Natl' Assoc. for Surface Finis v. EPA , 795 F.3d 1 ( 2015 )


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  •  United States Court of Appeals
    FOR THE DISTRICT OF COLUMBIA CIRCUIT
    Argued December 3, 2014              Decided July 21, 2015
    No. 12-1459
    NATIONAL ASSOCIATION FOR SURFACE FINISHING,
    PETITIONER
    v.
    ENVIRONMENTAL PROTECTION AGENCY AND GINA
    MCCARTHY,
    RESPONDENTS
    CALIFORNIA COMMUNITIES AGAINST TOXICS, ET AL.,
    INTERVENORS
    Consolidated with 12-1460, 13-1147
    On Petitions for Review of Final Agency Action of
    the United States Environmental Protection Agency
    Jerry Stouck argued the cause for petitioner National
    Association for Surface Finishing. With him on the briefs
    was Christopher L. Bell. Joel F. Visser and Roger R.
    Martella Jr. entered appearances.
    Emma C. Cheuse argued the cause for petitioners Clean
    Air Council et al. With her on the briefs was James S. Pew.
    Khushi K. Desai entered an appearance.
    2
    Jonathan A. Wiener, Deputy Attorney General, Office of
    the Attorney General for the State of California, argued the
    cause for amici curiae California Air Resources Board, et al.
    With him on the brief were Kamala D. Harris, Attorney
    General, Robert W. Byrne, Senior Assistant Attorney General,
    Gavin G. McCabe, Supervising Deputy Attorney General,
    Ross H. Hirsch, Deputy Attorney General, Eric T.
    Schneidermann, Attorney General, Office of the Attorney
    General for the State of New York, Michael J. Myers,
    Assistant Attorney General, Kurt R. Wiese, and Barbara B.
    Baird.
    William L. Wehrum, Elizabeth L. Horner, Leslie A.
    Hulse, and Quentin Riegel were on the brief for amicus curiae
    Chromium RTR Coalition in support of petitioner National
    Association for Surface Finishing.
    John T. Suttles, Myra D. Blake, and Patrice L. Simms
    were on the brief for American Lung Association, et al. as
    amici curiae in support of environmental petitioners.
    Scott L. Nelson and Allison M. Zieve were on the brief for
    amicus curiae United States Representative Henry A.
    Waxman in support of environmental petitioners.
    T. Monique Peoples, Attorney, U.S. Department of
    Justice, argued the cause for respondents. With her on the
    brief were Sam Hirsch, Acting Assistant Attorney General,
    Stephanie J. Talbert, Attorney, and Jan M. Tierney, Attorney,
    U.S. Environmental Protection Agency.
    Robert G. Dreher and Jon M. Lipshultz, Attorneys, U.S.
    Department of Justice, entered appearances.
    3
    Jerry Stouck and Christopher L. Bell were on the brief for
    intervenor-respondent National Association of Surface
    Finishing.
    Emma C. Cheuse and James S. Pew were on the brief for
    environmental respondents-intervenors Clean Air Act
    Council, et al.
    Before: GRIFFITH and PILLARD, Circuit Judges, and
    WILLIAMS, Senior Circuit Judge.
    Opinion for the Court filed by Circuit Judge PILLARD.
    PILLARD, Circuit Judge: In this case we consider a pair
    of challenges to a 2012 regulation promulgated by the U.S.
    Environmental Protection Agency (EPA), revising Clean Air
    Act standards for emissions of hexavalent chromium.
    Hexavalent chromium is a carcinogenic compound emitted
    into the air during various chrome-finishing processes at more
    than a thousand facilities across the country. The facilities
    regulated under the challenged rule provide final, shiny,
    corrosion-resistant coatings on the surfaces of products
    ranging from plumbing fixtures to airplane wings. The
    various finishing processes used at those facilities all have the
    unfortunate side effect of generating misty chromium
    emissions that, if not properly controlled, can cause cancer.
    Facilities limit those emissions through the use of devices that
    capture emissions from the finishing tanks, or with fume
    suppressants that inhibit chromium droplets from bursting
    from the tank surface into the air in the first place. The new
    rule imposes more stringent emissions limitations than its
    predecessor and mandates the phase-out of a category of fume
    suppressants containing the toxic compound perfluorooctyl
    sulfonate (PFOS).
    4
    Various environmental organizations and an industry
    association have filed petitions challenging EPA’s revised
    rule. The environmental petitioners—the Clean Air Council,
    California Communities Against Toxics, and the Sierra
    Club—argue that the rule is too lax because EPA ignored
    relevant information and impermissibly considered costs in
    calculating revised emissions standards.         The industry
    petitioner—the National Association for Surface Finishing
    (the Association)—argues that the rule is too stringent. The
    Association contends that EPA failed to make a determination
    of developments in practices, processes, or control
    technologies that the Association claims is a statutorily
    required precondition to rule revision, that the agency lacked
    adequate support in the record for phasing out the PFOS-
    based fume suppressants, and that EPA unreasonably assessed
    public health risk. The environmental petitioners and the
    Association intervened in each other’s cases, and we
    consolidated the cases for review. We deny the petitions.
    I.
    Section 112 of the Clean Air Act requires EPA to
    promulgate, and periodically revise as appropriate, national
    emissions standards for hazardous air pollutants. See 42
    U.S.C. § 7412(d). When Congress enacted that emissions
    standards program in 1970, it directed EPA to identify and
    regulate hazardous air pollutants. Dissatisfied with EPA’s
    progress in identifying hazardous air pollutants, Congress
    amended the Act in 1990 to name nearly 200 such pollutants,
    including chromium compounds, and charged EPA with
    identifying sources of those pollutants and setting emissions
    standards for them. See 42 U.S.C. § 7412(b)(1), (c), (d); see
    also, e.g., Mexichem Specialty Resins, Inc. v. EPA, 
    787 F.3d 544
    , 549-50 (D.C. Cir. 2015); Natural Res. Def. Council v.
    EPA (“NRDC”), 
    529 F.3d 1077
    , 1079 (D.C. Cir. 2008). EPA
    5
    undertakes two basic regulatory tasks under section 112 that
    are relevant to this case: initial promulgation, followed by
    periodic review and potential revision, of emissions standards.
    EPA promulgates an emissions standard for a given
    pollutant by first determining the average emissions already
    achieved by the top tier of least polluting emitters, then
    considering whether a more demanding standard might be
    practicable and cost effective, and, if so, setting a standard
    that pushes beyond current practice. For starters, the agency
    identifies the 12% of facilities that emit the pollutant at the
    lowest levels, and then calculates the average level of
    emissions achieved by those facilities.            42 U.S.C.
