Town of Weymouth v. MA Dept. of Envir. Protection ( 2020 )


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  •           United States Court of Appeals
    For the First Circuit
    No. 19-1794
    TOWN OF WEYMOUTH, MASSACHUSETTS; ROBERT HEDLUND, Mayor of Town
    of Weymouth; PATRICK M. O'CONNOR, State Senator; MICHAEL SMART,
    Vice President District Six; KENNETH J. DIFAZIO, District Three
    Councilor; JANE HACKETT, Councilor at Large; ED HARRINGTON,
    District Five Councilor; REBECCA HAUGH, District One Councilor;
    ARTHUR MATHEWS, District Four Councilor; MICHAEL MOLISSE,
    Councilor at Large; SCOTT DOWD, Conservation Commissioner;
    GEORGE LORING, Conservation Commissioner; THOMAS TANNER,
    Conservation Commissioner; FRANK SINGLETON, Conservation
    Commissioner; JOHN REILLY, Conservation Commissioner; CITY OF
    BRAINTREE, MASSACHUSETTS; TOWN OF HINGHAM, MASSACHUSETTS; CITY
    OF QUINCY, MASSACHUSETTS,
    Petitioners,
    v.
    MASSACHUSETTS DEPARTMENT OF ENVIRONMENTAL PROTECTION,
    Respondent,
    ALGONQUIN GAS TRANSMISSION, LLC,
    Intervenor.
    No. 19-1797
    ELIZABETH MOULDS; JENNIFER MATHIAN; OLIVIA LANNA; PRIYA HOWELL;
    KATHERINE ROGERS; MICHAEL MULLALEY; HEATHER KAAS; KATIE MCBRINE;
    JANICE DEYOUNG; A. SILVIA FABRIZIO; KATHLEEN CRONIN,
    Petitioners,
    v.
    MASSACHUSETTS DEPARTMENT OF ENVIRONMENTAL PROTECTION,
    Respondent,
    ALGONQUIN GAS TRANSMISSION, LLC,
    Intervenor.
    No. 19-1803
    DOROTHY ANDERSON; ALICE ARENA; MARGARET BELLAFIORE; WENDY
    CULLIVAN; SUSAN GREENE; REBECCA HAUGH; ANDREA HONORE; MICHAEL
    LANG; CURTIS NORDGAARD, M.D.; THOMAS PENDERGAST; JUDY ROBERTS;
    FRANK SINGLETON; BETSY SOWERS; BERNADETTE WILSON,
    Petitioners,
    v.
    MASSACHUSETTS DEPARTMENT OF ENVIRONMENTAL PROTECTION,
    Respondent,
    ALGONQUIN GAS TRANSMISSION, LLC,
    Intervenor.
    PETITIONS FOR REVIEW OF AN ORDER OF
    THE MASSACHUSETTS DEPARTMENT OF ENVIRONMENTAL PROTECTION
    Before
    Thompson, Lipez, and Kayatta,
    Circuit Judges.
    Brian F. Bertram, J. Raymond Miyares, Katherine E. Stock,
    Miyares and Harrington, LLP, Joseph Callanan, Town Solicitor, Town
    of Weymouth, Nicole I. Taub, Town Solicitor, Town of Braintree,
    Kerry T. Ryan, Special Counsel, Town of Hingham, Bogle, DeAscentis
    & Coughlin, P.C., and Janet Petkun, Assistant City Solicitor, City
    of Quincy, on brief for petitioners Town of Weymouth, et. al.
    Lawrence K. Kolodney, Adam J. Kessel, Natalie Galley, Eda
    Stark, Kayleigh E. McGlynn, and Fish & Richardson P.C. on brief
    for petitioners Moulds, et. al.
    Michael H. Hayden and Morrison Mahoney LLP on brief for
    petitioners Anderson, et. al.
    Seth Schofield, Senior Appellate Counsel, Office of the
    Attorney General of Massachusetts, Maura Healey, Attorney General
    for the Commonwealth of Massachusetts, Julie E. Green, Assistant
    Attorney General, Office of the Attorney General of Massachusetts,
    and Joshua Olszewski-Jubelirer, Assistant Attorney General, Office
    of the Attorney General of Massachusetts, on brief for respondent.
    Jeremy C. Marwell, Joshua S. Johnson, Vinson & Elkins LLP,
    James T. Finnigan, and Rich May, P.C. on brief for intervenor.
    June 3, 2020
    KAYATTA,   Circuit   Judge.     These    consolidated      cases
    involve a proposed natural gas compressor station set to be built
    in Weymouth, Massachusetts, as part of Algonquin Gas Transmission,
    LLC's "Atlantic Bridge Project," a natural gas pipeline connecting
    the Northeastern United States and Canada.                The Massachusetts
    Department of Environmental Protection (DEP) approved Algonquin's
    non-major   comprehensive   plan    application   for      the   station   and
    granted the station's air permit, certifying its compliance with
    the Massachusetts Clean Air Act (CAA), Mass. Gen. Laws ch. 111,
    §§ 142A–142F.     Nearby municipalities and two citizen-petition
    groups challenge DEP's decision in this court, invoking original
    jurisdiction     pursuant   to   the   Natural      Gas     Act,   15 U.S.C.
    § 717r(d)(1).    The petitioners raise a slew of arguments that DEP
    violated the Massachusetts CAA and related laws and regulations.
    Because we find that DEP did not follow its own established
    procedures for assessing whether an electric motor was the Best
    Available Control Technology (BACT), we vacate the air permit and
    remand to the agency to redo that analysis.                 We resolve the
    remaining issues in favor of DEP.          See, e.g., Swajian v. Gen.
    Motors Corp., 
    916 F.2d 31
    , 35 (1st Cir. 1990) ("The remainder of
    this opinion will discuss other issues raised by the parties which
    are likely to recur [on remand] and should therefore be passed
    upon by us.").
    - 4 -
    I.
    Algonquin, a natural gas transmission company based in
    Houston, Texas, proposed its Atlantic Bridge Project in response
    to rising demand for natural gas in the Northeastern United States
    and Canada.    See Algonquin Gas Transmission, LLC v. Weymouth, 
    919 F.3d 54
    , 59 (1st Cir. 2019).          Algonquin submitted its proposal for
    the project to the Federal Energy Regulatory Commission (FERC) in
    October 2015,
    id., and at
    the same time filed its air-permit
    application with DEP seeking the agency's approval of the project,
    see 310 Mass. Code Regs. § 7.02.
    As with all natural gas pipelines, the Atlantic Bridge
    Project needs "[c]ompressor stations" to be "strategically placed
    along the pipeline to boost the system pressure to maintain
    required flow rates."        FERC, An Interstate Natural Gas Facility on
    My   Land?:           What    Do      I        Need        to     Know?     28      (2015),
    http://bit.ly/2PBe0Tz.          One       of    the    compressor          stations    that
    Algonquin     plans    to     build       will        be    located        in    Weymouth,
    Massachusetts, near the Fore River Energy Center (an unrelated
    power plant) and King's Cove recreation area (a public park).
    Algonquin   proposed     to    operate         the    Weymouth        station     using    a
    "SoLoNOx"     Solar    Taurus 60      combustion                turbine,    which     is   a
    proprietary model of a Dry Low Nitrogen Oxide (NOx) combustion
    - 5 -
    turbine owned by Solar.1             Dry Low NOx turbines burn natural gas and
    reduce      emissions    of    NOx    by    operating      at    a     lower    combustion
    temperature.      In layman's terms, the Weymouth station will burn a
    small amount of natural gas in order to generate pressure that
    will allow the bulk of the gas to flow through the pipeline.
    FERC, for its part, approved Algonquin's plans for the
    Atlantic      Bridge    Project,       including     the    Weymouth         Station,    and
    issued a "certificate of public convenience and necessity" under
    15 U.S.C. § 717f(c) in January 2017.                  Algonquin Gas 
    Transmission, 919 F.3d at 57
    , 59 (citing Algonquin Gas Transmission, LLC Mars.
    & Ne. Pipeline, LLC, 158 FERC ¶ 61061, 
    2017 WL 383829
    , at *1
    (Jan. 25, 2017)); see also Town of Weymouth v. FERC, No. 17-1135,
    
    2018 WL 6921213
    , at *1 (D.C. Cir. Dec. 27, 2018) (per curiam)
    (denying      Weymouth's      petition      challenging         FERC's      certificate).
    This       approval    came    after       FERC    completed         its    environmental
    assessment      pursuant      to     the   National      Environmental         Policy    Act
    (NEPA), 42 U.S.C. § 4332(2)(C), finding that, "with appropriate
    mitigating measures," the project "would not constitute a major
    federal action significantly affecting the quality of the human
    environment."           FERC's     approval,       however,       is       conditioned    on
    Algonquin's      compliance        with    the     CAA   (state      and     federal2)    as
    1"Solar" is a turbine manufacturer owned by Caterpillar,
    Inc. "Taurus" is a family of turbines that Solar manufactures.
    2  The Environmental Protection Agency (EPA) has approved the
    Massachusetts CAA and accompanying regulations as a State
    - 6 -
    determined by DEP.      Algonquin Gas Transmission, 
    2017 WL 383829
    , at
    *45; see also 15 U.S.C. § 717b(d)(2) ("[N]othing in this chapter
    affects   the    rights      of   States     under . . .     the   Clean    Air
    Act . . . ."); cf. Algonquin Gas 
    Transmission, 919 F.3d at 57
    –60,
    63–66   (dealing      with   DEP's   approval    under     the   Coastal   Zone
    Management Act).
    DEP staff reviewed Algonquin's air-permit application
    and issued a "draft permit" in March 2017 stating that the proposed
    Weymouth station was "in conformance with the Air Pollution Control
    regulations     and    current    air   pollution    control       engineering
    practice."      DEP provided a public comment period on the draft
    permit, and in response to public concerns, Massachusetts Governor
    Charles Baker directed DEP and the Massachusetts Department of
    Public Health to prepare a health impact assessment (HIA) of the
    Weymouth station.
