    Id. at 28,282/3
    (emphasis added).
    In other words, a source can be subject to s 126 controls only
    if it is at least at risk of being subject to SIP controls.  The
    effect, of course, is to displace the discretion the state would
    enjoy in the SIP process under s 110(a)(2)(D)(i).  But this
    displacement of state power seems not materially greater
    than is inherent in EPA's interpretation of s 126, which we
    uphold vis-A-vis the objections petitioners raised in their
    initial briefs.  
    See supra
    Part II.B.  EPA's current reading,
    to be sure, may not be the only possible or even the most
    compelling view of s 126.  Perhaps the EPA could reasonably
    read it as petitioners would, and require that stationary
    sources as a whole independently satisfy some "meaningful
    contribution" test before they may be subject to s 126 find-
    ings.  But given s 126's silence on what it means for a
    stationary source to violate s 110(a)(2)(D)(i), EPA's approach
    is at least reasonable, and therefore entitled to deference
    under Chevron.
    Petitioners point to language we used in Michigan striking
    down part of what EPA had done there.  For certain states
    EPA had analyzed emissions data only from a portion of the
    state closest to the affected downwind areas, and, finding that
    portion to have made contributions exceeding the threshold,
    had made "contribution" findings for the entire state.  We
    held this extension to the whole state invalid because EPA
    might well have included areas that were "wholly innocent of
    material contributions."  
    Michigan, 213 F.3d at 681-85
    .  In
    that context, we said that a significant contribution finding
    required evidence of a "measurable contribution" and that
    "[i]nterstate contributions cannot be assumed out of thin air."
    
    Id. at 684.
    In the present case Non-State Petitioners do not dispute
    that emissions from affected s 126 sources actually contribute
    to total manmade NOx emissions that, at the statewide aggre-
    gate level, meet the EPA criteria upheld in Michigan.  The
    process here does not involve sweeping up individual sources
    that might well not be part of the problem at all.  The
    concern that drove our discussion in Michigan is inapplicable.
    Non-EGU Petitioners, by contrast, suggest a point that
    might conceivably implicate Michigan's "measurable contri-
    bution" concern.  They argue that because EPA failed to
    model the contribution of each particular source individually,
    its findings ignore the effects of industrial sources' having
    lower smoke stacks than utility sources.  If in fact NOx
    emissions from stationary sources with low smoke stacks do
    not reach other states as easily as emissions from other
    sources, these petitioners might have a point as to the scope
    of what Michigan allows.  But the petitioners' vague claim
    that lower stack height "affects the downwind impact" in no
    way quantifies the effect, much less makes out a claim that
    certain sources do not measurably contribute to downwind
    nonattainment.  In Michigan we left "EPA free to select
    states as a unit of measurement," saying that "[i]n turn,
    states (or the areas of states that believed themselves inno-
    cent of material contributions, or sources located therein),
    might respond by offering finer-grained 
    computations." 213 F.3d at 684
    .  So, too, the low-stack sources might have come
    forward with such numbers, but they have not.  Or they
    might have shown that EPA's modeling bore "no rational
    relationship to the reality it purport[ed] to represent," Sierra
    Club v. EPA, 
    167 F.3d 658
    , 662 (D.C. Cir. 1999), thereby
    throwing the burden back on EPA, but they have not.
    A final challenge to the "contribution" findings is the Non-
    State Petitioners' argument that for four states (Indiana,
    Kentucky, Michigan and New York) EPA used state-based
    aggregations to find the contribution but then applied con-
    trols to sources in only part of each state.  This is a reverse
    of what we struck down in Michigan:  there extension from
    part to the whole, here, contraction from the whole to a part.
    EPA's explanation was that while the modeling was state-
    wide, s 126 empowered it only to address sources named in
    the downwind states' petitions (which here they did by area).
    See Jan. 2000 Rule, 65 Fed. Reg. at 2685/1.  Petitioners do
    not contest EPA's legal assumption, but simply say that the
    process invalidates the finding.
    EPA questions whether this objection was raised with
    reasonable specificity, which under 42 U.S.C. s 7607(d)(7)(B)
    is a precondition for judicial review.  But in the rulemaking
    itself EPA plainly acknowledged a claim that it was wrong to
    rely on all manmade emissions from an entire state where the
    petitions sought relief "from sources located in only a portion
    of the upwind State."  May 1999 Rule, 64 Fed. Reg. at
    28,292/3.  Nonetheless, petitioners' claim leaves out a critical
    point.  Extension of a finding from an area responsible for
    pollution problems to another area, where the two are linked
    only by falling within state boundaries, raises obvious risks of
    burdening the innocent with the guilty.  That risk is far lower
    in moving from the whole to a part, at least in the absence of
    some reason to doubt that the part in question shared in the
    state's "contribut[ory]" role or that it had been rationally
    selected on the basis of relevant criteria.  Accordingly, the
    principle that we accepted above in the context of the broad
    claim (based on s 126's exclusive focus on stationary
    sources)--namely, that EPA may subject to s 126 controls
    any source that might have been subject to SIP controls
    properly adopted under s 110(a)(2)(D)(i), see 
    id. at 28,282/3--
    appears to cover this issue equally well--at least in the
    absence of any contention that the petitioning states were
    arbitrary or discriminatory in their designation of sources
    (whether they identified them by geographic category, as
    here, or otherwise).
    D.   Emission Limitation Determinations
    In order to allocate NOx emission allowances to individual
    sources, the EPA made state-by-state emission projections
    for 2007.  The EPA based each state's NOx emission budget
    on projected 2007 heat input (or "utilization") for electric
    generating units ("EGUs") and projected 2007 emissions for
    non-electric generating, industrial facilities ("non-EGUs").
    The projections were developed with computer models work-
    ing off of "baseline" emissions and heat input data from 1995
    and 1996.  Various petitioners challenge the EPA's budget
    allocations as arbitrary and capricious.  While we generally
    uphold the EPA's authority to make emission projections and
    set emission limitations accordingly, we do so only where the
    EPA adequately responded to comments and explained the
    basis for its decisions.  Thus, although we uphold the EPA's
    use of the Integrated Planning Model ("IPM") as against the
    specific challenges forwarded by MW & SE Petitioners, we
    conclude that at least one application of the model is suffi-
    ciently unexplained that we must remand the EPA's IPM-
    derived growth factors for further explanation.
    1.   Standard of Review
    Agency determinations based upon highly complex and
    technical matters are "entitled to great deference."  Public
    Citizen Health Research Group v. Brock, 
    823 F.2d 626
    , 628
    (D.C. Cir. 1987);  see also Huls Am., Inc. v. Browner, 
    83 F.3d 445
    , 452 (D.C. Cir. 1996) ("[W]e will give an extreme degree
    of deference to the agency when it 'is evaluating scientific
    data within its technical expertise.' " (citation omitted)).  In a
    prior case named Appalachian Power Co. v. EPA, 
    135 F.3d 791
    , 802 (D.C. Cir. 1998), we described statistical analysis as
    "perhaps the prime example" of an area
    of technical wilderness into which judicial expeditions are
    best limited to ascertaining the lay of the land.  Although
    computer models are "a useful and often essential tool
    for performing the Herculean labors Congress imposed
    on EPA in the Clean Air Act," their scientific nature
    does not easily lend itself to judicial review....  [I]t is
    only when the model bears no rational relationship to the
    characteristics of the data to which it is applied that we
    will hold that the use of the model was arbitrary and
    capricious.
    
    Id. at 802
    (citation omitted).
    Under this standard, the EPA has "undoubted power to
    use predictive models" so long as it "explain[s] the assump-
    tions and methodology used in preparing the model" and
    "provide[s] a complete analytic defense" should the model be
    challenged.  Small Refiner Lead Phase-Down Task Force v.
    EPA, 
    705 F.2d 506
    , 535 (D.C. Cir. 1983) ("SRLPTF") (cita-
    tions and internal quotation marks omitted).  That a model is
    limited or imperfect is not, in itself, a reason to remand
    agency decisions based upon it.
    Ultimately, ... we must defer to the agency's decision on
    how to balance the cost and complexity of a more elabo-
    rate model against the oversimplification of a simpler
    model.  We can reverse only if the model is so oversim-
    plified that the agency's conclusions from it are unrea-
    sonable.
    
