Housatonic River Initiative v. U.S. Environmental Protection Agency ( 2023 )


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  •           United States Court of Appeals
    For the First Circuit
    No. 22-1398
    HOUSATONIC RIVER INITIATIVE;
    HOUSATONIC ENVIRONMENTAL ACTION LEAGUE,
    Petitioners,
    v.
    UNITED STATES ENVIRONMENTAL PROTECTION AGENCY,
    New England Region,
    Respondent,
    GENERAL ELECTRIC COMPANY;
    HOUSATONIC REST OF RIVER MUNICIPAL COMMITTEE,
    Intervenors.
    PETITION FOR REVIEW OF AGENCY ACTION OF
    THE UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
    Before
    Gelpí, Lynch, and Montecalvo,
    Circuit Judges.
    Andrew Rainer, Stephanie R. Parker, and Katy T. Garrison,
    with whom Brody, Hardoon, Perkins & Kesten, LLP, O'Connor Carnathan
    & Mack LLC, and Murphy & Riley, PC were on brief, for petitioners.
    Jeffrey Hammons, Trial Attorney, United States Department of
    Justice, Environment and Natural Resources Division, with whom
    Todd Kim, Assistant Attorney General, United States Department of
    Justice, Environment and Natural Resources Division, John Kilborn,
    United States Environmental Protection Agency, Region One, Timothy
    Conway, United States Environmental Protection Agency, Region One,
    and Brian Grant, United States Environmental Protection Agency,
    Office of General Counsel, were on brief, for respondent.
    Kwaku A. Akowuah, with whom James R. Bieke, Madeleine Joseph,
    Sidley Austin LLP, Jeffrey R. Porter, Mintz, Levin, Cohn, Ferris,
    Glovsky & Popeo, P.C., and Andrew J. Thomas were on brief, for
    General Electric Company.
    Matthew Pawa, with whom Seeger Weiss LLP was on brief, for
    Housatonic Rest of River Municipal Committee.
    July 25, 2023
    LYNCH,    Circuit Judge.           Petitioners Housatonic River
    Initiative ("HRI") and Housatonic Environmental Action League
    ("HEAL," and collectively with HRI, the "Petitioners") object to
    a permit, issued in 2020 by the Environmental Protection Agency
    (the "EPA") and affirmed in 2022 by the Environmental Appeals Board
    (the "EAB"), that requires General Electric Company ("GE") to clean
    up polychlorinated biphenyls ("PCBs") from the "Rest of River"
    reaches of the Housatonic River.                 The permit is supported by
    respondent-intervenors        GE     and   the   Housatonic     Rest   of    River
    Municipal      Committee        (the       "Municipal        Committee"),       an
    intergovernmental entity comprised of elected officials from the
    five towns most affected by the PCB contamination in the Rest of
    River.   The permit is also supported by the State of Connecticut,
    and is not opposed by the Commonwealth of Massachusetts, which
    helped negotiate its terms.            Should GE's cleanup of the Rest of
    River not achieve the goals set forth in the permit, the permit
    requires further measures.           The task of this court is to evaluate
    the   Petitioners'       legal       challenges,      both      procedural     and
    substantive.       After careful review, we deny the petition.
    I.    Background
    A.   Statutory Background
    This     petition      for     review     legally     involves     the
    intersection    of    three   environmental         statutes:    (1)   the   Toxic
    Substances Control Act ("TSCA"), 
    15 U.S.C. § 2601
     et seq.; (2) the
    - 3 -
    Resource Conservation and Recovery Act ("RCRA"), 
    42 U.S.C. § 6901
    et    seq.;   and   (3)    the     Comprehensive    Environmental     Response,
    Compensation, and Liability Act ("CERCLA"), 
    id.
     § 9601 et seq.                  We
    briefly summarize the relevant provisions of each statute.
    Congress    passed    TSCA   in    1976   with   the   purpose    of
    "regulat[ing] chemical substances and mixtures which present an
    unreasonable risk of injury to health or the environment."                      
    15 U.S.C. § 2601
    (b)(2).         Among other provisions, TSCA requires the
    EPA to regulate the use and disposal of PCBs. See 
    id.
     § 2605(e)(1);
    Town of Westport v. Monsanto Co., 
    877 F.3d 58
    , 63 (1st Cir. 2017).
    Under those regulations, any person disposing of "PCB remediation
    waste" "shall do so based on the concentration at which the PCBs
    are found" in that waste.            
    40 C.F.R. § 761.61
    .        In particular,
    materials with PCB concentrations of under 50 parts per million
    ("ppm") can be disposed of in a facility licensed to manage
    municipal solid waste or non-municipal non-hazardous waste.                    See
    
    id.
        §   761.61(a)(5)(i)(B)(2)(ii),           .61(a)(5)(v)(A)(1)-(2).         By
    contrast, materials with PCB concentrations equal to or exceeding
    50 ppm must be disposed of in a more protective facility dedicated
    to hazardous waste or PCBs. See id. §§ 761.61(a)(5)(i)(B)(2)(iii),
    .75; 
    42 U.S.C. §§ 6924
    , 6926.
    Congress enacted RCRA, also in 1976, with the goal of
    closing "the last remaining loophole in environmental law, that of
    unregulated land disposal of discarded materials and hazardous
    - 4 -
    waste."             Me.    People's        All.     &   Nat.      Res.       Def.
    Council v. Mallinckrodt, Inc., 
    471 F.3d 277
    , 287 (1st Cir. 2006)
    (quoting H.R. Rep. No. 94-1491, pt. 1, at 4 (1976)).                         RCRA
    generally requires any owner or operator of a facility that
    "treat[s], stor[es], or dispos[es] of hazardous waste" to acquire
    a permit.       
    42 U.S.C. § 6925
    (a); see W.R. Grace & Co.--Conn. v.
    U.S. EPA, 
    959 F.2d 360
    , 361 (1st Cir. 1992).                That permit must
    require "corrective action for all releases of hazardous waste"
    from the facility, 
    42 U.S.C. § 6924
    (u), and may also include any
    "terms and conditions as the [permit issuer] determines necessary
    to protect human health and the environment," 
    id.
     § 6925(c)(3).
    Following any administrative appeals to the EAB, see 
    40 C.F.R. § 124.19
    (a)(l), "any interested person" may seek immediate review
    of a RCRA permit in the federal court of appeals, 
    42 U.S.C. § 6976
    (b).
    Finally, CERCLA, enacted in 1980, empowers the EPA to
    require remedial action when there is a "release or substantial
    threat    of    release"    of   "any   hazardous   substance"    or    of   "any
    pollutant      or   contaminant    which    may   present   an   imminent     and
    substantial danger to the public health or welfare."                   
    42 U.S.C. § 9604
    (a)(1); see Emhart Indus., Inc. v. U.S. Dep't of the Air
    Force, 
    988 F.3d 511
    , 516 & n.3 (1st Cir. 2021).             Under CERCLA, the
    EPA can order        "responsible parties"        to carry out the chosen
    response action.          Emhart, 988 F.3d at 517 (quoting Key Tronic
    - 5 -
    Corp. v. United States, 
    511 U.S. 809
    , 813-14 (1994)); see 
    42 U.S.C. § 9607
    (a).      That remedial action must achieve an adequate degree
    of cleanup, see 
    42 U.S.C. § 9621
    (d)(1), and typically must conform
    to "applicable or relevant and appropriate" state and federal
    standards, 
    id.
     § 9621(d)(2)(A), known as "ARARs."                         Unlike a RCRA
    permit, a CERCLA remedial action order often cannot be challenged
    by a responsible party until the EPA has taken action to enforce
    the order.          See id. § 9613(h).            Regulations governing CERCLA
    remedial actions are set forth in the National Oil and Hazardous
    Substances Pollution Contingency Plan (the "National Contingency
    Plan").   See 
    40 C.F.R. § 300.1
     et seq.
    B.     Factual Background
    1.    The PCB Contamination
    The Housatonic River originates in two separate branches
    several miles north of the City of Pittsfield, Massachusetts.
    Below the confluence of those two branches, the Housatonic extends
    south   for    over    125       miles   through       western   Massachusetts        and
    Connecticut, ultimately emptying into Long Island Sound.                              The
    portion of the river downstream from the confluence is known, for
    purposes of this litigation, as the "Rest of River."                        The Rest of
    River   comprises      twelve       segments      or    "reaches,"    designated       as
    Reaches 5 through 16.            This petition concerns the Rest of River.
    For    much   of    the    twentieth      century,     GE    operated    an
    electrical transformer manufacturing facility along one of the
    - 6 -
    branches north of the confluence.            The decades-long operation of
    this facility resulted in extensive contamination of the river
    with PCBs.     The worst of the contamination occurred north of the
    confluence, but the PCBs also migrated throughout the Rest of
    River.
    2.     The Consent Decree
    In     the    1970s,     the     EPA     and   Massachusetts    began
    investigating and implementing remedial actions to address the PCB
    contamination in the Housatonic.           That process culminated in 2000,
    when GE entered into a Consent Decree with the United States,
    Massachusetts,    Connecticut,       the    City    of   Pittsfield,   and    the
    Pittsfield Economic Development Authority.1               The Consent Decree,
    which was approved by the U.S. District Court for the District of
    Massachusetts    in    October    2000,    was     intended   "to   resolve   the
    [parties'] claims for response actions, response costs and natural
    resource damages in connection with" the PCB contamination from
    GE's manufacturing facility.             In particular, under the Consent
    Decree, GE agreed to conduct remediation of the river, and the
    various government signatories agreed to resolve GE's liability
    under RCRA, CERCLA, and other applicable law.
    1    The Consent Decree included, as an attachment, a draft
    RCRA permit that was to be revised upon the selection of a remedy
    for the Rest of River. We refer to the Consent Decree and the
    attached permit collectively as the "Consent Decree."
    - 7 -
    The Consent Decree laid out a cleanup plan for two
    different portions of the Housatonic.               First, GE was required to
    remediate the contamination at the facility itself and at nearby
    areas north of the confluence.             That cleanup is not at issue in
    this case.
    Second,   the    Consent    Decree    created      a   process   for
    selecting a remedy for the Rest of River (i.e., Reaches 5 through
    16).   Under the Consent Decree, that remedy -- which is the subject
    of the present litigation -- would be embodied in a RCRA corrective
    action permit, but would also "be considered to be the final remedy
    selection decision pursuant to Section 121 of CERCLA and Section
    300.430 of the [National Contingency Plan]." See 
    42 U.S.C. § 9621
    ;
    
    40 C.F.R. § 300.430
    .           This unusual remedial structure afforded GE
    and    other    interested      persons    the   immediate   rights     of    review
    associated with a RCRA permit, see 
    42 U.S.C. § 6976
    (b), while
    subjecting       the     selected    response       action   to       the    cleanup
    requirements of CERCLA and the National Contingency Plan.                        One
    such CERCLA provision requires conforming to federal and state
    ARARs,2 see 
    id.
     § 9621(d)(2)(A), including TSCA's PCB disposal
    restrictions, see 
    15 U.S.C. § 2605
    (e)(1); 
    40 C.F.R. §§ 761.61
    ,
    .75.       Consistent       with    RCRA     regulations,      see      40    C.F.R.
    2  The Consent Decree also expressly required the EPA to
    identify ARARs and, if the EPA decided to waive any such ARARs,
    see 
    42 U.S.C. § 9621
    (d)(4), to explain the basis for any such
    waiver.
    - 8 -
    § 124.10(a)(1)(ii), the Consent Decree further required that the
    proposed permit be subject to public comment.
    The    Consent      Decree    laid    out     a    phased     process       for
    selecting the Rest of River remedy, including the performance of
    new and various studies and investigations by both GE and the EPA.
    Of particular importance to this petition for review, the Consent
    Decree required the consideration of, "[a]t a minimum," nine
    criteria (the "Selection Criteria") in selecting the remedy.                               The
    Selection Criteria are as follows: (1) "Overall Protection of Human
    Health and the Environment"; (2) "Control of Sources of Releases";
    (3) "Compliance with [ARARs]"; (4) "Long-Term Reliability and
    Effectiveness";            (5)   "Attainment    of        Interim    Media    Protection
    Goals"; (6) "Reduction of Toxicity, Mobility, or Volume of Wastes";
    (7)     "Short-Term         Effectiveness";         (8)    "Implementability";             and
    (9) "Cost."          The Consent Decree envisioned a remedy that would be
    "best     suited      to    meet   the   [first      three       criteria]    .   .    .    in
    consideration of the [latter six criteria] . . . including a
    balancing of [the latter six criteria] against one another."3
    3.    The 2016 Permit Issued After Notice and Comment
    In June 2014, after over a decade of further research by
    GE and the EPA, the EPA issued a draft RCRA permit embodying a
    3   The nine Selection Criteria closely resemble analogous
    factors promulgated in the National Contingency Plan that are used
    to select a response action under CERCLA.          See 
    40 C.F.R. § 300.430
    (e)(9)(iii), (f)(1)(i).
    - 9 -
    proposed remedy for the Rest of River.               In conjunction with the
    draft permit, the EPA published a written analysis (the "2014
    Comparative      Analysis")    comparing       various    cleanup      alternatives
    under the nine Selection Criteria and explaining the EPA's basis
    for its proposed choice.            Following a public comment period and
    formal dispute resolution invoked by GE, the EPA issued a final
    permit in October 2016 (the "2016 Permit").
    In designing the 2016 Permit, the EPA faced three major
    issues that are central to this case: (1) how to remediate the PCB
    contamination in the Rest of River, including whether and how to
    remove PCB-contaminated material from that area; (2) whether and
    how to apply treatment technologies to that removed material in
    order to reduce its toxicity and the risk of PCB dispersal; and
    (3) where and how to dispose of the removed material.                      The EPA
    resolved those issues as follows in the 2016 Permit.