    Frustrated by the protracted approval process, Algonquin
    sued DEP in the D.C. Circuit under 15 U.S.C. § 717r(d)(2) seeking
    to hurry along DEP's final decision.             See Petition for Review,
    Algonquin Gas Transmission, LLC v. Mass. Dep't of Envtl. Prot.,
    No. 18-1045 (D.C. Cir. Feb. 16, 2018).          The result of that lawsuit
    Implementation Plan (SIP) under the federal CAA. See 40 C.F.R.
    §§ 52.1119–52.1169; see also 42 U.S.C. § 7410(a). As such, "[t]he
    EPA has delegated authority to the Massachusetts DEP to administer
    the [federal] CAA in Massachusetts." Algonquin Gas Transmission,
    
    2017 WL 383829
    , at *45.
    - 7 -
    was an out-of-court agreement between DEP and Algonquin to the
    following timeline:     DEP promised to complete the HIA by January
    2019 and to limit any subsequent adjudicatory hearings on the air
    permit to six months.
    In keeping with the established timeline, DEP completed
    the HIA on January 4, 2019, "predict[ing] no substantial changes
    in health from direct exposures from the station itself with the
    exception of estimated sound levels during construction."       The
    following week, DEP's regional Air Quality Section Chief issued a
    "Non-Major Comprehensive Air Quality Plan Approval" (i.e., air-
    permit approval) for the Weymouth station.
    Petitioners in this case (described below) filed an
    administrative appeal to DEP's Office of Appeals and Dispute
    Resolution, raising a number of claims that the permit violated
    Massachusetts law.    The Presiding Officer of that appeal dismissed
    some of these claims without opinion on April 11, 2019, and then,
    after a hearing, issued a full "Recommended Final Decision" on
    June 27, 2019.     That decision affirmed the air permit with some
    revisions.    On July 12, 2019, the DEP Commissioner issued a "Final
    Decision" adopting in full the Presiding Officer's Recommended
    Final Decision.      In response to the Commissioner's request for
    clarification (on issues not relevant to this case), the Presiding
    Officer issued a "Recommended Final Decision on Reconsideration"
    - 8 -
    on August 5, 2019, and the Commissioner adopted this decision in
    full on August 7, 2019.
    The three groups of petitioners all challenge DEP's
    approval of the Weymouth station air permit.              In case 19-1794
    (docketed Aug. 8, 2019), petitioners include the Town of Weymouth,
    several nearby municipalities, and state and local officials.               In
    cases    19-1797    and   19-1803     (both   docketed    Aug. 9,        2019),
    petitioners are eleven and fourteen (respectively) residents of
    these nearby municipalities.        See Mass. Gen. Laws ch. 30A, § 10A
    (authorizing "not less than ten persons [to] intervene in any
    adjudicatory       proceeding . . .     in    which      damage     to     the
    environment . . . is or might be at issue").             We have original
    jurisdiction3 under the Natural Gas Act, which states that:
    The United States Court of Appeals for the
    circuit in which a facility subject to [15
    U.S.C. § 717f] is proposed to be constructed,
    expanded, or operated shall have original and
    exclusive jurisdiction over any civil action
    for the review of an order or action of a
    Federal agency (other than [FERC]) or State
    administrative agency acting pursuant to
    Federal law to issue, condition, or deny any
    permit,      license,     concurrence,     or
    approval . . . required under Federal law,
    other than the Coastal Zone Management Act of
    1972 . . . .
    3  No party has argued that any justiciability barrier
    (mootness, ripeness, finality, standing, etc.) precludes our
    review of these cases. See generally Berkshire Envtl. Action Team,
    Inc. v. Tenn. Gas Pipeline Co., 
    851 F.3d 105
    (1st Cir. 2017)
    (addressing    the   finality   requirement   under    15   U.S.C.
    § 717r(d)(1)). We are satisfied that there are no such barriers.
    - 9 -
    15 U.S.C. § 717r(d)(1).      Here, we review "an order" of a "State
    administrative agency" (DEP) "acting pursuant to Federal law" (the
    CAA4) "to issue" a "permit" required by that federal law.               We
    consolidated    these   cases,   and      Algonquin   intervened   as   a
    respondent.    As required by the Natural Gas Act, we expedited our
    review.   See 15 U.S.C. § 717r(d)(5).
    II.
    A.   Standard of Review
    The Natural Gas Act does not provide a standard of
    review, so we are left to look elsewhere.         The parties dispute,
    however, where we should look.      According to petitioners, we can
    consult the federal Administrative Procedure Act (APA), 5 U.S.C.
    § 706(2), and "borrow" its standards of review.        And several other
    circuits have done so in reviewing state approval of natural-gas
    facilities.    See Del. Riverkeeper Network v. Sec'y Pa. Dep't of
    Envtl. Prot., 
    833 F.3d 360
    , 377 (3d Cir. 2016); AES Sparrows Point
    4  As indicated, 
    see supra
    note 2, the CAA adopts a
    "cooperative federalism" approach, see Berkshire Envtl. Action
    
    Team, 851 F.3d at 113
    , such that DEP, in enforcing the
    Massachusetts CAA, is in fact acting pursuant to the federal CAA.
    This also provides the federal "ingredient" for purposes of
    Article III jurisdiction. See Osborn v. Bank of U.S., 22 U.S. (9
    Wheat.) 738, 823 (1824) ("[W]hen a question to which the judicial
    power of the Union is extended by the constitution, forms an
    ingredient of the original cause, it is in the power of Congress
    to give the Circuit Courts jurisdiction of that cause, although
    other questions of fact or of law may be involved in it."); see
    also Verlinden B.V. v. Cent. Bank of Nigeria, 
    461 U.S. 480
    , 494–
    95 (1983) (describing Article III "arising under" jurisdiction).
    - 10 -
    LNG, LLC v. Wilson, 
    589 F.3d 721
    , 727 (4th Cir. 2009); Islander E.
    Pipeline Co. v. Conn. Dep't of Envtl. Prot., 
    482 F.3d 79
    , 94 (2d
    Cir. 2006).     But DEP says the Massachusetts APA, Mass. Gen. Laws
    ch. 30A, § 10A, applies.       This makes some sense, as we will be
    mostly looking to Massachusetts substantive law to resolve the
    issues in this case, and because the federal APA by its terms does
    not apply to states.      See 5 U.S.C. § 551(1).
    Fortunately, the issue appears to be strictly academic
    in this case, for no party has demonstrated how it would make any
    difference whether the Massachusetts APA or federal APA applies.
    As relevant here, the standards do not vary materially, so we will
    apply those standards without worrying about their source.            Cf.
    Friends of Buckingham v. State Air Pollution Control Bd., 
    947 F.3d 68
    , 80–82 (4th Cir. 2020) (likewise avoiding the issue where the
    Virginia standards matched the federal standards).           As in most
    cases involving a decision of an administrative agency, we review
    formally adjudicated findings of fact for "substantial evidence,"
    and   reverse    agency   decisions   if   they    are   "arbitrary   and
    capricious."     Cent. Me. Power Co. v. FERC, 
    252 F.3d 34
    , 40 n.3
    (1st Cir. 2001); accord Friends & Fishers of Edgartown Great Pond,
    Inc. v. Dep't of Envtl. Prot., 
    848 N.E.2d 393
    , 399 (Mass. 2006).
    We will defer to an agency's otherwise lawful interpretation of
    its own regulation unless the regulation unambiguously forecloses
    that interpretation.      See Kisor v. Wilkie, 
    139 S. Ct. 2400
    , 2414–
    - 11 -
    23 (2019) (reaffirming and clarifying Auer v. Robbins, 
    519 U.S. 452
    (1997)); Town of Brookline v. Comm'r of Dep't of Envtl. Quality
    Eng'g ("Brookline II"), 
    497 N.E.2d 9
    , 15 (Mass. 1986).
    B.   Discussion
    1.   Best Available Control Technology
    All parties agree that, under Massachusetts regulations,
    the Weymouth station, a non-major source of air pollution, must
    employ the Best Available Control Technology (BACT) for reducing
    NOx emissions.    See 310 Mass. Code Regs. § 7.02(8)(a)(2).   BACT is
    defined as:
    [A]n emission limitation based on the maximum
    degree of reduction of any regulated air
    contaminant emitted from or which results
    from any regulated facility which the
    Department, on a case-by-case basis taking
    into account energy, environmental, and
    economic impacts and other costs, determines
    is achievable for such facility through
    application of production processes and
    available methods, systems and techniques for
    control of each such contaminant. The best
    available         control          technology
    determination . . . may include a design
    feature,   equipment    specification,   work
    practice, operating standard, or combination
    thereof.
    Id. § 7.00;
    see also 42 U.S.C. § 7479(3).      BACT is distinct from
    more stringent standards, like Lowest Achievable Emission Rate
    (LAER), in that BACT takes into consideration economic factors
    (i.e., costs).    See 310 Mass. Code Regs. § 7.00.
    - 12 -
    The     Environmental       Protection       Agency     (EPA)      has
    established a five-step "top-down" approach for determining BACT,
    see   EPA,   New    Source    Review    Workshop      Manual:      Prevention    of
    Significant Deterioration and Nonattainment Area Permitting B.5–
    B.6 (1990)5 [hereinafter NSR Workshop Manual], and DEP has adopted
    this approach, see DEP, Best Available Control Technology (BACT)
    Guidance:        Air Pollution Control Requirements for Construction,
    Substantial Reconstruction or Alteration of Facilities that Emit
    Air Contaminants 3 (2011) [hereinafter BACT Guidance].                  The five
    steps are:
    •    STEP 1:    IDENTIFY           ALL         CONTROL
    TECHNOLOGIES.
    •    STEP 2:    ELIMINATE TECHNICALLY INFEASIBLE
    OPTIONS.
    •    STEP 3:    RANK      REMAINING            CONTROL
    TECHNOLOGIES     BY            CONTROL
    EFFECTIVENESS.
    •    STEP 4:    EVALUATE MOST EFFECTIVE CONTROLS
    AND DOCUMENT RESULTS.
    •    STEP 5:    SELECT BACT.
    NSR Workshop 
    Manual, supra
    , at B.6.
    Algonquin's air permit application applied the five-step
    approach and concluded that the SoLoNOx turbine was the BACT for
    NOx for the Weymouth station.          DEP agreed.      Petitioners argue that
    5 Despite being marked as a "draft," this document is
    frequently cited by courts as authoritative on BACT issues. See,
    e.g., Sierra Club v. EPA, 
    499 F.3d 653
    , 654 (7th Cir. 2007).