    § 7412(d)(3). That calculation is dubbed the “MACT floor”
    because it is based on “maximum achievable control
    technology,” and the standard EPA promulgates must not be
    less stringent than that performance “floor.” See 
    Mexichem, 787 F.3d at 549-50
    & n.2; Nat’l Lime Ass’n v. EPA, 
    233 F.3d 625
    , 629 (D.C. Cir. 2000). EPA then considers whether,
    taking into account costs, certain health and environmental
    effects, and energy requirements, a standard might be
    practicable that would go beyond the emissions reductions
    those existing facilities already achieve. See 42 U.S.C.
    § 7412(d)(2); Nat’l 
    Lime, 233 F.3d at 629
    . If a more stringent
    standard is practicable in view of those factors, EPA
    promulgates a “beyond-the-floor” standard at that more
    stringent level; otherwise the agency sets the standard at the
    performance-based MACT floor. See 
    Mexichem, 787 F.3d at 549-50
    .
    EPA then periodically reviews and, if appropriate, revises
    the promulgated emissions standard, starting within eight
    years of the initial promulgation. That entails two distinct,
    parallel analyses: a recurring “technology review” under
    section 112(d)(6) and a one-time “risk review” under section
    6
    112(f)(2). In the technology review, EPA periodically
    assesses, no less often than every eight years, whether
    standards should be tightened in view of developments in
    technologies and practices since the standard’s promulgation
    or last revision, and, in particular, the cost and feasibility of
    developments and corresponding emissions savings. See 42
    U.S.C. § 7412(d)(6); see also Ass’n of Battery Recyclers, Inc.
    v. EPA (“ABR”), 
    716 F.3d 667
    , 673-74 (D.C. Cir. 2013).
    Separately, in the one-time risk review, EPA addresses,
    within eight years of a standard’s promulgation, lingering
    public health risk that the initial standard did not eliminate.
    See 42 U.S.C. § 7412(f)(2). To that end, EPA first considers
    whether the residual health risk is “acceptable,” a threshold
    EPA generally interprets as carrying cancer incidence no
    greater than 100 in one million. 75 Fed. Reg. 65,068, 65,071-
    72 (Oct. 21, 2010); see 
    NRDC, 529 F.3d at 1082
    . If the risk is
    not acceptable, EPA sets a more stringent standard regardless
    of cost to bring the risk down to an acceptable level. Even if
    a risk would be deemed acceptable because it is under that
    threshold, however, EPA considers whether a more stringent
    standard is “required in order to provide an ample margin of
    safety to public health.” 42 U.S.C. § 7412(f)(2)(A). What
    determines whether a more stringent standard providing an
    ample margin of safety is statutorily required is the agency’s
    consideration of health information as well as costs, economic
    impact, feasibility, and other relevant factors. See id.; see
    also 
    NRDC, 529 F.3d at 1083
    ; 75 Fed. Reg. at 65,072. If,
    taking those relevant considerations into account, further risk
    reductions are attainable beyond the “acceptable” threshold,
    they are required.
    7
    II.
    Two decades ago, EPA promulgated standards restricting
    emissions of hexavalent chromium from the types of
    chromium electroplating and anodizing facilities regulated
    under the rule challenged in this case.1 60 Fed. Reg. 4,948
    (Jan. 25, 1995). The agency has reviewed and revised those
    standards over the years. At issue here is the 2012 Final Rule
    that most recently updated them. See Final Rule, National
    Emissions Standards for Hazardous Air Pollutant Emissions:
    Hard and Decorative Chromium Electroplating and
    Chromium Anodizing Tanks; and Steel Pickling—HCl
    Process Facilities and Hydrochloric Acid Regeneration Plants,
    77 Fed. Reg. 58,220 (Sept. 19, 2012).
    The initial, 1995 rule set emissions limits and allowed
    facilities to demonstrate compliance with them either by
    directly measuring chromium emissions or by gauging the
    surface tension of the chemical baths in their finishing tanks.
    60 Fed. Reg. at 4,953-54, 4,956, 4,959. The latter compliance
    option worked because of the “direct link between surface
    tension and emissions.” 
    Id. at 4,959.
    As we explain below,
    surface tension describes how strongly a fluid sticks together
    where it meets the air. The surface tension of the chromium
    solution in which products are submerged during the finishing
    1
    Electroplating facilities finish products by dipping them in a salty
    chemical solution containing chromium and passing an electrical
    current through the solution. That causes chromium particles to
    deposit onto the products’ submerged surfaces, forming a protective
    seal. Anodizing facilities use a distinct but similar process to create
    a protective oxidation film over products’ surfaces. The challenged
    rule also regulates steel pickling facilities, but those facilities were
    not part of the earlier rulemakings recounted herein and are not
    directly implicated by the challenges in this case.
    8
    process determines the force with which non-chromium gas
    bubbles generated in the process burst out of the solution in
    the finishing tanks. Reducing surface tension makes it easier
    for bubbles to pass through the solution into the air, which
    diminishes the force of bubble-bursting at the surface. That,
    in turn, reduces the amount of harmful chromium droplets that
    pop into the air and create misty toxic emissions. In a 2004
    rulemaking, EPA reaffirmed and modified the option of
    compliance by controlling surface tension. 69 Fed. Reg.
    42,885, 42,886-88 (July 19, 2004).2
    Before issuing the Final Rule petitioners challenge, EPA
    published a 2010 notice of proposed rulemaking (Notice) and
    a 2012 supplemental notice of proposed rulemaking
    (Supplemental Notice). In the initial Notice, EPA proposed to
    determine that the data before the agency did not warrant
    tightening the existing emissions standards. 75 Fed. Reg. at
    65,093-94. EPA nonetheless solicited additional data and
    comments. 
    Id. at 65,125.
    Meanwhile, EPA proposed to
    phase out surfactant-based chemical fume suppressants
    containing the hazardous chemical PFOS. 
    Id. at 65,094.
    Surfactants reduce the surface tension of solutions to which
    they are added. EPA concluded that less toxic, non-PFOS-
    based fume suppressants had proven effective at controlling
    surface tensions, even though they were not yet used
    extensively in the industry. The agency saw no reason why
    non-PFOS-based suppressants could not cost-effectively
    replace their toxic PFOS-containing counterparts, so the
    agency solicited input on its proposal to prohibit PFOS. 
    Id. 2 EPA
    did not timely conduct the full technology and risk reviews
    required by the statute, see 69 Fed. Reg. at 42,888-89—a timing
    failure not at issue in this case.