    First, as to remediation, the 2016 Permit required GE to
    excavate   and    remove    almost     one   million      cubic   yards    of    PCB-
    contaminated     sediment     and    soil    from   the    Rest   of    River,    its
    floodplain, and certain surrounding areas.                GE would then install
    engineered caps in many of those areas in order to "physically and
    chemically     isolate      the     residual     PCBs     in   [the     remaining]
    sediment[,] . . . provide habitat for aquatic plants and animals[,]
    - 10 -
    and reduce downstream transport of PCBs."4         These removal and
    capping activities -- which generally would aim to reduce the
    average PCB concentrations in remaining sediment to 1.00 ppm in
    most areas -- would occur primarily in the upstream areas of the
    Rest of River, where PCBs are more prevalent; in particular, these
    activities were required in Reaches 5, 6, and 8, and in the
    impoundments of Reach 7.      For the areas further downstream, the
    2016 Permit did not require any removal of sediment or soil;
    rather, it mandated "monitored natural recovery" ("MNR").5          MNR
    relies on natural processes -- rather than active remediation
    measures like removal and capping -- to reduce PCB contamination
    over time.6
    Second, as to treatment of the excavated and removed
    material,     the   EPA   considered   various   forms   of   treatment
    technologies and studied two of them in depth.       One of those two
    4    The 2016 Permit further required the placement of
    backfill material in certain areas following sediment and soil
    removal.
    5    MNR was the selected remedy for the flowing subreaches
    of Reach 7 and for Reaches 9 through 16.
    6    To be precise, the 2016 Permit defined MNR as "a remedy
    for contaminated sediment that typically uses ongoing, naturally
    occurring   processes  to   contain,   destroy,   or  reduce   the
    bioavailability or toxicity of contaminants in sediment, and
    requires monitoring the natural processes and/or concentrations of
    contaminants in surface water, sediment, or biota to see if
    recovery is occurring at the expected rate, and the maintenance of
    institutional controls until the necessary reductions in risk have
    occurred."
    - 11 -
    treatment technologies was thermal desorption, which        "removes
    contaminants [from sediment and soil] by raising the temperature
    of the contaminated material to transfer the contaminants from the
    sediment or soil to a gas stream," which is then separately treated
    and disposed of.7   The EPA ultimately decided not to require any
    treatment of the removed sediment and soil.     The 2016 Permit did,
    however, require GE to use "activated carbon or [an]other sediment
    amendment"8 in certain areas of the Rest of River to reduce the
    toxicity of sediment and soil that would not be removed.
    Finally, as to disposal, the EPA considered whether to
    require fully offsite disposal or fully onsite disposal of the
    removed material.   The EPA did not consider or evaluate any other
    proposal for disposing of untreated material other than fully
    offsite or fully onsite disposal.      Fully offsite disposal "would
    involve the transportation of removed sediment and floodplain soil
    to commercial solid waste and/or TSCA-licensed landfill(s) for
    disposal."   Fully onsite disposal, on the other hand, "would
    7    The other treatment technology considered in depth by
    the EPA was "chemical extraction," which is the "process of mixing
    an extraction fluid/solvent with removed sediment and soil, so
    that PCBs in the sediment or soil are . . . transferred into the
    extraction fluid."
    8    Treatment with activated carbon involves "increasing the
    sediment['s] organic carbon content" in order to "decrease[]
    contaminant bioavailability," which in turn "allow[s] higher
    concentrations of contaminants to remain" in the sediment "without
    adverse biological effects."
    - 12 -
    involve the permanent disposition of the removed sediment/soil at
    an [onsite] [f]acility constructed in close proximity to the
    [r]iver, but outside the 500-year floodplain."9    Comparing these
    two alternatives through the lens of the nine Selection Criteria,
    the EPA found that both options "would provide protection of human
    health and the environment," but ultimately concluded that fully
    offsite disposal was preferable. As between the two, the EPA found
    that fully offsite disposal would best prevent releases of PCBs,
    would be more reliable and effective than fully onsite disposal in
    the long term, and would have various other benefits. Accordingly,
    the 2016 Permit required GE to transport all removed material to
    existing licensed offsite facilities.
    4.   The 2018 EAB Decision
    In November 2016, five parties petitioned the EAB for
    review of the 2016 Permit.   Two of those parties -- GE and a local
    landowner named C. Jeffrey Cook -- argued that the remedy under
    the 2016 Permit was too extensive.      The other three parties --
    HRI, the Berkshire Environmental Action Team, and the Municipal
    Committee -- contended that the cleanup was not extensive enough.
    The Municipal Committee was formed under an intergovernmental
    agreement by five towns in Berkshire County, Massachusetts: Great
    9    The EPA also considered onsite disposal in a "confined
    disposal facility . . . in a local waterbody," but it ultimately
    rejected that alternative, and that alternative is not relevant to
    this case.
    - 13 -
    Barrington, Lee, Lenox, Sheffield, and Stockbridge.             Those five
    towns, as well as the City of Pittsfield, are apparently the
    municipalities most affected by the Rest of River cleanup.
    Several    other   entities    --   including   Massachusetts,
    Connecticut, the City of Pittsfield, and the Massachusetts Audubon
    Society -- participated in the proceedings before the EAB by filing
    either amicus briefs or responses to petitions.
    In January 2018, the EAB, finding legal error in part of
    EPA's selection of the disposal remedy, issued a 152-page opinion
    remanding the 2016 Permit in part and denying review in part.            In
    re Gen. Elec. Co. (Gen. Elec. I), 
    17 E.A.D. 434
     (EAB 2018).             The
    opinion   addressed   challenges,    raised    variously   by    the   five
    petitioners, to all three major aspects of the 2016 Permit:
    remediation, treatment, and disposal.
    As to the remediation of the Rest of River and the
    removal of the PCB-contaminated material from that area, the EAB
    upheld almost all provisions of the 2016 Permit, see 
    id.
     at 487-
    519, 523-58, remanding the permit on only one ground that is not
    relevant here, see 
    id. at 520-23
    .        Of particular relevance to this
    case, the EAB rejected HRI's challenge to the provisions of the
    2016 Permit that selected MNR as the remedy for most of the
    downstream reaches of the Rest of River.        See 
    id. at 536-40
    .      The
    EAB found that HRI had failed to adequately explain why the EPA's
    - 14 -
    selection     of    MNR       for    those   downstream       reaches         was   clearly
    erroneous.        See 
    id.
    The EAB also rejected HRI's argument that the 2016 Permit
    should     have    required         treatment   of   the    excavated         and   removed
    material from the upstream reaches.                  See 
    id. at 577-83
    .              First,
    addressing HRI's assertion that the EPA should have mandated
    thermal     desorption,         the    EAB   found    that        HRI   had    failed    to
    demonstrate that that issue was raised during the public comment
    period.     See 
    id. at 577-81
    .           Next, the EAB rejected HRI's argument
    that the 2016 Permit should have required "bioremediation," see
    
    id. at 581-82
    ,       a    treatment     technology       that      "would      involve
    introducing microorganisms and/or nutrients into the [sediment and
    soil] to increase ongoing biodegradation rates of PCBs."                            Finally,
    the EAB rejected HRI's contention that the 2016 Permit failed to
    comply with CERCLA's preference for treatment, see 
    42 U.S.C. § 9621
    (b)(1) (generally requiring the EPA to "select a remedial
    action . . . that utilizes permanent solutions and alternative
    treatment technologies or resource recovery technologies to the
    maximum    extent     practicable"),         finding       that    no   individual       had
    raised the issue during the public comment period and that the
    argument would fail on substantive grounds in any event, see Gen.
    Elec. I, 17 E.A.D. at 582-83, 583 n.63.
    Highly pertinent to this case, the EAB also addressed
    GE's argument that the EPA erred in selecting                            fully      offsite
    - 15 -
    disposal.    See Gen. Elec. I, 17 E.A.D. at 559-69.              On this issue,
    the EAB remanded the 2016 Permit, finding that the EPA had failed
    to exercise considered judgment.         See id. at 565-69.        The EAB noted
    that the EPA had premised its selection of fully offsite disposal
    largely on the conclusion that a fully onsite disposal facility
    would be unable to satisfy TSCA regulations governing the disposal
    of materials     containing PCBs in concentrations of 50 ppm or
    greater.    See id. at 559, 561-65; 
    40 C.F.R. § 761.75
    .                 The EAB
    held, to the contrary, that the EPA had failed to address GE's
    arguments that an onsite facility could satisfy those regulations
    and could qualify for a waiver of certain TSCA requirements.                  See
    Gen. Elec. I, 17 E.A.D. at 565-69.
    The EAB thus denied HRI's petition in full, including
    its challenges to the 2016 Permit's provisions regarding MNR and
    treatment.10     See id. at 584.        In response to GE's petition, the
    EAB   remanded   the   2016    Permit    for   the    EPA   to   reconsider   the
    "provisions of the [2016] Permit pertaining to" disposal.                Id. at
    584-85.
    5.    The Settlement
    Following the EAB's remand of the permit, the EPA invited
    various    stakeholders   to       participate   in    confidential    mediated
    10  The EAB also denied the petitions of C. Jeffrey Cook,
    the Municipal Committee, and the Berkshire Environmental Action
    Team. See Gen. Elec. I, 17 E.A.D. at 584.
    - 16 -
    discussions to attempt to agree upon a revised remedy.               The EPA
    invited all five petitioners from the prior EAB proceedings –- GE,
    HRI, the Municipal Committee, the Berkshire Environmental Action
    Team, and C. Jeffrey Cook -- as well as HEAL, the State of
    Connecticut,    the   Commonwealth     of   Massachusetts,    the    City   of
    Pittsfield, and the Massachusetts Audubon Society.                  Of these
    parties, all proceeded to participate in mediation except for the
    Petitioners.     HRI attended the discussions initially, but then
    "declined to participate in any discussions or agreement that
    involved onsite disposal and from which the general public was
    excluded."      HEAL, similarly, was unwilling to participate in
    confidential discussions.11
    The mediation ultimately concluded in February 2020 with
    the signing of a settlement agreement (the "Settlement").                   The
    Settlement was signed by almost all of the participants in the
    mediation: the EPA, GE, the Municipal Committee, the Berkshire
    Environmental    Action   Team,   C.    Jeffrey    Cook,     the    State   of
    Connecticut, the City of Pittsfield, and the Massachusetts Audubon
    Society.     The Municipal Committee joined the Settlement through
    the signatures of the chairpersons of each of the five member
    11   The parties to this case disagree on whether HEAL was
    "excluded" from the discussions or, like HRI, voluntarily declined
    to participate. But the Petitioners concede that to the extent
    HEAL was "excluded," that exclusion was due to its unwillingness
    to maintain the confidentiality of the mediation.
    - 17 -
    towns' select boards.          The Commonwealth of Massachusetts did not
    sign the Settlement but also did not oppose it.                 Neither HRI nor
    HEAL signed the Settlement.
    The Settlement required the EPA to propose a revised
    permit, which would be "subject to a regulatory public comment
    process"    and      which      the     signatories       "agree[d]      not     to
    challenge . . . unless it [was] inconsistent with the terms of
    th[e] Settlement."        The revised permit would include revised
    provisions regarding both the remediation of the Rest of River and
    the disposal of removed PCB-contaminated material.
    As to remediation, the revised proposal would require GE
    to excavate and remove an increased amount of contaminated sediment
    and soil from the Rest of River, including from areas not required
    under the 2016 Permit.         In certain areas of the Rest of River, the
    increased sediment removal would reduce PCB contamination to a
    sufficiently low level that capping would no longer be necessary.
    The   revised   proposal       would    also     impose   new   and    additional
    requirements    on   GE   to    remediate       more   than   twenty   additional
    residential properties; remove two dams; conduct a pilot study on
    a revised remedial approach for vernal pools;                    and develop a
    quality-of-life plan addressing various community impacts such as
    noise, air pollution, odor, road use, and public safety.                       Most
    other remedial measures from the 2016 Permit -- including MNR for
    the downstream reaches -- would remain unchanged.
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    Crucially for purposes of this case, as to the disposal
    of excavated and removed material, the Settlement envisioned a new
    approach called "hybrid disposal," which utilized both offsite and
    onsite disposal based on the degree of contamination of the soil
    and sediment removed from the Rest of River.                 Under the hybrid
    disposal approach, floodplain and bank soil with average PCB
    concentrations equal to or exceeding 50 ppm, and sediment with
    average PCB concentrations exceeding 25 ppm, would be transported
    for disposal in a licensed offsite facility.           Floodplain and bank
    soil with average PCB concentrations below 50 ppm, and sediment
    with average PCB concentrations of 25 ppm or lower, would be
    disposed of in an onsite facility with the significant protections
    of a cap, double liner, leachate collection system, groundwater
    monitoring     network,    and   stormwater    management      system.      The
    Settlement further provided that GE would be required to dispose
    of at least 100,000 cubic yards of contaminated material offsite.
    In addition to the provisions regarding the revised
    permit proposal, the Settlement included several other covenants
    between the signatories.         For example, GE "agreed to commence and
    perform     investigation    and    design   work"   on   the    Settlement's
    effective date, with that obligation to "continue unless and until"
    the   EPA   issued   a    revised   permit    with   terms    that   were   not
    "substantially similar" to the agreed-upon proposal.                  GE also
    agreed to make payments and donate land to the City of Pittsfield,
    - 19 -
    the Massachusetts Audubon Society, and the five towns represented
    by     the      Municipal      Committee,    and     agreed     to    make   aesthetic
    improvements to various other properties.                       The EPA agreed to
    "facilitate opportunities for research and testing of innovative
    treatment" for "reducing PCB toxicity and/or concentrations" in
    excavated and removed material.
