                   FOR PUBLICATION
  UNITED STATES COURT OF APPEALS
       FOR THE NINTH CIRCUIT

UNITED STATES OF AMERICA,                 
                             Plaintiff,
                and
DEPARTMENT OF TOXIC SUBSTANCES
CONTROL, STATE OF CALIFORNIA,
                 Plaintiff-Appellant,
                                                No. 03-17125
                 v.
                                                 D.C. Nos.
BURLINGTON NORTHERN & SANTA
FE RAILWAY COMPANY, as
                                             CV-92-05068-OWW
                                              CV-96-06226-OWW
successor in interest to the                  CV-96-06228-OWW
Atchison, Topeka & Santa Fe
Railway Company; UNION PACIFIC
TRANSPORTATION COMPANY, as
successor in interest to the
Southern Pacific Transportation
Company; SHELL OIL COMPANY,
              Defendants-Appellees.
                                          




                               3209
3210 DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN



UNITED STATES OF AMERICA,                 
                 Plaintiff-Appellant,
                and
DEPARTMENT OF TOXIC SUBSTANCES
CONTROL, STATE OF CALIFORNIA,
                             Plaintiff,
                 v.                             No. 03-17153
BURLINGTON NORTHERN & SANTA
FE RAILWAY COMPANY, as
                                                 D.C. No.
                                              CV-92-05068-OWW
successor in interest to the
Atchison, Topeka & Santa Fe
Railway Company; UNION PACIFIC
TRANSPORTATION COMPANY, as
successor in interest to the
Southern Pacific Transportation
Company; SHELL OIL COMPANY,
              Defendants-Appellees.
                                          
       DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN 3211



UNITED STATES OF AMERICA;                  
DEPARTMENT OF TOXIC SUBSTANCES
CONTROL, STATE OF CALIFORNIA,
                Plaintiffs-Appellees,
                 v.
BURLINGTON NORTHERN & SANTA
FE RAILWAY COMPANY, as
successor in interest to the                       No. 03-17169
Atchison, Topeka & Santa Fe
Railway Company; UNION PACIFIC                    D.C. No.
                                               CV-92-05068-OWW
TRANSPORTATION COMPANY, as                         OPINION
successor in interest to the
Southern Pacific Transportation
Company,
                         Defendants,
                and
SHELL OIL COMPANY,
               Defendant-Appellant.
                                           
         Appeal from the United States District Court
             for the Eastern District of California
         Oliver W. Wanger, District Judge, Presiding

                  Argued and Submitted
       September 12, 2005—San Francisco, California
        Submission Withdrawn September 14, 2005
               Resubmitted March 16, 2007

                       Filed March 16, 2007

       Before: Betty B. Fletcher, John R. Gibson,* and
              Marsha S. Berzon, Circuit Judges.

   *The Honorable John R. Gibson, Senior United States Circuit Judge for
the Eighth Circuit, sitting by designation.
3212 DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN
                 Opinion by Judge Berzon
3216 DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN


                         COUNSEL

Aaron P. Avila, Department of Justice, Washington, D.C.,
argued the case for appellant EPA; Kelly Johnson, Acting
Assistant Attorney General, David C. Shilton, James R.
MacAyeal, and John T. Stahr, Department of Justice, Envi-
ronment and Natural Resources Division, Washington, D.C.,
Allyn Stern, Office of Regional Counsel, EPA, were on the
briefs for appellant EPA.

Reed Sato, Deputy Attorney General of the State of Califor-
nia, Sacramento, California, argued the case and was on the
briefs for appellant California Department of Toxic Sub-
stances Control; Bill Lockyer, Attorney General of the State
of California, Tom Greene, Chief Assistant Attorney General,
and Theodora P. Berger, Senior Assistant Attorney General,
Sacramento, California, were on the briefs for appellant Cali-
fornia Department of Toxic Substances Control.

John F. Barg, San Francisco, California, argued the case for
appellees Burlington Northern & Santa Fe Railway Company
and Union Pacific Transportation Company; Marc A. Zeppe-
       DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN 3217
tello, San Francisco, California, was on the briefs for the
appellees.

