Asarco LLC v. Atlantic Richfield Co. ( 2020 )


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  •                 FOR PUBLICATION
    UNITED STATES COURT OF APPEALS
    FOR THE NINTH CIRCUIT
    ASARCO LLC, a Delaware                    No. 18-35934
    corporation,
    Plaintiff-Appellee,            D.C. No.
    6:12-cv-00053-
    v.                             DLC
    ATLANTIC RICHFIELD COMPANY,
    LLC, a Delaware corporation,                OPINION
    Defendant-Appellant,
    and
    BRITISH PETROLEUM, PLC, a United
    Kingdom Corporation; AMERICAN
    CHEMET CORPORATION, a Montana
    Corporation,
    Defendants.
    Appeal from the United States District Court
    for the District of Montana
    Dana L. Christensen, District Judge, Presiding
    Argued and Submitted April 27, 2020
    Seattle, Washington
    Filed September 14, 2020
    2             ASARCO V. ATLANTIC RICHFIELD
    Before: M. Margaret McKeown, N. Randy Smith, and
    Jacqueline H. Nguyen, Circuit Judges.
    Opinion by Judge Nguyen
    SUMMARY *
    Environmental Law
    The panel affirmed in part and vacated in part the district
    court’s judgment, after a bench trial, in favor of the plaintiff
    in a contribution action under the Comprehensive
    Environmental Response, Compensation, and Liability Act.
    Plaintiff ASARCO LLC entered into a consent decree
    with the Environmental Protection Agency to clean up
    environmental contamination at several sites, including a
    Superfund Site in East Helena, Montana. Asarco, former
    operator of a lead smelting facility, then brought a CERCLA
    contribution action against Atlantic Richfield Co., successor
    in interest to the operator of a zinc fuming plant The district
    court found that Asarco had incurred $111.4 million in
    necessary response costs for the cleanup of the Site and that
    Atlantic Richfield was responsible for 25% of that sum.
    Vacating and remanding in part, the panel held that the
    district court erred in its determination of the necessary
    response costs incurred by Asarco. Specifically, the district
    court erred when it counted the full settlement amount,
    *
    This summary constitutes no part of the opinion of the court. It
    has been prepared by court staff for the convenience of the reader.
    ASARCO V. ATLANTIC RICHFIELD                   3
    including about $50 million of funds that had not been, and
    might never be, spent on the Site cleanup, as response costs
    subject to contribution at this stage of the Site cleanup. The
    panel remanded for further consideration of what response
    costs were sufficiently concrete and non-speculative such
    that they would be eligible for contribution under CERCLA.
    Affirming in part, the panel held that the district court
    did not err in allocating responsibility for 25% of the
    response costs to Atlantic Richfield. The panel held that the
    district court property exercised its discretion in its
    consideration of appropriate equitable factors and did not
    clearly err in its factual findings supporting its allocation
    decision.
    COUNSEL
    Shannon Wells Stevenson (argued), Benjamin B. Strawn,
    and Kellen N. Wittkop, Davis Graham & Stubbs LLP,
    Denver, Colorado; Elisabeth S. Theodore and Stephen K.
    Wirth, Arnold & Porter Kaye Scholer LLP, Washington,
    D.C.; for Defendant-Appellant.
    Gregory Evans (argued), McGuireWoods LLP, Los
    Angeles, California; Benjamin L. Hatch, McGuireWoods
    LLP, Washington, D.C.; Kris A. McLean, Kris A. McLean
    Law Firm PLLC, Missoula, Montana; Rachel H. Parkin,
    Milodragovich Dale & Steinbrenner P.C., Missoula,
    Montana; for Plaintiff-Appellee.
    4           ASARCO V. ATLANTIC RICHFIELD
    OPINION
    NGUYEN, Circuit Judge:
    In June 2009, ASARCO LLC (“Asarco”) agreed to settle
    with the government and enter into a consent decree to clean
    up environmental contamination at several sites, including a
    Superfund Site in East Helena, Montana (the “Site”). Asarco
    then brought a contribution action under the Comprehensive
    Environmental Response, Compensation, and Liability Act
    of 1980 (“CERCLA”), 42 U.S.C. §§ 9601–9675, against
    Atlantic Richfield Company, LLC (“Atlantic Richfield”).
    Following a bench trial, the district court entered judgment
    in favor of Asarco, finding that Asarco had incurred
    $111.4 million in necessary response costs for the cleanup of
    the Site and that Atlantic Richfield was responsible for
    twenty-five percent of that sum.          Atlantic Richfield
    appealed. We have jurisdiction pursuant to 28 U.S.C.
    § 1291. We hold that the district court erred in its
    determination of the necessary response costs incurred by
    Asarco, but the court did not err in allocating twenty-five
    percent liability to Atlantic Richfield. We therefore vacate
    and remand in part, and affirm in part.