    9
    Nearly a year and a half later, after having received more
    accurate and comprehensive data in response to the Notice,
    EPA in the Supplemental Notice proposed to reverse its prior
    tentative determinations that more stringent emissions
    standards were unnecessary. 77 Fed. Reg. 6,628 (Feb. 8,
    2012). EPA suggested that revised standards were warranted
    based on both its technology review and its risk review. 
    Id. at 6,631-52.
    In its technology review, EPA noted its additional
    analyses based on new data and explained its proposed
    selection of feasible, cost-effective options to further limit
    emissions. 
    Id. at 6,632,
    6,638-45. EPA solicited information
    regarding whether the surface tension limits proposed in the
    Supplemental Notice were achievable using non-PFOS-based
    suppressants. 
    Id. at 6,645.
    In its risk review, EPA proposed
    to conclude that cancer risk was well below the “acceptable”
    100-in-one-million level, and that the same standards the
    agency was proposing as a result of the technology review
    would likewise provide the requisite “ample margin of safety”
    for purposes of its risk review. 
    Id. at 6,648-49.
    EPA issued the Final Rule in September 2012, adopting
    the emissions standards proposed in the Supplemental Notice.
    77 Fed. Reg. at 58,225. EPA explained that additional
    information submitted during the interim period and
    additional analyses the agency had performed bolstered the
    determinations proposed in the Supplemental Notice. 
    Id. at 58,225-26.
    EPA also finalized the phase-out of PFOS-based
    fume suppressants, emphasizing data the agency collected
    from Minnesota facilities that had been controlling surface
    tensions effectively using non-PFOS-based suppressants. 
    Id. at 58,230,
    58,236-37.
    10
    III.
    This court applies the familiar, deferential standard
    announced in Chevron, U.S.A., Inc. v. Natural Resources
    Defense Council, Inc., to sustain any reasonable agency
    interpretation of ambiguity in the Clean Air Act. 
    467 U.S. 837
    , 842-44 (1984). We reverse EPA’s determinations under
    the Act when they are “arbitrary, capricious, an abuse of
    discretion, or otherwise not in accordance with law.” 42
    U.S.C. § 7607(d)(9)(A). Under arbitrary-and-capricious
    review, EPA’s determinations are “presumptively valid
    provided [they] meet[] a minimum rationality standard.”
    Natural Res. Def. Council, Inc. v. EPA, 
    194 F.3d 130
    , 136
    (D.C. Cir. 1999). We uphold EPA’s determinations so long
    as “EPA acted within its delegated statutory authority,
    considered all of the relevant factors, and demonstrated a
    reasonable connection between the facts on the record and its
    decision.” Ethyl Corp. v. EPA, 
    51 F.3d 1053
    , 1064 (D.C. Cir.
    1995). We afford special deference “where the agency’s
    decision rests on an evaluation of complex scientific data
    within the agency’s technical expertise.” Troy Corp. v.
    Browner, 
    120 F.3d 277
    , 283 (D.C. Cir. 1997).
    The environmental petitioners challenge the Final Rule as
    too lax on the grounds that EPA unreasonably (1) declined to
    recalculate a technology-based emissions stringency floor that
    is independent of cost considerations, and (2) ignored
    emissions data from California in calculating revised
    standards.      The Association challenges the rules as
    unauthorized and overly stringent on the grounds that EPA
    (1) did not adequately tie its revision of standards to
    technological “developments” that had occurred since the
    initial   standard-promulgation,     (2) concluded     without
    sufficient evidentiary support that non-PFOS-based fume
    suppressants are capable of achieving the rule’s emissions
    11
    limits, and (3) in its risk review, unreasonably failed to
    determine whether existing emissions limits provided the
    requisite margin of safety, deviated from the agency’s prior
    determination that the requisite margin of safety had been
    attained, and relied on inaccurate data.
    A.
    The environmental petitioners contend that EPA was
    required to calculate a new MACT floor when it revised
    emissions standards pursuant to its technology review under
    section 112(d)(6). Subparagraph (d)(6) requires EPA, no less
    often than every eight years, to “review, and revise as
    necessary (taking into account developments in practices,
    processes, and control technologies) emission standards
    promulgated under” that section. 42 U.S.C. § 7412(d)(6).
    The environmental petitioners assert that EPA’s revision of
    standards in its technology review must be treated as a
    “promulgation” of an emissions standard, such that it triggers
    the Clean Air Act’s requirement that any promulgation must
    begin with EPA setting a MACT floor. They argue, in effect,
    that EPA must calculate a new MACT floor whenever the
    agency revises an existing emissions standard based on its
    periodic technology review under section 112(d)(6). A new
    MACT floor, if EPA set one, would be based purely on the
    achievements of the best-performing facilities in the industry
    after initial emissions standards had been operative for several
    years, and thus presumably would be more stringent than the
    existing MACT floor, and likely also more stringent than
    technology or risk-based revisions that take costs and other
    potentially constraining factors into account.
    12
    EPA itself has not so read the statute, and our precedent
    binds us to reject the environmental petitioners’ argument that
    it must so read it.3 We initially confronted a version of this
    question in NRDC, a case in which EPA had conducted a
    technology review but determined that revision was not
    
    warranted. 529 F.3d at 1080
    . The parties in NRDC briefed
    the argument the environmental petitioners press here. We
    concluded that the agency was not required to recalculate the
    MACT floor at the outset of its technology review, at least
    where EPA had decided not to revise emissions standards as a
    result of that review. 
    Id. at 1084.
    We had occasion to address the issue more squarely in
    ABR, a case in which EPA had not only reviewed, but also
    revised, standards after a technology 
    review. 716 F.3d at 670
    .
    The court in ABR was not persuaded by petitioners’
    contention—pressed again by the environmental petitioners
    here—that our decision in NRDC was inapposite on the
    ground that it dealt with an EPA review that yielded no
    revision of any standard. ABR emphasized that NRDC rested
    “on two independent conclusions,” and that in such a case,
    “the ruling on neither is obiter [dictum], but each is the
    judgment of the court, and of equal validity with the other.”
    
    Id. at 673
    (internal quotation marks omitted). We held in
    ABR that the petitioners’ argument that the agency must
    recalculate the MACT floor, “although far better developed
    3
    Neither this case nor any of our precedents addresses the distinct
    question whether, had EPA itself adopted the environmental
    petitioners’ reading, its interpretation would be valid under
    Chevron.
    13
    than the identical claim in [NRDC], [was] barred by that
    decision.” Id.4
    The environmental petitioners incorrectly suggest that
    our decisions on this point in ABR and NRDC were abrogated
    by our later decision in White Stallion Energy Ctr., LLC v.
