Natural Resources Defense Council v. Environmental Protection Agency ( 2013 )


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  •  United States Court of Appeals
    FOR THE DISTRICT OF COLUMBIA CIRCUIT
    Argued October 17, 2012        Decided January 4, 2013
    No. 08-1250
    NATURAL RESOURCES DEFENSE COUNCIL AND SIERRA CLUB,
    PETITIONERS
    v.
    ENVIRONMENTAL PROTECTION AGENCY,
    RESPONDENT
    FINE PARTICULATE LITIGATION GROUP ET AL.,
    INTERVENORS
    Consolidated with 09-1102, 11-1430
    On Petitions for Review of Final Rules of the
    United States Environmental Protection Agency
    Paul Cort argued the cause for the petitioners. Tim D.
    Ballo and David S. Baron entered appearances.
    Brian H. Lynk, Attorney, United States Department of
    Justice, argued the cause for the respondent. Geoffrey L.
    Wilcox and Stephanie L. Hogan, Attorneys, United States
    Environmental Protection Agency, were on brief.
    Charles H. Knauss, Shannon S. Broome, Robert T. Smith,
    Denise W. Kennedy, John A. Bryson, Emily C. Schilling,
    2
    Leslie S. Ritts, Norman W. Fichthorn, Lauren E. Freeman,
    Lucinda Minton Langworthy and Lorane F. Hebert were on
    brief for the intervenors. Michelle M. Schoeppe entered an
    appearance.
    Before: HENDERSON and TATEL, Circuit Judges, and
    WILLIAMS, Senior Circuit Judge.
    Opinion for the Court filed by Circuit Judge HENDERSON.
    KAREN LECRAFT HENDERSON, Circuit Judge: The four
    petitioners1 seek review of two final rules, promulgated
    pursuant to the Clean Air Act (CAA, Act), which govern
    implementation of the national ambient air quality standard
    (NAAQS) for “fine” particulate matter—that is, particulate
    matter (PM)2 having a diameter equal to or less than 2.5
    micrometers (PM2.5). See Final Clean Air Fine Particle
    Implementation Rule, 72 Fed. Reg. 20,586 (Apr. 25, 2007)
    (PM2.5 Implementation Rule); Implementation of the New
    Source Review (NSR) Program for Particulate Matter Less
    Than 2.5 Micrometers (PM2.5), 73 Fed. Reg. 28,321 (May 16,
    2008) (PM2.5 NSR Implementation Rule) (collectively, Final
    1
    They include the Natural Resources Defense Council, Sierra
    Club, American Lung Association and Medical Advocates for Healthy
    Air.
    2
    “Particulate matter is the generic term for a broad class of
    chemically and physically diverse substances that exist as discrete
    particles (liquid droplets or solids) over a wide range of sizes.” The
    particles “originate from a variety of anthropogenic stationary and
    mobile sources as well as from natural sources” and “may be emitted
    directly or formed in the atmosphere by transformations of gaseous
    emissions such as sulfur oxides (SOx), nitrogen oxides (NOx), and
    volatile organic compounds (VOC).” National Ambient Air Quality
    Standards for Particulate Matter, 62 Fed. Reg. 38,652, 38,653 (July
    18, 1997).
    3
    PM2.5 Implementation Rules).3 In particular, the petitioners
    challenge the decision of the Environmental Protection
    Agency (EPA) to promulgate the Final PM2.5 Implementation
    Rules pursuant to the general implementation provisions of
    Subpart 1 of Part D of Title I of the Act, 42 U.S.C. §§ 7501-
    7509a (Subpart 1), rather than the particulate-matter-specific
    provisions of Subpart 4 of Part D of Title I, 
    id. §§ 7513-7513b (Subpart
    4). We agree with the petitioners that EPA erred in
    applying the provisions of Subpart 1 rather than Subpart 4.
    I.
    Section 109 of the Act mandates that EPA establish a
    primary NAAQS for each air pollutant for which EPA has
    issued “air quality criteria” under CAA section 108. 42
    U.S.C. § 7409(a)(1).4 The Act defines each such NAAQS as
    that standard “the attainment and maintenance of which in the
    judgment of the Administrator, based on such criteria and
    allowing an adequate margin of safety, are requisite to protect
    the public health.” 
    Id. § 7409(b)(1). EPA
    is required to
    “complete a thorough review” of each pollutant’s standard
    and air quality criteria “at five-year intervals” and “make such
    revisions in such criteria and standards and promulgate such
    new standards as may be appropriate.” 