    - 13 -
    that conclusion (or at least the analysis getting there) was flawed
    in two respects:         (1) it excluded consideration of using an
    electric motor instead of the SoLoNOx turbine, and (2) it wrongly
    determined that a Dry Low NOx turbine plus a selective catalytic
    reduction (SCR) was not cost feasible.       We address each argument
    in turn.
    a.   Electric Motor
    Algonquin's air-permit application initially made no
    mention of an electric-motor option.       But during the adjudication
    process, petitioners asserted that an electric motor would be a
    more   effective   and   economically   feasible   alternative   to   the
    SoLoNOx turbine.    Essentially, the petitioners proposed that the
    compressor station could be hooked up to the existing electrical
    grid and create the necessary pressure without burning any natural
    gas.   This would eliminate all emissions of NOx from the Weymouth
    station.   And at least some compressor stations in other parts of
    the country operate with such an electric motor.
    Algonquin revised its application in May 2018 to address
    the feasibility of an electric motor.        Algonquin explained that
    this option was excluded for several reasons, including the high
    cost of upgrading the existing power infrastructure.         Algonquin
    also cited the fact that FERC's environmental assessment concluded
    that an electric motor would not offer a significant environmental
    advantage over the proposed gas-fired turbine.      DEP staff accepted
    - 14 -
    Algonquin's exclusion, relying on FERC's assessment and concededly
    not making an independent determination for purposes of BACT.
    Algonquin and DEP refocused their position before the
    Presiding Officer, arguing that the electric-motor option was
    properly excluded from Step 1 of the BACT analysis as a project
    "redesign."      Per the NSR Workshop Manual, Step 1 is a wide-ranging
    process,    in    which   applicants   "should   initially   identify   all
    control options with potential application to the emissions unit
    under review."        NSR Workshop 
    Manual, supra
    , at B.7 (emphasis
    added).     However, a technology may be excluded from Step 1 if it
    would "redefine the source."       Helping Hand Tools v. EPA, 
    848 F.3d 1185
    , 1194 (9th Cir. 2016).       "In a classic and simple example, a
    coal-burning power plant need not consider a nuclear fuel option
    as a 'cleaner' fuel because it would require a complete redesign
    of the coal-burning power-plant."
    Id. (citing Sierra
    Club v. EPA,
    
    499 F.3d 653
    , 655 (7th Cir. 2007)); see also Friends of 
    Buckingham, 947 F.3d at 74
    , 82–85 (analyzing whether an electric motor would
    redefine the source of a proposed gas-fired compressor station
    turbine).
    The     Presiding   Officer    was   not   persuaded   by   the
    "redesign" argument.        She stated that DEP erred in relying on
    FERC's environmental assessment and that DEP should have included
    "all control technologies in the BACT analysis" (emphasis in
    original).       She left unresolved whether the electric motor would
    - 15 -
    in fact constitute a redesign if properly analyzed as such by DEP
    staff.6       Instead, she determined that, "even assuming use of an
    electric driven compressor would not redefine the source," the
    electric motor would properly be excluded at Step 4 of the BACT
    analysis as not cost feasible.
    The support for the Presiding Officer's cost-feasibility
    conclusion came largely from the testimony of Algonquin witness
    William Welch.           Welch testified, with respect to the redesign
    issue, that an electric motor at the Weymouth station would require
    substantial infrastructure investment, including construction of
    a new substation and the laying of half a mile of underground
    electric transmission line.            In total, Welch estimated that these
    upgrades could cost between $9 million and $12 million.                          The
    Presiding Officer acknowledged that "there is no corroboration of
    these       numbers,    and   [that]   they   seem   to   be     based   on   several
    conversations or meetings at which no notes apparently were taken."
    However, she stated, "there is no evidence disputing them," since
    petitioners'           witness   did    not     take      into     account      these
    Neither DEP nor Algonquin argue on this appeal that we can
    6
    affirm on the ground that an electric motor would constitute a
    redesign.   Nor could they, since DEP's final decision does not
    rest on that ground. See Motor Vehicle Mfrs. Ass'n of U.S., Inc.
    v. State Farm Mut. Auto. Ins. Co., 
    463 U.S. 29
    , 50 (1983) (citing
    SEC v. Chenery Corp., 
    332 U.S. 194
    , 196 (1947)); NSTAR Elec. Co.
    v. Dep't of Pub. Utils., 
    968 N.E.2d 895
    , 900–01 (Mass. 2012).
    Algonquin reserves the right to reassert its redesign argument on
    remand to DEP.
    - 16 -
    infrastructure       costs   in   his   own   cost   estimates.     She   thus
    "infer[red] that the total cost for this infrastructure would be
    substantial."    So, she concluded, Algonquin's evidence, "though
    scant and uncorroborated by any documentation, at least provides
    some basis to infer that" the electric motor would not be cost
    feasible.
    Petitioners challenge that conclusion on three grounds:
    (1) they    assert    that   "scant     and   uncorroborated"     evidence   of
    infrastructure costs cannot be considered "substantial evidence,"
    as would be needed for us to affirm an agency's finding of fact;
    (2) they argue that neither the Presiding Officer nor anyone else
    at DEP ever provided a full Step 4 analysis as required by DEP's
    BACT Guidance; and (3) they contend that the Presiding Officer
    raised the Step 4 issue sua sponte after the hearing without
    providing an opportunity for the parties to weigh in, thus denying
    them their Due Process rights and violating Massachusetts law.
    We easily dispatch with the first of these arguments.
    Welch offered an estimate that does not seem irrational on its
    face, and petitioners offered no contrary estimate of what must be
    a real cost.     So while the Presiding Officer fairly noted the
    unimpressive support for the estimate, we cannot say that the
    evidence was insubstantial as a matter of law. See Bath Iron Works
    Corp. v. U.S. Dep't of Labor, 
    336 F.3d 51
    , 56 (1st Cir. 2003)
    (recognizing that, under the "substantial evidence" standard, "we
    - 17 -
    will accept the findings and inferences drawn" by an agency so
    long as they are not "irrational," meaning that "the record
    contains 'such relevant evidence as a reasonable mind might accept
    as adequate to support a conclusion'" (quoting Barker v. U.S. Dep't
    of Labor, 
    138 F.3d 431
    , 434 (1st Cir. 1998), and Sprague v. Dir.,
    Office of Workers' Comp. Programs, U.S. Dep't of Labor, 
    688 F.2d 862
    , 865 (1st Cir. 1982))).
    Petitioners' second argument fares better.7            According
    to the NSR Workshop Manual, "[c]ost effectiveness is the economic
    criterion used to assess the potential for achieving an objective
    at least cost.         Effectiveness is measured in terms of tons of
    pollutant emissions removed." NSR Workshop 
    Manual, supra
    , at B.36.
    So at Step 4 of the BACT analysis, the agency (or the applicant)
    must       calculate   the   cost   effectiveness   of   the   most   effective
    technology remaining after Step 3 and eliminate that technology if
    it falls above a predetermined cost-feasibility threshold.                 For
    NOx, DEP has established that technologies falling in (or below)
    the range of $11,000 to $13,000 per ton of NOx removed per year
    will be considered cost feasible.          BACT 
    Guidance, supra, at 5
    .
    DEP never calculated cost effectiveness for an electric
    motor, nor did it compare that figure to the range established in
    7Because we vacate DEP's decision on this ground, see infra
    subpart II(C), we need not address petitioners' third argument or
    Algonquin's response that petitioners waived that particular
    argument by not moving for reconsideration.
    - 18 -
    its BACT Guidance.       And even in their briefs before us, DEP and
    Algonquin do not attempt to perform the required mathematical
    calculations.      Instead, DEP states that "the full calculation was
    unnecessary because the infrastructure costs were so obviously
    substantial."        Effectively,    DEP    argues   that   a   $9–12 million
    infrastructure cost is so high that the cost effectiveness, if
    calculated, would necessarily exceed the $13,000-per-ton cutoff.
    Without a more detailed explanation by DEP, we cannot be
    so    sure.       According   to   the     NSR   Workshop   Manual,   "[c]ost
    effectiveness calculations can be conducted on an average, or
    incremental basis." NSR Workshop 
    Manual, supra
    , at B.36. Starting
    with average cost effectiveness, the manual provides us with the
    following formula:
    Average cost Effectiveness (in dollars per
    ton removed) =
    (Control option annualized cost) /
    (Baseline emissions rate – Control option
    emissions rate)
    Id. at B.37
       (mathematical    notations     reformatted).       And,   to
    annualize costs for capital investments, the manual tells us to
    multiply up-front costs by:
    (real interest rate) *
    (1 + real interest rate)^(economic life of
    equipment in years) /
    ((1 + real interest rate)^(economic life of
    equipment in years) - 1)
    Id. at b.10
    (mathematical notations reformatted).
    - 19 -
    When we attempt to solve for average cost effectiveness,
    it becomes apparent that the record before us does not contain
    enough information.    As to the numerator, we are assuming that the
    infrastructure     costs   of   the    electric   motor    would     be   between
    $9 million and $12 million based on Welch's testimony.                     But we
    cannot annualize that figure because we do not know the lifespan
    of the equipment.      The NSR Workshop Manual tells us that "[t]he
    economic life of a control system typically varies between 10 to
    20 years and longer,"
    id., but that
    hardly narrows things.                       We
    also do not know what interest rate DEP would use.                   The manual
    says   that   "[t]he   value     used     in   most     control    analyses      is
    10 percent,"
    id. at b.11,
    but again this is not a categorical
    pronouncement.     So we cannot tell what the annualized cost of the
    electric   motor    infrastructure       would    be.      We     also    have   no
    information on the annual operating expenses for the electric
    motor, although anything above zero would be helpful to DEP in
    this exercise.
    Even more difficult is the denominator.                 We know that
    the emissions rate for the electric motor is zero, but the record
    is incomplete as to what the baseline emissions rate would be.
