Court Opinion

ID: 4565249
Source: CourtListenerOpinion
Date Created: 2020-09-14 17:00:59.098128+00
Date Added: 2024-06-11T12:40:18.028247
License: Public Domain

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.