    Id. 2. The
    Integrated Planning Model
    The MW & SE Petitioners contend that the EPA's emis-
    sions growth projections were arbitrary and capricious be-
    cause they relied upon a computer model--the "IPM"--that
    underestimated growth rates for electric power generation in
    some upwind states.  Several states, including North Car-
    olina, submitted comments to the EPA arguing that they
    projected significantly greater growth in electric power gen-
    eration than that predicted by the IPM.
    Rather than address the specific complaints of each com-
    menting state, the EPA defended its reliance upon the IPM
    on three broad grounds.  First, all state NOx budget growth
    rates should be based upon the same methodology to ensure
    consistency in the NOx cap's application.  Responses to Sig-
    nificant Comments on the Proposed Findings of Significant
    Contribution and Rulemaking on Section 126 Petitions for
    Purposes of Reducing Interstate Ozone Transport at 111
    (April 1999) ("April 1999 RTC").  Second, the IPM "has
    received extensive comment, review, and revision over the
    past several years" during the NOx SIP call and other
    proceedings.  Id.;  see also Appalachian 
    Power, 135 F.3d at 814-15
    (upholding the EPA's use of the IPM).  Third, the
    IPM "provides a reasonable forecast of State growth rates
    because it carefully takes into account the most important
    determinants of electricity generation growth that are facing
    the power industry today."  April 1999 RTC at 112.
    Given the highly deferential standard of review applied to
    such questions, and the EPA's clear authority to rely upon
    computer models in place of inconsistent, incomplete, or
    unreliable empirical data, the Agency's decision to rely upon
    the IPM, rather than the projections offered by individual
    states, was not arbitrary and capricious.  See Texas Mun.
    Power Agency v. EPA, 
    89 F.3d 858
    , 870 (D.C. Cir. 1996).  In
    the EPA's judgment, the IPM offered a more comprehensive
    and consistent means of allocating emission allowances than
    sorting through the various state-specific projections.  That
    the EPA's projections depend, in large part, on economic
    projections, rather than environmental factors, makes little
    difference.  "[I]t is within the scope of the agency's expertise
    to make such a prediction about the market it regulates, and
    a reasonable prediction deserves our deference notwithstand-
    ing that there might also be another reasonable view."  Envi-
    ronmental Action, Inc. v. FERC, 
    939 F.2d 1057
    , 1064 (D.C.
    Cir. 1991).  MW & SE State Petitioners may believe their
    projections are superior to the EPA's--and they may even be
    correct--but they have not proved their case.
    3.   EGU Growth Factors
    Accepting the EPA's general reliance upon the IPM, Non-
    State Petitioners object to the EPA's use of growth rates
    generated by the IPM for 2001-2010 to estimate facility
    utilization growth for the period 1996-2007.  According to
    petitioners, this yielded estimates for facility utilization in
    2007 that not only fail to reflect the best information available
    to the Agency but that are flatly inconsistent with observed
    growth rates through 1998.  Such apparently anomalous esti-
    mates, petitioners claim, are arbitrary and capricious, at least
    absent any explanation from the agency as to why they are
    appropriate.  As a result, Non-State Petitioners claim, at
    least some EGUs are subject to excessively stringent emis-
    sion limitations.
    The EPA based its state-specific emission budget limita-
    tions on projections of facility utilization for 2007.  This
    projection was calculated by taking a baseline utilization rate
    and applying a "growth factor" to project the 2007 utilization
    rate, upon which the emission budget limitation would then be
    imposed.  For the starting baseline utilization rate, the EPA
    used the actual EGU utilization rate for either 1995 or 1996,
    whichever was greater.  For the growth factors, the EPA
    relied upon the IPM facility utilization projections for the
    2001-2010 period to generate an average annual growth rate
    that was then applied to the 1996-2007 period.
    Petitioners contend that the EPA's resulting projections
    significantly underestimated growth rates in some states.  In
    Michigan and West Virginia, for example, actual utilization in
    1998 already exceeded the EPA's projected levels for 2007.
    This, on its face, raises questions about the reliability of the
    EPA's projections.  While courts routinely defer to agency
    modeling of complex phenomena, model assumptions must
    have a "rational relationship" to the real world.  See, e.g.,
    Chemical Mfrs. Ass'n v. EPA, 
    28 F.3d 1259
    , 1265 (D.C. Cir.
    1994).  Future growth projections that implicitly assume a
    baseline of negative growth in electricity generation over the
    course of a decade appear arbitrary, and the EPA can point
    to nothing in the record to dispel this appearance.
    Despite the apparent disparity between the EPA's growth
    projections and observed growth rates, the EPA claims its
    growth factors were reasonable and due deference from this
    court.  Yet even in the face of evidence suggesting the EPA's
    projections were erroneous, the EPA never explained why it
    adopted this particular methodology.  The EPA claims it
    made a reasonable choice--and it may be right--but simply
    to state such a claim does not make it so.  There must be an
    actual reason articulated by the agency at some point in the
    rulemaking process.  There is none here.
    The EPA tries to defend its projections by claiming that
    they may, at least in some instances, actually inflate utiliza-
    tion projections generating "slack" for affected EGUs.  Yet
    the fact that some petitioners may benefit from the inaccura-
    cy of the EPA's projections does not make them reasonable.
    Faced with evidence that its projections for 2007 are lower
    than actual utilization rates in 1998 for some states, the EPA
    has little answer.  The EPA first claims that regulated
    facilities can always purchase additional allowances, albeit at
    their own expense.  This is no answer.  The EPA then
    suggests that facility utilization can fluctuate from year to
    year.  For example, the EPA found in some states that
    utilization rates were higher in 1995 than 1996.  This may be
    true from one year to the next, but the EPA offers no
    plausible explanation for how interannual variation can ex-
    plain utilization rates in 2007 substantially lower than those
    observed in 1998.  Finally, the EPA claims that when the
    projections are considered on a region-wide level such dispari-
    ties are likely to disappear.  As budgets are set on a state-by-
    state level, this is small consolation to petitioners.  The EPA
    is well aware of its obligation to "examine the relevant data
    and articulate a satisfactory explanation for its action," yet it
    failed to discharge this obligation here.  Motor Vehicle Mfrs.
    Ass'n v. State Farm Mut. Auto. Ins. Co., 
    463 U.S. 29
    , 43
    (1983).
    The EPA had other ways of generating 2007 utilization
    projections.  The EPA readily admits that it had IPM projec-
    tions for the 1996-2001 period, as well as for 2007.  The EPA
    makes no claim that these results, as opposed to the projec-
    tions offered up by the states, are inherently less reliable or
    consistent than the growth projections the EPA used here.
    The EPA readily acknowledges it utilized one set of growth-
    rate projections to set allowance budgets, another to assess
    emission reduction costs.  As it explained in its Response to
    Comments:
    The budgets were constructed using growth rates for
    1996-2007 that were consistent with the growth rates in
    IPM for 2001-2010, which may be higher or lower than
    the growth rates for the years 1996-2001.  EPA's analy-
    sis of the costs of complying with these budgets, howev-
    er, was conducted using IPM, which incorporates inter-
    nally consistent growth assumptions--i.e., the growth for
    1996 through 2001 is based on IPM assumptions for 1996
    through 2001, and the growth for 2001 through 2010 is
    based on IPM assumptions for 2001 through 2010.
    April 1999 RTC at 112-13.  While admitting that two sets of
    growth rates were used, the EPA offers no cogent explana-
    tion for this difference.  Instead, the EPA merely asserts,
    without adequate explanation, that each choice was reason-
    able.  The EPA further offers no comprehensible explanation
    how relying upon erroneously low growth rates will not cause
    petitioners harm.
    As we discussed above, the EPA has "undoubted power to
    use predictive models" but only so long as it "explain[s] the
    assumptions and methodology used in preparing the model"
    and "provide[s] a complete analytic defense" should the model
    be challenged.  
    SRLPTF, 705 F.2d at 535
    (citations and
    internal quotation marks omitted).  In this case, the EPA has
    not fully explained the bases upon which it chose to use one
    set of growth-rate projections for costs and another for
    budgets, nor has it addressed what appear to be stark
    disparities between its projections and real world observa-
    tions.  "With its delicate balance of thorough record scrutiny
    and deference to agency expertise, judicial review can occur
    only when agencies explain their decisions with precision, for
    'it will not do for a court to be compelled to guess at the
    theory underlying the agency's action ...' "  American Lung
    Ass'n v. EPA, 
    134 F.3d 388
    , 392 (D.C. Cir. 1998) (quoting
    SEC v. Chenery Corp., 
    332 U.S. 194
    , 196-97 (1947)).  As a
    result, we have no choice but to remand the EPA's EGU
    growth factor determinations so that the agency may fulfill its
    obligation to engage in reasoned decisionmaking on how to
    set EGU growth factors and explain why results that appear
    arbitrary on their face are, in fact, reasonable determinations.
    4.   Non-EGU Budget Determinations
    Non-State Petitioners allege that the EPA repeatedly mod-
    ified the growth assumptions in its calculation of non-EGU-
    sector NOx budgets in such a fashion as to preclude any
    meaningful opportunity to comment.  According to petition-
    ers, when the EPA modified successive versions of its techni-
    cal support document ("TSD") it did not include a complete
    set of non-EGU growth factors.  Then, when the EPA issued
    the final non-EGU growth budgets in December 1999, it
    released modified growth rates without any explanation.  The
    EPA explained that "corrections to the growth rates ... were
    made to reflect the growth rates misapplied in the May 14,
    1999 version of the budget."  Technical Amendment to the
    Finding of Significant Contribution and Rulemaking for Cer-
    tain States for Purposes of Reducing Regional Transport of
    Ozone, 65 Fed. Reg. 11,222, 11,223 (Mar. 2, 2000).  Because
    these changes were made without notice or explanation, peti-
    tioners contend they must be set aside.
    The EPA asserts petitioners waived this claim.  "[T]he
    procedural requirements of the Clean Air Act do not permit
    [petitioners] to raise this objection for the first time on
    appeal."  API v. Costle, 
    665 F.2d 1176
    , 1190-91 (D.C. Cir.
    1981).  Under section 307(d)(7)(B) of the Act, a reviewing
    court may only consider "an objection to a rule or procedure
    which was raised with reasonable specificity during the period
    for public comment."  42 U.S.C. s 7607(d)(7)(B).  The peti-
    tioner is only excused from raising an objection where it is
    "impracticable ... or if the ground for such objection arose
    after the period for public comment."  Yet even then the
    petitioner must first seek a proceeding for reconsideration.
    