    I. BACKGROUND
    A. Operations at the Site
    Asarco and its predecessors owned and operated a lead
    smelting facility at the Site from 1888 to 2001. Asarco’s
    lead smelting facility was the largest operation at the Site.
    This operation recovered lead and other metals by smelting
    a variety of foreign and domestic concentrates, ores, fluxes,
    and other non-ferrous, metalbearing materials and
    byproducts.        Those materials contained arsenic
    concentrations as high as 190,000 parts per million (“ppm”).
    ASARCO V. ATLANTIC RICHFIELD                   5
    The smelting operation produced slag as a waste product,
    which contained small residual quantities of metals and
    arsenic. It is undisputed that Asarco “released significant
    amounts of arsenic into the environment” from its smelting
    facility.
    Atlantic Richfield is the successor in interest to
    Anaconda, which leased a portion of the Site from Asarco to
    construct and operate a zinc fuming plant. Using a blast
    furnace fueled with coal, Anaconda reprocessed slag that it
    purchased from Asarco to recover zinc. Anaconda used and
    produced several arsenic-bearing materials in its fuming
    operation, albeit with a lower arsenic concentration than
    Asarco’s primary materials. Anaconda operated the zinc
    fuming plant from 1927 to 1972, at which point it sold the
    plant to Asarco. Asarco then operated the zinc fuming plant
    for another decade.
    B. EPA Involvement and Remediation
    In 1984, the Environmental Protection Agency (“EPA”)
    added the Site to the CERCLA National Priorities List,
    targeting it for environmental remediation. The primary
    environmental concern at the Site was arsenic contamination
    of the groundwater. In the years that followed, Asarco
    entered into a series of agreements with the EPA to begin the
    process of remediation.
    In 1990, Asarco and the EPA finalized a settlement
    agreement and consent decree in CERCLA litigation
    concerning the contamination of the process ponds at the
    Site. Pursuant to the consent decree, Asarco agreed to
    undertake a cleanup of the process ponds, which it
    substantially completed by 1997.
    6              ASARCO V. ATLANTIC RICHFIELD
    In 1998, Asarco and the EPA entered into another
    settlement agreement and consent decree, this time resolving
    claims brought by the EPA under the Resource Conservation
    and Recovery Act and the Clean Water Act. The settlement
    did not raise any claims under CERCLA.
    On August 9, 2005, Asarco filed a Chapter 11
    bankruptcy petition. In connection with the bankruptcy
    proceedings, the United States, the State of Montana, and the
    State of Montana Department of Environmental Quality all
    filed proofs of claim for Asarco’s projected liability under
    CERCLA. Asarco, the United States, and the State of
    Montana reached two complementary settlement agreements
    and consent decrees in February and June 2009, resolving
    Asarco’s outstanding environmental liabilities at several
    Montana sites, including the Site at issue in this case.
    The June 2009 consent decree established a custodial
    trust for the affected sites, and the Montana Environmental
    Trust Group (“METG”) was appointed as the custodial
    trustee for the East Helena Site. The June 2009 consent
    decree also designated the EPA as the lead agency for the
    Site, placing it in charge of selecting, approving, and
    authorizing all work performed and funds expended by
    METG. Pursuant to the June 2009 consent decree, Asarco
    paid approximately $111.4 million 1 for cleanup of the East
    Helena Site—accounting for comprehensive damage done to
    the Site by all responsible parties. That sum included:
    (a) $99.294 million into the East Helena Custodial Trust
    1
    In total, Asarco paid $1.8 billion to settle environmental claims
    related to hazardous waste in the bankruptcy proceedings.
    ASARCO V. ATLANTIC RICHFIELD                       7
    Cleanup Account for a groundwater remedy; 2 (b)
    $6,403,743 toward the establishment of the Custodial Trust
    and the funding of the Custodial Administrative Account to
    be used for trust administration expenses; (c) $706,000 to the
    U.S. Department of the Interior for natural resource
    restoration and future oversight costs for the Site; and (d) $5
    million to the State of Montana for compensatory natural
    resource damages at the Site.
    METG has begun its remediation work at the Site. So
    far, it has fully implemented three interim measures to curb
    the spread of contaminants and further environmental
    degradation at the Site. METG also has implemented
    institutional controls for the Site and the surrounding areas,
    designed to prevent property owners from using their
    domestic water wells to avoid contact with contaminated
    groundwater. METG proposes one additional future project:
    capping the portion of the slag pile at the Site that consists
    of unfumed slag. METG has not instated and does not plan
    to install a pump-and-treat system.