    Id. § 7409(d)(1). Once
    a NAAQS has been established, each state must adopt
    3
    Under the Act’s NSR provisions, new or modified pollutant
    sources must meet “strict standards,” while existing sources are
    “ ‘grandfathered.’ ” New York v. U.S. EPA, 
    413 F.3d 3
    , 13 (D.C. Cir.
    2005).
    4
    The Act also requires EPA to promulgate a secondary standard,
    “the attainment and maintenance of which . . . is requisite to protect
    the public welfare from any known or anticipated adverse effects
    associated with” the pollutant. 42 U.S.C. § 7409(b)(2). In this case,
    EPA promulgated a single NAAQS as both the primary and the
    secondary standard.
    4
    and submit to EPA for approval a State Implementation Plan
    (SIP) that “provides for implementation, maintenance, and
    enforcement of [the NAAQS] in each air quality control
    region (or portion thereof) within such State.”            
    Id. § 7410(a)(1). Each
    SIP must “include enforceable emission
    limitations and other control measures, means, or techniques
    . . . , as well as schedules and timetables for compliance, as
    may be necessary or appropriate to meet the [CAA’s]
    applicable requirements.” 
    Id. § 7410(a)(2)(A). Part
    D of CAA Title I governs “Plan Requirements for
    Nonattainment Areas” (that is, areas that have not attained
    compliance with the applicable NAAQS) and Subpart 1
    thereof, added to the Act in 1977, addresses “Nonattainment
    Areas in General.” Subpart 1 provides generally that, once
    EPA designates an area as “nonattainment,” it “may classify
    the area” so as to establish an attainment deadline and it must
    establish a schedule for the state encompassing the
    nonattainment area to submit a SIP. 
    Id. § 7502(a)(1)(A). The
    SIP, in turn, is required, inter alia, to (1) provide for
    implementation of control measures, (2) inventory existing
    emissions, (3) identify and quantify pollutant emissions
    permissible under the SIP from the construction and operation
    of all major new stationary emission sources, (4) require NSR
    permits for such construction and operation and (5) establish
    compliance schedules and timetables. 
    Id. § 7502(c). Pursuant
    to this regime, in 1971, EPA established a particulate matter
    NAAQS applicable to “Total Suspended Particles,” i.e.,
    particulate matter up to 25-45 micrometers in diameter.
    In 1987, EPA revised the NAAQS to apply only to
    particles equal to or smaller than 10 micrometers (PM10)—a
    “size-specific indicator” it determined “represent[ed] those
    particles small enough to penetrate to the thoracic region”
    because “[t]he risks of adverse health effects associated with
    deposition of typical ambient fine and coarse particles in the
    5
    thorax (tracheobronchial and alveolar regions of the
    respiratory tract) are markedly greater than those associated
    with deposition in the extrathoracic (head) region.” Revisions
    to the National Ambient Air Quality Standards for Particulate
    Matter, 52 Fed. Reg. 24,634, 24,639 (July 1, 1987) (footnote
    omitted) (1987 PM NAAQS Revisions).
    In 1990, the Congress amended CAA Part D by adding to
    it Subparts 2 through 5, each of which contains additional
    provisions governing nonattainment plan requirements for a
    particular pollutant or group of pollutants. At issue here,
    Subpart 4 applies to “Particulate Matter Nonattainment
    Areas” and covers such matters as setting attainment dates for
    PM nonattainment areas, classifying the nonattainment areas
    (as “moderate” or “serious”), reclassifying them (e.g., upon
    failure to attain) and extending attainment dates. 42 U.S.C.
    §§ 7513-7513b; see also 
    id. §§ 7511-7511f (ozone-specific
    requirements); 
    id. §§ 7512-7512a (carbon
    monoxide-specific
    requirements).
    In 1997, EPA again revised the particulate matter
    NAAQS, this time setting separate PM2.5 standards for fine
    particles (having a diameter of 2.5 micrometers or less), while
    retaining the existing PM10 standards. National Ambient Air
    Quality Standards for Particulate Matter, 62 Fed. Reg. 38,652,
    38,654 nn.5-6 (July 18, 1997) (Final PM NAAQS Rule). We
    upheld the new particulate matter standards in 2002 after
    remand from the United States Supreme Court. See Am.