    Id. Only then
    may petitioner seek judicial review.  This
    court "enforces this provision 'strictly.' "  MEMA v. Nichols,
    
    142 F.3d 449
    , 462 (D.C. Cir. 1998) (citation omitted).
    These objections were never raised during the notice and
    comment period, nor did petitioner ever seek reconsideration.
    Neither of these facts is contested by petitioners.  Thus, even
    if, as petitioners claim, it was impracticable for many facilities
    to determine their growth factors, they waived their claim.
    Moreover, the EPA notes that petitioners do not cite any
    facilities that were unable to determine their growth factors
    due to the EPA's alleged omissions, suggesting that there is
    no harm to redress.  Accordingly, the relevant petitions are
    denied.
    5.   Local Regulation and Permit Trading
    The MW & SE State Petitioners have also argued that the
    permit trading system contravenes CAA s 116, which allows
    a state to impose a local air quality standard more stringent
    than the corresponding NAAQS.  42 U.S.C. s 7416.  The
    petitioners' concern is that a source might purchase permits
    in excess of applicable local limits and then claim the right to
    pollute in excess of those limits, up to the full amount of its
    permits.  The EPA properly denies that the permit trading
    program would make such a claim viable.  Nothing in the
    challenged rules exempts from s 116 a source that has ac-
    quired permits.
    Although they are unable to point to any provision of the
    rule that allows permit trading to trump a local rule autho-
    rized by s 116, the petitioners worry in their reply brief that
    "other interpretations" might prevail in the future.  Perhaps
    so, but for now, and until such time as it may conduct a new
    rulemaking, the EPA is committed to the position that it
    espouses here.  The petitioners also suggest that the EPA
    might decline to approve a SIP that imposes stringent local
    limits because of its commitment to a market in emissions
    permits;  but non-approval of a SIP is subject to judicial
    review, and an argument based upon the incompatibility of
    EPA policy and s 116 may be raised when and if the EPA
    disapproves a SIP in order to advance the market for emis-
    sions permits.
    E.   Regulation of "Future" Sources
    The section 126 rule establishes a NOx budget for each
    upwind state found to contribute significantly to nonattain-
    ment in the petitioning states.  Ninety-five percent of this
    budget is allocated in the form of NOx emission allowances to
    existing sources.  Five percent of each state's budget is set
    aside for future sources.  In this fashion, the rule caps
    emissions on existing and proposed sources, as well as
    sources to be proposed and built in the future.
    MW & SE State Petitioners challenge the EPA's authority
    to impose the NOx cap limits to future, as-yet-unproposed
    stationary sources under section 126.  Petitioners argue that
    the statute does not authorize the EPA to regulate future
    sources, and that the EPA's contrary interpretation of section
    126 is unreasonable.  We disagree.
    We review the EPA's interpretation under the two-part
    analysis established in Chevron U.S.A. Inc. v. Natural Re-
    sources Defense Council, Inc., 
    467 U.S. 837
    (1984).  "First,
    always," we must consider "whether Congress has directly
    spoken to the precise question at issue." An affirmative
    answer "is the end of the matter;  for the court, as well as the
    agency, must give effect to the unambiguously expressed
    intent of Congress."  
    Id. at 842-43.
     If, on the other hand,
    "the statute is silent or ambiguous with respect to the specific
    issue," we must uphold "a reasonable interpretation made by
    the administrator of an agency."  
    Id. at 843,
    844;  see also
    American Bus Ass'n v. Slater, 
    231 F.3d 1
    , 4 (D.C. Cir. 2000).
    Under section 126(b) a downwind state "may petition the
    Administrator for a finding that any major source or group of
    stationary sources emits or would emit any air pollutant" in
    an amount which contributes significantly to nonattainment in
    the petitioning state.  42 U.S.C. s 7426(b).  Once the EPA
    makes a section 126(b) finding, section 126(c) provides that:
    it shall be a violation of this section and the applicable
    implementation plan in such State--
    (1) for any major proposed new (or modified) source
    with respect to which a finding has been made under
    subsection (b) of this section to be constructed or to
    operate in violation [of this section or section 110], or
    (2) for any major existing source to operate more than
    three months after such finding has been made with
    respect to it.
    