    EPA, 
    748 F.3d 1222
    (D.C. Cir. 2014), which the Supreme
    Court recently partially reversed in Michigan v. EPA, No. 14-
    46, 
    2015 WL 2473453
    , 576 U.S. __ (June 29, 2015).5 In
    4
    The environmental petitioners argue that this court “has never
    addressed or decided the statutory issue presented here: that
    revised standards promulgated following a § 112(d)(6) review are
    ‘emissions standards promulgated under this subsection’ and,
    therefore, subject to the stringency requirements in § 112(d)(2) and
    (d)(3).” Envtl. Pet. Br. 35. As they see it, NRDC addressed a
    different question, and ABR then erroneously treated the scant
    reasoning in NRDC as binding. See 
    id. at 32-37.
    “Because ABR is
    directly at odds with clear statutory text that neither ABR nor NRDC
    addresses,” they request en banc action via an Irons footnote. 
    Id. at 33,
    37; see Irons v. Diamond, 
    670 F.2d 265
    , 267-68 & n.11 (D.C.
    Cir. 1981); Policy Statement on En Banc Endorsement of Panel
    Decisions (January 17, 1996). This is not, however, the kind of
    minor or marginal issue, nor one on which our precedents have
    been shown by intervening decisions to be clearly incorrect, such as
    might call for reversal in an Irons footnote.
    5
    The Supreme Court held in Michigan that EPA may not decline to
    consider cost as part of a required threshold inquiry under Clean
    Air Act section 112(n)(1)(A) into whether it is “appropriate and
    necessary” to regulate power plants. 
    Michigan, supra
    , slip op. at 6-
    14; see 42 U.S.C. § 7412(n)(1)(A).         The “unique” section
    112(n)(1)(A) precondition to power-plant regulation that the Court
    reviewed in Michigan is “[q]uite apart from the hazardous-air-
    pollutants program” at issue here. See 
    Michigan, supra
    , slip op. at
    2. The “appropriate and necessary” provision that the Court held
    EPA unlawfully interpreted does not apply to the program that
    14
    White Stallion, we addressed EPA’s interpretation of Clean
    Air Act section 112(n)(1)(A), and its relationship to section
    
    112(d). 748 F.3d at 1242-44
    . Section 112(n)(1)(A) provides
    for EPA regulation of fossil-fuel-fired power plants when
    “appropriate and necessary.” 42 U.S.C. § 7412(n)(1)(A). We
    sustained as reasonable EPA’s interpretation of “under this
    section,” as used in that provision, to refer to the entirety of
    section 112, such that the regulation required whenever
    section 112(n)(1)(A)’s “appropriate and necessary” criteria
    are met must comport with the procedures of the rest of
    section 112, including those of section 112(d), addressing
    emissions standards 
    generally. 748 F.3d at 1243-44
    ; see 42
    U.S.C. § 7412(d). The environmental petitioners assert that
    the relationship between section 112(n)(1)(A), with its
    “regulate” as “appropriate and necessary” trigger, and section
    112, governing hazardous air pollution regulation generally
    (including the setting of MACT floors under section
    112(d)(2)-(3)), is the same as the relationship between section
    112(d)(6), with its “review, and revise as necessary”
    language, and section 112(d)(2)-(3). However, White Stallion
    did not tie section 112(n)(1)(A) to section 112(d)(2)-(3)
    specifically, as the petitioners’ analogy assumes. Nor did that
    decision address the distinction EPA makes here between
    initial promulgation under section 112(d)(2)-(3) and
    promulgation of revised standards as necessary under section
    112(d)(6). We simply deferred to EPA’s view that regulation
    triggered under section 112(n)(1)(A) must follow the
    procedures of section 112(d).
    regulates hexavalent chromium emissions from chrome-plating
    facilities.
    15
    B.
    The environmental petitioners also contend that EPA
    unreasonably disregarded, in both its technology and risk
    reviews, the emissions reductions and technological
    advancements achieved in California, where that state’s more
    stringent emissions standards require facilities to employ
    more ambitious controls.
    EPA took account of the California emissions data. In its
    technology and risk reviews, EPA estimates actual nationwide
    emissions and costs by extrapolating data collected from a
    sample of facilities across the country in order to establish
    baselines against which the agency can assess emissions
    decreases, health risk, and cost effectiveness associated with
    different practices, technologies, and emissions limitations.
    See, e.g., 77 Fed. Reg. at 6,631-34. EPA did not ignore
    California’s emissions data; it omitted it only from the dataset
    from which the agency extrapolated other states’ emissions.
    
    Id. at 6,633-34.
    That was prudent as a matter of statistical
    accuracy because “California plants are not representative of
    emissions for non-California plants.” 
    Id. at 6,634;
    see also
    J.A. 531 (same in response to comments). EPA used
    California data, meanwhile, to estimate emissions for other
    plants in that state. 77 Fed. Reg. at 6,634. The agency thus
    “did not exclude the California [emissions] data from the
    overall analysis,” but rather “treated the data from plants in
    California differently” so as to achieve a statistically accurate
    portrait of nationwide emissions. 
    Id. EPA’s approach
    was
    reasonable because extrapolating California’s nationally
    unrepresentative data to the rest of the country would have
    distorted the emissions figures that EPA uses in its cost-
    effectiveness and risk analyses, whereas reliance on that data
    for California-specific estimates had no such distorting effect.
    16
    EPA also did not ignore California’s technological
    advances in assessing the cost effectiveness of applying
    nationally the standards in effect in California. The agency
    acknowledged that California emissions standards require
    controls that are more stringent than those required elsewhere,
    and that they had been feasibly implemented in California.
    The agency weighed the costs and benefits of requiring those
    controls nationally, and concluded that the relatively minimal
    reductions in emissions and risk that could be expected from
    extending California-like controls across the country would
    not warrant the associated expense. EPA “considered the
    option of requiring controls similar to standards adopted in
    California, which would essentially require facilities to install
    high efficiency particulate air (HEPA) filters,” but found that
    “overall costs for that option were significantly higher than
    . . . other options” EPA had examined, “and would have
    resulted in much greater economic impacts to small
    businesses.” 77 Fed. Reg. at 58,227.
    The agency further explained that “requirements similar
    to the California standards” were “not appropriate . . . to
    provide an ample margin of safety to protect public health” in
    light of “the high overall costs and economic impacts.” 
    Id. Responding to
    a comment that EPA had “failed to provide
    any explanation for not considering the California
    reductions,” the agency explained that it had “evaluated . . .
    the controls used to comply with the standards in California”
    and concluded “that requiring these controls throughout the
    industry was not appropriate under either section 112(d)(6)
    [technology review] or section 112(f)(2) [risk review].” 