    Trucking Ass’ns v. EPA, 
    283 F.3d 355
    (D.C. Cir. 2002)
    (applying Whitman v. Am. Trucking Ass’ns, 
    531 U.S. 457
    (2001)).
    In 2005, EPA published its Proposed Rule To Implement
    the Fine Particle National Ambient Air Quality Standards, 70
    Fed. Reg. 65,984 (Nov. 1, 2005). EPA subsequently issued
    the final fine particle implementation rule in two stages. In
    2007, it published the PM2.5 Implementation Rule, setting out
    6
    the general SIP requirements for PM2.5. EPA followed up in
    2008 with the PM2.5 NSR Implementation Rule to govern the
    NSR permitting process. In each of the two Final PM2.5
    Implementation Rules, EPA expressly followed the general
    implementation provisions in Subpart 1 of Part D rather than
    Subpart 4’s particulate-material-specific provisions. See
    PM2.5 Implementation Rule, 72 Fed. Reg. at 20,589 (“EPA is
    issuing this rule to implement the 1997 PM2.5 NAAQS in
    accordance with the statutory requirements of the CAA set
    forth in Subpart 1 of Part D of Title 1, i.e., sections 171-179B
    of the Act. . . . EPA has concluded that Congress did not
    intend the Agency to implement particulate matter NAAQS
    other than those using PM10 as the indicator in accordance
    with Subpart 4 of Part D of Title 1 . . . .”); PM2.5 NSR
    Implementation Rule, 73 Fed. Reg. at 28,332 (“We do not
    agree that subpart 4 of part D applies to PM2.5 nonattainment
    areas. Subpart 4 was added to the Act by Congress
    specifically to address the PM10 NAAQS. We believe that the
    PM2.5 standard should be implemented under subpart 1 of part
    D, which is the general provision of the Act related to
    NAAQS implementation.”). The petitioners filed timely
    petitions for review of both the PM2.5 Implementation Rule
    and the PM2.5 NSR Implementation Rule.
    II.
    We review EPA’s interpretation of the CAA under
    Chevron U.S.A. Inc. v. Natural Res. Def. Council, Inc., 
    467 U.S. 837
    (1984). See Natural Res. Def. Council v. EPA, 
    489 F.3d 1250
    , 1257 (D.C. Cir. 2007). Under Chevron:
    We first ask “whether Congress has directly spoken
    to the precise question at issue,” in which case we
    “must give effect to the unambiguously expressed
    intent of Congress.” If the “statute is silent or
    ambiguous with respect to the specific issue,”
    however, we move to the second step and defer to
    7
    the agency’s interpretation as long as it is “based on
    a permissible construction of the statute.”
    
    Id. (quoting Chevron, 467
    U.S. at 842-43) (other quotation
    marks omitted). Before addressing whether EPA correctly
    applied Subpart 1 under the Chevron framework, we first
    consider the timeliness of the petitioners’ instant challenge.
    A.
    EPA contends the petitioners’ challenge is untimely
    because it should have been raised in 1997 when EPA issued
    the Final PM NAAQS Rule, which, EPA maintains, set out its
    final decision on Subpart 1’s applicability. Because we
    conclude EPA did not take final reviewable action in 1997,
    the petitioners’ challenge is timely.5
    In urging that it finalized its decision in 1997, EPA relies
    on two excerpts from the preamble to the 1997 Final PM
    NAAQS Rule. First, EPA cites its response to comments
    challenging its authority to promulgate a separate PM2.5
    standard given that the 1990 amendments referred only to a
    PM10 standard. At the conclusion of its response, EPA offered
    the following defense of its authority to promulgate the new
    PM2.5 standards, rooted in Subpart 1, couched in plainly
    tentative language:
    EPA’s analysis of its ability to implement a PM2.5
    standard under the provisions of subpart 1 of Part D
    of Title I does not support the view that Congress
    prohibited EPA from promulgating such a standard.
    Congress clearly specified an approach to the
    5
    EPA acknowledges the instant petitions for review of the PM2.5
    Implementation Rule and the PM2.5 NSR Implementation Rule were
    timely filed within sixty days after each rule’s publication as required
    under 42 U.S.C. § 7607(b)(1). See Br. of Resp’t 1.
    8
    implementation of the PM10 standard in the
    provisions of subpart 4 of Part D of Title I of the Act.