    Id. s 7426(c).
     The Administrator may allow the continued
    operation of existing sources beyond three months provided
    such sources comply with emission reductions provided by the
    Administrator to "bring about compliance ... as expeditious-
    ly as practicable, but in no case later than three years after
    the date of such finding."  
    Id. Petitioners argue
    that the EPA's interpretation fails at the
    first step of Chevron, contending that section 126(c) autho-
    rizes the EPA to regulate existing and proposed sources but
    not future sources that are not as yet proposed.  In petition-
    ers' view, the enumeration of two classes of sources that may
    be controlled--"major existing sources" and "proposed new
    (or modified) sources"--precludes the EPA's authority over a
    third class of sources--"future as-yet-unproposed" sources.
    Expressio unius est exclusio alterius.  Petitioners argue that
    irrespective of whether the EPA can make findings with
    regard to future, as-yet-unproposed sources, it is not empow-
    ered to prohibit their construction or limit their emissions
    under section 126(c).
    We reject petitioners' contention that the statute unambig-
    uously reflects congressional intent to limit the EPA to the
    two categories defined by petitioners.  Section 126 is at least
    subject to the interpretation that Congress intended to autho-
    rize the regulation of emissions from future sources.  Under
    section 126(b), the EPA may find that "any major source or
    group of stationary sources emits or would emit" pollution in
    violation of section 110.  The inclusion of the future condition-
    al phrase "would emit" arguably contemplates the EPA's
    intervention to prevent future emissions that would contrib-
    ute significantly to nonattainment in downwind states.  Simi-
    larly, as the EPA argues, section 126(c) explicitly bars the
    construction or operation of "any major new proposed
    sources."  By barring the construction of those sources, the
    statute clearly contemplates the imposition of controls on at
    least some facilities that do not yet exist.  These provisions,
    taken together, may not compel the regulation of future
    sources under section 126, but they do not unambiguously
    forbid it.  At the least, they introduce sufficient ambiguity
    into the statutory scheme to prevent resolution of this issue
    under Chevron step one.
    In the absence of an unambiguous expression of congres-
    sional intent in the plain language of the statute, we advance
    to the second step of the Chevron analysis to determine
    whether the EPA's interpretation of section 126 is a reason-
    able one.  We conclude that it is.  Prior to 1990, section
    126(b) only authorized EPA findings that "a major source
    emits or would emit any air pollutant" which contributes
    significantly to nonattainment in a downwind state.  42
    U.S.C. s 7426(b) (1977).  The 1990 Clean Air Act Amend-
    ments expanded the scope of this provision by allowing EPA
    findings with regard to "any major source or group of sta-
    tionary sources."  42 U.S.C. s 7426(b) (1994) (emphasis add-
    ed).  Similarly, the EPA notes that the cross-referenced
    provision of the act, section 110(a)(2)(D)([i]) prohibits "type[s]
    of emissions activity" that contribute significantly.  42 U.S.C.
    s 7410(a)(2)(D)(i).  Like section 126, section 110 confers au-
    thority based upon the kind of activity in question.  It does
    not impose any temporal limit.
    The statutory language allows the EPA to regulate facili-
    ties in upwind states as a class or category, e.g. all coal-fired
    power plants in North Carolina.  If such facilities, as a class,
    contribute significantly to nonattainment in northeastern
    states, this is as true for as-yet-unbuilt plants as it is for
    existing ones.  Therefore, the EPA argues, it is reasonable to
    include future sources in the "group of stationary sources"
    found to contribute significantly to downwind nonattainment
    under section 126(b).  Indeed, it would be irrational to enable
    the EPA to make findings that a group of sources in an
    upwind state contribute to downwind nonattainment, but then
    preclude the EPA from regulating new sources that contrib-
    ute to that same pollution.  As the EPA explained in its
    Response to Comments:
    Once EPA has determined that the emissions from the
    existing sources in an upwind State already make a
    significant contribution to one or more petitioning down-
    wind States, any additional emissions from a new source
    in that upwind State would also constitute a portion of
    that significant contribution, unless the emissions from
    that new source are limited to the level of highly effective
    controls.
    April 1999 RTC at 39.  The EPA's construction of section 126
    avoids this result.
    The language of section 126(c) does not make the EPA's
    interpretation an unreasonable one.  Petitioners note that
    section 126(c) specifically identifies two classes of sources--
    "major existing sources" and "proposed new (or modified)
    sources"--and makes no mention of future, as-yet-unproposed
    sources.  What petitioners ignore is that section 126(c), by its
    terms, defines what constitutes a violation of section 126.
    For a facility to violate the law, by definition it must either
    exist or be proposed.  Future, as-yet-unproposed sources are
    not mentioned because unproposed, unbuilt facilities cannot
    themselves be in violation of anything.  At the time they
    become subject to the section 126(c) limitation, however, they
    will either be an "existing" or "proposed new" source.  That
    is to say, section 126(c) has no direct effect on plants that
    have yet to be proposed for the precise reason that they have
    not yet been proposed.  This does not mean, however, that
    facilities proposed after the promulgation of the EPA's find-
    ings are exempt from section 126(c).  Once they are pro-
    posed, they become part of the regulated class.
    Perhaps it would be reasonable for the EPA to interpret
    the statute as urged by petitioners.  Section 126 is arguably a
    stop-gap provision designed to protect downwind states from
    upwind pollution by empowering the federal government to
    take direct action against those specific upwind facilities
    which cause downwind harm.  From a structural standpoint,
    this interpretation may seem intuitive:  States regulate all
    emitters;  the EPA only regulates those emitters shown to
    contribute significantly to downwind nonattainment despite
    the existence of a SIP.  Yet however rational this alternative
    interpretation of the Clean Air Act may be, under Chevron
    step two, the EPA's interpretation controls so long as it is
    based upon a permissible construction of the statute.  As we
    conclude that the EPA adopted a reasonable interpretation of
    section 126's somewhat ambiguous provisions, its interpreta-
    tion is upheld.
    F.   The Dorris Report
    In comments submitted on August 9, 1999, North Carolina
    requested that the EPA consider and comment upon "all
    materials submitted to it by Dr. Gary Dorris, Hagler-Bailly,
    or Stratus Consulting since July 1, 1998."  Dr. Dorris was
    hired by the EPA to conduct modeling work in conjunction
    with the NOx SIP call.  According to North Carolina, Dr.
    Dorris's "extensive" modeling "shows that North Carolina
    does not significantly contribute to nonattainment areas"
    and provides "a rational basis for determining significant
    contribution that considers cost effectiveness...."  In its
    comments, North Carolina identified numerous materials
    submitted by Dr. Dorris, including briefing documents and
    preliminary analytical results.  North Carolina states that it