    Id. at 58,231-32;
    see also 75 Fed. Reg. at 65,092-94 (assessing risk
    level and cost associated with HEPA filters).             The
    environmental petitioners suggest that EPA should have
    performed additional analyses beyond that related to HEPA
    filters but, as the agency reasonably explained, EPA lacked
    17
    the necessary information to do so: EPA was not provided
    with, and was otherwise unaware of, the detailed explanations
    of the assumptions and methodology behind California cost
    analyses that the agency would have needed to parse
    California’s data and accurately assess its applicability to the
    national regulatory context. See, e.g., J.A. 543.
    EPA took into account the statutorily required
    considerations of, inter alia, cost, emissions reductions, and
    health risk. The agency then provided a transparent, reasoned
    explanation of its decisions, considering all relevant
    information in the record. The statute does not mandate a
    particular method of cost-benefit analysis. Therefore, we
    defer to EPA’s methodology as well as its ultimate balancing
    decisions. See Husqvarna AB v. EPA, 
    254 F.3d 195
    , 200
    (D.C. Cir. 2001); cf. Brown v. United States, 
    327 F.3d 1198
    ,
    1205-06 (D.C. Cir. 2003) (deferring to an agency’s reasoned
    methodology even under the less deferential Skidmore
    standard of review).6
    C.
    The Association, in the first of its three challenges,
    asserts that EPA unreasonably determined in its technology
    review that “developments” had occurred after the original
    rulemaking that required revision of the existing emissions
    standards. The statute calls on EPA to revise promulgated
    standards “as necessary (taking into account developments in
    6
    The environmental petitioners’ related challenges to EPA’s
    treatment of the California data—that the agency’s disregard of that
    data derogated from its duty to consider all significant aspects of
    the statutory problem, and contravened the purpose of the Clean Air
    Act—also fail because they rest on the same false premise,
    addressed above, that EPA unreasonably disregarded the data.
    18
    practices, processes, and control technologies).” 42 U.S.C.
    § 7412(d)(6). EPA and the Association agree that the agency
    could not revise standards in its technology review unless
    such pertinent “developments” occurred after the 1995 rule.
    The Association argues, however, that EPA failed to identify
    the requisite “developments” and failed to specify how its
    revised standards were tied to them. The Association also
    suggests EPA was arbitrary and capricious in changing
    course: in 2010 its proposed determination was that
    “developments” did not warrant revision, but in 2012 EPA
    concluded that revision was warranted after all. The
    Association further argues that EPA’s statistical analysis of
    emissions data was unreasonably flawed.
    EPA permissibly identified and took into account
    cognizable developments in practices, processes and control
    technologies. The agency interprets “developments” to
    encompass not only wholly new methods, but also
    technological “improvements . . . that could result in
    significant additional emission reduction.” 75 Fed. Reg. at
    65,083. “Developments” thus include “improvements in
    efficiency, reduced costs or other changes that indicate that a
    previously considered option for reducing emissions may now
    be cost effective or technologically feasible.” 77 Fed. Reg. at
    58,231.
    The Association does not directly challenge those
    interpretations, but maintains that EPA failed to identify what
    specific     “developments,”        including     technological
    “improvements,” occurred in this case that warranted
    revision. EPA identified several technologies, such as
    emissions elimination devices, HEPA filters, enclosing tank
    hoods, and fume suppressants. 77 Fed. Reg. at 6,632 (2012
    Supplemental Notice referencing developments identified in
    2010 Notice); 75 Fed. Reg. at 65,083, 65,093-94 (Notice
    19
    identifying the aforementioned developments); J.A. 152-54
    (2010 technology review memorandum discussing the same).
    EPA further explained that, although the technologies were
    not brand new, improvements in the performance of some of
    them had resulted in emissions reductions. J.A. 516 (2012
    response to comments); see also 77 Fed. Reg. at 6,631-32
    (acknowledging      data   showing     improved     facility
    performance).
    It suffices for EPA to assess and discuss the collective
    impact of the developments it has identified, and to revise
    standards appropriately in light thereof. Section 112(d)(6)
    simply requires that EPA “take[] into account developments
    in practices, processes, and control technologies” when
    considering whether to revise standards.          The agency
    explained that it had examined what emissions levels could be
    achieved using various add-on control devises and fume
    suppressants, including developments the agency had
    previously identified. See, e.g., 77 Fed. Reg. at 6,632. EPA
    went on to provide details regarding the costs and emissions
    reductions identified, and evaluated in the course of arriving
    at its conclusion that specified, best-available control
    technologies could cost-effectively meet more stringent
    emissions standards. See, e.g., 
    id. at 6,640.
    The statute does
    not require EPA to identify a nexus between each distinct
    development and the revised standards. EPA’s decision-
    making was sufficiently clear and rational.          See Int’l
    Fabricare Inst. v. EPA, 
    972 F.2d 384
    , 389 (D.C. Cir. 1992).
    Moreover, the shift in EPA’s position from 2010 to 2012
    was reasonable because the agency received intervening
    information relevant to its decision. See, e.g., Sierra Club v.
    EPA, 
    353 F.3d 976
    , 986-87 (D.C. Cir. 2004) (“[T]he
    adequacy of the underlying justification offered by the agency
    is the pertinent factor—not what the agency did on a different
    20
    record . . . .”). In 2010, EPA proposed to leave the existing
    emissions standards in place, not because no technological
    developments had occurred, but because the agency
    determined based on the data before it that requiring
    nationwide implementation of those technologies was not
    feasible, cost effective, and otherwise warranted. 75 Fed.
    Reg. at 65,093-95. EPA’s Notices solicited comments,
    however, and EPA contacted pollution control authorities to
    gain fuller, more accurate data. New data showed that
    facilities were performing better with respect to emissions
    than previously thought. 77 Fed. Reg. at 58,225-26, 58,231;
    77 Fed. Reg. at 6,631-32. Reductions in emissions are, of
    course, relevant to the cost effectiveness of emissions-control
    technologies in controlling emissions. See, e.g., J.A. 483-89
    (2012 memorandum). The agency thus concluded, based on
    the improved data, that more stringent technology-based
    standards were cost effective and otherwise appropriate. See
    77 Fed. Reg. at 58,225-26; 77 Fed. Reg. at 6,632-33, 6,638-
    45. EPA’s change in position therefore was not arbitrary and
    capricious.
    Finally, the dataset EPA used to estimate facilities’
    compliance rates—a component of the agency’s technology
    review—was not impermissibly small or inaccurate. The
    Association charges that EPA’s analysis was not designed to
    provide an accurate cross-section of the industry. It asserts
    that EPA did not sample facilities “on any statistical or
    representative basis,” and faults the agency for not requesting
    “all emissions data the states had in their files.” Ass’n Br. 30.