    As of the most recent accounting available, METG had
    spent a little less than half of the trust funds at its disposal,
    leaving it with approximately $50 million for further
    remediation efforts. Atlantic Richfield’s expert estimated
    the ongoing costs for operations and maintenance at
    $9.2 million, and METG estimated the cost of covering the
    unfumed slag at $3.7 million. Adding those sums to the
    dollar amount already expended by METG, the total cleanup
    cost for the Site would approximate $61.4 million. Asarco
    contends that Atlantic Richfield’s expert vastly understates
    2
    This figure was based on estimates for a pump-and-treat system
    recommended by the State of Montana’s experts, William Bucher and
    Ann Maest.
    8              ASARCO V. ATLANTIC RICHFIELD
    how costly the cleanup would be. Asarco’s expert opined
    that METG’s proposed remedies would be insufficient to
    address the groundwater contamination and that more
    substantial remediation work would be necessary.
    C. Procedural History
    In 2012, Asarco brought this contribution action against
    Atlantic Richfield under CERCLA §§ 107 and 113. The
    district court granted summary judgment in favor of Atlantic
    Richfield, finding the action barred by the statute of
    limitations. Asarco appealed, and we concluded that
    Asarco’s contribution claim was, in fact, timely. See Asarco
    LLC v. Atlantic Richfield Co., 
    866 F.3d 1108
    (9th Cir. 2017).
    We vacated the district court’s summary judgment order and
    remanded for further proceedings before the trial judge.
    Id. On remand, the
    district court conducted an eight-day
    bench trial, weighted heavily toward expert testimony.
    Following trial, the district court issued detailed findings of
    fact and conclusions of law and entered judgment in favor of
    Asarco. The court found that Asarco had expended
    $111,403,743 in necessary response costs for cleanup of the
    Site 3 and that Atlantic Richfield was liable for twenty-five
    percent of those costs, i.e., $27,850,936. The court also
    granted an additional $1 million award to Asarco, based on
    its findings as to Atlantic Richfield’s failure to cooperate
    with the authorities and its misrepresentations to the EPA
    and to Asarco. 4 Atlantic Richfield moved to alter or amend
    3
    This figure is the amount paid by Asarco in connection with the
    June 2009 consent decree.
    4
    Atlantic Richfield does not challenge on appeal the imposition of
    this additional $1 million award.
    ASARCO V. ATLANTIC RICHFIELD                   9
    the judgment, but the district court denied the motion. This
    appeal timely followed.
    II. ANALYSIS
    A. The District Court Erred by Including Speculative
    Future Costs in its Tabulation of Necessary Response
    Costs Eligible for Contribution Under CERCLA.
    Atlantic Richfield argues that the district court erred in
    finding that Asarco incurred $111.4 million in necessary
    response costs for the environmental cleanup of the Site,
    because that sum improperly included (i) costs that had not
    yet been, and might never be, incurred; and (ii) costs that
    were not necessary to protect human health and the
    environment. Atlantic Richfield contends those costs are
    unrecoverable under CERCLA, and that the response costs
    eligible for contribution should be limited to the
    $61.4 million that it represents have been incurred so far to
    remediate the Site.
    We review for clear error the district court’s findings of
    fact following a bench trial, and we review de novo its
    conclusions of law and mixed questions of law and fact.
    OneBeacon Ins. Co. v. Haas Indus., Inc., 
    634 F.3d 1092
    ,
    1096 (9th Cir. 2011). We hold that the district court erred
    when it counted the full settlement amount—including about
    $50 million of funds that had not been, and might never be,
    spent on the Site cleanup—as response costs subject to
    contribution at this stage of the Site cleanup. We therefore
    vacate and remand for further consideration of what
    response costs are sufficiently concrete and non-speculative
    such that they would be eligible for contribution under
    CERCLA.
    10           ASARCO V. ATLANTIC RICHFIELD
    The parties agree on the initial premise that, pursuant to
    the CERCLA contribution regime, Asarco is entitled to
    recover an allocated proportion of the “necessary costs of
    response incurred . . . consistent with the national
    contingency plan.” 42 U.S.C. § 9607(a)(4)(B). From that
    point, their positions diverge.
    Atlantic Richfield contends that those funds not yet spent
    or earmarked for specific, imminent work cannot qualify as
    costs “incurred.” It relies on cases that prohibit recovery
    under CERCLA for future response costs or the award of
    speculative damages unmoored to concrete expenses. See
    Stanton Rd. Assocs. v. Lohrey Enters., 
    984 F.2d 1015
    , 1021–
    22 (9th Cir. 1993); In re Dant & Russell, Inc., 
    951 F.2d 246
    ,
    249–50 (9th Cir. 1991). Atlantic Richfield asserts that
    METG no longer expects to implement the costly pump-and-
    treat remedy, instead planning to carry out cheaper remedial
    actions that would leave a large portion of the settlement
    funds untouched. It also cites to a reversion provision in the
    settlement agreement, whereby unused settlement funds
    would be redirected to remediate other sites for which
    Atlantic Richfield has no liability.