    The EPA believes that the clear and express linkage
    of that approach to the PM10 standard indicates that a
    different PM standard should be implemented under
    the general principles of subpart 1 of Part D of Title I
    of the Act. That Congress directed specifically how
    EPA and the States should implement the PM10
    standard does not carry with it the implication that
    Congress intended to prohibit EPA from exercising
    its otherwise clear and express authority to adopt a
    PM standard based on a different metric . . . .
    Final PM NAAQS Rule, 62 Fed. Reg. at 38,695 (emphases
    added).     Some pages later, in a footnote, EPA more
    affirmatively, albeit summarily, stated its position that
    implementation of the new standard need not and would not
    be governed by Subpart 4: “The SIP requirements of subpart 4
    of Part D of Title I of the Act apply to SIPs for areas
    designated as not attaining NAAQS for PM10. Those
    requirements will not apply to SIPs to implement the PM2.5
    NAAQS.” 
    Id. at 38,704 n.96.
    We conclude these two
    unembellished snippets, buried in the preamble to the 1997
    Final PM NAAQS Rule, did not constitute final agency action
    so as to be reviewable in 1997.
    “A final agency action is one that marks the
    consummation of the agency’s decisionmaking process and
    that establishes rights and obligations or creates binding legal
    consequences.” Natural Res. Def. Council v. EPA, 
    559 F.3d 561
    , 564 (D.C. Cir. 2009) (citing Bennett v. Spear, 
    520 U.S. 154
    , 177-78 (1997)). We have observed that “[w]hile
    preamble statements,” such as those just quoted, “may in
    some unique cases constitute binding, final agency action
    susceptible to judicial review, this is not the norm.” 
    Id. at 9 564-65
    (citations omitted). As this case is not a “unique” one,
    we adhere to the norm.
    The above quoted excerpts appear in a document
    expressly intended to “describe[] EPA’s decision to revise the
    national ambient air quality standards (NAAQS) for
    particulate matter (PM),” Final PM NAAQS Rule, 62 Fed.
    Reg. at 38,652 (emphasis added)—it did not purport to detail
    how the revised standards should be implemented. Indeed,
    EPA had earlier addressed the issue of implementation in a
    separate Interim Implementation Policy on New or Revised
    Ozone and Particulate Matter (PM) National Ambient Air
    Quality Standards (NAAQS), 61 Fed. Reg. 65,752 (Dec. 13,
    1996) (Interim Implementation Policy). Although the Interim
    Implementation Policy likewise expressed an intent to apply
    Subpart 1 to implement the PM2.5 standard, 61 Fed. Reg. at
    65,753, it made clear that, as its name suggests, it was only a
    temporary policy, which “would represent EPA’s preliminary
    views” and “while it m[ight] include various statements that
    States must take certain actions, these statements [we]re made
    pursuant to EPA’s preliminary interpretations, and thus d[id]
    not bind the States and public as a matter of law.” 
    Id. at 65,752 (emphases
    added). Accordingly, “[o]nly after EPA
    ha[d] made its interpretations final through rulemaking”—
    “follow[ing] the requirements of the Administrative
    Procedure Act, 5 U.S.C. section 553(b) and (c)”—“will they
    be binding on the States and public as a matter of law.” 
    Id. Given EPA’s expressed
    intent to issue a final, binding notice-
    and-comment rule on the issue—to supplant its “preliminary”
    policies—we do not see how the quoted lines from the
    preamble to the 1997 rule revising the standard itself “mark
    the consummation of the agency’s decisionmaking process”
    on how to implement the standard so as to constitute final
    agency action. Bennett v. 
    Spear, 520 U.S. at 177-78
    (internal
    quotation marks omitted).         Instead, we conclude EPA
    consummated the decisionmaking process to implement the
    10
    PM2.5 standard only when it published its final views in the
    two Final PM2.5 Implementation Rules now under review.
    Notwithstanding its express and indefinite deferral of a final
    implementation policy in 1997, EPA argues the Supreme
    Court’s decision in Whitman v. American Trucking
    Associations, 
    531 U.S. 457
    (2001), requires us to hold
    otherwise. We are not so persuaded.