    According to Algonquin's air-permit application, the "Base Case"
    is "Good Combustion Practices" (presumably a gas-fired turbine
    - 20 -
    that, unlike SoLoNOx, employs no control of NOx emissions).8             But
    the application does not give a value for "Potential NOx Emissions"
    for   this     option.    The   control   technology   just   above   "Good
    Combustion Practices" is "Water Injection," which the application
    tells us has an emissions rate of "20 to 42 ppm (water)."             So, it
    is probably safe to assume that the baseline emissions rate is at
    least that high, and probably higher.         We are also not provided
    with a formula for converting ppm (parts per million) to tons per
    year.       We know that the SoLoNOx turbine will result in 10.03 tons
    of NOx per year and that it has an emissions rate of 9 ppm, so for
    ballparking purposes a one-to-one conversion would seem to be good
    enough (although we must accept a wide margin of error, especially
    since we do not know what "(water)" means).
    So, if we assume, reasonably, that the interest rate is
    10% and that the lifespan of the electric motor infrastructure is
    twenty years, then the average cost effectiveness of a $12 million
    electric motor would be below $13,000 per ton per year if the "Good
    Combustion Practices" emissions exceed 108 tons per year.9            For a
    The electric motor, unlike the SCR discussed below, is a
    8
    process-control technology, rather than an add-on technology
    (i.e., the compressor station needs either an electric motor or a
    SoLoNOx turbine, but not both). As such, the baseline emissions
    rate is not the emissions rate of the SoLoNOx turbine.
    9 $13,000    per    ton ≥ ($12,000,000 *  0.1 *    (1.120) /
    (1.120 - 1)) / (Baseline emissions rate - 0).
    Baseline emissions rate ≥ ($12,000,000 * 0.1 * (1.120) /
    (1.1 - 1)) / ($13,000 per ton).
    20
    Baseline emissions rate ≥ 108.42 tons.
    - 21 -
    $9 million motor, that value would drop to 81 tons per year.10
    These values are higher than the 42 ppm for "Water Injection" (as
    we expected they would be), but not so high as to be unthinkable,
    given what we know from this incomplete record.11
    Turning to incremental cost effectiveness, we run into
    similar, though different, problems. The NSR Workshop Manual gives
    us this formula:
    Incremental Cost (in dollars per incremental
    ton removed) =
    (Total costs (annualized) of control option –
    Total costs (annualized) of next control
    option) /
    (Next control option emission rate – Control
    option emissions rate)
    Id. at B.41
    (mathematical notations reformatted).
    Here the "control option" is the electric motor, and the
    "next control option" is the SoLoNOx turbine.       And we know the
    denominator will be 10.03 tons (10.03 minus zero).      But we run
    10    $13,000    per    ton ≥ ($9,000,000 *   0.1 *   (1.120) /
    (1.120   - 1)) / (Baseline emissions rate - 0).
    Baseline emissions rate ≥ ($9,000,000 * 0.1 * (1.120) /
    (1.1 - 1)) / ($13,000 per ton).
    20
    Baseline emissions rate ≥ 81.32 tons.
    11   To illustrate how much wiggle room there is in these
    numbers, we can adjust our assumptions to a 1% interest rate and
    a fifty-year equipment lifespan.        At that point, a $9 million
    electric motor would be cost feasible if the uncontrolled emissions
    rate is above 17.7 tons per year (which, based on the "Water
    Injection" figures, it almost certainly is).
    $13,000   per   ton ≥ ($9,000,000 *   0.01 *   (1.0150) /
    (1.0150 - 1)) / (Baseline emissions rate - 0).
    Baseline emissions rate ≥ ($9,000,000 * 0.01 * (1.0150) /
    (1.01 - 1)) / ($13,000 per ton).
    50
    Baseline emissions rate ≥ 17.66 tons.
    - 22 -
    into the same problems as before with annualizing the costs of the
    electric motor, and more importantly, we have no information from
    the record of what the costs -- annual or capital -- are for the
    SoLoNOx   turbine.    Indeed,   Algonquin's     application   includes   a
    line-item cost breakdown of the SCR (discussed below), but in the
    column for SoLoNOx, the fields are all blank.         Sticking with our
    ballparking approach and assuming a 10% interest rate and twenty-
    year lifespan on the electric motor (and zero costs for the
    electric motor beyond capital expenses), a $9 million electric
    motor would be cost feasible if the annualized SoLoNOx costs
    (factoring   in   capital   investments   and    operating    costs)   are
    $926,747 or higher.12   The actual costs for SoLoNOx may in fact be
    far less than that, but not so "obviously" that we can shrug off
    the lack of data in the record.      And, in any event, it is DEP's
    job, not ours, to do these calculations properly.              See Motor
    Vehicle Mfrs. Ass'n of U.S., Inc. v. State Farm Mut. Auto. Ins.
    12    $13,000    per   ton ≥ (($9,000,000 *    0.1 *   (1.120) /
    (1.120   - 1)) - annualized SoLoNOx costs) / (10.03 tons - 0).
    Annualized SoLoNOx costs ≥ ($9,000,000 * 0.1 * (1.120) /
    (1.1 - 1)) - ($13,000 per ton * 10.03 tons).
    20
    Annualized SoLoNOx costs ≥ $926,746.62.
    With a 1% interest rate and a fifty-year lifespan, 
    see supra
    note 11, the $9 million motor would be cost feasible if the
    annualized SoLoNOx costs exceed $99,225.
    $13,000   per   ton ≥ (($9,000,000 *   0.01 *   (1.0150) /
    (1.0150 - 1)) - annualized SoLoNOx costs) / (10.03 tons - 0).
    Annualized SoLoNOx costs ≥ ($9,000,000 * 0.01 * (1.0150) /
    (1.01 - 1)) - ($13,000 per ton * 10.03 tons).
    50
    Annualized SoLoNOx costs ≥ $99,224.58.
    - 23 -
    Co., 
    463 U.S. 29
    , 50 (1983) ("It is well-established that an
    agency's action must be upheld, if at all, on the basis articulated
    by the agency itself." (citing SEC v. Chenery Corp., 
    332 U.S. 194
    ,
    196 (1947))); NSTAR Elec. Co. v. Dep't of Pub. Utils., 
    968 N.E.2d 895
    , 900–01 (Mass. 2012).
    Algonquin tries to paper over the gaps in the record by
    pointing to something for which there is ample evidence: the costs
    for the SCR.      As will be discussed in the next section, the
    Presiding Officer found that the SCR/turbine combination was not
    cost feasible.        And, based on Algonquin's line-item analysis in
    its application, the total capital costs for SCR were $1,432,058,
    which     Algonquin    translated    into     $135,176     annualized.      So,
    Algonquin reasons, a technology with a $9–12 million capital cost
    must be even more infeasible.
    We consider the comparison to the SCR unhelpful for two
    reasons.     First, SCR is an add-on technology, and, as will be
    discussed shortly, the calculations for cost effectiveness for
    add-on     technologies    differ     from    those      for   process-control
    technologies like the electric motor.              See also supra note 8.
    Second,     Algonquin     compares     only     one   variable --        capital
    costs -- where the formulae encompass multiple variables.                  Even
    assuming the lifespan and annual operating costs of each technology
    are identical, we know that the electric motor is more effective
    at reducing NOx emissions than the SCR.         So the denominator of each
    - 24 -
    formula (average and incremental cost effectiveness) would be
    higher for the electric motor, thus offsetting (at least in part)
    the higher numerator.
    We concede that our own calculations are not obviously
    correct.     The problem for the DEP and Algonquin is that no one has
    provided a basis for concluding that our calculations are so
    obviously incorrect as to obviate the need for any calculation at
    all by Algonquin or DEP.        The record does not even contain a Fermi
    estimate13       fixing   the   magnitude    of   the    quotient   above      the
    regulatory cost-effectiveness cut-off.
    The bottom line is this: DEP's established BACT protocol
    requires     a    cost-effectiveness    analysis        before   eliminating    a
    technology at Step 4, and the results of such an analysis do not
    strike us as so obvious as to overlook as harmless DEP's failure
    either to follow that protocol or at least do enough to make it
    clear that following the protocol would eliminate the electric
    motor as a cost-effective option.           "An agency may not . . . depart
    from a prior policy sub silentio or simply disregard rules that
    are still on the books."          FCC v. Fox Television Stations, Inc.,
    
    556 U.S. 502
    , 515 (2009); see also Nat'l Envtl. Dev. Ass'n's Clean
    Air Project v. EPA, 
    752 F.3d 999
    , 1009 (D.C. Cir. 2014) ("[A]n
    13 See Robert N. Ronau, Number Sense, 81 Mathematics Tchr.
    437, 439–40 (1988). See generally Hans Christian von Baeyer, The
    Fermi Solution: Essays on Science (1993).
    - 25 -
    agency action may be set aside as arbitrary and capricious if the
    agency fails to 'comply with its own regulations.'"               (quoting
    Environmentel, LLC v. FCC, 
    661 F.3d 80
    , 85 (D.C. Cir. 2011)));
    Tofias v. Energy Facilities Siting Bd., 
    757 N.E.2d 1104
    , 1111
    (Mass. 2001); Town of Northbridge v. Town of Natick, 
    474 N.E.2d 551
    , 556 (Mass. 1985).         Thus, we find that DEP's final decision
    excluding the electric motor on this ground was arbitrary and
    capricious.
    b.     Selective Catalytic Reduction
    Unlike the electric motor, the SCR was analyzed in
    Algonquin's application.        According to the application, "SCR is a
    post-combustion gas treatment process in which NH3 [ammonia] is
    injected into the exhaust gas upstream of a catalyst bed."             SCR
    can reduce NOx emissions from a gas-fired turbine like SoLoNOx by
    up to 90%.
    In Step 3 of the BACT analysis, Algonquin's application
    ranked the SCR as the most effective technology at reducing NOx
    emissions,    and    the    only   technology   included   that   outranked
    SoLoNOx.     However, Algonquin excluded the SCR at Step 4 as not
    cost feasible.       Using the 9-ppm SoLoNOx emissions rate as a
    baseline, Algonquin calculated the SCR's cost effectiveness at
    $41,541 per ton of NOx removed, which well exceeded DEP's $11,000–
    $13,000 range.      DEP agreed, leaving SoLoNOx as the BACT.