    would have commented on these materials directly, however
    the EPA had denied North Carolina's FOIA requests for
    access to the studies.
    On November 24, 1999, Dr. Dorris submitted his final
    report to the EPA.  According to the EPA, the report used
    computer modeling to assess the relative cost-effectiveness of
    NOx emission reductions in upwind states in comparison to
    emission reductions in downwind states.  This report conclud-
    ed, among other things, that the relative contribution of a ton
    of NOx emissions will vary due to "emission source location,
    stack elevation, and chemical species."  This, in turn, impacts
    the cost-effectiveness of emission reductions in upwind states.
    In promulgating its final section 126 rule, the EPA made no
    mention of the Dorris Report or any of Dr. Dorris' prelimi-
    nary findings.  While the report was relevant to the signifi-
    cant contribution issue, the EPA maintains that it made its
    final significant contribution determination with the May 1999
    section 126 rule.  When North Carolina submitted its com-
    ments in August, the EPA was only considering narrow
    issues related to the stay of the SIP submission deadlines and
    the impact of American Trucking Ass'ns v. EPA, 
    175 F.3d 1027
    , reh'g granted in part and denied in part, 
    195 F.3d 4
    (D.C. Cir. 1999), rev'd in part sub nom. Whitman v. Ameri-
    can Trucking Ass'n, 
    121 S. Ct. 903
    (2001).
    North Carolina contends that the EPA erred in refusing to
    consider the Dorris Report in the section 126 rulemaking.
    There is no doubt that the EPA is required to examine the
    relevant data and articulate a sufficiently reasoned explana-
    tion for its action.  See Motor Vehicle Mfrs. Ass'n, Inc. v.
    State Farm Mut. Auto. Ins. Co., 
    463 U.S. 29
    , 43 (1983).  This
    Court is obligated to "overturn a rulemaking as arbitrary and
    capricious where the EPA has failed to respond to specific
    challenges that are sufficiently central to its decision."  Inter-
    national Fabricare Inst. v. EPA, 
    972 F.2d 384
    , 389 (D.C. Cir.
    1992).  An agency is not required to consider issues and
    evidence in comments that are not timely filed.  Personal
    Watercraft Indus. Ass'n v. Dept. of Commerce, 
    48 F.3d 540
    ,
    543 (D.C. Cir. 1995) ("Agencies are free to ignore such late
    filings.").  Therefore, if North Carolina did not raise the
    Dorris Report at the appropriate time, the EPA may ignore
    the findings contained therein.
    Contrary to North Carolina's claims, the EPA was justified
    in ignoring the Dorris materials because they pertained to
    aspects of the section 126 rule which the EPA had already
    finalized by the time North Carolina submitted its regulatory
    comments.  It may well be true that the EPA had access to
    draft copies of the Dorris Report while the comment period
    was still open.  Yet the EPA was no longer considering the
    significant contribution issues when North Carolina first re-
    quested review of the Dorris materials.  Significant contribu-
    tion was considered in the prior rulemaking and finalized in
    the May 1999 rule.  Jan. 2000 Rule, 65 Fed. Reg. at 2684-85.
    Because North Carolina's request that the EPA consider
    the Dorris Report with respect to the significant contribution
    issues was not timely filed, the EPA did not arbitrarily and
    capriciously ignore the Dorris Report.  Instead of considering
    the Dorris Report as part of the section 126 rulemaking, the
    EPA treated North Carolina's submission as a petition for
    reconsideration.  See 
    id. at 2676.
    Under CAA section 307(d), any documents "which become
    available after the proposed rule has been published and
    which the Administrator determines are of central relevance
    to the rulemaking shall be placed in the docket as soon as
    possible after their availability."  42 U.S.C. s 7607(d)(4)(B)(i).
    Under both the plain language of this provision and this
    Court's precedents, the Administrator enjoys substantial def-
    erence in determining whether to consider material submitted
    after the close of the comment period.  See, e.g., Eastern
    Carolinas Broad. Co. v. FCC, 
    762 F.2d 95
    , 103 (D.C. Cir.
    1985) ("Courts normally reverse an agency's decision not to
    reopen the record only for abuse of discretion.").
    The EPA maintains its comments reveal that it carefully
    considered the report and its relevance to the section 126
    rule.  After such consideration, however, the EPA concluded
    that the report was too preliminary and limited to justify
    reopening the record and reconsidering its prior determina-
    tion.  While the Dorris Report relates to issues at the core of
    the NOx SIP call and section 126 rulemaking, the EPA viewed
    the report as "preliminary" and its findings limited.  In its
    August 2000 Response to Comments, the EPA noted the
    report "has not undergone scrutiny through notice-and-
    comment rulemaking" or "careful scientific and technical re-
    view."  Rulemaking for Section 126 Petitions-Responses to
    Significant Comments Which are [sic] Outside the Scope of
    the June 24, 1999 Notice of Proposed Rulemaking at 8 (Aug.
    2000).  The EPA further noted that the approach put forward
    by the report conflicts with the implementation of a market-
    based NOx emission trading program.  Given the deferential
    standard employed in this context, the EPA's refusal to
    reopen and reconsider its significant contribution findings
    must be upheld.
    III. NON-ELECTRIC GENERATING UNIT ISSUES
    A.   Alleged Budget Allocation Errors
    Non-EGU Petitioners complain that the EPA made sub-
    stantial errors in the allocation of emission allowances which
    can only be cured by a remand and reallocation of all
    emission allowances in the affected states.  Specifically, Non-
    EGU Petitioners identify two facilities for which there is a
    great disparity between allocated emissions and actual emis-
    sions.6  In one case, the EPA allocated a facility less than
    one-seventh what it should have been allocated because it
    used erroneous heat-input data.  In another, it grossly over-
    estimated a facility's share of state-wide NOx emissions.
    These errors not only impact the facilities in question, peti-
    __________
    6  Non-EGU Petitioners also argue that non-EGU sources that
    began operating between 1995 and May 1, 1997 were never allocat-
    ed the required NOx allowances.  We do not consider this claim
    because the EPA addressed the claims of the three units identified
    that fell into this category.  See Appalachian Power Co. v. EPA,
    No. 99-1200, 
    2000 WL 1683469
    (D.C. Cir. Oct. 13, 2000) (order,
    inter alia, severing claims of petitioners and holding them in
    abeyance pending implementation of settlement agreements).
    tioners claim, but all facilities in the state due to the state-
    wide NOx caps.
    The EPA argues that such claims are waived because they
    were not raised during the notice and comment period, nor
    does the record contain any indication that petitioners filed a
    motion for reconsideration.  The EPA allocated allowances
    based upon the heat input data it received from covered
    entities.  Where the EPA received information from covered
    facilities indicating an allocation error, it made corrections.
    Insofar as a covered facility failed to ensure that the EPA
    was making its allocation based upon proper data, the claim is
    waived and cannot be addressed via judicial review.  Of the
    two facilities cited by Petitioners in their brief, the EPA notes
    that one has settled its claim with the EPA, and the other
    was specifically identified in the EPA's rulemaking.  Oct.