    Asarco responds that the costs for which it seeks
    contribution were actually “incurred.” It argues that the
    entire sum paid in settlement, $111.4 million, was intended
    to fund the environmental cleanup of the Site, as evidenced
    by the fact that the reversion provision does not allow the
    return of any funds to Asarco’s hands. Based on its
    irrevocable payment, Asarco says it “incurred” those
    response costs within the meaning of the statute. Asarco
    attempts to distinguish the cases cited by Atlantic Richfield,
    noting that they occurred in different contexts and lacked the
    same type of firm monetary commitment that Asarco
    undertook here. And Asarco points to cases from other
    ASARCO V. ATLANTIC RICHFIELD                    11
    circuits allowing recovery of future costs, arguing that
    precluding recovery for such costs could undermine
    CERCLA’s policy objective of incentivizing settlements and
    early, accountable cleanup. See RSR Corp. v. Commercial
    Metals Co., 
    496 F.3d 552
    , 558–60 (6th Cir. 2007); Am.
    Cyanamid Co. v. Capuano, 
    381 F.3d 6
    , 26–27 (1st Cir.
    2004); Action Mfg., Co. v. Simon Wrecking Co., 287 Fed.
    App’x 171, 174–76 (3d Cir. 2008); PCS Nitrogen, Inc. v.
    Ross Dev. Corp., 
    104 F. Supp. 3d 729
    , 744 (D.S.C. 2015).
    On this factual record, Atlantic Richfield has the better
    argument. We have held that the full dollar value of a
    settlement agreement to discharge CERCLA liability is not
    automatically subject to contribution. AmeriPride Servs.
    Inc. v. Texas E. Overseas Inc., 
    782 F.3d 474
    , 490 (9th Cir.
    2015) (“[I]f a party who was liable under § 9607(a) entered
    into a settlement agreement to discharge its CERCLA
    liability to a third party, it can seek contribution under
    § 9613(f)(1) only for the settlement costs that were for
    necessary response costs incurred consistent with the
    NCP.”). In many cases, the full settlement amount may
    equate with the necessary response costs incurred—but that
    is not inherently so. Thus, funding a settlement obligation,
    on its own, does not automatically render the entire sum
    compensable in a contribution action, even if that payment
    is irrevocable. A party seeking contribution must still show
    that the settlement amount represents “necessary response
    costs incurred consistent with the NCP.”
    Id. Although the meaning
    of “incur” is sufficiently broad that it does not
    require that an expense already be paid, it is also not so broad
    that it encompasses future expenses that are mere
    potentialities. See Trimble v. Asarco, Inc., 
    232 F.3d 946
    , 958
    (8th Cir. 2000) (“We do not dispute plaintiffs’ point that a
    party may be found to have ‘incurred’ a cost without having
    actually paid for it[;] . . . a finding that a cost has been
    12           ASARCO V. ATLANTIC RICHFIELD
    ‘incurred’ may be based upon an existing legal obligation.
    However, the mere possibility, even the certainty, that an
    obligation to pay will arise in the future does not establish
    that a cost has been incurred, but rather establishes that a cost
    may be incurred, or will be incurred.”), abrogated on other
    grounds by Exxon Mobil Corp. v. Allapattah Servs., Inc.,
    
    545 U.S. 546
    (2005); see also Chubb Custom Ins. Co. v.
    Space Sys./Loral, Inc., 
    710 F.3d 946
    , 961 (9th Cir. 2013)
    (explaining that courts apply the ordinary meaning of the
    term “incur” in the CERCLA context, “which is ‘[t]o acquire
    or come into,’ ‘[t]o become liable or subject to as a result of
    one’s action,’ to ‘bring upon oneself’” (quoting Am.
    Heritage Dictionary (4th ed. 2000)) (alterations in original)).
    Reinforcing our focus on non-speculative costs actually
    incurred, our circuit historically has refused to award future
    response costs. Stanton 
    Rd., 984 F.2d at 1021
    –22 (holding
    that “CERCLA prohibits awards of future response costs”
    and finding error in the district court’s order requiring
    defendants to place $1.1 million in escrow for future cleanup
    costs); Dant & 
    Russell, 951 F.2d at 249
    –50 (explaining that
    response costs not yet incurred cannot be recovered under
    CERCLA, and highlighting that “[s]ection 9607(a)(4)(B)
    permits an action for response costs ‘incurred’—not ‘to be
    incurred’”). Likewise, we have found “no suggestion in the
    statute that Congress intended CERCLA to create a general
    federal right of contribution for damages and response costs
    that are not otherwise cognizable under the statute.”
    
    AmeriPride, 782 F.3d at 490
    (quoting Cty. Line Inv. Co. v.