    6.    The 2020 Permit Issued After Notice and Comment
    In July 2020, the EPA issued a draft revised permit which
    incorporated the terms of the Settlement.                 In conjunction with the
    draft revised permit, the EPA published a written analysis (the
    "2020 Comparative Analysis") comparing the draft revised permit
    with the 2016 Permit under the nine Selection Criteria.
    The    2020    Comparative        Analysis    concluded      that   the
    remedial portions of the draft revised permit outperformed those
    of   the     2016     Permit    because     the    revised    draft    would    include
    significant           new   benefits,       including    increased       removal     of
    contaminated material, reduced need for capping, and enhanced
    habitat restoration. As to disposal, the 2020 Comparative Analysis
    found that hybrid disposal better satisfied the nine Selection
    Criteria than the fully offsite disposal approach embodied in the
    2016     Permit.            Acknowledging      that     fully    offsite       disposal
    outperformed hybrid disposal with respect to some criteria, the
    EPA found that hybrid disposal had various benefits, including
    significantly reduced greenhouse gas emissions from transporting
    - 20 -
    lesser quantities of contaminated material to an offsite facility
    (or multiple offsite facilities if one did not meet the needed
    capacity), decreased number of truck trips and associated injuries
    and   fatalities,    approval   and    cooperation     from   the   affected
    municipalities, and lower cost. With regard to "Overall Protection
    of Human Health and the Environment" (i.e., the first of the
    Selection Criteria), the 2020 Comparative Analysis also noted that
    the hybrid disposal approach was "part of a Settlement . . . that
    includes numerous enhancements to the floodplain and sediment
    remedies, an expedited start to implementation, and community
    coordination and benefits."     Comparing the draft revised permit to
    the 2016 Permit in their totalities, the EPA concluded that the
    "combination"   of   the   updated    remedial      provisions    and    hybrid
    disposal approach in the revised draft permit was "best suited" to
    satisfy the Selection Criteria and "satisfactorily addresse[d] the
    issues raised by the EAB" in its 2018 decision.
    The EPA received public comments on the draft revised
    permit from July to September 2020.           Those comments concerned
    various aspects of the revised draft, including its provisions
    concerning   MNR,    treatment,      and   hybrid     disposal.         Several
    commenters also raised questions about the mediations that had
    produced the Settlement.        In December 2020, the EPA issued a
    lengthy document responding to the various comments.             Although the
    EPA declined to adopt most of the commenters' suggestions, it did
    - 21 -
    agree to make several minor changes to the permit and summarized
    those changes in an attachment to the document.
    Having considered the comments and the record, the EPA
    issued a final permit in December 2020 (the        "2020 Permit"),
    incorporating all major terms of the Settlement.    The 2020 Permit
    requires GE to remove over 1.1 million cubic yards of contaminated
    material from the Rest of River, its floodplain, and certain
    surrounding areas -- an increase of more than 14 percent from the
    2016 Permit.   The 2020 Permit also decreases reliance on capping.12
    Like the 2016 Permit, the 2020 Permit requires MNR -- rather than
    excavation and removal -- for downstream reaches of the Rest of
    River. Also like the 2016 Permit, the 2020 Permit does not require
    any treatment of removed material prior to disposal, but does
    require the application of activated carbon or another sediment
    amendment in certain areas of the Rest of River.
    With respect to disposal, the 2020 Permit incorporates
    the hybrid disposal approach articulated in the Settlement, such
    that excavated materials with higher levels of PCB contamination
    will be transported offsite, while less-contaminated materials
    will be sent to an onsite facility.      The 2020 Permit concludes
    12   Like the 2016 Permit, the 2020 Permit also requires the
    placement of backfill material in certain areas. The 2020 Permit
    reduces the amount of capping, backfill, and stabilization
    material by more than 150,000 cubic yards compared to the 2016
    Permit.
    - 22 -
    that the onsite facility will "not pose an unreasonable risk of
    injury to health or the environment," thus entitling GE to a waiver
    of TSCA's requirements for the disposal of PCB remediation waste
    with PCB concentrations under 50 ppm.         
    40 C.F.R. § 761.61
    (c)(2).
    The facility will be located in a former gravel mining pit near
    Woods Pond, a small portion of a much greater area that has been
    designated by Massachusetts regulation as an "Area of Critical
    Environmental Concern" (an "ACEC").           See 310 Mass. Code Regs.
    § 16.40(4)(d).   This Massachusetts regulation would, unless waived
    by the EPA, prevent the siting of a solid waste management facility
    within an ACEC, see id. § 16.40(4)(d)(1), but the 2020 Permit finds
    that even if the regulation is an ARAR, it can be waived under
    CERCLA because "compliance [with the regulation] . . . will result
    in   greater   risk   to    human   health   and   the   environment   than
    alternative options," 
    42 U.S.C. § 9621
    (d)(4)(B).
    7.    The 2022 EAB Decision
    In early 2021, the Petitioners petitioned the EAB for
    review of the 2020 Permit.      The Petitioners challenged two aspects
    of the 2020 Permit that were unchanged from the 2016 Permit and
    that had been upheld by the EAB in 2018: first, the EPA's selection
    of MNR (rather than excavation and removal) for downstream reaches
    of the Rest of River, and second, the EPA's decision not to require
    treatment of excavated material prior to disposal. The Petitioners
    further challenged the 2020 Permit's hybrid disposal provisions,
    - 23 -
    arguing that the EPA had reversed course and that that alleged
    reversal of course was unlawfully based on the Settlement rather
    than on a reasoned comparison of the disposal options.
    In February 2022, the EAB issued a 103-page opinion
    upholding the 2020 Permit in full.        In re Gen. Elec. Co. (Gen.
    Elec. II), 
    18 E.A.D. 575
     (EAB 2022).               The EAB rejected the
    Petitioners' various challenges to the EPA's overall conclusions
    as to MNR, treatment, and hybrid disposal.
    As   to   MNR   and   treatment,   the    EAB   held    that   the
    Petitioners' arguments were not within the EAB's scope of review,
    because the EAB had already upheld the MNR and treatment provisions
    in the 2016 Permit and those provisions had remained unchanged in
    the 2020 Permit.    See 
    id. at 663-77
    .       The EAB further concluded
    that even if it were to consider the Petitioners' new arguments as
    to MNR, those arguments would fail on the merits.13              See 
    id. at 674-77
    .
    As to hybrid disposal, the EAB rejected the Petitioners'
    claims that the EPA had reversed its position from the 2016 Permit,
    finding instead that the EPA had analyzed a new disposal option
    with different environmental implications.           See 
    id. at 619-63
    .
    13   Although the EAB did not, in its 2022 decision, discuss
    the merits of the Petitioners' arguments concerning treatment,
    those arguments were substantively the same as the ones the
    Petitioners had unsuccessfully advanced when challenging the 2016
    Permit.
    - 24 -
    The EAB further upheld the EPA's decision to waive Massachusetts'
    ACEC regulation under CERCLA, see 
    id. at 635-48
    , and rejected the
    Petitioners'   contention   that   the    Settlement    had   improperly
    influenced the EPA's remedy-selection process, see 
    id. at 652-61
    .
    Having been upheld by the EAB, the 2020 Permit became
    effective in March 2022.    We turn to the Petitioners' challenges,
    both procedural and substantive, to the 2020 Permit.
    II.   Constitutional Standing
    The EPA's issuance of a RCRA permit may be challenged by
    "any interested person."    
    42 U.S.C. § 6976
    (b).       The EPA does not
    dispute that the Petitioners are "interested person[s]" having a
    right to appeal the 2020 Permit.      The EPA does contend, however,
    that the Petitioners lack constitutional standing to challenge the
    2020 Permit.   This argument fails.
    Because   the Petitioners      are associations, they must
    demonstrate their "standing to bring suit on behalf of [their]
    members" by showing that (1) "[their] members would otherwise have
    standing to sue in their own right"; (2) "the interests [they]
    seek[] to protect are germane to the organization[s'] purpose[s]";
    and (3) "neither the claim asserted nor the relief requested
    requires the participation of individual members in the lawsuit."
    Hunt v. Wash. State Apple Advert. Comm'n, 
    432 U.S. 333
    , 343 (1977).
    The first two prongs of this test have constitutional dimensions;
    the third prong is prudential.      See United Food & Com. Workers
    - 25 -
    Union Loc. 751 v. Brown Grp., Inc., 
    517 U.S. 544
    , 554-58 (1996);
    see also Back Beach Neighbors Comm. v. Town of Rockport, 
    63 F.4th 126
    , 129 n.2 (1st Cir. 2023).           The Petitioners have each satisfied
    all three requirements.
    First, each association has adequately shown that "at
    least    one    of    its    members   would   have   standing   to   sue   as   an
    individual."         Animal Welfare Inst. v. Martin, 
    623 F.3d 19
    , 25 (1st
    Cir. 2010); see Draper v. Healey, 
    827 F.3d 1
    , 3 (1st Cir. 2016)
    (noting that "the association must, at the very least, 'identify
    [a] member[] who ha[s] suffered the requisite harm.'" (alterations
    in original) (quoting Summers v. Earth Island Inst., 
    555 U.S. 488
    ,
    499 (2009))).         Both HRI and HEAL identified at least one member
    who     "suffered       an    injury    in     fact   that   [was]     concrete,
    particularized, and actual or imminent," "likely caused by the
    defendant," and "likely [to] be redressed by judicial relief."
    Plazzi v. FedEx Ground Package Sys., Inc., 
    52 F.4th 1
    , 4 (1st Cir.
    2022) (quoting TransUnion LLC v. Ramirez, 
    141 S. Ct. 2190
    , 2203
    (2021)).       For example, affidavits submitted by the Petitioners
    identify members who live near the proposed onsite disposal site,
    use that area for recreation and/or commerce, and fear that the
    disposal facility will negatively impact their use and enjoyment
    of the area and their property values.                Those imminent injuries
    plainly constitute injuries in fact, see Friends of the Earth,
    Inc. v. Laidlaw Env't Servs. (TOC), Inc., 
    528 U.S. 167
    , 183 (2000)
    - 26 -
    ("[E]nvironmental plaintiffs adequately allege injury in fact when
    they aver that they use the affected area and are persons 'for
    whom the aesthetic and recreational values of the area will be
    lessened' by the challenged activity." (quoting Sierra Club v.
    Morton, 
    405 U.S. 727
    , 735 (1972))); Kathrein v. City of Evanston,
    
    636 F.3d 906
    , 914 (7th Cir. 2011) ("A demonstrable reduction in
    the market value of one's property is an injury in fact for
    standing purposes."), are caused by the EPA's approval of the
    onsite disposal facility, and would be redressed by the requested
    reversal of that approval.
    Second, the "interests at stake are germane to the
    [Petitioners'] purpose[s]."   Animal Welfare Inst., 
    623 F.3d at 25
    (quoting Friends of the Earth, 
    528 U.S. at 181
    ).    HRI was "formed
    with the specific mission of cleaning the Housatonic River and
    surrounding sites of PCB[s] and other chemical contamination."
    HEAL, in turn, is "dedicated to the protection of the Housatonic
    River and its watershed" and "ultimate[ly] [aims for] a swimmable
    and fishable river in both Massachusetts and Connecticut."         The
    "interests at stake" in this litigation are clearly "related to
    the [Petitioners'] core purposes."   Mallinckrodt, 
    471 F.3d at 283
    .
    Finally,   "individual   members'   participation   is   not
    necessary to either the claim asserted or the relief requested."
    Animal Welfare Ins., 
    623 F.3d at 25
    .     The Petitioners ask us to
    vacate the EPA's approval of the 2020 Permit and to order the EPA
    - 27 -
    to consider changing several permit provisions on remand.                That
    requested "prospective relief" would "inure to the benefit of those
    members   of   the    [Petitioners]   actually     injured,"    supporting   a
    finding of associational standing.          Warth v. Seldin, 
    422 U.S. 490
    ,
    515 (1975); see Playboy Enters., Inc. v. Pub. Serv. Comm'n of P.R.,
    
    906 F.2d 25
    , 35-36 (1st Cir. 1990).
    The       Petitioners   thus     have    satisfied     all   three
    requirements of associational standing.14 We now turn to the merits
    of the Petitioners' procedural and substantive challenges.
    III.   Procedural Challenge Regarding the Mediation Process
    We first address the Petitioners' procedural challenge
    to the 2020 Permit.          See 
    5 U.S.C. § 706
    (2)(D) (requiring a
    reviewing court to set aside any agency action made "without
    observance of procedure required by law").          The Petitioners do not
    dispute that the EPA satisfied RCRA's requirements concerning
    public notice and comment, see 
    40 C.F.R. § 124.10
    ; rather, they
    contend that the mediation process, which took place from 2018 to
    2020 and ultimately produced the Settlement, improperly influenced
    14   The EPA argues that because the "Petitioners' brief
    contains no discussion of their standing . . . [the] Petitioners
    have not met their burden to establish standing."     But no such
    requirement of explicitly proclaiming to have standing exists.
    See Fed. R. App. P. 28 (listing requirements for appellate briefs,
    but not requiring any express statement of standing).      Rather,
    parties seeking to avail themselves of the federal courts simply
    must plead "facts demonstrating standing," Animal Welfare Inst.,
    
    623 F.3d at 25
    , and the Petitioners have done so.
    - 28 -
    the remedy selection process and rendered the notice-and-comment
    process a "façade."        They argue that the EPA was required to allow
    public access to the mediation and maintain an administrative
    record of the negotiations, and that its failure to do so violated
    the   Consent    Decree,       CERCLA,    and     the   Administrative        Procedure
    Act ("APA"), 
    5 U.S.C. § 551
     et seq.
    We first reject out of hand the Petitioners' argument
    that the Consent Decree requires notice and comment prior to
    mediation and provides that mediation must occur on the record.