    1998 Rule, 63 Fed. Reg. at 56,369.  The EPA's proposed rule
    also specified what sorts of units would be covered, irrespec-
    tive of their inclusion on the proposed list of allocations.  
    Id. at 56,332.
    Petitioners nonetheless argue that the existence of any
    allocation error requires setting aside all allowance allocations
    for a given state because the EPA has imposed state-specific
    budgets.  Even were this claim to have merit, it too was
    waived. Under the CAA, "[o]nly an objection to a rule or
    procedure which was raised with reasonable specificity during
    the period for public comment ... may be raised during
    judicial review."  42 U.S.C. s 7607(d)(7)(B).  The general
    complaints raised by Non-EGU Petitioners during the rule-
    making about errors in allowance allocations are insufficient
    to meet this requirement as they failed to provide the agency
    with enough information to address the alleged failing of the
    rule.
    B.   Treatment of Cogenerators
    The world of significant stationary sources producing NOx
    can loosely be divided into two categories--electric generat-
    ing units ("EGUs") and sources that do not generate electrici-
    ty ("non-EGUs").  Cogenerators straddle these lines, as they
    serve two functions, electricity generation and some direct
    industrial activity.  We deal here with their classification.
    EPA concluded that the application of its $2000/ton cost-
    effectiveness principle called for different standards for the
    two types of units.  First, for "large EGUs"--boilers and
    turbines that serve generators capable of producing greater
    than 25 megawatts ("MWe") and that produce electricity for
    sale to an electric grid (with different minimum sales levels
    depending on the generator's date), see May 1999 Rule, 64
    Fed. Reg. at 28,300-01--EPA imposed a ceiling of .15 pounds
    per million Btu per hour ("lb./mmBtu/hr.").
    Second, for "large non-EGUs" or "large boilers"--boilers
    and turbines with a heat input greater than 250 mmBtu/hr.
    that, in general, only generate steam and/or mechanical work
    or that produce electricity for internal use only, see Jan. 2000
    Rule, 65 Fed. Reg. at 2731 (40 C.F.R. s 97.4(a)(1)-(2))--EPA
    required a 60% reduction in NOx emissions, which it says
    corresponds to an average control level of approximately 0.17
    lb./mmBtu/hr., May 1999 Rule, 64 Fed. Reg. at 28,301/2.
    We do not know why EPA frames one limit in terms of NOx
    emissions per mmBtu and the other as a percentage reduc-
    tion.  In the original SIP call, EPA stated a preference for a
    flat limit over a percentage reduction for EGUs, noting that a
    percentage reduction rule tended to benefit states that had
    made less effort.  62 Fed. Reg. at 60,351/1.  We've found, and
    the parties offer, no explanation for rejecting this logic for
    non-EGUs.  But here the concern is that large cogenerators
    selling electricity to the grid end up being treated as large
    EGUs (at least if they sell at the minimum levels specified),
    subject to the more stringent rule (evaluated in terms of
    maximum emissions per mmBtu/hour).
    Petitioners claim that EPA departed without adequate
    explanation from a long-standing agency and congressional
    policy favoring cogeneration, and also failed affirmatively to
    justify the new classification.  We do not find the historical
    policy concerns to be dispositive, but we agree on their
    second point.
    In previous regulatory contexts, EPA and Congress have
    treated cogenerators as non-EGUs if they sold to the grid
    less than one-third of their potential capacity, or less than 25
    MWe per year.  May 1999 Rule, 64 Fed. Reg. at 28,297/2.  In
    proposing its new definition of large EGUs in the preamble to
    the May 1999 rule, EPA offered two relevant responses to
    comments.  First it argued that when the agency began using
    the earlier division in 1978, it served broadly as "a proxy" to
    distinguish between units that were, or were not, owned by
    utilities.  But it reasoned that since 1990 deregulation had
    had a dramatic effect on the industry, allowing non-utilities
    increasingly to compete with utilities.  EPA believed that this
    effect obviated the need to differentiate between utilities and
    non-utilities.  See 
    id. In addition,
    EPA cited a supplemental
    notice of proposed rulemaking under the NOx SIP call for the
    proposition that "there is no relevant physical or technological
    difference between utilities and other power generators," 
    id. at 28,297/3
    (quoting 63 Fed. Reg. at 25,923), and stated that it
    "continue[d] to believe that cogeneration units can achieve
    similar NOx emission reductions as utility units," 
    id. at 28,298/1.
    The explanation by reference to electric utility deregulation
    may well explain abandonment of the old definition, although
    the point is hard to evaluate since the link between choosing
    suitable emissions limits and the degree of direct competition
    between the classes of regulated firms is unexplained and not
    self-evident.  In any event, the rationality of moving away
    from the prior classification in itself says nothing about why
    EPA chose the new one.  On that score, EPA's current
    reasoning, to the extent that we are able to discern it,
    supports the new classification as a means to implement the
    cost-effectiveness criteria.  While as we noted above the
    standard for large EGUs is more stringent than the one for
    large non-EGUs when evaluated in terms of emissions per
    mmBtu/hour heat input (.15 lb. as opposed to .17 lb.), a table
    in the preamble to the May 1999 rule indicates that the two
    control levels have virtually identical predicted incremental
    costs ($1,468 for the former, $1,467 for the latter, all in terms
    of estimated cost per ton in 1990 dollars in 2007).  See 
    id. at 28,300
    (Table II-4).7
    If this analysis is correct (and EPA has presented no
    alternative), then the classification of cogenerators should
    turn on whether their NOx reduction costs best match those
    of EGUs or non-EGUs.  We note at the outset that the non-
    EGU class includes cogenerators that produce electricity for
    internal purposes only.  Thus sources that apparently may be
    identical physically are subject to different standards--a di-
    vergence hard to reconcile to the supposedly controlling
    criterion of cost.  To the extent that it is linked to EPA's
    former concern over competition with utilities, the agency's
    own abandonment of that concern renders it obsolete.  In-
    deed, EPA does not even attempt to justify the distinction.
    It merely notes that "it may be appropriate at some time in
    the future to consider all units generating electricity, whether
    for sale or internal use, as a single category."  
    Id. at 28,298/1.
    EPA does assert that "there is no relevant physical or
    technological difference between utilities and other power
    generators."  
    Id. at 28,297/3
    (quoting 63 Fed. Reg. at 25,923).
    If true, this similarity would support treating cogenerators as
    EGUs, but EPA cites no record support.  See 
    id. Otherwise, EPA
    merely claimed that "it continues to believe that indus-
    trial cogeneration units can achieve similar NOx emission
    limitations reductions as utility units" and that selective cata-
    lytic reduction and selective non-catalytic reduction are "prov-
    __________
    7  The preamble to the final rule presents updated figures that
    are more divergent, estimating the large EGU controls to cost
    $1,432 per ton in 1990 dollars in 1997, and the large non-EGU
    controls to cost $1,589.  Jan. 2000 Rule, 65 Fed. Reg. at 2677.
    en technologies demonstrated on industrial and utility units."
    