    Tinney, 
    933 F.2d 1508
    , 1517 (10th Cir. 1991)). Therefore,
    we conclude that speculative, potential future response costs
    are not recoverable in a CERCLA contribution action, even
    if the party seeking contribution has already made an outlay
    for such costs pursuant to a settlement. Instead, a declaratory
    judgment, whereby liability for future response costs would
    ASARCO V. ATLANTIC RICHFIELD                            13
    be allocated at a set percentage across responsible parties, is
    the proper mechanism for recouping future response costs in
    the CERCLA regime. 5 See Boeing Co. v. Cascade Corp.,
    
    207 F.3d 1177
    , 1191 (9th Cir. 2000) (holding that
    declaratory judgments are appropriate not only in the context
    of cost recovery actions brought under 42 U.S.C. § 9607, but
    also in CERCLA contribution actions brought under
    42 U.S.C. § 9613).
    Here, based on the most recent accounting as of trial,
    METG had spent only about $48.5 million of its allocated
    funds, leaving it with another $50 million for further cleanup
    efforts. Although the settlement figure was based on the
    estimated cost of a pump-and-treat remedy, 6 METG does not
    plan to implement a pump-and-treat remedy at this time. It
    considers a pump-and-treat remedy too costly, potentially
    ineffective, and risky in that it could affect the stability of
    the arsenic-contaminated groundwater plume. Instead,
    METG’s proposed final remedies are meaningfully less
    costly—quoted to bring the full cleanup costs for the Site to
    about $61.4 million.
    Asarco challenges METG’s assessment and proffered
    the expert testimony of Margaret Staub, who emphasized
    that the original settlement contemplated implementation of
    a pump-and-treat system at the Site. Staub opined that the
    5
    We also do not intend to foreclose a settling party from seeking
    contribution for costs not yet incurred in a future action, once those costs
    have been incurred within the meaning of CERCLA, to the extent
    otherwise permitted by law.
    6
    The settlement does not require that any particular remedial
    measure be taken to clean up the Site. Therefore, the settlement does not
    specifically mandate a pump-and-treat remedy, even though it was
    priced with such a remedy in mind.
    14           ASARCO V. ATLANTIC RICHFIELD
    measures proposed by METG likely would not restore the
    groundwater to acceptable levels, and that, while she could
    not say definitively what the final remedy would be,
    “something at some point is going to have to be done.” But
    Staub’s opinion, upon which the district court relied, does
    not provide sufficiently concrete evidence that the entire sum
    would likely be expended to remediate the Site. Not only is
    Staub’s opinion steeped in speculation to begin with, but
    there is a vast logical leap from the broad conclusion that
    “something” further will need to be done to remediate the
    Site, to the specific quantification of the necessary response
    costs for the Site at $111.4 million or greater.
    In short, Asarco relies on conjecture rather than firmly-
    grounded facts and figures. As noted, METG has not paid
    for or assumed an obligation to pay for a pump-and-treat
    remedy, nor has it earmarked any funds for that purpose. At
    this stage, any such response costs remain speculative.
    Further adding to the uncertainty surrounding total response
    costs, the settlement contains a reversion provision that
    redirects any unused Site cleanup funds to other causes,
    including the other contaminated properties subject to the
    broader settlement. Although Asarco is liable for the
    cleanup of all the covered properties, Atlantic Richfield is
    not.
    Asarco’s argument, which the district court adopted,
    strays from CERCLA’s legal framework. The district court
    explained:
    The Court . . . concludes that unless and until
    the groundwater is restored to achieve
    [maximum contaminant levels] and drinking
    water standards, something more substantial
    will need to be done. Whether there remain[]
    sufficient funds in the trust to accomplish this
    ASARCO V. ATLANTIC RICHFIELD                   15
    task, and whether a pump and treat system is
    the ultimate solution, are not the controlling
    questions. Regardless of the answer to those
    two questions, and notwithstanding Atlantic
    Richfield’s arguments to the contrary, the
    Court is convinced that the balance of the
    approximate $50 million in the trust will most
    likely be expended to achieve the mandated
    remediation results.
    Working from that premise, the court found the full
    $111.4 million settlement amount to be necessary response
    costs eligible for contribution. While we do not question the
    district court’s finding that further remedial action may be
    necessary in the future, its forecast was not adequately
    tethered to any concrete evidence in the record.
    If, as the district court concludes, “something more
    substantial will need to be done,” a party in Asarco’s
    position ultimately can recover the corresponding response
    costs from its fellow responsible parties. But until further
    information is known about the nature and costs of that
    “something more,” those future costs are not eligible for
    contribution. In the meantime, the contribution-seeker can
    pursue (i) contribution for those necessary response costs
    that have been incurred to date, and (ii) a declaratory
    judgment to establish liability and a contribution allocation
    for those costs that have not been incurred yet, but may be
    incurred in the future.