    This argument misconstrues the Consent Decree, which in fact
    requires only that the draft permit for the Rest of River cleanup
    be    subject    to     RCRA    regulations,        "including     the    provisions
    requiring public notice and an opportunity for public comment,"
    and provides that after the public comment period, GE may invoke
    an "administrative dispute resolution" process that must be on the
    record.   Outside of that formal dispute resolution process, which
    is not at issue here, the Consent Decree contains no requirement
    of    public    input    prior     to     mediation      or   of   maintaining      an
    administrative record of negotiations.                    On the contrary, the
    Consent   Decree      provides     that     any     "participants        in   mediated
    discussions . . . shall execute a confidentiality agreement."
    The Petitioners' invocations of CERCLA are similarly
    unavailing.      The Petitioners correctly note that CERCLA requires
    the EPA to "[p]rovide a reasonable opportunity" for public comment
    - 29 -
    "[b]efore adoption of any plan for remedial action."     
    42 U.S.C. § 9617
    (a)(2).   But the notice-and-comment period here did take
    place before the issuance of the 2020 Permit, and the Petitioners
    identify no provision in CERCLA prohibiting the EPA from engaging
    in mediation to investigate potential remedies.   In fact, "early
    settlement[]" of the liability of potentially responsible parties
    "is an integral part of the statutory plan" under CERCLA.   Emhart,
    988 F.3d at 517 (alteration in original) (quoting United States v.
    Cannons Eng'g Corp., 
    899 F.2d 79
    , 92 (1st Cir. 1990)).
    Beyond these narrow arguments concerning the Consent
    Decree and CERCLA, the Petitioners contend more broadly that an
    agency should not be permitted to use mediation to help determine
    what provisions to include in a draft permit, particularly when
    that mediation is off the record and closed to the public.    This
    argument fails to account for the Supreme Court's consistent
    statements that "[b]eyond the APA's minimum requirements, courts
    lack authority 'to impose upon [an] agency [their] own notion of
    which procedures are "best" or most likely to further some vague,
    undefined public good.'"   Perez v. Mortg. Bankers Ass'n, 
    575 U.S. 92
    , 102 (2015) (second alteration in original) (quoting Vt. Yankee
    Nuclear Power Corp. v. Nat. Res. Def. Council, Inc., 
    435 U.S. 519
    ,
    549 (1978)); see Vt. Yankee, 
    435 U.S. at 524
     ("Agencies are free
    to grant additional procedural rights in the exercise of their
    discretion, but reviewing courts are generally not free to impose
    - 30 -
    them if the agencies have not chosen to grant them.").              And nothing
    in the APA prohibits mediation prior to issuing a draft permit,
    requires any such mediation to be on the record, or provides for
    public access to such mediation.           See, e.g., N.Y. State Dep't of
    L. v. FCC, 
    984 F.2d 1209
    , 1218-19 (D.C. Cir. 1993) (rejecting
    petitioner's       argument   that   the   APA   "single[s]   out   settlement
    discussions and related proposals as requiring public disclosure
    and opportunity for comment and/or involvement" and noting that
    even in the context of formal adjudications, "informal settlement"
    is "authorized . . . before undertaking the more formal hearing
    procedure" (alteration in original) (quoting S. Doc. No. 248, at
    24 (1945))).15      We thus conclude that no procedural violation has
    occurred.    Cf. City of Taunton v. EPA, 
    895 F.3d 120
    , 132 (1st Cir.
    2018) (rejecting petitioner's argument that the "EPA repeatedly
    stymied     [the    petitioner's]     access     to   the   [EPA]'s    .   .   .
    15   The Petitioners cite Home Box Office, Inc. v. FCC, 
    567 F.2d 9
     (D.C. Cir. 1977), for the proposition that "the public
    record must reflect what representations were made to an agency"
    and that "communications [cannot be] made to [an] agency in
    secret."    
    Id. at 54
    .       But that case involved ex parte
    communications made to an agency after it proposed a rulemaking,
    see 
    id. at 51-53
    , and the D.C. Circuit specifically stated that
    "communications which are received prior to" such a proposal "do
    not, in general, have to be put in a public file," 
    id. at 57
    (emphasis added). And in any event, the holding of Home Box Office
    has since been limited to ex parte communications occurring in
    rulemaking proceedings that involve "competing claims to a
    valuable privilege." Action for Child.'s Television v. FCC, 
    564 F.2d 458
    , 477 (D.C. Cir. 1977) (citing Home Box Off., 
    567 F.2d at 61
     (MacKinnon, J., concurring specially)).
    - 31 -
    documentation" because the petitioner did "not argue that the EPA
    ran afoul of any applicable legal requirement"); 
    id.
     ("[B]ecause
    the [petitioner] fails to show that it was procedurally entitled
    to anything more than what the EPA afforded it, we do not find the
    EPA's    actions       in    this    respect     to   have   been   arbitrary      or
    capricious.").
    Nor is there any purchase to the Petitioners' argument
    that    the   Settlement      rendered     the    notice-and-comment      period    a
    "façade."     Importantly, as the Petitioners concede, the Settlement
    did not legally constrain the EPA in deciding what provisions to
    include in the final permit.               Compare Nat. Res. Def. Council,
    Inc. v. U.S. EPA, 
    859 F.2d 156
    , 194 (D.C. Cir. 1988) (discussing
    a settlement in which the EPA "bound itself only to propose
    regulations," but "never bound itself as to the content of the
    final regulations," thus ameliorating concerns about whether the
    EPA    had    a    "mind[]    open    to   whatever     insights    the   comments
    produced"), with Nat'l Audubon Soc., Inc. v. Watt, 
    678 F.2d 299
    ,
    311 (D.C. Cir. 1982) (declining to consider whether the "government
    may enter into judicially enforceable contracts relinquishing or
    limiting its policymaking discretion").                  On the contrary, the
    Settlement expressly provided that the proposed remedy would be
    "subject      to   a   regulatory      public     comment    process,"    and   the
    signatories reserved the right to challenge the final permit if it
    was "inconsistent with the terms of th[e] Settlement."                    Following
    - 32 -
    the issuance of the draft permit in July 2020, the EPA conducted
    a 67-day public comment period and then made various changes to
    the permit based on the comments.          The EPA also responded to the
    comments, articulating its rationales for either implementing or
    declining to implement the commenters' suggestions.           Notably, GE
    filed a comment requesting revisions to portions of the draft
    permit that GE believed were inconsistent with the Settlement, but
    the EPA declined to incorporate various of those revisions.
    The Petitioners offer no evidence that the EPA did not
    follow proper procedures in considering the commenters' various
    suggestions and selecting which ones to incorporate into the final
    permit.      Cf. U.S. Postal Serv. v. Gregory, 
    534 U.S. 1
    , 10 (2001)
    (noting that courts attach a "presumption of regularity . . . to
    the     actions   of   [g]overnment   agencies"    when   evaluating   the
    "fairness of [those agencies'] own procedure[s]").          And the fact
    that the 2020 Permit ultimately included the same major provisions
    as the draft permit does not support a finding that the 2020 Permit
    should be set aside.       See Biden v. Texas, 
    142 S. Ct. 2528
    , 2547
    (2022) (rejecting "criticisms of agency closemindedness based on
    an identity between proposed and final agency action").           We thus
    see no reason to conclude that the Settlement rendered the notice-
    and-comment process a "façade."16          Our conclusion is consistent
    16      Contrary to the Petitioners' intimations, GE's agreement
    under      the Settlement to make payments, donations, and other
    - 33 -
    with cases confronting agency settlement agreements in roughly
    similar contexts.      See Citizens for a Better Env't v. Gorsuch, 
    718 F.2d 1117
    ,   1120-21,      1127-30      (D.C.    Cir.    1983)   (upholding   a
    settlement      in   which    the    EPA    agreed    to    promulgate   certain
    regulations, where the settlement "did not specify the substantive
    result of any regulations [the] EPA was to propose and only
    required [the] EPA to initiate 'regulatory action'" subject to
    "full notice and comment"); Save Our Sound OBX, Inc. v. N.C. Dep't
    of   Transp.,    
    914 F.3d 213
    ,    226    (4th    Cir.   2019)   (upholding   a
    settlement that required an agency to identify a course of action
    as the "preferred alternative" but did not require selecting that
    action as the "final approved alternative").17
    concessions to several other stakeholders does not compel such a
    conclusion. Those covenants of the Settlement -- which largely
    concerned funding for economic development and aesthetic and
    recreational improvements -- ran solely between GE and the City of
    Pittsfield, the Massachusetts Audubon Society, and the five towns
    comprising the Municipal Committee. They were not embodied in the
    draft permit or the 2020 Permit, and no payments were made to the
    EPA. The Petitioners offer no reason to believe that the payments
    influenced the EPA's decisionmaking.
    17 In support of their argument that the EPA predetermined
    the provisions of the 2020 Permit based on the Settlement, the
    Petitioners cite two cases involving the disqualification of an
    agency commissioner due to that commissioner's prejudging the
    outcome of a formal administrative hearing. See Cinderella Career
    and Finishing Schs., Inc. v. FTC, 
    425 F.2d 583
    , 589-92 (D.C. Cir.
    1970); Texaco, Inc. v. FTC, 
    336 F.2d 754
    , 759-60 (D.C. Cir. 1964),
    vacated on other grounds, 
    381 U.S. 739
     (1965). Those cases' facts
    bear little resemblance to the development of the 2020 Permit,
    which was subject to public notice and comment. See Ass'n of Nat'l
    Advertisers, Inc. v. FTC, 
    627 F.2d 1151
    , 1161 (D.C. Cir. 1979)
    (limiting the application of Cinderella and Texaco to formal
    "adjudication or quasi-adjudication").     Further, the Settlement
    - 34 -
    Accordingly,      we    conclude        that    the     mediation   and
    resulting Settlement were procedurally sound.                    The EPA invited to
    the mediation all of the parties that had challenged the 2016
    Permit     --   GE,   HRI,   the   Municipal        Committee,      the   Berkshire
    Environmental Action Team, and C. Jeffrey Cook -- as well as
    Connecticut,      Massachusetts,      the      City        of     Pittsfield,   the
    Massachusetts Audubon Society, and HEAL.                        The mediation thus
    benefited from the interplay of the various and competing interests
    of environmentalists; landowners; industry representatives; and
    local, state, and federal government entities.                    And the mediation
    resulted in an agreement that was acceptable to all involved
    parties except for the Petitioners.18                 Our "[r]espect for the
    [EPA]'s role is heightened in this situation" because a "crew of
    sophisticated players, with sharply conflicting interests, s[a]t
    at the table" and "hammered out an agreement at arm's length."
    Cannons Eng'g Corp., 899 F.2d at 84.                It bears emphasizing that
    the   Municipal       Committee    joined     the    Settlement       through   the
    signatures of the elected chairpersons of each of the five member
    towns' select boards.        To the extent the Petitioners argue -- as
    here concerned only the EPA's proposed remedy, not the final
    permit. Cf. id. at 1173 ("The period before the [agency] first
    decides to take action on a perceived problem is . . . the best
    time for a rulemaker to engage in dialogue with concerned
    citizens.").
    18  Although Massachusetts did not sign the Settlement, it
    did not object to it or to the 2020 Permit.
    - 35 -
    their counsel did at oral argument -- that the Municipal Committee
    did not speak for "the people" when signing the Settlement, that
    rhetorical flourish presents no argument to this court.
    IV.   Substantive Challenges to the 2020 Permit
    We    now   turn   to   the    Petitioners'    three    substantive
    challenges to the 2020 Permit.            First, the Petitioners challenge
    the EPA's decision to require MNR -- rather than excavation and
    removal of contaminated sediment -- as the remedy for certain
    downstream reaches of the Rest of River.           Second, the Petitioners
    contend that the EPA should have required GE to treat excavated
    and   removed       material       with     thermal      desorption        and/or
    bioremediation.        Finally,    the    Petitioners    challenge    the    2020
    Permit's   hybrid      disposal    approach,    arguing     that     the    EPA's
    selection of hybrid disposal constituted an arbitrary reversal of
    its previous choice to mandate fully offsite disposal in the 2016
    Permit.
    Under the APA, we will set aside the EPA's actions only
    if they were "arbitrary, capricious, an abuse of discretion, or
    otherwise not in accordance with law."           
    5 U.S.C. § 706
    (2)(A).         We
    leave agency actions undisturbed unless
    the agency has relied on factors which
    Congress has not intended it to consider,
    entirely failed to consider an important
    aspect of the problem, offered an explanation
    for its decision that runs counter to the
    evidence before the agency, or is so
    implausible that it could not be ascribed to
    - 36 -
    a difference in view or the product of agency
    expertise.
    Motor Vehicle Mfrs. Ass'n v. State Farm Mut. Auto. Ins. Co., 
    463 U.S. 29
    , 43 (1983).           "This deference goes to the entire agency
    action, which here includes both the EPA's permitting decision and
    the   EAB's    review   and    affirmance    of   that   decision."19     Upper
    Blackstone Water Pollution Abatement Dist. v. U.S. EPA, 
    690 F.3d 9
    , 20 (1st Cir. 2012).         And "the 'scientific and technical nature
    of the EPA's decisionmaking' increases our level of deference."
    City of Taunton, 
    895 F.3d at 126
     (quoting Upper Blackstone, 
    690 F.3d at 20
    ).
    An agency may change its existing position on an issue
    "as long as [it] provide[s] a reasoned explanation for the change."