    Id. at 28,298/1.
     But the point that cogenerators can imple-
    ment these technologies hardly shows that they can do so at
    the same costs as other EGUs.
    In its brief, EPA claims that it "specifically reviewed the
    cost-effectiveness of controls for cogeneration facilities in
    response to comments" and "determined that the control
    technologies that EPA had determined to be highly cost-
    effective for EGUs ..., had been successfully applied to
    cogeneration facilities, and, therefore, there was no technical
    reason to distinguish between generating facilities owned by
    utilities and other electric generators, including cogenera-
    tors."  But, once again, neither this statement nor any of the
    record documents cited in support purports to assess the
    costs of "successfully" applying such controls to cogenerators.
    Additional materials cited in EPA's brief are equally silent on
    the subject.  See Office of Air and Radiation, U.S. Environ-
    mental Protection Agency, "Analyzing Electric Power" (July
    1996);  62 Fed. Reg. at 60,349 (Table III-3),
    60,350/3.
    Finally, EPA's brief also notes that "EPA's analysis of
    which controls are highly cost-effective for EGUs included all
    cogeneration units that generated electricity for sale."  But
    the fact that all units currently classified as "EGUs" can, on
    average, cost-effectively implement the EGU cap, see May
    1999 Rule, 64 Fed. Reg. at 28,300 (Table II-4), says nothing
    about whether cogenerators, as a discrete subclass, can do so.
    Indeed, if cogenerators represented a small enough portion of
    the sample size, even astronomical control costs would have
    little effect on the average.  On the central question of
    whether EPA actually compared the costs of cogenerator
    controls to those of other EGUs, EPA does not speak and the
    documents it cites shed no light.
    As EPA has failed to explain its classification of cogenera-
    tors, see, e.g., American Lung Ass'n v. EPA, 
    134 F.3d 388
    ,
    392 (D.C. Cir. 1998), and its failure to respond to significant
    comments leaves us only to guess whether its decision was
    "based on a consideration of the relevant factors," see, e.g.,
    Thompson v. Clark, 
    741 F.2d 401
    , 409 (D.C. Cir. 1984)
    (quoting Citizens to Preserve Overton Park v. Volpe, 
    401 U.S. 402
    , 416 (1971)), we vacate and remand that portion of the
    rule.
    C.   Source-Specific Issues
    1.   AK Steel Corporation
    AK Steel, one of the Non-EGU Petitioners, claims that the
    final rule improperly subjected four of its waste heat boilers
    to regulation as large non-EGUs.  The regulations at issue
    apply to these boilers only if they (a) are "fossil fuel fired"
    boilers with a 1995 "heat input" comprised more than 50% of
    fossil fuel, Jan. 2000 Rule, 65 Fed. Reg. at 2728/3, 2731/1 (40
    C.F.R. s 97.2 (definitions of "unit" and "fossil fuel fired")),
    and (b) have a "maximum design heat input" greater than 250
    mmBtu/hr., 
    id. at 2731/2
    (40 C.F.R. s 97.4(a)(2)(i)).
    AK Steel argues initially that its four furnaces fail to meet
    the first criterion:  The waste heat input from its "slab heat
    furnaces" is great enough to render its fossil fuel input less
    than 50% of the total, so that its boilers are not "fossil fuel-
    fired."  EPA argues that AK Steel failed to raise its objection
    with the necessary specificity.  See 42 U.S.C. s 7607(d)(7)(B)
    ("Only an objection to a rule or procedure which was raised
    with reasonable specificity during the period for public com-
    ment ... may be raised during judicial review.").  We think
    its submission adequate, though only barely so.  On the
    merits, however, AK Steel is mistaken;  it hasn't read the
    regulations carefully enough.
    EPA correctly notes that the regulation defines "heat
    input" as excluding "heat derived from preheated combustion
    air, recirculated flue gases, or exhaust from other sources."
    Jan. 2000 Rule, 65 Fed. Reg. at 2729/1 (40 C.F.R. s 97.2).
    The EPA asserts, and petitioners do not dispute, that the
    waste heat input that it invokes is precisely such "preheated
    combustion air" or "exhaust from other sources."  So those
    inputs do not prevent its boilers from satisfying the 50%
    fossil-fuel calculation.
    In their reply brief, petitioners raise a new issue.  There
    they argue that waste heat should be excluded from calcula-
    tion of the 250 mmBtu/hr. threshold for "maximum design
    heat input," see 
    id. at 2731/2
    (40 C.F.R. s 97.4(a)(2)(i)), which
    if true would mean that their boilers would not exceed the 250
    mmBtu/hr standard.  AK Steel has no explanation for why
    waste heat should be counted in one context and not the
    other, but EPA does offer a defense of the opposite position,
    arguing that, unlike the definition for "heat input," the capaci-
    ty-based definition of "maximum design heat input" does not
    exclude specific input types.  See Jan. 2000 Rule, 65 Fed.
    Reg. at 2729/1 (40 C.F.R. s 97.2) (defining maximum design
    heat input as "the ability of a unit to combust a stated
    maximum amount of fuel per hour ... on a steady state basis,
    as determined by the physical design and physical character-
    istics of the unit").  But because of petitioners' failure to raise
    the issue in their opening brief, we do not address it on the
    merits.  See United States v. Wilson, 
    240 F.3d 39
    , 45 (D.C.
    Cir. 2001).
    2.   New Boston Coke Corporation
    New Boston Coke Corporation operates two regulated boil-
    ers subject to the same set of regulations.  Its brief states
    that these boilers "are each designed with maximum heat
    capacity of 464 mmBtu/hr.," but claims that in actual opera-
    tion the heat input of each is less than half that figure.  One
    boiler is usually kept in reserve while the other fires, and the
    one that fires usually does so at 40% of capacity or less.
    Thus, argues New Boston, the normal input capacity for the
    units is less than 232 mmBtu/hr., below the 250 mmBtu/hr.
    threshold.
    The EPA responds that New Boston has forfeited the claim
    because it never raised the objection before the agency, as
    required by s 307(d)(7)(B) of the Clean Air Act, 42 U.S.C.
    s 7607(d)(7)(B).  New Boston's rebuttal is that it never re-
    ceived notice of the proposed rule, arguing that its name
    didn't appear in the appendix to that notice and denying that
    it was included by virtue of the notice's generic terms.  See
    Oct. 1998 Rule, 63 Fed. Reg. 56292, 56,332 (40 C.F.R.
    s 52.34(k) & Table F-1), 56,341 (40 C.F.R. s 97.4), 56,360-91.
    (This same defect in notice is raised by the Non-EGU
    Petitioners on behalf of an unspecified group of sources, but it
    is only for New Boston that petitioners claim that the sup-
    posed defect had any adverse effect (from petitioners' per-
    spective) on the ultimate regulation, and so we address the
    claim only in this connection.)
    Section 307(d)(7)(B) addresses the possibility of defective
    notice.  It excuses a party's failure to object in the course of
    the rulemaking where it was "impracticable to raise" the
    objection, and the agency's failure to give proper notice would
    plainly create such impracticality.  American Petroleum In-
    stitute v. Costle, 
    665 F.2d 1176
    , 1190-91 (D.C. Cir. 1981).
    Section 307(d)(7)(B), however, explicitly makes the excuse
    conditional on the party's seeking relief before the agency by
    petition for reconsideration.  See 
    id. at 1191-92.
     As there is
    no evidence that any such petition was submitted, we cannot
    reach the merits of petitioners' claim, including even the claim
    of defective notice.
    IV. FACILITY-SPECIFIC ISSUES
    Two petitioners raise facility-specific objections to the sec-
    tion 126 rule.  In each case, we have no occasion to reach the
    merits of petitioners' arguments.  By failing to raise their
    objections to the EPA prior to seeking judicial review, peti-
    tioners waived their claims.
    A.   Midland Cogeneration Venture
    Petitioner Midland Cogeneration Venture ("MCV") oper-
    ates a "combined cycle" cogeneration plant that produces
    electricity and steam in Midland, Michigan.  MCV alleges
    that the EPA was arbitrary and capricious in applying the
    section 126 rule to its facility because MCV is legally and
    operationally incapable of emitting in excess of the rule's
    "NOx Cap."8
    __________
    8  MCV also challenges the EPA's treatment of cogeneration
    facilities.  This issue is 
    addressed supra
    Part III.B.
    This Court has no jurisdiction to consider MCV's claims.
    Under section 307(d) of the Act, "[o]nly an objection to a rule
    or procedure which was raised with reasonable specificity
    during the period for public comment ... may be raised
    during judicial review."  42 U.S.C. s 7607(d)(7)(B).  MCV
    does not dispute that its comments did not address this issue.
    Its defense is that no such comments were possible because,
    as the EPA admits, the agency did not have sufficient data on
    cogenerators to develop an output-based approach to setting
    emission limits for given facilities.  This may be so, but "the
    procedural requirements of the Clean Air Act do not permit
    [MCV] to raise this objection for the first time on appeal."
    API v. Costle, 
    665 F.2d 1176
    , 1190 (D.C. Cir. 1981).  Rather,
    the CAA requires a petitioner to first raise its objection to the
    agency though a petition for reconsideration.  See 
    id. at 1191
    ("The statute states that before this court may review a
    procedural objection the parties must raise the objection on a
    petition for reconsideration before the EPA when the grounds
    for such objection 'arose after the period for public comment
    (but within the time specified for judicial review).' ");  Appala-
    chian Power Co. v. EPA, 
    135 F.3d 791
    , 799 n.14 (D.C. Cir.
    1998) (same).  Because MCV never registered its objections
    with the agency, let alone filed a formal petition for reconsid-
    eration, we cannot reach the merits of its claim.
    B.   Indiana Municipal Power Agency
    Petitioner Indiana Municipal Power Agency ("IMPA") is a
    municipal power agency that operates four combustion tur-