    In Whitman, the Supreme Court reviewed EPA’s decision
    to implement its “8-hour” 0.08 ppm NAAQS for ozone—
    which replaced the previous 1-hour ozone standard of 0.12
    ppm—under Subpart 1’s general nonattainment area
    provisions rather than under Subpart 2’s ozone-specific
    provisions added in 1990. See National Ambient Air Quality
    Standards for Ozone, 62 Fed. Reg. 38,856, 38,873 (July 18,
    1997) (Final Ozone NAAQS Rule) (“[T]he provisions of
    subpart 1 of part D of Title I of the Act would apply to the
    implementation of the new 8-hour O3 standards.”). The Court
    concluded that, in the main, the new ozone NAAQS should be
    implemented pursuant to Subpart 2 notwithstanding Subpart 2
    was enacted to address the former 1-hour standard and some
    provisions might therefore be “ill fitted to implementation of
    the revised standard” and thus leave “gaps” for EPA to fill
    under Chevron step 2. 
    Whitman, 531 U.S. at 483-84
    . The
    Whitman Court first addressed the threshold question whether
    Subpart 1 constituted final agency action subject to review
    and concluded that it did. See 
    id. at 477-78. Addressing
    the Interim Implementation Policy, which
    covered both the ozone and the particulate matter standards,
    the Whitman Court acknowledged: “If the EPA had done no
    more, we perhaps could accept its current claim that its action
    was not final.” 
    Id. at 477. The
    Court explained, however,
    that, vis-à-vis the ozone standard, EPA had done “more.”
    After the White House issued a “ ‘Memorandum for the
    Administrator of the Environmental Protection Agency’ that
    11
    prescribed implementation procedures for the EPA to follow,”
    EPA “supplemented this memorandum with an explanation of
    the implementation procedures.” Id.; see Implementation of
    Revised Air Quality Standards for Ozone and Particulate
    Matter, 62 Fed. Reg. 38,421, 38,422 (July 18, 1997)
    (Memorandum of July 16, 1997); Implementation Plan for
    Revised Air Quality Standards, 62 Fed. Reg. 38,423
    (Implementation Memorandum Supplement). In a section of
    the Implementation Memorandum Supplement titled
    “Implementation of Ozone Standard,” EPA explained that,
    after receiving comments on the proposed Interim
    Implementation Policy, it had “reconsidered” its interpretation
    in part and determined that “Subpart 2 should continue to
    apply as a matter of law for the purpose of achieving
    attainment of the current 1-hour standard.” 
    Id. at 38,424. But
    EPA made clear it adhered to its previously expressed view
    that “[o]nce an area attains the 1-hour standard, those
    provisions will no longer apply and the area’s implementation
    of the new 8-hour standard would be governed only by the
    provisions of Subpart 1 of Part D of Title I.” 
    Id. EPA subsequently “published
    [this interpretation] in the
    explanatory preamble to its final ozone NAAQS under the
    heading, ‘Final decision on the primary standard.’ ”
    
    Whitman, 531 U.S. at 477-78
    (citing Final Ozone NAAQS
    Rule, 62 Fed. Reg. at 38,873). Based on this chronology, the
    Supreme Court found EPA’s ozone implementation policy
    was final and reviewable, explaining:
    The EPA’s “decisionmaking process,” which began
    with the 1996 proposal and continued with the
    reception of public comments, concluded when the
    agency, “in light of [these comments],” and in
    conjunction with a corresponding directive from the
    White House, adopted the interpretation of Part D at
    issue here. Since that interpretation issued, the EPA
    has refused in subsequent rulemakings to reconsider
    12
    it, explaining to disappointed commenters that its
    earlier decision was conclusive.
    
    Whitman, 531 U.S. at 478-79
    (citing 63 Fed. Reg. 31,014,
    31,018-19 (1998)). The history of the PM2.5 standard reveals
    no comparable decisionmaking process regarding
    implementation.       The Implementation Memorandum
    Supplement did not even mention Subpart 1 or Subpart 4 in its
    discussion of the PM2.5 implementation—much less
    distinguish between them or discuss their applicability vel non
    to implementation of the PM2.5 standard. See 62 Fed. Reg. at
    38,427-29 (section titled “Implementation of New PM2.5
    NAAQS”). Nor did EPA thereafter overtly treat its “interim”
    PM2.5 implementation policy as final when it promulgated the
    2007 and 2008 Final PM2.5 Implementation Rules challenged
    here. Accordingly, we conclude the petitioners’ challenge is
    timely and proceed to EPA’s substantive decision to
    implement the NAAQS under Subpart 1.
    B.
    EPA contends that because Subpart 4 repeatedly refers to
    PM10—rather than to PM2.5 or “particulate matter”
    generally—the statutory language limits Subpart 4’s
    applicability to implementation of the current PM10 standard.