    Encino Motorcars, LLC v. Navarro, 
    579 U.S. 211
    , 221 (2016).                That
    requirement     "ordinarily      demand[s]    that   [the    agency]    display
    awareness that it is changing position," FCC v. Fox Television
    Stations, Inc., 
    556 U.S. 502
    , 515 (2009), but does not constitute
    a "heightened standard" of review, 
    id. at 514
    .              The agency "need
    not demonstrate . . . that the reasons for the new policy are
    19  Because no final agency action occurred until after the
    EAB upheld the 2020 Permit, the Petitioners could not directly
    appeal the EAB's 2018 decision.      See 
    40 C.F.R. § 124.19
    (l)(2)
    (specifying that final agency action does not occur when the EAB
    remands a permit, but rather only occurs once the EAB denies review
    or once remand proceedings are completed).        Our review thus
    encompasses the pertinent holdings of both the 2018 and 2022 EAB
    decisions, as well as the EPA's other actions.
    - 37 -
    better than the reasons for the old one; it suffices that the new
    policy is permissible . . ., that there are good reasons for it,
    and that the agency believes it to be better."                    
    Id. at 515
    .         A
    "more detailed justification" may be required, however, when the
    agency's new position "rests upon factual findings that contradict
    those which underlay [the] prior" position or when the agency's
    prior position "has engendered serious reliance interests."                        Id.;
    see NLRB v. Lily Transp. Corp., 
    853 F.3d 31
    , 36 (1st Cir. 2017)
    (Souter, J.) ("[A]n about-face . . . owing to facts changed from
    those underlying the prior view requires that the new facts be
    addressed explicitly by reasoned explanation for the change of
    direction.").         Further,      "when    an    agency     rescinds        a   prior
    [position,]      its     reasoned          analysis      must         consider      the
    'alternative[s]'       that   are   'within       the   ambit    of     the   existing
    [position].'"     DHS v. Regents of the Univ. of Cal., 
    140 S. Ct. 1891
    , 1913 (2020) (second alteration in original) (quoting State
    Farm, 
    463 U.S. at 51
    ).
    We    now    consider      the    Petitioners'        three    substantive
    challenges in turn.
    A. Challenge to the 2020 Permit's
    Monitored Natural Recovery (MNR) Provisions
    As     to     the    2020        Permit's     provisions        concerning
    remediation,    the    Petitioners     challenge        the   EPA's      decision    to
    require MNR -- rather than excavation, removal, and capping -- for
    - 38 -
    the downstream reaches of the Rest of River.                 The 2020 Permit's
    applicable provisions concerning MNR are unchanged from those in
    the 2016 Permit; both permits included MNR as the remedy for the
    flowing subreaches of Reach 7 and for Reaches 9 through 16.
    In its response to comments on the draft version of the
    2016 Permit, the EPA explained its rationale for selecting MNR as
    the remedy for the downstream reaches.               The EPA noted that "PCB
    concentrations in these . . . reaches are low and . . . diffuse
    over    large   areas";    that   the     sediment    in   these   reaches   "is
    reasonably stable"; that "[h]uman health and ecological risks" in
    these reaches "are generally low"; and that "decreasing trends in
    fish and benthic invertebrate PCB levels . . . have been observed"
    in Reaches 9 through 16.        The EPA concluded that MNR, coupled with
    "[l]ong-term     monitoring,"     was     an   appropriate    remedy   for   the
    downstream reaches. The EPA also noted two examples of sites where
    MNR had been used to remedy PCB contamination.               See, e.g., United
    States v. P.H. Glatfelter Co., 
    768 F.3d 662
    , 666-67 (7th Cir. 2014)
    (discussing one of these sites).
    Notwithstanding this explanation provided by the EPA,
    the Petitioners now raise four challenges to the 2020 Permit's MNR
    provisions.     They rely on their own purported characterizations of
    the 2020 Permit to assert that (1) insufficient data concerning
    PCB    concentrations     in   sediment    existed    to   support   the   EPA's
    selection of MNR; (2) the EPA's failure to set a performance
    - 39 -
    standard for PCB concentrations in sediment renders the MNR remedy
    ineffectual; (3) the 2020 Permit lacks a reasonable timeframe in
    which cleanup standards in the downstream reaches must be attained;
    and (4) the 2020 Permit fails to articulate a contingency plan
    should MNR fail to achieve adequate remediation.
    At the outset, the EPA contends that the Petitioners
    waived these arguments by failing to demonstrate that the arguments
    were raised during the public comment period for the draft version
    of the 2016 Permit, and/or failing to raise them to the EAB when
    challenging the 2016 Permit.     See Upper Blackstone, 
    690 F.3d at 30
    (finding that a petitioner waived an argument "by failing to
    present it either to the EPA . . . during the permitting process
    or during the initial round of briefing before the EAB").          As the
    EPA   largely   concedes,    however,     the   Petitioners   raised   the
    arguments when challenging the 2020 Permit, both in their public
    comments and to the EAB.20    The EPA's waiver argument thus depends
    on the proposition that the Petitioners' raising the MNR arguments
    when challenging the 2020 Permit was insufficient to preserve those
    20  The EPA does contend that the Petitioners forfeited
    their argument concerning inadequate data, asserting that the
    Petitioners did not raise that argument until their reply brief to
    the EAB. We disagree. In their initial brief to the EAB when
    challenging the 2020 Permit, the Petitioners argued that "[i]n
    Connecticut, PCB sampling has been limited and scattershot," with
    "only 60 individual samples . . . taken" since the Consent Decree
    was entered. That statement sufficiently raised the issue to the
    EAB.
    - 40 -
    arguments here.     Although the EAB found that "[t]he scope of [the
    EAB's] review of a revised permit following remand is limited to
    the issues the [EAB] remanded and any other changes to the permit
    made during the remand period," Gen. Elec. II, 18 E.A.D. at 664,
    we note that the EPA's regulations do not unambiguously support
    this finding, see 
    40 C.F.R. § 124.13
     (requiring commenters to
    "raise all reasonably ascertainable issues . . . by the close of
    the public comment period").     Given this ambiguity, we choose to
    bypass the waiver issue and instead resolve the merits of the
    Petitioners' arguments, which we may do because those arguments
    fail.   We now address, and reject, each of the Petitioners' four
    arguments in turn.
    1.   Challenge Regarding Adequacy of Baseline Data
    The Petitioners first argue that the EPA analyzed an
    insufficient amount of baseline data from the Connecticut reaches
    of the Rest of River to support its selection of MNR as the remedy
    for those reaches.       They contend that the 2020 Permit's MNR
    provisions   thus     violate   the   National   Contingency   Plan's
    requirement that the EPA "collect data necessary to adequately
    characterize the site for the purpose of developing and evaluating
    effective remedial alternatives."     
    40 C.F.R. § 300.430
    (d)(1).
    As the EPA explained in its response to comments on the
    draft version of the 2016 Permit, and as the Petitioners concede,
    the EPA analyzed data from 540 sediment samples in Connecticut
    - 41 -
    from 1980 through 2005.      The average PCB concentration was 0.79
    ppm in samples collected prior to 1998 and 0.18 ppm in samples
    collected in 1998 or later. PCB concentrations in surface sediment
    were even lower.   Those concentrations were already well below the
    1.00 ppm performance standard that the 2020 Permit sets for
    sediment in most upstream reaches where excavation and removal
    will   occur,   supporting     the   EPA's   conclusion   that   "PCB
    concentrations are relatively very low (or not detected) and more
    widely dispersed" in Connecticut and thus that MNR is appropriate
    for those reaches.     Notably, the Petitioners do not challenge the
    1.00 ppm performance standard for the upstream reaches in this
    appeal.   Cf. Upper Blackstone, 
    690 F.3d at 28-29
     (noting that when
    an agency "set[s] a numerical standard, courts will not overturn
    the agency's choice of a precise figure where it falls within a
    'zone of reasonableness'" (quoting Nat'l Mar. Safety Ass'n v. OSHA,
    
    649 F.3d 743
    , 752 (D.C. Cir. 2011))).
    The Petitioners contend that the EPA's reliance on the
    Connecticut sediment samples is "unreasonable and scientifically
    invalid" because the samples are outdated and "extremely limited."
    This argument fails.      "Our standard of review . . . does not
    deputize us to second-guess the EPA's choice of data, so long as
    the agency acts 'with a reasonable basis' in selecting and applying
    it."   City of Taunton, 
    895 F.3d at 139
     (quoting Upper Blackstone,
    
    690 F.3d at 26
    ).     The Petitioners offer no persuasive explanation
    - 42 -
    for why the 540 existing sediment samples are unreliable, and do
    not    identify     any   convincing       reason    to     believe     that   PCB
    concentrations in the Connecticut reaches have increased since
    those samples were taken.            We have rejected similar arguments
    concerning    the   EPA's   choice    of    data    in    the   past.    See   
    id.
    (rejecting petitioner's "challenge[] [to]                 the facial validity
    of . . . data [relied upon by the EPA]" based on "the time that
    had elapsed since its collection," because the EPA "had good reason
    for relying on the . . . data, which drew from 22 different
    monitoring stations"); Sur Contra La Contaminación v. EPA, 
    202 F.3d 443
    , 449 (1st Cir. 2000) (rejecting petitioner's contention
    that "the EPA relied on outdated" data and "should have relied on
    more recent data," because the EPA adequately explained that it
    had "no reason to question the continuing validity" of the data
    (internal quotation marks omitted)).
    2.   Challenge Regarding Adequacy of Performance Standards
    Next, the Petitioners assert that the EPA was required
    to set a performance standard for PCB concentration to be achieved
    in sediment in the downstream reaches where MNR is the selected
    remedy.     As previously noted, the 2020 Permit sets a sediment
    performance standard of 1.00 ppm in most of the upstream reaches
    subject to excavation and removal, but because the data sampled
    from downstream reaches demonstrated that PCB concentrations in
    sediment are already below that level, the EPA elected not to
    - 43 -
    require a sediment performance standard in those reaches.                   The
    Petitioners argue that this decision was contrary to the Consent
    Decree,    which   requires   GE   to    achieve      certain   "[p]erformance
    [s]tandards" in the Rest of River, and to CERCLA, which requires
    remedial actions to       "attain a degree of cleanup,"             
    42 U.S.C. § 9621
    (d)(1).
    Although the 2020 Permit does not include a sediment
    performance standard for the downstream reaches subject to MNR, it
    does include two other performance standards applicable to those
    reaches.    First, the 2020 Permit includes a "Downstream Transport
    Performance   Standard"    setting      limits   on    the   amounts   of   PCBs
    crossing certain monitoring areas.           One of those monitoring areas
    is downstream from the flowing subreaches of Reach 7, meaning that
    the   Downstream    Transport      Performance     Standard     measures    PCB
    migration from those subreaches (which are subject to MNR) as well
    as all other upstream reaches.
    Second, and more importantly, the 2020 Permit includes
    a "Short-Term Biota Performance Standard" requiring the cleanup to
    achieve a PCB concentration of 1.50 ppm in "fish fillet" in all
    reaches of the Rest of River, including those subject to MNR.                The
    EPA's decision to select this fish tissue performance standard
    rather than a sediment performance standard is consistent with
    human health risk assessments conducted by the agency, which
    revealed that consumption of fish from the Rest of River would
    - 44 -
    pose both cancer and non-cancer risks outside of an acceptable
    range,     whereas   direct    contact    with     sediment   did    not      pose
    unacceptable cancer risks and posed lesser non-cancer risks than
    fish consumption.      Further, the EPA used a computerized food chain
    model to analyze the connection between PCB concentrations in
    sediment and fish tissue, and the Petitioners do not meaningfully
    contest the validity of that model.               Cf. Upper Blackstone, 
    690 F.3d at 27
     ("The EPA is not limited to models which perfectly
    replicate real world conditions."). It is true, as the Petitioners
    emphasize, that the 2020 Permit defines MNR as a "remedy for
    contaminated sediment," but the 2020 Permit then states that MNR
    "requires monitoring the natural processes and/or concentrations
    of contaminants in surface water, sediment, or biota."               (Emphasis
    added).    The EPA's decision to monitor fish tissue as a proxy for
    sediment is consistent with this definition.
    Petitioners do not identify any legal requirement that
    the EPA must set performance standards specific to sediment in all
    reaches of the Rest of River.      And the EPA has adequately explained
    its decision not to do so in the downstream reaches, given that
    PCB concentrations there are already below the standard set for
    upstream    reaches.     The   EPA's     choice    to   instead   rely   on    the
    Downstream Transport Performance Standard and the Short-Term Biota
    Performance Standard is well-reasoned and consistent with the
    Consent Decree and CERCLA.
    - 45 -
    3.   Alleged Lack of Timeframes to Achieve Performance Standards
    Third, the Petitioners contend that the 2020 Permit does
    "not establish[] any timeframe for [MNR] to be effective, let alone
    a reasonable timeframe."         They argue that the 2020 Permit thus
    violates   EPA    guidance     documents       that   require    MNR     to   attain
    "remediation objectives in a time period that is reasonable."
    This argument is contrary to the record and fails to
    account for the provisions of the 2020 Permit concerning the
    Downstream Transport Performance Standard and the Short-Term Biota
    Performance Standard.         As the EPA wrote in its 2014 Comparative
    Analysis, the MNR provisions of the permit will "include monitoring
    to confirm progress toward achieving cleanup levels in fish tissue
    and   reducing    ecological    risk     and    downstream      transport."       In
    particular,      the   2020   Permit    requires      GE   to   ensure    that   the
    Downstream Transport Performance Standard not be exceeded "in any
    three or more years within any 5-year period," and that the Short-
    Term Biota Performance Standard "be achieved within 15 years" of
    the completion of certain construction-related activities and not
    be "exceeded in any two consecutive monitoring periods after" that
    15-year timeframe.       The Petitioners fail to address the existence
    of these timeframes, let alone develop any argument that they are
    unreasonable.
    - 46 -
    4.   Alleged Lack of Contingency Measures
    Finally, the Petitioners argue that the 2020 Permit
    "lacks any mechanism for a contingent response if MNR is not
    adequately protective."          They posit that by failing to include
    provisions     concerning    contingency        measures,       the    EPA   violated
    CERCLA's requirement of considering "the potential for future
    remedial action costs if the . . . remedial action in question
    were to fail."      