Michael K. Johnson, San Francisco, California, argued the
case for appellee-cross-appellant Shell Oil Company; Randall
J. Heldt, Shell Oil Company, Houston, Texas, was on the
briefs for appellee-cross-appellant Shell.


                              OPINION

BERZON, Circuit Judge:

   A now-defunct company, Brown & Bryant, Inc. (B&B),
owned and operated a facility at which toxic chemicals were
stored and distributed. Part of the land on which the chemical
operation was located was owned by two railroad companies
(the Railroads), and some of the chemicals used by B&B were
supplied and delivered to the facility by Shell Oil Company
(Shell). Because toxic chemicals remaining at the facility
threatened groundwater and may continue to do so in the
future, the United States Environmental Protection Agency
(EPA) and the State of California’s Department of Toxic Sub-
stances Control (DTSC) spent a considerable amount of
money to clean up the site and may need to spend more in the
future. The two agencies sought to recover these response
costs under the Comprehensive Environmental Response,
Compensation, and Liability Act, 42 U.S.C. §§ 9601 9675,1
(CERCLA), but the district court held the Railroads and Shell
liable for only a minor portion of the total cleanup costs. B&B
was defunct by that time, and so could not contribute to the
cleanup costs. The agencies were thus left holding the bag for
a great deal of money.
  1
   Unless otherwise noted, all statutory citations are to Title 42 and the
2000 edition of the U.S. Code.
3218 DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN
   Seeking to hold the Railroads and Shell jointly and sever-
ally liable for the entire judgment, the agencies appeal. Shell
cross-appeals, claiming that it was not an “arranger” under
CERCLA, § 9607(a)(3), and therefore is not a party on whom
any cleanup liability can be imposed. We reverse the portion
of the judgment that declined to impose full joint and several
liability on the Railroads and Shell and affirm the portion of
the judgment that imposed liability on Shell as an arranger.2

                           I.   Background

   Beginning in 1960, B&B operated an agricultural chemical
storage and distribution facility in Arvin, California on a 3.8-
acre parcel of land (the B&B parcel). In 1975, B&B’s agricul-
tural chemical distribution business outgrew that parcel, and
B&B began leasing a 0.9-acre parcel of land adjacent to its
own parcel. The 0.9-acre parcel (the Railroad parcel) was
jointly owned by the Railroads — Atchison, Topeka & Santa
Fe Railroad Co., the predecessor in interest to Burlington
Northern & Santa Fe Railway Co., and Southern Pacific
Transportation Co., the predecessor in interest to Union
Pacific Transportation Co. B&B used the Railroad parcel
principally to park fertilizer rigs.

  The Railroad parcel comprised the western portion of the
Arvin site.3 Directly to the east of the Railroad parcel sat
B&B’s warehouse. The Railroad parcel, like the rest of the
Arvin site, was graded toward a drainage pond on the B&B
parcel.
  2
     The Railroads have requested judicial notice of the EPA proceedings
concerning their suit for reimbursement from the government and of the
stay of those proceedings pending the determination of joint and several
liability in this case. These proceedings do not “ ‘have a direct relation to
matters at issue.’ ” United States ex rel. Robinson Rancheria Citizens
Council v. Borneo, Inc., 971 F.2d 244, 248 (9th Cir. 1992) (citation omit-
ted). We therefore deny the Railroads’ request for judicial notice.
   3
     We refer to the B&B and Railroad parcels together as the “Arvin site.”
       DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN 3219
   B&B used the Railroad parcel as an integral part of its
overall agricultural chemical facility. From its facility B&B
sold local growers agricultural chemical products produced by
various manufacturers. In particular, B&B purchased,
received delivery of, stored on the Arvin site, and distributed
two Shell-produced agricultural chemicals: the soil fumigants
D-D and Nemagon. D-D and Nemagon — members of a class
of chemicals called nematocides — are designed to kill nema-
todes, microscopic worms that attack the roots of crops.
Nematocides work by penetrating the soil and then dispersing.
B&B also stored on the Arvin site dinitro (dinoseb) weed
killer, purchased from Dow Chemical Company.