    - 26 -
    Petitioners argued before the Presiding Officer, and now
    before us, that Algonquin incorrectly calculated the SCR's cost
    effectiveness.      They claim that Algonquin should have used a
    baseline emissions rate of 25 ppm, which represents the emissions
    rate of older models of Dry Low NOx turbines.           Put differently,
    petitioners fault Algonquin for considering only the SCR added to
    its   preferred     technology,   SoLoNOx,    without   considering     the
    combination of SCR plus a cheaper, less effective turbine.
    According    to   petitioners,    the   SCR-plus-older-turbine
    combination would be more effective at reducing emissions than
    SoLoNOx alone and would have a cost effectiveness of $14,483. That
    value is still over the $13,000 threshold, but petitioners go on
    to argue that DEP set that threshold in 1990 and that it should be
    updated for inflation at a minimum.14         So adjusting, petitioners
    claim, would make the SCR/turbine combination cost feasible.
    We need not reach the inflation issue because we agree
    with DEP that 9 ppm was the correct baseline under the applicable
    BACT guidance.15    The NSR Workshop Manual addresses this situation
    under the instructions for average cost effectiveness:                "When
    calculating   the    cost    effectiveness    of   adding   post   process
    14 The Presiding Officer rejected petitioners' argument in
    this case but recommended that DEP consider updating its thresholds
    for inflation going forward.
    15  Petitioners do not argue that an inflation adjustment
    alone would make $41,541 per ton cost feasible.
    - 27 -
    emissions     controls   to   certain     inherently   lower   polluting
    processes, baseline emissions may be assumed to be the emissions
    from the lower polluting process itself.       In other words, emission
    reduction credit can be taken for use of inherently lower polluting
    processes."    NSR Workshop 
    Manual, supra
    , at B.37.       The SCR is a
    post-process emissions control, and SoLoNOx is an inherently lower
    polluting process (as compared to other Dry Low NOx turbines), so
    SoLoNOx's 9-ppm emissions rate is the proper baseline.
    If there was any doubt as to whether the above rule
    applies here, DEP's 2011 BACT Guidance offers an even more on-
    point case study.    It says:
    In the recent past, boiler manufacturers have
    developed "ultra-low NOx burners" (UNLBs)
    which can achieve an oxides of nitrogen
    emission rate of 9 parts per million (ppm).
    Before the advent of UNLBs, BACT for NOx for
    boilers with capacity above approximately
    50 million British thermal units per hour was
    achieved by the use of Selective Catalytic
    Reduction (SCR) to reduce NOx emissions to
    5 ppm, accompanied by a 5 ppm ammonia (NH3)
    slip. When analyzing the incremental cost of
    using SCR to reduce the 9 ppm NOx emission
    rate attained by UNLB to reach a 5 ppm NOx
    emission limit, it became readily apparent
    that requiring SCR with added NH3 emissions
    would be economically infeasible, on a
    dollar-per-ton-of-pollutant-removed    basis.
    Therefore, NOx BACT for this category of
    emission units is now 9 ppm, with no NH3
    emissions.
    - 28 -
    BACT 
    Guidance, supra, at 5
    (footnote omitted).    Algonquin and DEP
    followed this guidance to a T, so we can hardly call DEP's decision
    arbitrary and capricious.16
    Petitioners argue that DEP's approach yields undesirable
    results.    "Algonquin's 9-ppm turbine may be state-of-the-art,"
    they say, "but the BACT process is focused not on technological
    progress for its own sake. . . .       If pairing two older or less
    effective technologies will achieve a better result than cutting
    edge, standalone technology, BACT favors the former."
    Perhaps. But on the other hand, there may be good policy
    reasons for DEP's current approach.    Requiring applicants to fully
    analyze every combination of add-on technology and process-control
    technology, including different models of the same technology,
    would make an already drawn out and expensive process even more
    so.   And, as the case study shows, exclusion of the SCR in this
    situation may result in slightly higher NOx emissions, but it also
    results in lower emissions of ammonia, another air pollutant.
    16Petitioners attempt to distinguish the NSR Workshop Manual
    rule by arguing that the phrase "inherently lower polluting
    processes" does not apply to newer models of an existing technology
    like SoLoNOx, which provide "incremental refinement." But as the
    BACT Guidance case study suggests, that is not necessarily the
    case. See also 310 Mass. Code Regs. § 7.00 ("The best available
    control technology determination . . . may include a[n] . . .
    equipment specification . . . .").    The better understanding of
    the phrase "inherently lower polluting processes," as DEP has
    interpreted it, is any control technology yielding a lower
    emissions rate that is not an add-on technology (i.e., a process-
    control technology).
    - 29 -
    Lastly,      promoting          technological          development        of        cleaner
    technologies may indeed be a goal of the BACT framework.                            Even if
    the application of that technology in the instant case does not
    reduce emissions, the fact that there is an economic incentive for
    manufacturers to develop cleaner technologies may benefit the
    state   as   a     whole     by,   for   example,      improving    the     New      Source
    Performance Standards (NSPS) applicable to other facilities.                           See
    42 U.S.C. § 7411; 310 Mass. Code Regs. § 7.00 (citing 40 C.F.R.
    pt. 60).
    In any event, our task is not to pick the better policy.
    As DEP points out, nothing in its rules or regulations requires
    applicants       to   consider      every      possible   combination          of   older,
    dirtier technologies in order to achieve the lowest possible
    emissions outcome.
    Finally, we note that petitioners argue that Algonquin
    used the wrong formula in calculating the SCR's cost effectiveness,
    saying that Algonquin "focused only on incremental costs when the
    analysis required demands a focus on average cost."                        Petitioners
    miss the point.             The NSR Workshop Manual says that, for add-on
    technologies,         the    baseline    for    the    average-cost-effectiveness
    calculation is the emissions rate for the technology to which it
    is being added (here, SoLoNOx).                  Incremental cost effectiveness
    compares     one      control      technology     to   the   next    most      effective
    technology (again, SoLoNOx).                So for the SCR, the two formulae
    - 30 -
    would yield the same result of $41,541 per ton.       It matters not
    whether Algonquin called this "average" or "incremental" cost
    effectiveness.
    2.   Toxic Emissions
    Petitioners raise two arguments concerning the Weymouth
    station's emissions of toxic air pollutants.       According to DEP,
    the Weymouth station's SoLoNOx turbine may emit up to 0.91 tons of
    toxic pollutants (combined) per year, with up to 0.41 tons of that
    being attributable to formaldehyde emissions.      Formaldehyde is a
    genotoxic carcinogenic chemical that can form from incomplete
    combustion of natural gas.       Incomplete combustion can occur at
    lower temperatures, so formaldehyde can be a particular problem
    for Dry Low NOx turbines.
    Since the 1980s, DEP has handled air toxics through
    Allowable Ambient Limits (AAL) and Threshold Effects Exposure
    Limits (TEL).17 See DEP Office of Research & Standards, Methodology
    for Updating Air Guidelines:     Allowable Ambient Limits (AALS) and
    Threshold Effects Exposure Limits (TELS) 1–2 (2011); see also DEP,
    Ambient   Air    Toxics    Guidelines,    https://www.mass.gov/files/
    documents/2017/11/07/Ambient%20Air%20Toxics%20Guidelines.pdf. TEL
    17  For context, EPA regulates air toxics at the federal level
    through the National Emission Standards for Hazardous Air
    Pollutants (NESHAP). See 42 U.S.C. § 7412. Petitioners do not
    argue that the Weymouth station will exceed or in any way implicate
    the NESHAP for formaldehyde or any other pollutant.
    - 31 -
    is a 24-hour-based measurement reflecting toxic concentrations at
    a   low-enough      level         that    no     health     effects       at    all,     even
    noncarcinogenic effects like eye irritation, "are expected in the
    population, including sensitive populations, over a lifetime of
    continuous exposure."             In common parlance, the record labels the
    risk at these levels "de minimis; i.e., the added risk is so small
    that   it   makes      no   meaningful         difference."         AAL    is   an     annual
    measurement focused on risks of cancer in humans and is determined
    by the lower of the TEL and the Non-Threshold Effects Exposure
    Limits (NTEL).         For certain air toxics, scientists consider any
    non-zero concentration in the air to produce some risk of cancer
    in humans, see Brookline 
    II, 497 N.E.2d at 11
    , so NTEL represents
    a de minimis cancer risk rather than no risk at all.
    We   turn       now    to     each   of   the     petitioners'       arguments
    concerning AAL and TEL.
    a.    Background Toxic Levels
    Petitioners claim that DEP violated the Massachusetts
    CAA and associated regulations because it failed to account for
    background levels of air toxics near the Weymouth station when
    considering      AAL    and       TEL.         They   point    to    three      chemicals:
    formaldehyde, benzene, and acrolein.                  They accept, for purposes of
    this   argument,       but       see     infra   section II(B)(2)(b),            that    the
    marginal emissions from the Weymouth station for each of these air
    toxics fall below the AAL and TEL, but they contend that the
    - 32 -
    Weymouth     emissions   plus    the      already-existing      background
    concentrations exceed those values.         In fact, even without the
    Weymouth emissions, background levels from other sources in that
    area already exceed the AAL and TEL for these three air toxics,
    such that any additional emissions would, as petitioners argue,
    contribute to an exceedance.     Since Algonquin and DEP ignored this
    cumulative effect and only compared the marginal increase to the
    AAL   and   TEL,   petitioners    claim    the   air   permit     violates
    Massachusetts law.
    In support of their position, petitioners point us to
    two Massachusetts regulations.         First, they point us to the
    definition of "air pollution," which says in full:
    AIR POLLUTION means the presence in the
    ambient air space of one or more air
    contaminants or combinations thereof in such
    concentrations and of such duration as to:
    (a) cause a nuisance;
    (b) be injurious, or be on the basis of
    current information, potentially injurious to
    human or animal life, to vegetation, or to
    property; or
    (c) unreasonably    interfere     with    the
    comfortable enjoyment of life and property or
    the conduct of business.
    310 Mass. Code Regs. § 7.00 (second emphasis added).         Second, the
    "General Regulations to Prevent Air Pollution" state:
    No person owning, leasing, or controlling the
    operation of any air contamination source
    shall willfully, negligently, or through
    failure to provide necessary equipment or to
    take   necessary   precautions,  permit   any
    emission for said air contamination source or
    - 33 -
    sources   of    such   quantities    of  air
    contaminants which will cause, by themselves
    or   in    conjunction    with    other  air
    contaminants, a condition of air pollution.