    42 U.S.C. § 9621
    (b)(1)(F).
    Once again, this argument is inconsistent with the terms
    of the 2020 Permit.        Those terms do, in fact, contemplate further
    actions if the performance standards applicable to the downstream
    reaches are not met.       Under the 2020 Permit, if PCB concentrations
    fail to meet the Downstream Transport Performance Standard or the
    Short-Term Biota Performance Standard within those standards'
    respective     timeframes    described     above,       GE    must    "evaluate    and
    identify     the    potential      cause(s)       of      the       exceedance     and
    propose . . . additional         actions       necessary        to     achieve     and
    maintain"    the    standards.     The     EPA    will       then    "determine    any
    additional     actions     necessary     to     achieve       and     maintain"    the
    standards "in accordance with the [Consent Decree]."                    Although the
    EAB's   2018    decision    apparently        imposed    some       limits   on   what
    "additional actions" the EPA can require under these provisions,
    see Gen. Elec. I, 17 E.A.D. at 517-19, the Petitioners develop no
    - 47 -
    argument      that       those    limits     render       the   contingency        response
    provisions inadequate.
    Accordingly, we reject the Petitioners' challenges to
    the MNR provisions of the 2020 Permit.
    B.      Challenge to the EPA's Rejection of Certain Treatment
    Technologies as to Excavated Material
    In    their       second    substantive       challenge       to    the   2020
    Permit, the Petitioners argue that the EPA should have required GE
    to apply treatment technologies to excavated and removed material
    prior to disposal, in order to reduce that material's toxicity and
    lessen the risk of PCB dispersal.                  Like the provisions concerning
    MNR,    the   relevant          provisions    of    the     2020     Permit      concerning
    treatment are unchanged from the 2016 Permit.                               Both permits
    required the use of activated carbon or another sediment amendment
    in certain areas of the Rest of River, but do not require any
    treatment of removed material.
    The Petitioners raise three challenges regarding the
    application of treatment technologies.                      They argue that (1) the
    EPA should have required GE to treat removed material with thermal
    desorption,        (2)    the    EPA     should    have    required     GE    to    utilize
    bioremediation to treat the removed material, and (3) the EPA's
    failure to require treatment of the removed material violates
    CERCLA.21
    21     The    EPA    contends       that    certain      of    the    Petitioners'
    - 48 -
    1.   Challenge to the EPA's Rejection of Thermal Desorption
    The Petitioners first challenge the EPA's decision not
    to require GE to treat removed sediment and soil with thermal
    desorption.   This challenge fails.
    The EPA studied thermal desorption in depth prior to
    issuing the 2016 Permit; in particular, in the 2014 Comparative
    Analysis, the agency discussed the performance of that treatment
    approach under the nine Selection Criteria.         The 2014 Comparative
    Analysis concluded that treating removed material with thermal
    desorption    could   "potentially    result   in    long-term   adverse
    environmental impacts," would "produce the greatest amount of
    [greenhouse gas] emissions of any of the alternatives," and would
    require compliance with additional ARARs.      The EPA also noted that
    there was "limited precedent" supporting the efficacy of using
    thermal desorption on large volumes of sediment, rendering the
    "adequacy and reliability of [thermal desorption] . . . uncertain."
    Further, treating the removed material with thermal desorption was
    the "most expensive alternative."      In its response to comments on
    challenges concerning treatment are waived due to the Petitioners'
    failure to demonstrate that those challenges were raised during
    the public comment period for the draft version of the 2016 Permit.
    Like the EPA's waiver argument concerning MNR, the EPA's waiver
    argument here depends on the proposition that the Petitioners'
    raising their concerns when challenging the 2020 Permit was
    insufficient to prevent waiver. We again choose to bypass that
    question and instead resolve the Petitioners' challenges on the
    merits.
    - 49 -
    the draft version of the 2016 Permit, the EPA reiterated that it
    elected not to require thermal desorption "[d]ue in part to its
    high cost, and the likelihood that all of the treated material
    could not be reused" but rather would need to be transported to an
    offsite landfill.
    When developing the 2020 Permit, the EPA again noted
    that   treating    removed    material     with     thermal   desorption     could
    potentially "present operational challenges and leave treatment
    residuals that would still require land disposal." In its response
    to comments on the draft version of the 2020 Permit, the EPA
    further explained that it had "not typically selected large-scale
    treatment at large sediment sites" when the "extraordinary size or
    complexity of a site makes implementation of [such] treatment
    technologies      impracticable."          The    EPA    acknowledged     comments
    identifying an example of the use of thermal desorption at a large
    sediment site in Vietnam, but explained that that example did "not
    contradict" the EPA's analysis regarding the downsides of thermal
    desorption,    including      the   need   to     landfill    treated   material.
    Further,   the    EPA   listed      various      other   drawbacks   of   thermal
    desorption,       including      the     "[r]equirement        to    treat     air
    emissions . . . [and] leachate produced by the process" and the
    risk of community opposition to the long-term operation of a
    treatment facility.      See 
    42 U.S.C. § 9621
    (b)(2) (allowing the EPA
    - 50 -
    to "take into account the degree of support" for remedial actions
    involving treatment).
    The record thus demonstrates that in evaluating whether
    to require GE to treat removed material with thermal desorption,
    "the EPA neither relied on impermissible factors nor failed to
    consider a crucial aspect of the problem," and that the EPA's
    explanation for declining to require thermal desorption treatment
    "neither       flouted       the    evidence      in    the    record       nor   [was]    'so
    implausible that it could not be ascribed to a difference in view
    or the product of agency expertise.'"                       City of Taunton, 
    895 F.3d at 141
     (quoting State Farm, 
    463 U.S. at 43
    ).
    2.    Challenge to the EPA's Rejection of Bioremediation
    The Petitioners next argue that the 2020 Permit should
    have required treatment of removed material with bioremediation.
    We reject this argument.
    The EPA did not include a bioremediation alternative as
    part    of    the     2014    Comparative         Analysis,         because    the   EPA   had
    previously          concluded       that    there       was     insufficient         evidence
    demonstrating          that        bioremediation           would      be     suitable     for
    "applica[tion]          to      [the       Rest    of       River's]        conditions      or
    contaminants."          That conclusion was based, in part, on research
    indicating that "biological treatment processes ha[d] not been
    successfully demonstrated full-scale for PCBs in soil" and that
    there        were     various       obstacles          to     the     implementation        of
    - 51 -
    bioremediation, including the "[i]nability [of bioremediation] to
    achieve low . . . residual PCB concentrations" and the "[o]verall
    resistance of PCBs to microbial degradation."            In its response to
    comments on the draft version of the 2016 Permit, the EPA again
    explained that there had "not been to date sufficient demonstration
    that bioremediation would be effective and meet the project goals."
    The EPA cited, as an example, the fact that a pilot bioremediation
    project had been terminated by Massachusetts due in part to
    evidence    that    the   biological    treatment   had     "dilut[ed]   and
    redistribut[ed]" contaminants rather than reducing them.                 When
    responding to comments on the draft version of the 2020 Permit,
    the EPA declined to further elaborate on its analysis of that
    project, but the Petitioners develop no argument on appeal that
    the EPA's initial analysis was incorrect.
    The    Petitioners   do    not   identify    any   impermissible
    factors in the EPA's analysis of bioremediation or point to any
    additional information about bioremediation that the EPA failed to
    consider.    See State Farm, 
    463 U.S. at 43
    .            We uphold the EPA's
    decision not to require GE to treat removed sediment and soil with
    bioremediation.
    3. Alleged Noncompliance With
    CERCLA's Preference for Treatment
    Finally, the Petitioners contend that the EPA's failure
    to require treatment of removed material was "not in accordance
    - 52 -
    with law," 
    5 U.S.C. § 706
    (2)(A), because it was inconsistent with
    CERCLA's preference for "alternative treatment technologies," 
    42 U.S.C. § 9621
    (b)(1).        The relevant provision of CERCLA provides:
    The [EPA] shall select a remedial action that
    is protective of human health and the
    environment, that is cost effective, and that
    utilizes permanent solutions and alternative
    treatment technologies or resource recovery
    technologies    to   the    maximum    extent
    practicable. If the [EPA] selects a remedial
    action not appropriate for a preference under
    this subsection, the [EPA] shall publish an
    explanation as to why a remedial action
    involving such reductions was not selected.
    
    42 U.S.C. § 9621
    (b)(1).        The Petitioners argue that by declining
    to require GE to treat removed sediment and soil with thermal
    desorption, bioremediation, or other treatment technologies, the
    2020 Permit violates CERCLA's requirement that the EPA "select a
    remedial action . . . that utilizes . . . alternative treatment
    technologies . . . to the maximum extent practicable."              
    Id.
         We
    reject this argument for three reasons.
    First,    the    2020   Permit    satisfies    §   9621(b)(1)'s
    requirement that the EPA select a remedy that is both "protective
    of human health and the environment" and "cost effective."                Id.;
    cf. Ohio v. U.S. EPA, 
    997 F.2d 1520
    , 1532 (D.C. Cir. 1993) (noting
    that the "statutory language [of § 9621(b)(1)] places as much
    emphasis on the selection of cost-effective remedies as it does on
    the selection of permanent remedies").             In the 2020 Comparative
    Analysis,    the     EPA    found   that     its   selected    remedy     will
    - 53 -
    "provide . . . high levels of . . . protection" by transporting
    some contaminated materials to a licensed offsite facility and
    other contaminated materials to an onsite facility with a cap,
    double liner, leachate collection system, groundwater monitoring
    network, and stormwater management system.               The EPA also found its
    selected remedy to be cost-effective relative to several other
    alternatives.       In contrast, although the EPA found that treatment
    with thermal desorption would provide "human health protection,"
    the EPA noted that such treatment could "potentially result in
    long-term      adverse    environmental     impacts,"      would     "produce     the
    highest   amount     of   [greenhouse      gas]    emissions    of    any    of   the
    alternatives," and would be the "most expensive alternative."                      As
    for bioremediation, the EPA found that there had "not been to date
    sufficient demonstration that bioremediation would be effective"
    and   that   bioremediation     could      in     fact   risk   "diluti[ng]       and
    redistributi[ng]" contaminants.
    Second, § 9621(b)(1) clearly contemplates that the EPA
    can   select    a   remedy   that   does    not     incorporate      all    possible
    treatment techniques.        Cf. Ohio, 
    997 F.2d at 1532
     (noting that the
    fact that § 9621(b)(1) "mandates the achievement of multiple goals"
    precludes an interpretation requiring the EPA to "select[] . . .
    permanent remedies whenever possible," because that interpretation
    would read the "mandate to select cost-effective remedies" out of
    the statute (emphasis added)).          In particular, the statute allows
    - 54 -
    the EPA to "select[] a remedial action not appropriate for a
    preference" for treatment if the EPA "publish[es] an explanation"
    for that decision.         
    42 U.S.C. § 9621
    (b)(1).          As discussed above,
    the EPA "publish[ed] . . . explanation[s]" justifying its decisions
    not   to   require     treatment     of   removed     material    with    thermal
    desorption, bioremediation, or other treatment technologies, 
    id.,
    and those explanations were not "arbitrary, capricious, an abuse
    of discretion, or otherwise not in accordance with law," 
    5 U.S.C. § 706
    (2)(A).
    Finally, although the 2020 Permit does not contemplate
    treatment of removed sediment and soil, it                   does require the
    application       of   alternative    treatment       technologies   in     other
    portions of the Rest of River in lieu of excavation and removal.
    In particular, the 2020 Permit requires GE to place "activated
    carbon and/or other comparable amendments" in certain portions of
    the Rest of River "to reduce the bioavailability of the remaining
    PCBs" in those areas.        We thus are not confronted with a situation
    in which the EPA has entirely eschewed requiring treatment.
    The    EPA's    choice   to   require     the    implementation    of
    certain    treatment     technologies     but   not    others,    coupled   with
    adequate explanations for rejecting certain technologies, is fully
    consistent with CERCLA's preference for alternative treatment.                We
    reject the Petitioners' challenges concerning the treatment of
    - 55 -
    contaminated material to be excavated and removed from the Rest of
    River.
    C.    Challenge to the 2020 Permit's Hybrid Disposal Provisions
    The Petitioners' third and final substantive challenge
    concerns the 2020 Permit's hybrid disposal provisions. Under those
    provisions, excavated materials with higher PCB concentrations
    will be transported to an offsite disposal facility, while less
    contaminated materials will be disposed of in an onsite facility
    near Woods Pond.      The Petitioners argue that the EPA arbitrarily
    and capriciously changed course from its previous conclusion,
    embodied in the 2016 Permit, that all contaminated material should
    be disposed of offsite.
    We    first   describe   our   scope   of   review   as    to   this
    challenge.       Like the EAB, we reject the Petitioners' request to
    supplement the record before us with stricken materials from a
    report that was never submitted to the EPA.             We then turn to the
    merits of the Petitioners' arguments.
    1.    Request for Supplementation of the Record
    When seeking review of the 2020 Permit by the EAB, the
    Petitioners sought to introduce a report written by a geoscientist
    named David J. DeSimone (the "DeSimone Report").                 The DeSimone
    Report assesses the geological characteristics of the Woods Pond
    site,    concluding   that   permeable     sediments    and   rock    fractures
    present the risk of PCB migration should the onsite disposal
    - 56 -
    facility's double liner and leachate collection system fail.              The
    Petitioners conceded to the EAB that the DeSimone Report was not
    presented to the EPA during the public comment period or otherwise
    included in the administrative record, but rather was prepared for
    litigation purposes after the EPA issued the 2020 Permit.                 See
    Gen. Elec. II, 18 E.A.D. at 611-12, 612 n.19.          The EAB allowed the
    Petitioners to add a portion of the DeSimone Report to the record,
    see id. at 613-14, but excluded most of the report, see id. at
    614-15.     The EAB explained that no basis existed to allow review
    of the extra-record document, rejecting the Petitioners' argument
    that the report discussed topics that the EPA had failed to
    consider.    See id.