    We emphasize, however, that our holding is a narrow
    one. We are presented with a cash-out bankruptcy
    settlement, reached as part of a global settlement of liability
    for several contaminated sites, with a reversion provision
    that diverts unused funds to other sites for which only one of
    16           ASARCO V. ATLANTIC RICHFIELD
    the parties is responsible. We likewise face the unusual
    scenario in which the projected costs of the remediation
    process, as well as the proposed means of remediation, have
    fluctuated dramatically since the time the settlement was
    reached; significantly, one of the core facets of the initial
    remediation plan, a pump-and-treat remedy, now appears
    extremely unlikely to come to fruition. On this record,
    Asarco has failed to adequately support its asserted response
    costs.
    Finally, to the extent the parties disagree about whether
    the costs of a pump-and-treat system (or other yet-to-be-
    incurred costs) would be “necessary,” we need not resolve
    the parties’ dispute. Because such costs have not been
    incurred, they cannot be awarded even if they satisfy the
    remaining requirements for contribution eligibility. For
    these reasons, we vacate the district court’s finding that the
    full $111.4 million settlement amount was eligible for
    contribution and remand for further consideration of what
    necessary response costs were actually incurred within the
    meaning of CERCLA.
    B. The District Court Did Not Err in Allocating
    Responsibility for Twenty-Five Percent of the
    Response Costs to Atlantic Richfield.
    Atlantic Richfield argues that the district court inflated
    its liability far beyond its actual environmental impact and
    ascribed to it a share of the response costs that bore little
    relation to the evidence presented at trial. Specifically,
    Atlantic Richfield contends that the district court failed to
    take account of the volume and toxicity of the waste each
    party handled; failed to explain adequately what factors it
    considered in reaching its allocation; and arrived at an
    allocation that meaningfully outpaced the level of
    contamination it could have caused. We disagree, and we
    ASARCO V. ATLANTIC RICHFIELD                            17
    hold that the district court did not err in devising an equitable
    allocation of liability for the Site cleanup.
    In a contribution action, CERCLA empowers a district
    court to “allocate response costs among liable parties using
    such equitable factors as the court determines are
    appropriate.” 42 U.S.C. § 9613(f)(1). On appeal, we then
    “review for an abuse of discretion the equitable factors that
    a district court considers in allocating CERCLA costs and
    review for clear error the allocation according to the selected
    factors.” TDY Holdings, LLC v. United States, 
    885 F.3d 1142
    , 1146–47 (9th Cir. 2018).
    As an initial matter, we conclude that the district court
    properly exercised its discretion by anchoring its analysis
    around the so-called “Gore factors.” 7 See
    id. at 1147
    (approving of the use of the Gore factors in CERCLA costs
    allocation); United States v. Burlington N. & Santa Fe Ry.
    Co., 
    520 F.3d 918
    , 940 n.26 (9th Cir. 2008) (same), rev’d on
    other grounds, 
    556 U.S. 599
    (2009). The district court also
    acted well within its discretion in its broader efforts to
    tabulate the parties’ historical responsibility for the
    contamination, its choice to ground that assessment in the
    expert testimony offered by the parties, and its concern with
    7
    The Gore factors are: (i) the ability of the parties to demonstrate
    that their contribution to a discharge, release, or disposal of a hazardous
    waste can be distinguished; (ii) the amount of the hazardous waste
    involved; (iii) the degree of toxicity of the hazardous waste involved;
    (iv) the degree of involvement by the parties in the generation,
    transportation, treatment, storage, or disposal of the hazardous waste;
    (v) the degree of care exercised by the parties with respect to the
    hazardous waste concerned, taking into account the characteristics of
    such hazardous waste; and (vi) the degree of cooperation by the parties
    with federal, state, or local officials to prevent any harm to public health
    or the environment. See TDY 
    Holdings, 885 F.3d at 1146
    n.1.
    18             ASARCO V. ATLANTIC RICHFIELD
    the duration of each party’s operations at the Site. 8 Nor was
    it improper for the court to determine that it could not and
    need not allocate response costs to a mathematical certainty,
    and that it could apply general principles of fairness and
    equity in deciding whether to err on the side of over- or
    under-compensation. The district court was not required to
    adopt the particular set of factors, or the weighting among
    them, for which Atlantic Richfield advocated. Because we
    find no abuse of discretion at this step of the analysis, the
    propriety of the district court’s allocation decision turns on
    whether it committed clear error in its allocation of Atlantic
    Richfield’s responsibility. See TDY 
    Holdings, 885 F.3d at 1146
    –47.