    Thus, by default, EPA contends, PM2.5 must be implemented
    pursuant to the general (and less stringent6) implementation
    6
    For example, (1) Subpart 4 requires a nonattainment area to be
    classified as “moderate” and upon failure to attain to be reclassified as
    “serious,” 42 U.S.C. § 7513(a)-(c), while under Subpart 1, EPA “may”
    but is not required to classify a nonattainment area, 
    id. § 7502(a)(1)(A); (2)
    under Subpart 4, a “serious” attainment date may
    be extended only once (for a maximum of 5 years) and only if the SIP
    includes the “most stringent measures” included in any state’s SIP or
    achieved in any State and feasible for the area, 
    id. § 7513(e), while
    Subpart 1 allows attainment date extensions of up to 10 years with no
    13
    procedure in Subpart 1. This argument ignores the plain
    meaning of the statute and the lesson of Whitman.
    Before the Congress enacted Subpart 4, EPA had
    promulgated a single particulate matter standard—the PM10
    standard—which encompassed all particulate matter with a
    diameter of 10 micrometers or less—including both coarse
    and fine particulate matter, that is, particulate matter now
    governed by both the PM10 and PM2.5 standards—and the
    1990 CAA amendments adopted this broad meaning in
    defining “PM10.” 1987 PM NAAQS Revisions, 52 Fed. Reg.
    at 24,639 (“The Administrator . . . has decided to replace
    [Total Suspended Particles] as the particle indicator for the
    primary standards with a new indicator that includes only
    those particles less than a nominal 10 [micrometers] in
    diameter. . . . In defining the standards for particulate matter,
    this new indicator is termed PM10.”); 42 U.S.C. § 7602(t)
    (“The term ‘PM-10’ means particulate matter with an
    aerodynamic diameter less than or equal to a nominal ten
    micrometers . . . .”). Thus, by its express terms, Subpart 4,
    when enacted, governed all PM10 particles, including those
    now denominated PM2.5.           The scope of the statutory
    definition—and consequently of Subpart 4’s application—did
    not change when EPA subdivided PM10 by regulation. As the
    “stringent measures” requirement therefor, 
    id. § 7502(a)(2)(A); (3)
    Subpart 4 subjects a “serious” nonattainment area that fails to timely
    attain to a mandatory annual 5% pollutant reduction, 
    id. § 7513a(d), while
    Subpart 1 includes no such requirement; (4) Subpart 4 requires
    that “reasonable available control measures” must be implemented
    within 4 years after designation, 
    id. § 7513a(a)(1)(C), while
    Subpart
    1 requires such measures be implemented “as expeditiously as
    practicable,” 
    id. § 7502(c)(1); and
    (5) Subpart 4 requires that best
    available control measures be implemented no later than 4 years after
    an area is classified or reclassified as “serious,” 
    id. § 7513a(b)(1)(B), while
    Subpart 1 has no best available control measures requirement.
    14
    Whitman Court made clear, the intent of the 1990
    amendments was to limit the broad implementation discretion
    Subpart 1 had previously granted EPA. Cf. 
    Whitman, 531 U.S. at 484
    (“The principal distinction between Subpart 1 and
    Subpart 2 is that the latter eliminates regulatory discretion
    that the former allowed.”). It makes no sense then that the
    Congress would have wanted EPA to relax Subpart 4’s more
    stringent, nondiscretionary requirements for implementing
    the PM2.5 standard at the same time EPA decided to
    strengthen the PM2.5 standard itself based on “evidence from
    numerous health studies demonstrating that serious health
    effects are associated with exposures to elevated levels of
    PM2.5.” PM2.5 Implementation Rule, 72 Fed. Reg. at 20,586;
    see also 
    id. at 20,586-87 (“Epidemiological
    studies have
    shown statistically significant correlations between elevated
    PM2.5 levels and premature mortality. Other important effects
    associated with PM2.5 exposure include aggravation of
    respiratory and cardiovascular disease (as indicated by
    increased hospital admissions, emergency room visits,
    absences from school or work, and restricted activity days),
    changes in lung function and increased respiratory symptoms,
    as well as new evidence for more subtle indicators of
    cardiovascular health. Individuals particularly sensitive to
    PM2.5 exposure include older adults, people with heart and
    lung disease, and children.”).7 Notwithstanding the plain
    7
    The regulations’ treatment of precursors provides a useful
    example of how the Agency has used Subpart 1 to establish a less
    stringent implementation regime than envisioned by Subpart 4.