    Id. § 7.01(1)
       (emphasis   added).       Because   these    regulations
    contemplate "combinations" of air contaminants, or contaminants
    "in conjunction" with one another, petitioners say that DEP is
    mandated to consider background levels of air toxics.
    DEP    responds   that    its   "longstanding    policy"   is   to
    compare only emissions from the new source to the applicable AAL
    and TEL, without regard to background levels.              According to its
    1989 policy statement, DEP requires new or modified sources of air
    contaminants to "assess, through computer modeling, the ambient
    concentrations caused solely by that source's emissions," and
    "[t]hese modelled concentrations are then compared to the AALs to
    determine whether there may be potentially unacceptable risks
    associated with that particular source."         DEP Div. of Air Quality
    Control, Air Toxics Implementation Update 2 (1989) [hereinafter
    1989 Air Toxics Update] (emphasis added).          DEP calls the AAL and
    TEL "screening guidelines," whereby new sources that exceed these
    values are subject to "further evaluation" and new sources below
    these values receive no further scrutiny.          And, DEP points out,
    most states have a similar two-step approach to air toxics, whereby
    - 34 -
    step one (here AAL and TEL comparison) is for screening purposes
    only.18
    Petitioners argue, in substance, that to interpret the
    regulation's "in conjunction with" language as not requiring an
    assessment of the cumulative level of background and proposed new
    emissions would be to adopt an irrational or absurd interpretation
    of the regulation.     We disagree, finding it perfectly rational to
    use   a    low   threshold    to   identify   those   instances   in   which
    additional, cumulative impacts need be examined.            Consider, for
    the sake of analogy, a baking hobbyist who plans on making a pie
    for a family reunion.        The baker knows he has sugar, but he is not
    certain how much, and he may not even have the full cup needed for
    the recipe.      Before he can start baking, his neighbor knocks on
    his door and asks to borrow some sugar.         And, to make this analogy
    more like this case, imagine that measuring the baker's current
    supply of sugar would be "resource intensive" for the baker and
    his neighbor at that particular moment when the neighbor needs the
    sugar.
    It would be a perfectly reasonable response in this
    scenario for the baker to ask his neighbor how much sugar he needs.
    If the neighbor wants only a teaspoon, the baker might simply give
    18 In practice, it appears, that applicants regard surviving
    step-one screening as essential, given that DEP Air Quality Section
    Chief Thomas Cushing could recall no instance in which DEP received
    an application for a project that exceeded an AAL or TEL.
    - 35 -
    it to the neighbor without first measuring his own supply.                    A
    teaspoon is likely too little to make a difference between having
    and not having a cup, and even if it would, the practical effect
    will not be noticeable.        But if the neighbor wants a quarter cup,
    then the baker might decide to spend the resources to measure his
    supply before agreeing to the neighbor's request.
    This is in essence the purpose of AAL and TEL.                Before
    deciding whether to require that the resources be spent to measure
    the current cumulative amount of air toxics, DEP asks whether the
    amount to be produced by the new source is like the teaspoon or
    like the quarter cup.      If it is like the teaspoon, DEP decides
    that it is unlikely to make a practical difference. And here DEP's
    case is perhaps even stronger than the pie example, because
    petitioners have not pointed us to any other cap on how much
    pollutant is too much cumulatively (other than NESHAP, 
    see supra
    note 17, and petitioners do not allege that the Weymouth station
    is even close to violating that standard).              In other words, it
    would be as if the pie recipe said "roughly one cup, depending on
    how sweet you want it."
    Petitioners,    for     their    own     analogy,   point     us   to
    California's rules for automobile tailpipe emissions.               See Motor
    Vehicle   Mfrs.   Ass'n   of    U.S.,   Inc.   v.    N.Y.   Dep't   of   Envtl.
    Conservation, 
    17 F.3d 521
    , 524–25 (2d Cir. 1994) (explaining
    California's unique exemption from federal preemption over mobile-
    - 36 -
    source regulations).         "[P]rior to the creation of California's
    stringent air pollution regulations," petitioners tell us, "daily
    emissions from millions of . . . vehicles resulted in a chronic
    condition    of     air   pollution --   smog --     in    the   City   of   Los
    Angeles . . . even though the incremental emissions from each of
    those   individual        vehicles   undoubtedly      represented       a    tiny
    contribution to the overall problem, and a de minimis risk to human
    health."
    The tailpipe example would be like our hypothetical
    example if the baker had twelve neighbors at his door all asking
    for sugar.    In that case, he might want to measure his supply even
    if each neighbor wanted only a teaspoon.           But surely there are not
    "millions"     of    proposed   stationary       sources   of    formaldehyde,
    benzene, and acrolein around Weymouth.            It is completely rational
    for DEP to treat this limited number of sources differently for
    screening purposes than California treats personal automobiles.
    Cf. 310 Mass. Code Regs. § 7.02(2)(b)(7) (excluding stationary
    sources not capable of emitting one ton or more of any pollutant
    from the air-permit requirement).             Moreover, there are plenty of
    other examples of air-pollution regulatory schemes that similarly
    screen out de minimis sources.        In addition to other states' rules
    on air toxics, DEP points us to the Significant Impact Limits
    (SILs) used by EPA when assessing compliance with the National
    Ambient Air Quality Standards (NAAQS).             See Sierra Club v. EPA,
    - 37 -
    
    705 F.3d 458
    , 461 (D.C. Cir. 2013) (explaining SILs); see also
    Sierra Club v. EPA, 
    955 F.3d 56
    , 58–60 (D.C. Cir. 2020); 40 C.F.R.
    § 51.166(b)(23)(i) (setting net-emissions-increase levels deemed
    "[s]ignficant"    for     purposes    of    Prevention     of    Significant
    Deterioration (PSD)).     The fact that some regulatory programs take
    a different approach does not make these programs irrational.
    Of course, the fact that DEP's two-step approach is
    rational does not dispense with petitioners' argument that the
    Massachusetts    regulations    compel     consideration    of   background
    levels.    Nevertheless, we defer to the agency's interpretation.
    The regulations to which petitioners point us, 310 Mass. Code Regs.
    §§ 7.00,   7.01(1),     are   broad   regulations    concerning    all   air
    pollution generally, not just air toxics.           See Town of Brookline
    v. Comm'r of Dep't of Envtl. Quality Eng'g ("Brookline I"), 
    439 N.E.2d 792
    , 799 (Mass. 1982) (giving DEP discretion to interpret
    310 Mass. Code Regs. § 7.01); see also Brookline 
    II, 497 N.E.2d at 13
    ("The Legislature has granted [DEP] broad authority.").            And we
    do not think that the language from those general regulations
    unambiguously forecloses DEP's approach to air toxics. The phrases
    "in conjunction with other air contaminants," 310 Mass. Code Regs.
    §§ 7.01(1), and "combinations thereof,"
    id. § 7.00,
    might mean, as
    petitioners argue, that DEP should consider background levels of
    a given pollutant.      Or they might reasonably be read as referring
    to situations where two different air pollutants produce a chemical
    - 38 -
    reaction in the air, as with ozone precursors, see Ill. State
    Chamber of Commerce v. EPA, 
    775 F.2d 1141
    , 1143 & n.3 (7th Cir.
    1985), in which case the regulations do not compel petitioners'
    approach.     Since the text is ambiguous, and traditional tools of
    construction do not resolve that ambiguity, we defer to DEP's
    reasonable interpretation.         See 
    Kisor, 139 S. Ct. at 2414
    –18;
    Brookline 
    II, 497 N.E.2d at 15
    .
    b.   Startup Emissions
    Petitioners also argue that the formaldehyde emissions
    solely    from   the   Weymouth   station   will,   in   fact,   exceed   the
    applicable AAL and TEL. They argue that Algonquin's air-dispersion
    model, which showed that formaldehyde emissions would be no more
    than 70% of the AAL, underestimated the actual emission rate
    because it did not include emissions during intermittent startup
    events.
    The proposed SoLoNOx turbine will not run continuously.
    Instead, it will be shut down and restarted up to 416 times per
    year.    Normally, the turbine will employ an oxidation catalyst to
    reduce formaldehyde emissions, but during the time it takes the
    turbine to start up, this catalyst will not be fully operational,
    meaning     formaldehyde    emissions   will   be    higher.      Algonquin
    estimates that startups will usually last only nine minutes, though
    the time may be longer if a startup fails initially.
    - 39 -
    The air permit as initially drafted by DEP staff allowed
    for startup times up to thirty minutes.         Petitioners opposed the
    allowed   startup   period   before   the   Presiding   Officer.    Their
    witness, John Hinckley, performed his own dispersion modeling
    that, unlike Algonquin's initial modeling,19 accounted for startup
    emissions -- one model representing thirty-minute startups, and
    another representing nine-minute startups.          Hinckley's thirty-
    minute model showed that formaldehyde emissions from the Weymouth
    station would exceed the AAL and TEL when measured at the property
    line as required by DEP guidance.      See 1 DEP, The Chemical Health
    Effects Assessment Methodology and the Method to Derive Allowable
    Ambient Limits 21 (1990).     Hinckley's nine-minute model showed an
    exceedance of the AAL, but not the TEL, at the property line.           In
    response, Algonquin's witness, Justin Fickas, put together a model
    representing   eighteen-minute    startups,     which   also   showed   an
    exceedance of the AAL.
    The Presiding Officer acknowledged that EPA's guidance
    does not require modeling of intermittent startups at all, but
    nevertheless expressed concern over the modeled exceedances.            As
    19 DEP policy requires an applicant to model emissions of air
    toxics only for sources subject to PSD, plus a few other types of
    facilities. See 1989 Air Toxics 
    Update, supra, at 3
    . The Weymouth
    Station does not meet any of these criteria, but DEP exercised its
    discretion to request that Algonquin perform this modeling. See
    310 Mass. Code Regs. § 7.02(5)(c)(6) (requiring applicants to
    furnish air-dispersion modeling "upon request by" DEP).