    EPA responds that it relied on data from a statistically
    significant number of facilities and a range that reflected
    “current, available information from facilities across all major
    regions of the country.” EPA Br. 50. Reacting to concerns
    raised after the 2010 Notice that the agency’s dataset was too
    small and unrepresentative, EPA sought detailed information
    21
    about emissions associated with various facility types. 77
    Fed. Reg. at 6,631. EPA explained that emissions data
    available for collection is limited because many smaller
    facilities are not required to submit annual emissions
    inventories—an informational dearth in light of which EPA
    gathered what it concluded was the “best information
    available to the Agency” and “minimized the [statistical]
    uncertainties to the extent feasible.” J.A. 535-36. In the face
    of those challenges, the agency obtained information from 24
    state and local agencies, as well as some information from the
    Association itself, to achieve a sample that included data from
    301 operational plants. 77 Fed. Reg. at 6,631. EPA
    determined that conducting a more in-depth industry-wide
    survey, requiring more facilities to collect and submit
    additional data, would have been statistically unnecessary and
    would not have warranted the substantial burden on smaller
    facilities. J.A. 537.
    Tellingly, the Association does not identify any specific,
    superior      statistical    threshold    of     data-gathering
    comprehensiveness that, in its view, would have been
    reasonable. Rather, acknowledging that a limited amount of
    emissions data is available to EPA, the Association simply
    criticizes the agency for not obtaining and evaluating more
    data. But “[w]e generally defer to an agency’s decision to
    proceed on the basis of imperfect scientific information,
    rather than to invest the resources to conduct the perfect
    study.” 
    NRDC, 529 F.3d at 1086
    (quoting Sierra Club v.
    EPA, 
    167 F.3d 658
    , 662 (D.C. Cir. 1999)). We recognize that
    EPA conceivably “could have used better data in conducting
    its risk analysis,” but that “misstates [our] inquiry under the
    arbitrary and capricious standard,” which is “whether EPA
    has acted reasonably, not whether it has acted flawlessly.” 
    Id. (emphasis omitted).
    We cannot say that the size and
    representativeness of the dataset EPA used to estimate
    22
    compliance rates was statistically unreasonable, nor can we
    characterize as arbitrary EPA’s considered judgment that
    collecting additional data was unnecessary and not worth the
    cost, keeping in mind the “wide latitude” we afford the
    agency in its data-gathering decisions. 
    Id. (quoting Sierra
    Club, 167 F.3d at 662
    ); see also White 
    Stallion, 748 F.3d at 1247-48
    (“EPA’s data-collection process was reasonable,
    even if it may not have resulted in a perfect dataset.”), rev’d
    in part on other grounds, 
    Michigan, supra
    . We are satisfied
    that EPA’s data-gathering and analysis was adequate.
    D.
    The Association further argues that EPA’s decision to
    phase out PFOS-based fume suppressants was arbitrary and
    capricious. As we explain below, fume suppressants reduce
    finishing baths’ surface tension and, consequently, their
    chromium emissions. The Association’s claim hinges on its
    contention that there is inadequate support in the record
    showing that non-PFOS-based substitutes can effectively
    achieve the emissions limits required by the Final Rule. The
    Association does not challenge the compliance option that
    facilities have enjoyed since the original 1995 rule to measure
    the surface tension of their finishing baths rather than the
    emissions therefrom. See 60 Fed. Reg. at 4,953-54, 4,956.
    Nor does it seriously question that the administrative record
    shows that non-PFOS-based suppressants are capable of
    meeting the Final Rule’s surface tension limits. Rather, the
    Association contends that EPA failed empirically to support
    the conclusion that the same emissions control will result
    from equal surface tension reductions, whether those
    reductions are achieved with non-PFOS-based suppressants or
    PFOS-based suppressants. To that end, the Association points
    to what it perceives as an absence of reliable studies that
    23
    measure the emissions from baths whose surface tension is
    controlled by non-PFOS-based suppressants.
    The Association’s challenge fails to appreciate the
    finding, documented in the record, that the relationship
    between surface tension and emissions does not depend on the
    identity of the suppressant used to achieve that surface
    tension. Reducing a finishing bath’s surface tension reduces
    emissions from that bath. Surface tension describes a liquid’s
    cohesive strength where the liquid meets the air. The higher
    the surface tension, the more the liquid will bulge when its
    surface is pressured and the more resistant it will be to
    allowing bubbles to break through. E.g., J.A. 349. That is
    significant in the context of surface finishing because the
    electrolysis-induced finishing process generates bubbles of
    gas within the finishing solution. When those bubbles fizz up
    through the chromium-solution bath and pop upon hitting the
    surface, the bursting action sends tiny droplets of the solution
    into the air as mist. J.A. 440. Adding a surfactant-based
    fume suppressant to the finishing solution reduces its surface
    tension, which allows gases generated within the bath to pass
    through the surface of the solution more easily. That results
    in less forceful bubble-popping at the surface, which in turn
    diminishes the amount of chromium mist emitted. E.g., 77
    Fed. Reg. at 58,236-37; J.A. 349, 440-43. Because the
    physical relationship between surface tension and emissions
    exists independent of the specific tension-controlling agent, it
    is sufficient for EPA to rely on the evidence in the record
    establishing the relationship between non-PFOS-based
    suppressants and surface tension; EPA need not identify
    studies directly confirming the relationship between the
    specific surface tension controlling agent and the emission
    reduction.
    24
    That physical relationship between surface tension and
    emissions level is the basis of EPA’s long-standing rule
    allowing facilities to demonstrate compliance with emissions
    standards by measuring finishing baths’ surface tension rather
    than directly measuring their emissions. It is the established
    “direct link between surface tension and emissions” that has
    supported EPA’s acceptance of surface tension control as a
    proxy for emissions control. 60 Fed. Reg. at 4,959 (1995
    rule).
    The 1995 rulemaking in which EPA determined to rely
    on the relationship between surface tension and emissions
    never suggested that the type of fume suppressant used to
    control surface tension matters to emissions level. See 
    id. (“Based on
    data collected by the EPA, the [emissions]
    performance of an electroplating bath controlled with a
    wetting agent-type [i.e. chemical surfactant] fume suppressant
    can be determined by the surface tension of the bath.”); see
    also 58 Fed. Reg. 65,768, 65,795 (Dec. 16, 1993) (original
    proposed rule) (“[M]easurement of the surface tension of the
    bath . . . at least once every 4 hours during operation of the
    tank would be sufficient to ensure continuous compliance
    with the emission limit.”).