    Ammonia is a precursor to fine particulate matter, making it a
    precursor to both PM2.5 and PM10. For a PM10 nonattainment area
    governed by Subpart 4, a precursor is presumptively regulated. See 42
    U.S.C. § 7513a(e). But under the PM2.5 rules challenged here, the
    EPA established a rebuttable presumption against regulating ammonia
    unless a State or the EPA “provides an appropriate technical
    demonstration” that shows emissions from ammonia “significantly
    15
    meaning of the statutory language and the force of Whitman,8
    EPA offers several unconvincing arguments to support
    implementing the new PM2.5 standard pursuant to Subpart 1
    rather than Subpart 4.
    First, EPA claims Subpart 4 “contains requirements that
    are expressly based upon the form of the PM10 NAAQS.” Br.
    of Resp’t 31. This may be true but Subpart 4 also expressly
    governs implementation of the “PM-10” standard, see 42
    U.S.C. §§ 7513-7513b, and the Act defines “PM-10” as
    “particulate matter with an aerodynamic diameter less than or
    contribute to PM2.5 concentration in the nonattainment area.” 40
    C.F.R. § 51.1002(c)(4)(i). When Congress enacted Subpart 4, it
    sought to end this administrative gamesmanship.
    8
    EPA offers several grounds to distinguish Whitman—none of
    them persuasive. First EPA notes that the text of Subpart 2 refers
    generically to “ozone” while Subpart 4’s text refers specifically to
    PM10, EPA Br. 36—but Subpart 4’s title refers generically to
    “Particulate Matter” and, as we have noted, when the 1990
    amendments to the CAA were enacted, PM10 included PM2.5 under
    both the new statutory definition and the existing EPA definition.
    Second, EPA argues that Subpart 4’s provisions do not
    “comprehensively prescribe[] classifications and attainment dates for
    all particulate matter nonattainment areas.” Br. of Resp’t 37
    (emphasis in original). Subpart 4 may not be as comprehensive as
    Subpart 2 but its requirements are specific, more stringent and far less
    discretionary than Subpart 1. See supra note 6. Third, EPA contends
    that in contrast to Whitman, EPA’s application of Subpart 1 to PM 2.5
    does not render Subpart 4 “utterly nugatory” because Subpart 4 still
    applies to the remaining PM10 standard. Br. of Resp’t 37 (quoting
    
    Whitman, 531 U.S. at 484
    ). But if EPA’s interpretation stands,
    Subpart 4 will be “utterly nugatory” with respect to implementation of
    the PM2.5 standard—notwithstanding the Congress expressly directed
    the standard applicable to all PM10 particles, including PM25, be
    regulated under Subpart 4.
    16
    equal to a nominal ten micrometers,” 42 U.S.C. § 7602(t).
    Thus, under Chevron step 1, EPA must implement all
    standards applicable to PM 10—including its PM 2.5
    standards—pursuant to Subpart 4.
    Second, EPA urges that because in the 1987 PM NAAQS
    Revisions, it “had considered whether to establish a separate
    NAAQS for fine particles, using PM2.5 as the indicator,” the
    Congress should have foreseen that it might do so later. Br.
    of Resp’t 32. It is not at all clear that the Congress should
    have so foreseen—EPA cites a single, vague footnote to
    support its claim the Congress was on notice such a change
    was likely. 
    Id. at 32 (citing
    52 Fed. Reg. at 24,639 n.2
    (“Particles in ambient air usually occur in two somewhat
    overlapping size distributions, fine (diameter less than 2.5
    [micrometers]) and coarse (diameter larger than 2.5
    [micrometers]. The two size fractions tend to have different
    origins and composition.” (staff document citation omitted)).
    But even were such notice clear, it does not follow that the
    Congress therefore intended that a separate PM2.5 standard (if
    promulgated) be exempt from Subpart 4’s requirements. As
    in Whitman, the possibility of such a change suggests only
    that gaps resulting therefrom might “prevent us from
    concluding that Congress clearly intended [the specific
    pollutant subpart] to be the exclusive, permanent means of
    enforcing a revised ozone standard in nonattainment areas.”
    
    Whitman, 531 U.S. at 484
    (emphasis added). It does not
    render “utterly nugatory” the restrictions that the 1990
    amendments imposed on EPA’s discretion in implementing
    the particulate matter standards for all particles 10
    micrometers or less in diameter. See 
    id. As the Supreme
    Court observed regarding Subpart 2, “[a] plan reaching so far
    into the future was not enacted to be abandoned the next time
    the EPA reviewed the [pollutant’s] standard—which
    Congress knew could happen at any time.” 