    We reject the Petitioners' contention that the EAB acted
    arbitrarily and capriciously in striking the bulk of the DeSimone
    Report from the record.         The EAB explained that, with certain
    exceptions, EPA regulations circumscribe the scope of the EAB's
    review to the administrative record, see 
    40 C.F.R. § 124.18
    (a)
    (requiring the EPA to "base final permit decisions . . . on the
    administrative record"); 
    id.
     § 124.18(b) (defining "administrative
    record" to include the record for the draft permit, the public
    comments    on   the   draft   permit,   the   EPA's   responses   to   those
    comments, the final permit, and several other documents), and that
    the DeSimone Report was not part of that record because the "record
    [was] complete on the date the final permit [was] issued," id.
    - 57 -
    § 124.18(c).      See Gen. Elec. II, 18 E.A.D. at 608-11.            The EAB
    then noted that even if it were to consider the DeSimone Report,
    the report did not "support[] an argument that the [EPA] did not
    consider    all   relevant     factors,"    because    the   topic   of   the
    report -- i.e., soil permeability at the Woods Pond site -- had
    already been studied extensively by the EPA.            Id. at 615; cf. 
    40 C.F.R. § 300.825
    (c) (requiring, with respect to CERCLA response
    actions, agencies to consider "comments submitted . . . after the
    close of the public comment period only to the extent that the
    comments contain significant information not contained elsewhere
    in the administrative record file           which could not have been
    submitted during the public comment period and which substantially
    support the need to significantly alter the response action"
    (emphasis   added)).     The    EAB   provided   adequate    reasoning    for
    declining to add most of the DeSimone Report to the record, and
    the Petitioners have "fail[ed] to convince us that the EAB acted
    arbitrarily or capriciously in policing its waiver rule."            City of
    Taunton, 
    895 F.3d at 132
    ; see 
    id.
     ("We . . . uphold the EAB's
    decision to strike documents that the [petitioner] attempted to
    submit for the first time at the administrative appeal stage.").
    The Petitioners now entreat this court to consider the
    stricken content of the DeSimone Report.              "[W]hen reviewing an
    agency's decision under the arbitrary and capricious standard,
    'the focal point for judicial review should be the administrative
    - 58 -
    record already in existence, not some new record made initially in
    the reviewing court.'"            
    Id. at 127
     (quoting Camp v. Pitts, 
    411 U.S. 138
    , 142 (1973)).             We have, however, recognized several
    exceptions     to    the   rule   against     record   supplementation.         For
    example, supplementation is permissible where there is a "strong
    showing of bad faith or improper behavior" by the agency.                    Town of
    Winthrop v. FAA, 
    535 F.3d 1
    , 14 (1st Cir. 2008) (quoting Olsen v.
    United States, 
    414 F.3d 144
    , 155 (1st Cir. 2005)).                    We may also
    supplement the record "to facilitate our comprehension of the
    record   or    the    agency's     decision,"    particularly        when   "highly
    technical, environmental matters" are at issue or when the agency
    has "fail[ed] to explain administrative action as to frustrate
    effective judicial review."              City of Taunton, 
    895 F.3d at 127
    (first citing Town of Winthrop, 
    535 F.3d at 14
    ; then quoting Valley
    Citizens for a Safe Env't v. Aldridge, 
    886 F.2d 458
    , 460 (1st Cir.
    1989) (Breyer, J.); and then quoting Olsen, 
    414 F.3d at 155-56
    ).
    Similarly, we have noted that the Ninth Circuit allows record
    supplementation "when necessary to determine whether the agency
    considered all relevant factors in making its decision" or "when
    the agency has relied on extra-record materials."                       Ruskai v.
    Pistole,   
    775 F.3d 61
    ,    66   (1st   Cir.   2014)   (quoting       WildWest
    Inst. v. Bull, 
    547 F.3d 1162
    , 1176 (9th Cir. 2008)).
    Notwithstanding      the    existence    of    these    exceptions,
    supplementation of the administrative record is "the exception,
    - 59 -
    not the rule, and is discretionary with the reviewing court." Town
    of Winthrop, 
    535 F.3d at 14
    .            We decline, in our discretion, to
    allow the Petitioners' request.          The topic of soil permeability is
    well-documented in the existing administrative record, such that
    the   DeSimone     Report   is    not     necessary   to     "facilitate      our
    comprehension" of that issue.           City of Taunton, 
    895 F.3d at 127
    .
    Further, the record demonstrates that the EPA has already analyzed
    the geological conditions of the Woods Pond site and concluded
    that a low-permeability cap, double liner, leachate collection
    system,   and    groundwater     monitoring   network      are   sufficient    to
    protect against PCB migration from the onsite disposal facility.
    Indeed, the Petitioners raised concerns about the "subsurface
    characteristics" of the site in their public comments, and the EPA
    directly responded to those comments.           The Petitioners thus fail
    to identify any "relevant factors" raised by the DeSimone Report
    that the EPA failed to consider.          Ruskai, 
    775 F.3d at 66
     (quoting
    WildWest Inst., 
    547 F.3d at 1176
    ); see Town of Winthrop, 
    535 F.3d at 15
     (declining to consider a document that "elaborate[d] on
    concerns already addressed in the record" and thus would not "bear
    on . . . whether the [agency] adequately considered th[o]se
    concerns"); cf. United States v. Akzo Coatings of Am., Inc., 
    949 F.2d 1409
    , 1429, 1431 (6th Cir. 1991) (finding that an affidavit
    concerning soil permeability offered "evidence . . . [that was]
    only 'supplementary' rather than 'new'" and thus that the "EPA
    - 60 -
    would still have acted as it did even had [it] considered" that
    affidavit).
    Accordingly,      we    base    our     review    on   the   existing
    administrative record when addressing the Petitioners' arguments
    concerning the 2020 Permit's hybrid disposal provisions.                  We now
    turn to those arguments.
    2.    Challenges Regarding Hybrid Disposal
    The Petitioners do not contest that the EPA "display[ed]
    awareness that it [was] changing position" when it opted to require
    hybrid disposal, rather than fully offsite disposal, in the 2020
    Permit.    Fox, 
    556 U.S. at 515
    .          Nor could they: the EPA expressly
    and    repeatedly    acknowledged         that    it   altered     the   disposal
    provisions following the EAB's remand of the 2016 Permit, and the
    EPA    directly    compared   the    hybrid       disposal    approach    to   the
    previously selected fully offsite disposal approach in the 2020
    Comparative       Analysis.         The     EPA     thus     "consider[ed]     the
    'alternative[s]' that [were] 'within the ambit of'" the 2016 Permit
    when developing the 2020 Permit.                 Regents, 
    140 S. Ct. at 1913
    (second alteration in original) (quoting State Farm, 
    463 U.S. at 51
    ).
    We note, too, that the EPA "did not merely revert back"
    to the fully onsite disposal approach it had rejected in the 2014
    Comparative Analysis, but rather "devised a new scheme" of hybrid
    disposal,   thus    "chang[ing]      the    factual    consequences"      of   the
    - 61 -
    selected disposal approach.              Lily Transp., 
    853 F.3d at 38
    .               In
    particular, by allowing only contaminated materials with average
    PCB concentrations below 50 ppm to be disposed of in the onsite
    disposal facility, the 2020 Permit obviates the requirement that
    the    onsite     facility    satisfy      TSCA   regulations       governing       the
    disposal of more highly contaminated substances.                       See 
    40 C.F.R. § 761.75
    .        Indeed,     the   EPA     estimated    that     the    average     PCB
    concentration of material disposed of onsite will be less than 25
    ppm.    Given that only less contaminated material will be disposed
    of onsite under the hybrid disposal approach, the EPA concluded
    that the onsite disposal facility will "not pose an unreasonable
    risk of injury to health or the environment."                
    Id.
     § 761.61(c)(2).
    The EPA has thus explained how "facts changed from those underlying
    the" 2016 Permit influenced the agency's finding that the onsite
    disposal facility can attain TSCA's standards.                   Lily Transp., 
    853 F.3d at 36
    ; see Fox, 
    556 U.S. at 515
    .                  Notably, this change in
    disposal provisions responded directly to the EAB's criticism, in
    remanding the 2016 Permit, that the EPA had previously failed to
    adequately      address    whether    an    onsite     disposal     approach       could
    satisfy    TSCA    requirements       or   qualify     for   a   waiver     of     those
    requirements.       See Gen. Elec. I, 17 E.A.D. at 561-69.
    Nevertheless, the Petitioners maintain that the EPA has
    failed to "provide a reasoned explanation for the change" in the
    disposal    approach.        Encino      Motorcars,    579   U.S.      at   221.     In
    - 62 -
    particular, the Petitioners mount two challenges to the 2020
    Permit's hybrid disposal provisions.      First, the Petitioners argue
    that the EPA's choice of hybrid disposal was improperly based on
    the agency's commitment to the Settlement, rather than on an
    objective weighing of the nine Selection Criteria.             Second, the
    Petitioners   challenge   the   EPA's   decision   to   site   the   onsite
    disposal facility within an area designated by Massachusetts as an
    ACEC.
    The EPA contends that the Petitioners waived these two
    arguments by failing to demonstrate that the arguments were raised
    during the public comment period for the draft version of the 2020
    Permit.   See Upper Blackstone, 
    690 F.3d at 30
    .          The Petitioners
    vigorously dispute this assertion, maintaining that their comments
    provided sufficient "notice to the EPA" concerning the substance
    of the Petitioners' challenges to the hybrid disposal provisions,
    even if the comments "d[id] not present technical or precise
    scientific or legal challenges."        Adams v. U.S. EPA, 
    38 F.3d 43
    ,
    52 (1st Cir. 1994); see 
    40 C.F.R. § 124.13
     (requiring commenters
    on draft RCRA permits to "raise all reasonably ascertainable issues
    and submit all reasonably available arguments supporting their
    position[s]").    We note, too, that the EPA's waiver argument
    depends on the proposition that the Petitioners have failed to
    identify any other commenters that sufficiently raised the two
    arguments to the EPA.     See Adams, 
    38 F.3d at
    52 n.7 (noting, in
    - 63 -
    analogous   permitting    context,     that    "[t]he      person    filing   the
    petition for review . . . does not necessarily have to be the
    individual who raised the issue during the comment period");
    Masias v. EPA, 
    906 F.3d 1069
    , 1080 (D.C. Cir. 2018) ("Although
    [the petitioner] need not have personally raised his current
    objection during the comment period . . . he must point [the court]
    to a commenter who did.").         Given the complexities involved in
    resolving this waiver question,22 we again elect to bypass the
    issue and instead address the Petitioners' two challenges on the
    merits.
    a.   Alleged Incongruity Between the Hybrid Disposal Provisions
    and the EPA's Analysis of the Nine Selection Criteria
    The Petitioners first argue that the EPA's decision to
    require hybrid disposal was not a rational extension of its
    analysis of the nine Selection Criteria.                   In particular, the
    Petitioners    contend   that    the   EPA    "reached     the     same   ultimate
    conclusion under each of the [Selection Criteria] in [the] 2020
    [Comparative    Analysis]   as    it   had    in   [the]    2014    [Comparative
    Analysis]," yet selected hybrid disposal "despite almost all the
    [Selection] Criteria pointing to [fully] offsite disposal as the
    22  For example, comments filed by Massachusetts discussed
    the EPA's decision to place the onsite disposal facility in an
    ACEC, but ultimately did not object to that decision. We need not
    decide   whether  those   comments   sufficed   to  preserve  the
    Petitioners' argument concerning the siting of the facility in an
    ACEC.
    - 64 -
    most favorable option." The Petitioners posit that the EPA, rather
    than    objectively   weighing      the   Selection   Criteria,          was    overly
    "focused on how its remedy selection decision would affect the
    continued viability of the Settlement."
    It   is   true   that    the    EPA    concluded,       in    the    2020
    Comparative Analysis, that fully offsite disposal would better
    meet several of the Selection Criteria than hybrid disposal.                      For
    example, with respect to "Control of Sources of Releases," the EPA
    found that unlike fully offsite disposal, the hybrid disposal
    approach would have a slight "potential for releases [of PCBs] to
    the Housatonic River watershed if, in the long term, the [onsite
    disposal] facility . . . is not properly operated."                  That remote
    risk of future PCB releases, along with impacts to local habitat
    from the construction of an onsite disposal facility, also led the
    EPA to find that fully offsite disposal would outperform hybrid
    disposal    as   to   "Long-Term      Reliability     and    Effectiveness."23
    Further, the EPA concluded that fully offsite disposal would
    require     compliance   with    fewer     ARARs    and     would    face       fewer
    "regulatory and zoning restrictions" than hybrid disposal.
    But even where fully offsite disposal would outperform
    hybrid disposal, it at best, as to those aspects, would do so by
    23 The impact on local habitat from the onsite facility's
    "operational footprint" was also considered as part of the EPA's
    analysis of "Short-Term Effectiveness."