    EPA explicitly confirmed in the 2004 rulemaking that the
    tension/emissions relationship does not depend on suppressant
    type when it recognized that “[s]ources will be in compliance
    with the emission limits provided the surface tension is
    maintained at or below the proposed limits, regardless of the
    type of fume suppressant used”; the data before the agency
    did not “indicate that emission control levels are a function of
    the type of fume suppressant used in the tank solution.” 69
    Fed. Reg. at 42,888.
    25
    EPA reiterated in 2012 that “emissions are a function of
    the surface tension” and that lower surface tension results in
    lower emissions “regardless of the specific chemicals used.”
    J.A. 479 (EPA memorandum cited in Final Rule); see also 77
    Fed. Reg. at 58,237 (“It is our understanding that this
    relationship between surface tension and chromium emissions
    is dependent primarily on the surface tension of the tank and
    not on the product used to reduce surface tension.”). It is the
    property of surface tension on the bath, not some other
    reaction unique to the particular surfactant employed, that
    affects the force with which bubbles in the chromium bath
    burst and send droplets into the air. See, e.g., J.A. 349, 440-
    43.
    Neither logic nor the record supports the Association’s
    conclusory suggestion that emissions will vary, given a
    constant surface tension, depending on whether PFOS- or
    non-PFOS-based fume suppressants are used to achieve that
    surface tension. The Association points out that EPA’s
    statements in earlier rulemakings were made in the context of
    considering only various PFOS-based suppressants. That
    ignores the fact that EPA restated in 2012, in a memorandum
    in which it was also considering the effectiveness of non-
    PFOS-based suppressants, that the suppressant’s chemical
    identity is irrelevant. See J.A. 479, 482. Moreover, the
    Association provides no explanation and points to no
    evidence supporting its suggestion that the principle EPA
    earlier recognized does not apply to non-PFOS-based
    suppressants. If EPA had established, in a rulemaking
    involving various kitchen stoves, that water boils when it
    reaches 212°F regardless of the type of stove used, and later
    took that boiling point as a given in a rulemaking involving
    campfires, we would not require EPA to document the same
    scientific phenomenon of water boiling at 212°F in the new,
    campfire context—at least not where a petitioner proffered
    26
    nothing suggesting why the heat-source difference might
    matter. The Association’s bare assertion that EPA needed to
    provide fresh empirical support for the applicability of the
    tension/emissions relationship in the context of non-PFOS-
    based suppressants is insufficient to undermine the
    documentation already in the record. “Agencies do not need
    to conduct experiments in order to rely on the prediction that
    an unsupported stone will fall.” Assoc’d Gas Distribs. v.
    FERC, 
    824 F.2d 981
    , 1008-09 (D.C. Cir. 1987); cf. Chamber
    of Commerce of U.S. v. SEC, 
    412 F.3d 133
    , 142 (D.C. Cir.
    2005) (“[W]e are acutely aware that an agency need not—
    indeed cannot—base its every action upon empirical
    data . . . .”).
    The studies in the administrative record are consistent
    with EPA’s understanding that surface tension is a reliable
    proxy for emissions regardless of the fume suppressant
    employed.      A 2011 study expressly contemplates the
    PFOS/non-PFOS dichotomy and treats that difference as
    immaterial to the tension-emissions relationship. See J.A.
    439-49 (Neil Patton & Gene Barlowe, Atotech, Non-PFOS,
    Permanent Mist Suppressants for Hard Chromium Plating,
    Decorative Chromium Plating and Chromic Etch
    Applications (2011)).          The study identifies “mist
    suppressants” as a general category of surfactants, noting they
    all “work by reducing the surface tension of the solution.”
    J.A. 442; see 
    id. (stating without
    reference to the surfactant’s
    chemical composition that reducing surface tension lowers
    mist generation).        The study then identifies several
    characteristics of effective suppressants—including the ability
    to control surface tension and emissions, as well as unrelated
    criteria such as effect on plating quality—without suggesting
    that ability to meet those criteria depends on PFOS
    composition. J.A. 444. The study explains that earlier
    generations of non-PFOS-based suppressants were disfavored
    27
    not because of non-correlation between surface tension and
    emissions, but rather because they were less stable and tended
    chemically to foment a scum that degraded plating quality.
    J.A. 445. The authors go on to recognize that newer non-
    PFOS-based suppressants for years have been performing
    “just as well” as PFOS-based suppressants. J.A. 444-47.
    Other studies in the record, which measured only emissions
    directly and did not document emissions’ relationship to
    surface tension, are consistent with that understanding.7
    Therefore, it suffices for EPA to show that non-PFOS-
    based suppressants are as effective at controlling surface
    tension as PFOS-based suppressants (which the Association
    does not contend are incapable of achieving the Final Rule’s
    surface tension limits). We conclude that the data from
    Minnesota facilities emphasized in the Final Rule shows that
    effectiveness. See 77 Fed. Reg. at 58,236-37. The Minnesota
    data show that non-PFOS-based suppressants perform, in the
    facilities’ experience, “pretty similarly” and pose “no
    noticeable differences” in comparison to PFOS-based
    suppressants. J.A. 415-16; see J.A. 417-21 (raw data
    7
    A 2011 Danish study and a 2012 German study directly compared
    emissions from PFOS and non-PFOS tanks without clearly
    recording surface tensions. See J.A. 410-13, 423-25. EPA
    interprets those studies as showing that non-PFOS-based
    suppressants are comparably effective at reducing emissions. See
    77 Fed. Reg. at 58,237; J.A. 507-512. The Association responds
    that the studies failed to demonstrate that non-PFOS-based
    suppressants can meet the Final Rule’s emissions limitations. We
    need not opine on that question because, as discussed above, the
    established relationship between surface tension and emissions
    means that it suffices for EPA to rely on data demonstrating that
    non-PFOS-based suppressants meet the Final Rule’s surface tension
    limits.
    28
    supporting those observations); J.A. 482 (additional data
    analysis). The Association does not meaningfully argue
    otherwise, conceding that the Minnesota data “indicate that
    non-PFOS fume suppressants might be used to meet the new
    surface tension standards.” Ass’n Br. 41.
    E.
    The Association argues that EPA’s risk review under
    section 112(f)(2) was unreasonable, for three reasons.8
    First, the Association asserts that EPA failed to make a
    finding in the Final Rule that a revised standard was “required
    in order to provide an ample margin of safety to public
    health.” 42 U.S.C. § 7412(f)(2). However, EPA did not skip
    the step of determining in the Final Rule that revised
    standards were required to provide an ample margin of safety.