    - 40 -
    such, she recommended reducing the allowable startup time from
    thirty minutes to eighteen minutes, and the Commissioner adopted
    this recommendation.    As to the fact that even the eighteen-minute
    model showed a concentration above the AAL, the Presiding Officer
    stated that "[t]he slight exceedance shown in the revised modeling
    beyond the fence line . . . does not, in my opinion, justify
    denying the permit."
    Petitioners' main argument before us is straightforward:
    the Weymouth station will, even under the revised air permit,
    create an exceedance of the AAL for formaldehyde, and so the permit
    should have been denied, and we should vacate DEP's contrary
    decision as arbitrary and capricious.       As its name suggests, AAL
    is meant to be a "limit," petitioners argue, so an exceedance
    should not be allowed, no matter how "slight."
    DEP counters that under the applicable policy, there was
    no exceedance here. EPA's guidance explains that "the intermittent
    nature   of   the      actual   emissions     associated   with . . .
    startup/shutdown [operations] in many cases, when coupled with the
    probabilistic form of the standard, could result in modeled impacts
    being significantly higher than actual impacts would realistically
    be expected to be for these emission scenarios."      Memorandum from
    Tyler Fox, Leader, Air Quality Modeling Grp., EPA, to Reg'l Air
    Div. Dirs., Additional Clarification Regarding Application of
    Appendix W Modeling Guidance for the 1-Hour NO2 National Ambient
    - 41 -
    Air Quality Standard 8 (Mar. 1, 2011), https://www.epa.gov/sites/
    production/files/2015-07/documents/appwno2_2.pdf.                         EPA        thus
    advises against using startup modeling.                 See
    id. at 9–10;
    see also
    DEP, Modeling Guidance for Significant Stationary Sources of Air
    Pollution    1    (2011)    (noting    that     DEP     generally    follows     EPA's
    guidance on air modeling); cf. 40 C.F.R. § 60.8(c) ("Operations
    during periods of startup, shutdown, and malfunction shall not
    constitute       representative       conditions        for   the    purpose     of     a
    performance test . . . .").            DEP relied on this guidance in not
    requiring Algonquin to account for startups in its application,
    and   petitioners       have   not   pointed       to   anything     in   DEP   policy
    requiring a contrary rule.           Although Algonquin provided additional
    (non-mandatory) modeling to explore the effects of startup events,
    such models have not been adopted into official department policy
    or regulations.         Thus, DEP acted within its discretion when it
    relied on a model excluding startup emissions to find, without
    further evaluation, that there was no exceedance of AAL or TEL.
    3.    Environmental Justice Policy
    Petitioners claim that DEP failed to comply with the
    Massachusetts Environmental Justice (EJ) Policy.
    The    EJ     Policy,    first    implemented       in    2002      by    the
    Massachusetts       Executive       Office    of    Energy     and    Environmental
    Affairs, states that "all people have a right to be protected from
    environmental pollution and to live in and enjoy a clean and
    - 42 -
    healthful environment," regardless of "race, ethnicity, class,
    gender,    or   handicap."    Environmental             Justice   Policy   of   the
    Executive       Office   of   Environmental             Affairs     2–3    (2002),
    https://www.mass.gov/files/documents/2017/11/29/ej%20policy%2020
    02.pdf; see City of Brockton v. Energy Facilities Siting Bd., 
    14 N.E.3d 167
    , 171 n.9 (Mass. 2014) (describing the various iterations
    of the EJ Policy prior to 2014).                The EJ Policy requires that
    agencies subject to it, including DEP, engage in "enhanced public
    participation" for projects that meet two criteria:                        (1) the
    project site is located within five miles (for air pollutants) of
    an   "EJ    population,"20    and     (2) emissions          will     exceed    the
    Environmental      Notification     Form        (ENF)    threshold     under    the
    Massachusetts Environmental Protection Act (MEPA), Mass. Gen. Laws
    ch. 30, §§ 61–62I. City of 
    Brockton, 14 N.E.3d at 172
    . The policy
    requires    "enhanced     analysis        and     review     of     'impacts    and
    mitigation'" for projects that meet the first of these criteria
    and where emissions will exceed the Environmental Impact Report
    (EIR) threshold under MEPA.
    Id. DEP and
    Algonquin acknowledge that the Weymouth station
    is located within five miles of EJ populations.                     However, they
    20  An EJ population is "a neighborhood where 25 percent of
    the households have an annual median household income that is equal
    to or less than 65 percent of the statewide median or 25% of its
    population is Minority or identifies as a household that has
    English Isolation." Environmental Justice Policy of the Executive
    Office of Energy and Environmental Affairs 3 (2017).
    - 43 -
    argue, the Weymouth station's emissions exceed neither the ENF nor
    the EIR thresholds, so the EJ Policy is not implicated.               Seeing no
    rejoinder from petitioners on this point, we agree.
    Petitioners nevertheless argue that DEP was required to
    do something more.        They cite City of Brockton, which stated in
    dicta that "[t]he EJ policy does impose a general, but affirmative,
    requirement   on    all    agencies   covered       by   it . . .   to    develop
    strategies designed 'to proactively promote environmental justice
    in all neighborhoods' in a manner tailored to and consistent with
    that agency's 'specific mission.'"
    Id. at 174
    n.17.       The City of
    Brockton court said there "may be an argument that under this
    general requirement," agencies must incorporate EJ principles into
    certain agency decisions for projects not implicating the enhanced
    public participation or enhanced analysis criteria, but the court
    ultimately left the question unresolved.
    Id. (emphasis added).
    Since DEP has not, in petitioners' view, developed any special
    "strategies," petitioners say we should invalidate the air permit
    for noncompliance with the EJ Policy.
    We decline to do so.       City of Brockton does not mandate
    that agencies go beyond the two requirements set out in the EJ
    Policy, only that there "may" be such a requirement. In this case,
    there is no real need to resolve this issue of Massachusetts law.
    Even   assuming    DEP    is   required   to   go    beyond   the   two    stated
    requirements, here DEP allowed for enhanced public participation
    - 44 -
    even though there was no exceedance of the ENF threshold.                     City of
    Brockton also recognized that agencies would need time to implement
    any special strategies,
    id., and the
    2017 updated EJ Policy (issued
    after City of Brockton) says that all agency strategies "will be
    consolidated into one Secretariat EJ Strategy and will be finalized
    by   a    date    established   by     the    Secretary       [for     Energy       and
    Environmental      Affairs],"   Environmental          Justice      Policy    of   the
    Executive Office of Energy and Environmental Affairs 9 (2017).                      So
    we can hardly blame DEP for the fact that this future date has not
    arrived    yet.     Petitioners      also    do    not    explain    what    special
    procedures they have in mind, only that DEP should have implemented
    something more than it did.           We are unwilling to disturb DEP's
    decision in this case with only the vague admonition that it needed
    to do more, without saying what more is needed.21
    Petitioners     point      us         to     Brockton     Power        Co.,
    Nos. 2011-025,      2011-026,   
    2016 WL 8542559
              (Mass.     DEP     July 29,
    2016), in which DEP "performed an enhanced substantive review" of
    a power plant even though the relevant MEPA thresholds were not
    21  Petitioners also argue, in one sentence, that the
    Presiding Officer's decision to dismiss the EJ Policy claim prior
    to the hearing was "arbitrary, capricious, an abuse of discretion,
    otherwise not in accordance with law, contrary to constitutional
    right or short of statutory right."     To the extent petitioners
    attempt to raise a separate challenge -- constitutional or
    otherwise -- to the Presiding Officer's procedure, we deem this
    argument waived for lack of development.     See United States v.
    Zannino, 
    895 F.2d 1
    , 17 (1st Cir. 1990).
    - 45 -
    triggered.
    Id. at *57.
        So, petitioners say, the EJ Policy does
    not prevent DEP from voluntarily doing more, and the unexplained
    departure from what DEP did in Brockton Power was arbitrary and
    capricious.    We disagree.     As Brockton Power recognizes, DEP can,
    in its discretion, engage in further review "on a case-by-case
    basis,"
    id., and in
    this case it chose not to do so (except for
    the enhanced public participation).
    Finally, petitioners draw our attention to Friends of
    Buckingham,    in     which   the   Fourth     Circuit   vacated   Virginia's
    approval of a compressor station because the agency failed to
    comply with Virginia's EJ 
    requirements. 947 F.3d at 87
    –92.
    Friends of Buckingham is easily distinguishable, though, because
    Virginia's      EJ     requirements      are     not     Massachusetts's   EJ
    requirements.        A violation of the former, even on similar facts,
    would not necessarily be a violation of the latter, and as we have
    determined, there was no violation of Massachusetts's EJ policy
    here.
    4.   Noise
    Petitioners argue that noise from the Weymouth station
    will cause a nuisance, and hence an impermissible "condition of
    air pollution," in violation of 310 Mass. Code Regs. §§ 7.00,
    7.01(1) 
    (quoted supra
    section II(B)(2)(a)).22
    Petitioners also mention "unpleasant odors" from the
    22
    Weymouth station, but do not explain how such odors would create
    - 46 -
    According to the HIA, the Weymouth station will produce,
    under   normal    nighttime    operating       conditions,    up   to   47 dB(A)
    (A-weighted      decibels)    of    noise     as   measured   at   King's    Cove
    recreation    area.     When       combined    with   background    noise,    the
    nighttime noise at one nearby residence will be 46 dB(A).                   While
    the station is under construction, noise is estimated to be up to
    113 dB(A).     The HIA also noted that "EPA recommends an average
    24-hr exposure limit of 45 dB(A) indoors and 55 dB(A) outdoors,"
    and that the World Health Organization (WHO) recommends nighttime
    exposure of "45 dB(A) or less."         Petitioners argue in effect that,
    because the estimated noise levels will exceed EPA's and WHO's
    recommendations, the station will create a nuisance.               They present
    no other argument for how the noise would be considered a nuisance,
    nor do they cite to any case or statute pertaining to Massachusetts
    nuisance law.
    DEP regulations specifically address noise.            See Morales
    v. Trans World Airlines, Inc., 
    504 U.S. 374
    , 384 (1992) ("[I]t is
    a commonplace of statutory construction that the specific governs
    the general . . . .").         310 Mass. Code Regs. § 7.10(1) states:
    "No person owning, leasing, or controlling a source of sound shall
    willfully, negligently, or through failure to provide necessary
    a nuisance.    We consider this argument waived for lack of
    development.   See 
    Zannino, 895 F.2d at 17
    .        To the extent
    petitioners claim that the Weymouth station will in any other way
    cause a nuisance, those arguments are likewise waived.