    - 65 -
    slim margins, and fully offsite disposal would impose detriments
    which hybrid disposal would avoid.              As to "Control of Sources of
    Releases," for example, the EPA determined that both "alternatives
    [would]   meet     the    criterion."           With    respect     to    "Long-Term
    Reliability and Effectiveness," the EPA found that the onsite
    disposal facility would "permanently isolate the [contaminated]
    materials" and in fact "be designed to be generally equivalent to
    a    facility    permitted      to    accept     much     higher      concentration
    materials."      The EPA further concluded that the short- and long-
    term impacts on local habitat from the construction of the onsite
    disposal facility would be minimal because the facility would be
    built at "an existing sand and gravel facility in close proximity
    to two other solid waste disposal facilities."                    In addition, the
    EPA noted that similar facilities are "routinely constructed and
    operated" with "techniques [that] are well known and demonstrated
    as   effective."         And   due   to   the    fact    that   the      most   highly
    contaminated materials would be sent to an offsite facility under
    the hybrid disposal approach, the EPA found that even where fully
    offsite   disposal       was   preferable       to     hybrid   disposal,       hybrid
    disposal was preferable to the fully onsite disposal option that
    was considered in the 2014 Comparative Analysis.                   Further, as the
    EPA noted, there was uncertainty as to the future availability of
    the needed capacity at offsite disposal sites.
    - 66 -
    Importantly, the EPA also found that hybrid disposal
    would outperform fully offsite disposal in various metrics.              For
    example,    the   hybrid   disposal   approach   would   result   in   fewer
    greenhouse gas emissions, involve fewer truck trips, and risk fewer
    transportation-related injuries and fatalities than fully offsite
    disposal.     Further, hybrid disposal would be significantly less
    costly than fully offsite disposal. The EPA also noted that "local
    governments    ha[d]   documented     their   acceptance"   of   the   hybrid
    disposal approach "through their acceptance of the Settlement."
    As to the first of the Selection Criteria -- "Overall
    Protection of Human Health and the Environment" -- the EPA noted
    that the hybrid disposal approach was "part of a Settlement . . .
    that includes numerous enhancements to the floodplain and sediment
    remedies, an expedited start to implementation, and community
    coordination and benefits," and thus that hybrid disposal would
    "provide better short- and long-term protectiveness" than fully
    offsite disposal.      That conclusion comported with the portion of
    the 2020 Comparative Analysis comparing the remediation provisions
    of the 2016 Permit with those of the draft version of the 2020
    Permit.     In that part of the 2020 Comparative Analysis, the EPA
    concluded that the draft revised permit would outperform the 2016
    Permit as to the majority of the Selection Criteria due to the
    various new remedial measures included in the new permit, such as
    the requirements that GE excavate additional contaminated sediment
    - 67 -
    and soil from the Rest of River, remediate more than twenty
    additional residential properties, remove two dams so as to restore
    natural    habitat,    develop   a     quality-of-life      plan       addressing
    community impacts, and begin "investigation and design work" on
    the Settlement's effective date.              The EPA thus concluded that,
    when scrutinizing the new provisions in the draft version of the
    2020 Permit holistically, "the combination of the . . . sediment
    and    floodplain     [revisions]      and      the    [h]ybrid        [d]isposal
    approach . . . [would be] best suited to meet the . . . Selection
    Criteria."
    In light of these determinations by the EPA, we disagree
    with the Petitioners' contention that "almost all the [Selection]
    Criteria   point[ed]    to   [fully]     offsite      disposal    as    the   most
    favorable option."      On the contrary, the EPA found that hybrid
    disposal   would    outperform   fully      offsite    disposal    on    "Overall
    Protection of Human Health and the Environment," "Cost," and
    certain aspects "Short-Term Effectiveness" and "Implementability."
    The EPA found that fully offsite disposal would outperform hybrid
    disposal as to three criteria -- "Control of Sources of Releases,"
    "Compliance    with    [ARARs],"      and     "Long-Term    Reliability        and
    Effectiveness" -- but only by slim margins.24           Given these findings
    24  The remaining two criteria -- "Attainment of Interim
    Media Protection Goals" and "Reduction of Toxicity, Mobility, or
    Volume of Wastes" -- were either inapplicable or equally satisfied
    by hybrid disposal and fully offsite disposal.
    - 68 -
    and the EPA's explanations for them, we cannot conclude that the
    EPA acted arbitrarily or capriciously in concluding, as required
    by the Consent Decree, that the hybrid disposal approach would be
    "best suited to meet the [first three Selection Criteria] . . . in
    consideration      of    the    [latter   six     Selection    Criteria]   .    .   .
    including a balancing of [the latter six Selection Criteria]
    against one another."            And to the extent the 2020 Comparative
    Analysis involved factual findings that differed from those in the
    2016 Comparative Analysis -- such as the finding that the onsite
    disposal facility no longer needed to satisfy TSCA requirements
    concerning contaminated materials with PCB concentrations of 50
    ppm or greater, and the finding that there was increased community
    support for disposing of certain materials onsite -- the EPA
    provided the requisite "detailed justification" for those findings
    in light of the changed circumstances following the remand of the
    2016 Permit.    Fox, 
    556 U.S. at 515
    .
    We   reject         the   Petitioners'    contention     that   it   was
    inappropriate for the EPA to consider the effects of the Settlement
    in the 2020 Comparative Analysis.               The Consent Decree does not
    limit what the EPA may take into account when evaluating the nine
    Selection Criteria, and a natural reading of several of those
    criteria allows consideration of the Settlement.                  In particular,
    the   Settlement    is    plainly      relevant     to   the   "Implementability"
    criterion, under which the EPA analyzed various factors bearing on
    - 69 -
    community and governmental backing for the Rest of River cleanup.
    It was not arbitrary or capricious for the EPA to conclude that
    the broad stakeholder support for hybrid disposal would aid the
    implementation of the 2020 Permit's provisions.                     Nor was it
    arbitrary or capricious for the EPA to consider the 2020 Permit's
    enhanced remediation provisions in conjunction with the hybrid
    disposal approach.         Nothing in the Consent Decree requires the
    Selection Criteria to be considered in a vacuum for each separate
    element of the cleanup; on the contrary, the Consent Decree broadly
    states that the EPA must determine "which corrective measure or
    combination of corrective measures" will best meet the Selection
    Criteria, "taking into consideration that the corrective measures
    ultimately selected will be implemented as a remedial action."
    (Emphasis added).         It thus was not inappropriate for the EPA to
    consider   the    terms    of   the   draft    version   of   the   2020   Permit
    holistically when conducting the 2020 Comparative Analysis.                   That
    is especially so because the enhanced remediation provisions were
    directly   tied    to     the   hybrid   disposal    approach       through   the
    Settlement, and would likely not have been added to the revised
    permit otherwise, given that the EAB had already upheld the prior,
    less protective remediation provisions of the 2016 Permit against
    several challenges, including by HRI.            See Gen. Elec. I, 17 E.A.D.
    at 487-519, 523-58.
    - 70 -
    The Petitioners also argue that it was inappropriate for
    the EPA to consider the fact that the Settlement expedited the
    implementation of the Rest of River cleanup, both by requiring GE
    to begin "investigation and design work" on the Settlement's
    effective date and by preventing signatories from challenging the
    2020 Permit "unless it [was] inconsistent with the terms of th[e]
    Settlement."     But importantly, we are not faced here with a
    situation where an agency has cited a desire to avoid litigation
    as the sole basis for its action.       Rather, the EPA considered the
    stakeholder support for the Settlement, and the accelerated start
    to   implementation,   as   two    factors    among   many   in    the   2020
    Comparative    Analysis.    That    limited   consideration       of   reduced
    litigation and implementation risk does not involve a "reli[ance]
    on factors which Congress has not intended [the EPA] to consider."
    State Farm, 
    463 U.S. at 43
    ; see, e.g., Regents, 
    140 S. Ct. at 1908
    ,
    1910 n.4 (rejecting an agency's post-hoc claim that its action was
    based on a desire to "avoid burdensome litigation," but not finding
    that considering litigation risk would have been inappropriate in
    the first instance); Omnipoint Corp. v. FCC, 
    78 F.3d 620
    , 633 (D.C.
    Cir. 1996) ("[A]n agency may properly consider the avoidance of
    litigation-related delay when revising its rules."); cf. Cannons,
    899 F.2d at 88 (noting that a "principal end" of CERCLA is the
    "achievement of prompt settlement and a concomitant head start on
    response activities").      And GE's agreement to not challenge the
    - 71 -
    2020   Permit   was   particularly   salient   given    that   it   thereby
    forfeited the immediate appeal rights afforded to it by the Consent
    Decree's requiring the Rest of River remedy to be embodied in a
    RCRA permit rather than a CERCLA remedial action order.             Compare
    
    42 U.S.C. § 6976
    (b) (providing generally for immediate appeals of
    RCRA permits), with 
    id.
     § 9613(h) (preventing most appeals of
    CERCLA remedial action orders until after the EPA has acted to
    enforce those orders).
    We conclude that the EPA did not act arbitrarily or
    capriciously    in    weighing   these   various   factors   in   the   2020
    Comparative Analysis and concluding that hybrid disposal -- along
    with the associated benefits by way of the Settlement -- better
    satisfied the Selection Criteria than fully offsite disposal.
    b.    Challenge to the Siting of the Onsite Disposal Facility in
    an Area of Critical Environmental Concern (ACEC)
    The Petitioners' final challenge concerns the planned
    location of the onsite disposal facility.          Under the 2020 Permit,
    that facility will be located in a 20-acre portion of a much larger
    area designated by Massachusetts as an ACEC.             A Massachusetts
    regulation provides that "[n]o site shall be determined to be
    suitable or be assigned as a solid waste management facility where
    such siting . . . would be located within an [ACEC]."             310 Mass.
    Code Regs. § 16.40(4)(d)(1).       The EPA waived the applicability of
    this Massachusetts regulation, however, through a provision of
    - 72 -
    CERCLA that allows waiver of ARARs at a facility where "compliance
    with such [ARARs] at that facility will result in greater risk to
    human health and the environment than alternative options."                        
    42 U.S.C. § 9621
    (d)(4)(B).             The Petitioners argue that the EPA's
    waiver    of     the   Massachusetts       regulation     was     arbitrary       and
    capricious.
    As    we   have   explained,     however,     the   EPA     adequately
    explained its conclusion that hybrid disposal would better meet
    the nine Selection Criteria than fully offsite disposal.                       And in
    particular, the EPA supportably found that hybrid disposal would
    outperform fully offsite disposal as to the "Overall Protection of
    Human Health and the Environment" criterion. The Petitioners offer
    no reason, and we discern none, why the analysis of that criterion
    differs from the determination under CERCLA that fully offsite
    disposal would "result in greater risk to human health and the
    environment" than hybrid disposal.             
    Id.
    In particular, and as previously discussed, the EPA
    found that fully offsite disposal would result in more greenhouse
    gas     emissions,     involve      more   truck     trips,     and     risk     more
    transportation-related        injuries      and      fatalities       than     hybrid
    disposal.      The EPA also noted that "the capacity of the [onsite
    disposal facility] is known and is sufficient to receive [the
    requisite] volume of material" and that utilizing hybrid disposal
    would    "save    capacity"    in    offsite    landfills     where     there     are
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    "uncertainties       about    the    future     availability     of    necessary
    capacity."      Further, the EPA determined that because the onsite
    disposal facility would be located at an "industrial and previously
    disturbed" former gravel mining pit, the facility would "not
    [cause] significant permanent loss of habitat or displacement of
    wildlife."      The EPA also explained that "[p]rompt implementation
    of the [hybrid disposal] remedy [would] translate[] directly into
    reduced risks to human health and the environment, by more quickly
    addressing the risks associated with PCB contamination," and that
    the   hybrid    disposal     provisions   were    associated    with       enhanced
    remediation measures by way of the Settlement.
    The EPA did not act arbitrarily and capriciously in
    concluding, based on these myriad considerations, that a waiver of
    the     Massachusetts      regulation     was     appropriate.             Notably,
    Massachusetts itself expressly stated in its public comments that
    it did "not object to . . . the waiver."
    The   Petitioners      contend     that   the    analysis      under
    § 9621(d)(4)(B) must be confined to local impacts, such that the
    EPA should not have "focuse[d] on the environmental risks posed to
    communities away from the [Rest of] River," including the risks
    related to the "location of the offsite disposal facility . . .
    [and]    by   greenhouse     gases   emitted     in   the   course    of    offsite
    transportation."      But this argument is at odds with the statutory
    text, which broadly authorizes the waiver of ARARs at a facility
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    if "compliance with such [ARARs] at that facility will result in
    greater risk to human health and the environment than alternative
    options."       Id.    Although the statute concerns the compliance with
    an ARAR at a specific "facility"25 -- here, the onsite disposal
    facility -- it does not likewise restrict the EPA's assessment of
    the "risk[s] to human health and the environment" to the risks
    occurring at that facility.               The statutory text thus unambiguously
    allows    the    EPA    to    consider      health   and   environmental     impacts
    resulting       from   the     compliance      or    noncompliance    with    ARARs,
    regardless of where those impacts occur.
    We conclude that the 2020 Permit's provisions mandating
    hybrid    disposal      are    not    "arbitrary,       capricious,   an   abuse   of
    discretion, or otherwise not in accordance with law."                      5. U.S.C.
    § 706(2)(A).
    V.    Conclusion
    The Petitioners' dedication to the remediation of the
    Housatonic River, and their decades of civic engagement in relation
    to that process, are commendable.               We trust that the EPA will, as
    its counsel avowed at oral argument, "continue engaging with the
    communities" affected by the contamination of the Rest of River.
    We also trust that should GE fail to attain the cleanup standards
    25   CERCLA defines "facility" to include, inter alia,
    "landfill[s]" and "site[s] or area[s] where a hazardous substance
    has been deposited, stored, disposed of, or placed, or otherwise
    come to be located." 
    42 U.S.C. § 9601
    (9).
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    required under the 2020 Permit, the EPA will enforce the permit's
    various contingency measures to ensure that conditions in the Rest
    of River continue to improve.
    Ultimately,   we   conclude    that   the   EPA's   challenged
    actions -- both procedural and substantive -- were not arbitrary
    or capricious.   Accordingly, the petition for review is denied.
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