    Id. at 485. 17
    EPA also argues that the Congress “could have easily
    used the general term ‘particulate matter,’ rather than the
    specific term ‘PM-10.’ ” Br. of Resp’t 33. That the Congress
    could have done so does not negate the reality that the “PM10”
    standard to which the Congress referred in fact included fine
    PM2.5 (both under the 1987 Rule and the 1990 statutory
    definition).
    In a final Chevron step 1 effort, EPA asserts that the
    legislative history makes the Congress’s intent clear.
    Assuming legislative history could override the plain,
    unambiguous directive of Subpart 4, the history cited here is
    unconvincing.     EPA relies on a single congressman’s
    statement: “ ‘The Title I PM-10 provisions of H.R. 3030
    somewhat reschedule the attainment dates that would
    otherwise apply under the PM-10 standards as promulgated
    by EPA.’ ” Br. of Resp’t 39 (quoting A Legislative History of
    the Clean Air Act Amendments of 1990, at 2996 (Comm. Print
    1993) (statement of Rep. John Murtha)). This statement
    avails EPA nought. “[P]utting to one side the fact that this
    was the statement of a single [member of Congress], . . . it is
    not necessarily inconsistent with” the petitioners’ view that
    Subpart 4 continues to apply to PM2.5 standards. See Grand
    Canyon Air Tour Coal. v. FAA, 
    154 F.3d 455
    , 474 (D.C. Cir.
    1998). At the time the statement was uttered, “the PM-10
    standards as promulgated by EPA” applied to all particulate
    matter having a diameter equal to or less than 10
    micrometers—including what is now denominated PM2.5.9
    9
    Moreover, “judges must exercise extreme caution before
    concluding that a statement made in floor debate, or at a hearing, or
    printed in a committee document may be taken as statutory gospel, in
    light of the endemic interplay, in Congress, of political and legislative
    considerations likely unrelated to the interpretive tasks of a court.”
    Tex. Mun. Power Agency v. EPA, 
    89 F.3d 858
    , 875 (D.C. Cir. 1996)
    (per curiam) (quotation marks and alterations omitted). Here, it is
    18
    See 1987 PM NAAQS Revisions, 52 Fed. Reg. at 24,639.
    EPA additionally argues that its “reading of the act is, at
    minimum, a ‘permissible’ interpretation entitled to deference
    under Chevron step two.” Br. of Resp’t 41 (upper case
    lowered). This argument is foreclosed, however, under
    Chevron step 1 because the statute is plain on its face.
    For the foregoing reasons, we grant the petitions for
    review of the Final Clean Air Fine Particle Implementation
    Rule, 72 Fed. Reg. 20,586 (Apr. 25, 2007), and the
    Implementation of the New Source Review (NSR) Program
    for Particulate Matter Less Than 2.5 Micrometers (PM2.5), 73
    Fed. Reg. 28,321 (May 16, 2008). We remand to EPA to re-
    promulgate these rules pursuant to Subpart 4 consistent with
    this opinion.10
    So ordered.
    hard to ignore “the irony that [EPA] points to the same floor
    statement that the [petitioners] contend[] supports [their] opposite
    view.” Grand Canyon Air Tour 
    Coal., 154 F.3d at 474
    (emphasis in
    original).
    10
    In light of our disposition, we need not address the petitioners’
    challenge to the presumptions in 40 C.F.R. § 51.1002(c)(3)-(4) that
    volatile organic compounds and ammonia are not PM2.5 precursors as
    Subpart 4 expressly governs precursor presumptions. See 42 U.S.C.
    § 7513a(e). Moreover, we decline the petitioners’ invitation to set a
    deadline for EPA upon remand or to retain jurisdiction pending such
    action. See Natural Res. Def. Council v. EPA, 
    489 F.3d 1364
    , 1375
    (D.C. Cir. 2007) (“We decline to set a two year limit on EPA’s
    proceedings on remand as the NRDC requests; mandamus affords a
    remedy for undue delay.”); North Carolina v. EPA, 
    550 F.3d 1176
    ,
    1178 (D.C. Cir. 2008) (per curiam) (declining invitation to “impose a
    definitive deadline by which EPA must correct [clean air rule’s]
    flaws” and reminding petitioners of availability of mandamus).