    - 47 -
    equipment,    service,   or   maintenance    or   to   take   necessary
    precautions cause, suffer, allow, or permit unnecessary emissions
    from said source of sound that may cause noise."
    Id. (emphasis added).
    23    DEP has established a "Noise Policy" interpreting when
    emissions of sound are unnecessary.         See Mass. Exec. Office of
    Envtl. Affairs, Dep't of Envtl. Quality Eng'g, Division of Air
    Quality            Control            Policy 90-001            (1990),
    https://www.mass.gov/doc/massdep-noise-policy/download.          Under
    that policy, a source of sound will violate the noise regulation
    if the source "[i]ncreases the broadband sound level by more than
    10 dB(A) above ambient" or "[p]roduces a 'pure tone' condition."
    Id. Petitioners do
    not argue that DEP's Noise Policy is an
    unreasonable interpretation of 310 Mass. Code Regs. § 7.10(1), so
    we give deference to that policy.     See 
    Kisor, 139 S. Ct. at 2414
    –
    18; Brookline 
    II, 497 N.E.2d at 15
    .      Petitioners also do not argue
    that the Weymouth station will create a "pure tone" condition or,
    except for the construction period and "emergency blowdowns,"24
    increase broadband sound by more than 10 dB(A) above ambient.
    Thus, there is no violation of the Noise Policy.         The fact that
    23"Noise" is defined as "sound of sufficient intensity
    and/or duration as to cause or contribute to a condition of air
    pollution." 310 Mass. Code Regs. § 7.00.
    24 A "blowdown" is a venting of gas.     Emergency blowdowns
    "will be extremely rare after initial commissioning" of the
    Weymouth station and would last no more than five minutes.
    - 48 -
    EPA or WHO might recommend a lower level of noise would presumably
    be of interest to DEP.             But that fact provides no basis for saying
    that DEP has violated any relevant law.
    As to the construction period, the HIA estimated that
    sound from construction equipment will increase ambient sound
    levels by 12 dB(A), which is over the Noise Policy's 10-dB(A)
    limit.25            However,      DEP    says   that    it     has    a   "longstanding
    practice" --             to    which      its   witnesses       testified        at     the
    hearing -- "not to apply the Noise Policy to temporary construction
    sound" for purposes of air permitting, and "instead to require
    appropriate noise mitigation measures."                       And DEP required just
    such mitigating measures for construction of the Weymouth station,
    including           limited     construction      hours,       mufflers        for     heavy
    equipment, quieter backup alarms, portable noise barriers, and a
    noise complaint hotline.                 Similarly, DEP says that it does not
    apply        the    Noise     Policy    to   "unplanned      emergency       events"   like
    blowdowns, which could increase ambient sound by up to 17 dB(A),
    and it instead required a "blowdown silencer" to muffle the noise
    from     such       an   event.         Petitioners    do    not     argue    that     DEP's
    "longstanding practice[s]" regarding construction and emergency
    events are unreasonable, nonexistent, or in any other way invalid,
    so we will again defer to those practices.                         See Doe v. Leavitt,
    DEP contends that the actual increase will be closer to
    25
    8 dB(A), below the limit.
    - 49 -
    
    552 F.3d 75
    , 80–81 (1st Cir. 2009) (describing deference based on
    Skidmore v. Swift & Co., 
    323 U.S. 134
    (1944)).
    5.     Manufacturer Guarantee
    Petitioners fault the Presiding Officer's finding that
    "[t]he Solar turbine specified for the proposed Project has a
    guaranteed    emission       rate   for    NOx   of    9 ppm,"      given   that   the
    technical proposal from Solar Turbines contains no guarantee of
    emissions rate.        Therefore, petitioners reason, the Presiding
    Officer's finding was not supported by substantial evidence, or
    DEP's decision based on that finding was otherwise arbitrary and
    capricious.
    Algonquin    contends         that   the       record    does   otherwise
    contain evidence of a guaranteed emissions rate from Solar.                        But
    even   assuming   it    does    not,      we   see    no   merit    in   petitioners'
    argument.     Petitioners point us to nothing in Massachusetts law
    suggesting that a guarantee from the equipment manufacturer is
    required for approval of Algonquin's air permit.                            And, more
    importantly, if the SoLoNOx turbine does not work as claimed in
    the permit, that will be Algonquin's problem, not petitioners' or
    even DEP's.    Simply put, Algonquin could be fined and ordered to
    reduce operations to eliminate any violation of its permitted
    limits. See Mass. Gen. Laws ch. 111, § 142B. Whether or not Solar
    could be liable to Algonquin for such a violation affects only the
    allocation of costs as between those parties.                      See Catlin v. Bd.
    - 50 -
    of Registration of Architects, 
    604 N.E.2d 1301
    , 1305 (Mass. 1992)
    ("The   appealing   party   has   the   burden     of   showing   that    his
    'substantial   rights . . .    may   have   been    prejudiced'    by     the
    agency's error."    (quoting Mass. Gen. Laws ch. 30A, § 14(7))); see
    also Sasen v. Spencer, 
    879 F.3d 354
    , 366 (1st Cir. 2018).
    6.    Insurance Requirement
    Petitioners claim that DEP violated Mass. Gen. Laws
    ch. 21C, § 4 by granting Algonquin's air permit without requiring
    Algonquin to obtain liability insurance or a surety bond.                That
    statute states:
    The department shall require that a licensee
    obtain and maintain in effect a contract of
    liability insurance, a surety bond or other
    evidence of financial responsibility in favor
    of the commonwealth sufficient to assure
    financial responsibility in the event of
    damages resulting from accidents, negligence,
    misconduct,   or    malfunctioning   in   the
    construction, maintenance and operation of a
    facility, or from any other circumstances
    reasonably foreseeable occurring during or
    after construction or in the course of the
    maintenance and operation of hazardous waste
    facilities.
    Mass. Gen. Laws ch. 21C, § 4.
    Petitioners' argument lacks merit because Mass. Gen.
    Laws ch. 21C, the Massachusetts Hazardous Waste Management Act,
    has nothing to do with air permitting.      Indeed, petitioners do not
    even attempt to argue that the Weymouth station is a "hazardous
    waste facilit[y]" subject to the insurance requirement.            See
    id. - 51
    -
    § 2 (defining "facility" and "hazardous waste"); see also 310 Mass.
    Code Regs. §§ 30.131–30.136 (listing hazardous wastes).                 We thus
    reject petitioners' argument.
    C.    Remedy
    Having determined that DEP erred in one regard, 
    see supra
    section II(B)(1)(a), we finally must determine the appropriate
    remedy. Algonquin urges us to remand to DEP to address the defects
    in the permitting process without vacating the permit approval.
    Petitioners say we should vacate and remand.
    Whether to vacate an agency's flawed decision or remand
    without vacatur is within our discretion as the reviewing court,
    and   "depends   inter   alia    on    the   severity   of   the   errors,   the
    likelihood that they can be mended without altering the order, and
    on the balance of equities and public interest considerations."
    Cent. Me. 
    Power, 252 F.3d at 48
    .                Algonquin argues that these
    factors favor remand without vacatur.            It says that DEP's failure
    to fully explain the BACT result could be easily remedied by DEP
    providing the missing explanation.                And Congress has already
    expressed   a    preference     for    the   speedy   resolution   of   matters
    concerning natural-gas facilities, see 15 U.S.C. § 717r(d)(5),
    particularly where FERC has already declared the facility to be
    required by considerations of "public convenience and necessity."
    So, Algonquin argues, the balance of equities favor a narrow
    remedy.
    - 52 -
    Petitioners say that, under the federal APA, vacatur is
    the default remedy, see 5 U.S.C. § 706(2) (requiring reviewing
    courts to "hold unlawful and set aside" defective agency actions),
    and that remand without vacatur is a limited exception that should
    apply mainly to agency rulemaking, see generally Note, Kristina
    Daugirdas, Evaluating Remand Without Vacatur:            A New Judicial
    Remedy for Defective Agency Rulemakings, 80 N.Y.U. L. Rev. 278
    (2005).   And they argue that the Central Maine Power factors favor
    vacatur because the BACT error was severe, correcting the error
    may potentially alter DEP's final decision (i.e., DEP might decide
    that the electric motor is the BACT), and the interests of the
    public in being protected against harmful air pollution tip the
    balance of equities.
    Both sides' arguments are persuasive, but we decide to
    vacate based on three additional considerations. First, we believe
    the administrative record as it exists now is insufficient for DEP
    to complete the BACT analysis. As shown by our attempts to perform
    the missing calculations, 
    see supra
    section II(B)(1)(a), it is
    impossible     even   to   calculate   the   magnitude    of   the   cost
    effectiveness of an electric motor without more information about
    either SoLoNOx's costs or the base-case emissions rate.               By
    vacating, we allow DEP to reopen the administrative record for the
    purpose of filling these evidentiary gaps.       DEP may also wish to
    elicit more evidence on the actual costs of the electric motor.
    - 53 -
    Second, Algonquin has expressed a desire to pursue its redesign
    argument, 
    see supra
    note 6, and vacating will allow DEP to fully
    consider that issue as well.   Third, we expect and anticipate that
    any further proceeding before the DEP will be limited to these
    purposes and will be expedited.
    III.
    For the foregoing reasons, we vacate the air permit and
    remand to DEP for it to conduct further proceedings, limited to
    the purposes we have identified.        We further order that if and
    when DEP determines that it cannot reasonably conclude those
    proceedings and issue a decision within seventy-five days of the
    date of this opinion, then DEP will consult with the other parties
    and make a filing with this court in this action showing cause why
    such additional time is reasonably required.       Any opposition to
    the show-cause filing must be filed within seven calendar days of
    DEP's filing.   We retain jurisdiction for the limited purpose of
    receiving and responding to such a filing.
    - 54 -
    

Document Info

Docket Number: 19-1794P

Filed Date: 6/3/2020

Precedential Status: Precedential

Modified Date: 6/3/2020

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