    We conclude that the district court did not clearly err in
    its factual findings supporting its allocation decision. The
    district court, in a ninety-five page order, made extensive
    findings about the historical use and contamination of the
    Site by Asarco and Atlantic Richfield. It described in detail
    each party’s operations at the Site; their respective uses and
    releases of arsenic, to the extent knowable from the historical
    records; their efforts, and failures, to prevent environmental
    contamination; and their interactions with the government
    concerning accountability and remediation. Although the
    district court’s discussion of the nexus between its factual
    findings and the Gore factors could have been clearer at
    times, the court’s findings and overarching analysis were
    8
    We are not persuaded by Atlantic Richfield’s argument that the
    comparative duration of the parties’ operations is “irrelevant” to an
    appropriate allocation. The number of years a polluter operates can be
    tied to the amount of pollution it generates and its overall responsibility
    for contamination. Atlantic Richfield contends that other factors would
    be superior, but that does not render the district court’s approach to be
    an abuse of discretion.
    ASARCO V. ATLANTIC RICHFIELD                    19
    sufficiently robust that we do not find reversible error on that
    basis here.
    The first Gore factor inquires into the ability of the
    parties to demonstrate that their contribution to a discharge,
    release, or disposal of a hazardous waste can be
    distinguished.
    Id. at 1146
    n.1. The district court explained
    that the “sparse historical record” complicated the task of
    distinguishing the parties’ contributions, noting a lack of
    clarity as to “the precise nature and amount of pollutants”
    historically emitted by each operator. It noted that the
    deficiencies in the record were partially attributable to
    Atlantic Richfield’s longstanding denial of responsibility for
    contamination at the Site. Nonetheless, the court found that
    the record generally “revealed enough information to
    understand the history of operations . . . at the Site,” coupled
    with the aid of expert testimony, such that it could make a
    rough assessment of the parties’ respective contributions.
    The second and third Gore factors ask how much
    hazardous waste was involved, as well as the degree of
    toxicity of that waste.
    Id. The fourth Gore
    factor considers
    the degree of involvement by the parties in the generation,
    transportation, treatment, storage, or disposal of the
    hazardous waste.
    Id. To this end,
    the district court made
    detailed findings about the historical operations of Asarco
    and Atlantic Richfield, including the manners in which each
    used and released arsenic at the Site. It recognized, as do
    both parties, that “the majority of the groundwater
    contamination METG is remediating at the Site was caused
    by Asarco’s operations.” But the court noted that both
    parties used vast quantities of arsenic-laden materials in their
    everyday operations and generated substantial amounts of
    arsenic-laden byproducts. Although the court could not
    quantify all of Atlantic Richfield’s past releases, given the
    20           ASARCO V. ATLANTIC RICHFIELD
    large gaps in the historical record, it noted that Atlantic
    Richfield released so much toxic fly ash and coal dust that it
    received complaints from the City of Helena. The court
    likewise made findings as to the relative toxicity of arsenic
    in the various materials used by Asarco and Atlantic
    Richfield, to the extent those toxicities could be ascertained.
    The fifth Gore factor assesses the degree of care
    exercised by the parties with respect to the hazardous waste
    concerned.
    Id. The district court
    reviewed the precautions
    taken by both Asarco and Atlantic Richfield to protect
    against environmental contamination, as well as the failures
    of certain preventive measures taken by each party—such as
    leakages in the protective infrastructure and the careless
    handling of contaminated wash-down water. The court
    further noted Asarco’s adoption of relatively intensive
    preventive measures toward the later years of its operation,
    including replacing Thornock Lake with a massive steel
    holding tank, as well as broader remediation efforts
    beginning in the 1990s.
    The sixth Gore factor evaluates the degree of cooperation
    by the parties with federal, state, or local officials to prevent
    any harm to public health or the environment.
    Id. As to this
    factor, the court explained that Atlantic Richfield had
    repeatedly evaded responsibility for any environmental
    contamination at the Site, flagrantly misled the EPA
    regarding its releases at the Site, and made ongoing
    misrepresentations throughout the course of the litigation.
    Atlantic Richfield contends the district court’s
    misrepresentation findings are “irrelevant” to its appeal of
    the twenty-five percent allocation because the court
    separately awarded a $1 million uncertainty premium
    pursuant to the sixth Gore factor. However, it is not
    inconsistent for the district court to award an uncertainty
    ASARCO V. ATLANTIC RICHFIELD                    21
    premium based on the egregiousness of its findings as to the
    sixth Gore factor, and also separately to consider Atlantic
    Richfield’s non-cooperation when weighing the equities in
    the context of reaching its baseline allocation.