    bines that provide supplemental power on days with high
    power usage. IMPA alleges that the "25-ton exemption" in 40
    C.F.R. s 97.4(b) is arbitrary and capricious because it "ig-
    nores actual emissions and instead calculates hypothetical
    maximum emissions" in determining whether a unit is eligible
    for the exemption.  By adopting a "worst-case-fuel assump-
    tion," the exemption treats IMPA as if its emissions were
    nearly five times greater than the actual emissions rate
    during normal operating conditions.
    Like MCV, IMPA never raised its objection in comments
    before the agency.  Unlike MCV, however, IMPA cannot
    claim that it was caught by surprise by the EPA's final rule.
    While the specific contours of the 25-ton exemption were not
    identified in the EPA's Notice of Proposed Rulemaking
    ("NOPR"), the NOPR did propose adopting the exemption
    contained in the NOx SIP regulations at 40 C.F.R. s 96.4(b).
    See Oct. 1998 Rule, 63 Fed. Reg. at 56,313.  The proposal
    used different language than s 97.4, but it similarly bases the
    exemption on a unit's "maximum potential hourly NOx mass
    emissions."  40 C.F.R. s 96.4(b)(1)(ii), (iii).  This satisfies the
    requirement that the final rule be a "logical outgrowth" of the
    proposed rule.  See Fertilizer Inst. v. EPA, 
    935 F.2d 1303
    ,
    1311 (D.C. Cir. 1991).  Therefore, IMPA had ample opportu-
    nity to comment on the proposed rule.  Because it did not, it
    waived its claim under section 307(d).  42 U.S.C.
    s 7607(d)(7)(B).
    V. PITTSBURGH
    Like many of the affected states, Pennsylvania is both an
    "upwind" state subject to the s 126 regulation and a "down-
    wind" state that has petitioned EPA under s 126 to regulate
    "upwind" contributions to Pennyslvania's own nonattainment
    problems.  Acting in its capacity as a downwind state, Penn-
    sylvania objects to EPA's refusal to use ozone pollution in the
    Pittsburgh area as a basis for s 126 findings (thus, it argues,
    potentially failing to impose crackdowns on additional sources
    upwind of Pittsburgh).  The problems arise from two circum-
    stances:  Pittsburgh appeared at the time of the rulemaking
    to be on the verge of being reclassified as in attainment of the
    1-hour standard, but also on the verge of being subject to the
    more stringent 8-hour rule.
    In its May 1999 Rule, EPA denied the portion of Pennsyl-
    vania's s 126 petition that alleged upwind contribution to the
    nonattainment of the 1-hour ozone standard in the Pittsburgh
    area.  Having received preliminary data showing that Pitts-
    burgh (and a number of other areas) were no longer in
    violation of that standard, and having taken steps to formally
    revoke its nonattainment determination, see 64 Fed. Reg. at
    28,257/2, EPA thought "it would not be appropriate" to
    consider whether the pertinent upwind areas were "signifi-
    cantly contributing" to a nonattainment that was apparently
    non-existent, 
    id. at 28,291/2.
     Section 110(a)(2)(D)(i) also re-
    quires that SIPs bar emissions that would "interfere with
    maintenance" of ambient standards, and petitioning states
    such as Pennsylvania asked for such a finding as to the 1-
    hour standard.  EPA declined this too, explaining that its
    policy was to revoke the 1-hour standard for any area that
    attained it and replace it with the stricter 8-hour standard.
    See 
    id. at 28,291-92.
     But in January 2000, after this court's
    decision in American Trucking Ass'ns v. EPA, 
    175 F.3d 1027
    ,
    reh'g granted in part and denied in part, 
    195 F.3d 4
    (D.C.
    Cir. 1999), rev'd in part sub nom. Whitman v. American
    Trucking Ass'n, 
    121 S. Ct. 903
    (2001), which remanded the 8-
    hour standard, EPA moved to reimpose the 1-hour standard
    for all areas where it had been revoked and has yet to re-
    introduce the 8-hour standard.  See Jan. 2000 Rule, 65 Fed.
    Reg. at 2678-79.  In its January 2000 rule, in which it
    converted its technical determinations into formal s 126 find-
    ings, EPA recognized that the 1-hour standard might once
    again become the sole NOx standard.  But it didn't seize the
    occasion to revisit its rejection of the "interfere with mainte-
    nance" portion of Pennsylvania's petition.  See 
    id. at 2678/3.
    Pennsylvania's first objection is that the Pittsburgh attain-
    ment data were only preliminary;  to this day they have not
    yielded a formal finding of attainment.  (In fact, data from
    the 1999 ozone season indicate renewed violations.)  More-
    over, the statute provides that a region in "moderate" nonat-
    tainment that fails to move into attainment will, at the very
    least, be reclassified as "serious" and thus subject to more
    stringent controls, see 42 U.S.C. ss 7511(b)(2), 7511a(c), and
    petitioners claim that such a fate awaits Pittsburgh.  Penn-
    sylvania argues that if EPA had pursued the "substantial
    contribution" inquiry, Pennsylvania would get the benefit of
    upwind states' being forced to share some of burden of
    achieving ozone attainment in Pittsburgh.
    EPA responds that Pennsylvania suffered no prejudice and
    thus lacks the "injury in fact" necessary to claim Article III
    standing.  Lujan v. Defenders of Wildlife, 
    504 U.S. 555
    , 560
    (1992).  It claims that had it granted Pennsylvania's petition
    with regard to Pittsburgh, EPA's modeling methods dictated
    that it would have found linkages with regard to North
    Carolina, Ohio, and West Virginia, all states on which EPA
    has imposed s 126 controls anyway, as a result of its findings
    as to the Philadelphia area.  But Pennsylvania observes that
    its s 126 petition had sought findings as to the contribution of
    a number of other upwind states, several of which were not
    ultimately subjected to s 126 findings.  EPA cannot, it ar-
    gues, deflect judicial review of its refusal to inquire into
    effects on Pittsburgh simply by filing a brief asserting that, if
    it had done so, it would have found no more than it did when
    it focused on Philadelphia.  If EPA's ground for refusing to
    crunch the data for Pittsburgh is illegal, Pennsylvania has
    been wrongly denied potential benefits.  Thus Pennsylvania
    asserts a real injury that the court could redress.  See 
    Lujan, 504 U.S. at 560-61
    .
    While Pennsylvania wins on the standing argument, it loses
    on the merits.  EPA observes that s 110(a)(2)(D)(i) speaks
    simply of emissions that "contribute significantly to nonattain-
    ment ... in any other State," with no language suggesting, as
    the Act does in a number of places, that formal designation or
    reclassification is critical.  See 42 U.S.C. s 7407(d)(1)(A) (al-
    lowing EPA to require state governors to supply EPA with a
    list designating areas as "attainment" or "nonattainment");
    s 7502 (framework for setting deadlines and plans for areas
    deemed "nonattainment");  s 7511(b)(2) (procedures for re-
    classifying areas that fail to meet attainment deadlines).  It
    seems reasonable for EPA to refrain from investigating
    whether upwind emissions "significantly contribute" to nonat-
    tainment that, according to evidently undisputed data, does
    not exist, rather than to march forward on the basis of a
    formal classification that it believed to be outdated and was in
    the process of revoking.  (In reaching this conclusion we
    express no opinion on the issue that intervenors Appalachian
    Power et al. tell us is raised in D.C. Cir. No. 00-1223, namely,
    whether EPA may make significant contribution determina-
    tions for areas that have never been formally classified as
    nonattainment.).
    Developments in the Pittsburgh area after the close of the
    present rulemaking record of course cannot be a basis for
    faulting EPA's decision on that record.  Nor did its January
    2000 decision, converting its May 1999 technical determina-
    tions into formal findings (without, as originally contemplated,
    conditioning such findings on the failure of the SIP process),
    require a reopening.  Pennsylvania may, of course, use later
    developments as the basis for another s 126 petition.
    Pennsylvania further argues that in light of EPA's rein-
    statement of the 1-hour ambient standard, it should have
    addressed the "interfere with maintenance" portion of Penn-
    sylvania's petition.  Here too EPA was reasonable.  Because
    the EPA policy in May 1999 was to supplant the 1-hour
    standard with the 8-hour standard as soon as an area met the
    1-hour standard, it made sense to decline all petitions seeking
    findings of interference with maintaining the 1-hour stan-
    dard;  there was then every reason to suppose that such
    findings would almost immediately become obsolete.  Once
    again, Pennsylvania can respond to later developments by
    submitting another s 126 petition.
    VI. CONCLUSION
    In summary, we remand the rules to the EPA to allow the
    agency to (1) properly justify either the current or a new set
    of EGU utilization growth factors to be used in estimating
    utilization in 2007, and (2) either alter or properly justify its
    categorization of cogenerators that sell electricity to the
    electric grid as EGUs.  With respect to all other issues,
    including those not discussed expressly herein, the petitions
    are denied.
    So ordered.
    

Document Info

Docket Number: 99-1200, 99-1205, 99-1206, 99-1246, 99-1266, 99-1285, 99-1289, 99-1291-99-1293, 99-1295, 99-1299-99-1301, 99-1303, 99-1304, 99-1306, 99-1307, 00-1013, 00-1021, 00-1022, 00-1024, 00-1038, 00-1042, 00-1050, 00-1071, 00-1074, 00-1077, 00-1083, 00-1087, 00-108

Citation Numbers: 249 F.3d 1032, 346 U.S. App. D.C. 38, 2001 U.S. App. LEXIS 9317

Judges: Ginsburg, Per Curiam, Sentelle, Williams

Filed Date: 5/15/2001

Precedential Status: Precedential

Modified Date: 10/19/2024

Authorities (35)

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american-petroleum-institute-v-douglas-m-costle-administrator-and , 665 F.2d 1176 ( 1981 )

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Reno v. Koray , 115 S. Ct. 2021 ( 1995 )

Christensen v. Harris County , 120 S. Ct. 1655 ( 2000 )

Whitman v. American Trucking Assns., Inc. , 121 S. Ct. 903 ( 2001 )

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