    The agency expressly stated that it was “promulgating
    standards under Section 112(f) to provide an ample margin of
    safety.” 77 Fed. Reg. at 58,226; see also 
    id. at 58,229
    (“[A]fter considering all the health and cost factors . . . , the
    agency has determined that . . . [the revised standard] will
    provide an ample margin of safety . . . .”).
    The Association argues that EPA’s determinations that
    revised standards would provide an ample margin of safety
    did not contain a determination that they were required to
    8
    While we affirm EPA’s determinations under section 112(f)(2),
    we note that even if we disapproved of them, the same emissions
    standards would survive because EPA determined that they were
    independently warranted by its technology review under section
    112(d)(6). See 77 Fed. Reg. at 58,224-25; 77 Fed. Reg. at 6,648.
    The Association’s counsel acknowledged as much at argument.
    Oral Arg. Tr. at 16:20-17:8.
    29
    provide that margin. That is simply not the case. In response
    to comments, for instance, the agency reiterated its
    understanding that section 112(f)(2) mandates revision when,
    “required to provide an ample margin of safety.” J.A. 527.
    The agency has consistently viewed itself as “required to
    propose emissions standards . . . that reduce risk to a level that
    is acceptable and provides an ample margin of safety.” 75
    Fed. Reg. at 65,091. It is precisely as a result of the further
    consideration and context-based determination that additional
    risk reductions can be achieved cost effectively and in light of
    other statutorily relevant factors that the agency’s obligation
    arises to tighten standards to provide an “ample margin of
    safety.” EPA’s determination that revision was required was
    therefore at least implicit.
    Second, the Association argues that any finding EPA may
    have made in 2012 that the revised standards were required to
    protect the public health was an arbitrary and capricious
    reversal of its earlier 2010 determination. The Association
    contends, more specifically, that it was unreasonable for EPA
    to conclude in 2010 that the requisite “ample margin of
    safety” was in place, but to conclude in 2012 that revised
    standards were necessary to achieve such a margin of
    safety—and to do so at the same time that EPA acknowledged
    that health risks were equal to or lower than it had thought
    they were in 2010. EPA’s “ample margin of safety”
    determination does not hinge solely on public health risk,
    however; it may also take into account “costs and economic
    impacts, technological feasibility, and other [non-health]
    factors.” 
    NRDC, 529 F.3d at 1083
    (internal quotation marks
    omitted). That being the case, the fact that EPA considered a
    prior standard to provide an ample margin of safety under
    older data does not prevent EPA from determining that new
    data on cost and feasibility require a more stringent standard.
    In this case, EPA gained significant new data between 2010
    30
    and 2012 that changed its calculus about cost effectiveness
    and feasibility. 77 Fed. Reg. at 58,225-26; J.A. 521-22
    (response to comments). EPA’s change in position was
    therefore reasonable. See Sierra Club, 
    353 F.3d 986-87
    ; cf.
    Nat’l Ass’n of Mfrs. v. EPA, 
    750 F.3d 921
    , 925 (D.C. Cir.
    2014) (“[W]e do not assign ‘presumptive validity’ to the prior
    [standards]; the question is whether EPA reasonably explains
    the current standards.”).
    Lastly, the Association characterizes EPA’s statistical
    methodology for estimating emissions (and, consequently,
    cancer risk) as unreasonably flawed. It asserts that the sample
    of facilities on which EPA based its emissions estimates in the
    Supplemental Notice included many facilities that were either
    closed or not subject to regulation, or that emissions estimates
    from those facilities were inaccurately high.
    The Association identified inaccuracies in the sample
    EPA had used by contacting facilities in that sample and
    comparing the information they provided against EPA’s
    assumptions. It also reported that those inaccuracies were
    corroborated by a supplemental sample it generated to check
    the accuracy of EPA’s model. J.A. 284-305, 312-27 (March
    2012 submission in response to Supplemental Notice). The
    Association claims that its supplemental data show that EPA’s
    initial sample was unacceptably unrepresentative of the larger
    population of facilities.
    EPA responded by adjusting its data inputs, removing all
    the data that the Association had identified as coming from
    closed facilities or those that did not emit hexavalent
    chromium, and added the more specific, verifiable data that
    the Association had provided. 77 Fed. Reg. at 58,235; J.A.
    546-47 (response to comment); see also J.A. 637-38 (EPA
    correspondence to the Association further explaining the
    31
    adjustments). EPA declined, however, to incorporate any of
    the Association’s data that the agency determined was too
    vague or lacking in detail to be reliable and susceptible of
    incorporation into its predictive model. J.A. 638. EPA also
    declined to adopt the Association’s extrapolations from its
    supplemental data sample because, the agency explained, the
    Association did not provide sufficient information about its
    sampling methodology for EPA to discern whether the
    supplemental data sample was collected in a statistically
    representative, reliable fashion. J.A. 647.
    The Association has never challenged EPA’s predictive
    model, as distinct from the data inputs into that model. EPA
    thus retained the “Monte Carlo” statistical technique of
    extrapolating an estimate of emissions from all facilities from
    actual emissions data from a smaller sample of facilities.
    EPA re-ran its model based on a dataset adjusted as just
    described, and determined that the resulting emissions
    estimates supported its risk conclusions. 77 Fed. Reg. at
    58,225-30, 58,235-36.
    We conclude that EPA’s methodology passes muster.
    Keeping in mind the “wide latitude” we afford EPA’s
    expertise-informed choice of data-gathering methodology, we
    find that EPA’s data-collection process was reasonable. See
    
    NRDC, 529 F.3d at 1086
    (quoting Sierra 
    Club, 167 F.3d at 662
    ); see also White 
    Stallion, 748 F.3d at 1247-48
    . The
    Association contends that EPA’s response to its submission—
    adjusting the inputs of its dataset—was insufficient. But we
    must bear in mind that “statistical analysis is perhaps the
    prime example of those areas of technical wilderness into
    which judicial expeditions are best limited to ascertaining the
    lay of the land.” Appalachian Power Co. v. EPA, 
    135 F.3d 791
    , 802 (D.C. Cir. 1998). We uphold EPA’s model as long
    as the agency “explain[s] the assumptions and methodology
    32
    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) (internal quotation marks omitted). As
    outlined above, EPA provided such an explanation and
    defense of how and why it formulated the sample and
    conducted the analysis that it did. See, e.g., 77 Fed. Reg. at
    58,235; see also J.A. 467-472 (memorandum specifically
    explaining and defending EPA’s revised emissions
    simulation). Moreover, the Association does not explain why
    the level of uncertainty resulting from EPA’s ultimate sample
    and analysis was statistically unacceptable, nor does it offer
    any superior method that it contends EPA should have used
    instead.
    *    *   *
    For the reasons above, we deny the petitions for review
    and uphold the Final Rule.
    So ordered.