    In addition to its core factual findings, the district court
    considered the expert testimony proffered by the parties in
    arriving at its allocation. Asarco’s expert proposed three
    alternative liability allocation strategies, which apportioned
    Atlantic Richfield’s responsibility at twenty-five percent to
    forty-one percent depending on the method. Atlantic
    Richfield’s expert focused on challenging Atlantic
    Richfield’s liability altogether and opined that Atlantic
    Richfield should have zero responsibility for the Site
    cleanup. The court reviewed the testimony of the parties’
    dueling experts, discussing the merits and shortcomings of
    each. The court found the opinions of Asarco’s expert, Andy
    Davis, “to be compelling and persuasive,” adding that he
    “was the only witness at trial who was qualified by
    education, training, experience, and the work he performed
    in this case, to quantify the contribution of arsenic made by
    Anaconda’s 45 years of operation at the Site.” By contrast,
    the court found that Atlantic Richfield’s expert, Brian
    Hansen, focused too much on Asarco’s operations and tried
    so hard to minimize Anaconda’s role that he failed to provide
    a useful quantification of its contamination. The court
    further found that Hansen failed to account for several
    material historical documents, and “le[ft] the majority of
    expert Davis’s opinions largely unchallenged.”
    The district court favored Davis’s most conservative
    allocation, which ascribed twenty-five percent of the total
    liability to Atlantic Richfield. It rejected Asarco’s higher
    proposed allocations, as well as Atlantic Richfield’s
    22             ASARCO V. ATLANTIC RICHFIELD
    proposed zero percent allocation. 9 Davis’s conservative
    allocation, i.e., “Strategy III,” assigned equal responsibility
    to Asarco and Atlantic Richfield for discharges into the north
    plume and the Thornock Pond and Lake area plume, adjusted
    for the respective time periods the parties operated in each
    region, and then adjusted for the square footage of the
    contaminated groundwater in each area. The court found
    this strategy appealing, because it accounted for the parties’
    differential time periods of ownership—notably, a factor that
    favored Atlantic Richfield due to its comparatively short-
    lived operations at the Site. Particularly given the failure of
    Atlantic Richfield’s expert to proffer a well-supported,
    sensible alternative allocation, the district court reasonably
    resorted to the most conservative of Asarco’s proposed
    allocations. 10
    The district court acknowledged that all the allocation
    strategies presented were imperfect and explained that it
    would compensate for the mathematical uncertainties by
    considering “such equitable factors as the court determines
    are appropriate,” per the framework of CERCLA. 42 U.S.C.
    9
    The district court also rejected three alternative allocations
    suggested by Atlantic Richfield in its proposed amended post-trial
    findings of fact and conclusions of law. Atlantic Richfield contests the
    court’s cursory rejection of those alternatives. However, Atlantic
    Richfield devoted nearly all of its energy at trial—and all of its expert
    testimony—to challenging any attribution of responsibility to Atlantic
    Richfield, so it provided minimal support for these alternative
    allocations. Although the court’s rejection was terse, it was sufficient
    under the circumstances—especially when coupled with the district
    court’s explanation of the allocation it did choose.
    10
    Moreover, that allocation aligned with the overarching theme of
    the court’s factual findings, i.e., that Asarco bore responsibility for the
    vast majority of the Site’s contamination, but Atlantic Richfield was
    more than a de minimis polluter.
    ASARCO V. ATLANTIC RICHFIELD                           23
    § 9613(f)(1). Ultimately, the court used the Gore factors—
    as well as the general equitable principle that the
    cooperating, settling party should receive the benefit of the
    doubt—to support its decision to adopt an allocation that
    erred on the side of over-compensation rather than under-
    compensation for the contamination emitted by Atlantic
    Richfield. Because these equitable factors weighed in
    Asarco’s favor, and the court found Davis’s “Strategy III” to
    be the most compelling of the proffered allocation strategies,
    it decided to stand by a twenty-five percent allocation of
    responsibility to Atlantic Richfield. Because the district
    court assessed the record evidence and underlying equities
    with sufficient rigor and care, we affirm. 11
    Finally, Atlantic Richfield argues that the district court’s
    decision provided an insufficient articulation of the
    reasoning behind its allocation. We conclude that the court
    below made a sufficient record to inform our review. The
    court’s ninety-five page decision is expansive and detailed,
    and it thoughtfully grapples with a challenging case. A
    decision need not be articulated with perfection to meet the
    standards we have set forth in our case law. See Traxler v.
    Multnomah County, 
    596 F.3d 1007
    , 1016 (9th Cir. 2016)
    (explaining that the district court must articulate its
    reasoning in a manner sufficient to permit meaningful
    appellate review, and remanding where the record “d[id] not
    11
    Atlantic Richfield further argues that a twenty-five percent
    allocation exceeds its realistic share of the Site contamination. But the
    district court was not required to allocate response costs precisely along
    the lines of the parties’ emissions. Because consideration of “equitable
    factors” is permissible, it is immaterial if the court did not apportion
    response costs perfectly in line with emissions—especially where no
    party has been able to quantify those emissions with precision.
    24            ASARCO V. ATLANTIC RICHFIELD
    permit [the court] to infer a rationale”). For these reasons,
    we affirm the district court’s allocation decision.
    Each party shall bear its own costs.
    AFFIRMED IN PART, VACATED IN PART, AND
    REMANDED.