   During the 1960s and 1970s, Shell strongly encouraged its
customers, including B&B, to purchase D-D in bulk, a policy
requiring customers to maintain large storage tanks. Shell
delivered the bulk D-D to B&B “FOB Destination” via com-
mon carrier trucks.4 When the trucks carrying D-D arrived at
the Arvin facility, the contents of the trucks were transferred
to B&B’s large tanks by hoses. The process was quite messy,
with frequent spills.

  To apply D-D to growers’ fields, B&B used rigs loaded
with the chemical. The rigs were stored on the Railroad par-
cel, as were bulk containers of dinoseb and, occasionally,
empty fertilizer cans. Chemicals also reached the Railroad
parcel through water flow from the B&B parcel.

   In 1978, after a windstorm destroyed the bulk D-D storage
tank used to store Shell D-D, B&B began using converted
stainless steel milk trailers to store the bulk D-D. The chemi-
cal, which is highly corrosive and eats through steel, can
cause leakage in steel tanks only a few years old. B&B kept
  4
    “FOB Destination” means “free on board” and “when the term is
F.O.B. the place of destination, the seller must at his own expense and risk
transport the goods to that place and there tender delivery of them.”
U.C.C. § 2-319(1)(b) (2003).
3220 DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN
these leak-prone tanks all over the Arvin facility, including on
the Railroad parcel.

   D-D, when it leaks, evaporates quickly if exposed to air but
is highly soluble in water. When D-D infiltrates the ground,
it moves through the soil by molecular diffusion, dispersing
in all directions. A slight pull from gravity, however, makes
the chemical a bit more likely to flow downward into ground-
water than laterally through the soil. Dinoseb, similarly, tends
to move to the groundwater table if there is water movement
in that direction. No toxic chemicals can reach the groundwa-
ter level currently used as a source of drinking water because
of an impermeable layer of soil. The next highest level, how-
ever, is a potential source of drinking water, and contamina-
tion can reach that level.

   After more than twenty years of leakage and dissemination
of hazardous materials, the DTSC in 1983 found B&B in vio-
lation of several hazardous waste laws. The EPA investigated
separately and found evidence of substantial soil and ground-
water contamination at B&B’s Arvin facility. The EPA and
DTSC (the Governments) began to remedy the contamination
pursuant to their cleanup authority under CERCLA, incurring
substantial remediation costs. In 1991, the EPA ordered the
Railroads to take specific preventative steps on the Railroad
parcel, including installing groundwater monitoring wells.
None of the contamination requiring immediate remediation
was on the Railroad parcel.

   In 1992, the Railroads filed an action against B&B and cer-
tain of its principals for contribution for costs incurred in the
EPA-ordered cleanup. Four years later, the Governments each
filed CERCLA actions against B&B, the Railroads, and Shell
for reimbursement of their investigation and cleanup costs.5
The district court consolidated the three cases and, after a
  5
  The relevant statutory sections covering contribution and reimburse-
ment actions, § 9613(f) and § 9607, are quoted later in this opinion.
       DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN 3221
twenty-seven day bench trial, issued an exceedingly detailed
185-page Findings of Fact and Conclusions of Law, thereafter
slightly amended.6

   The district court found the Railroads liable as owners of
the Arvin facility and as persons who “at the time of disposal
of any hazardous substance owned or operated any facility at
which such hazardous substances were disposed of.
§ 9607(a)(1), (2). Shell was held liable as a “person who . . .
arranged for disposal . . . of hazardous substances.”
§ 9607(a)(3). Turning to whether the Railroads and Shell were
liable for all or only a portion of the cleanup costs, the district
court found that the harm to the Arvin site was capable of
apportionment and proceeded to apportion it. The Railroads
and Shell had, by acknowledging no liability at all, taken what
the district court termed a “ ‘scorched earth,’ all-or-nothing
approach to liability,” and so provided little assistance on the
apportionment issue. The district court nonetheless proceeded
to “perform the equitable apportionment analysis demanded
by the circumstances of the case.”

   For the Railroads, the court multiplied three proportions:
(1) the percentage of the overall site that was owned by the
Railroads, 19.1%;7 (2) the percentage of time that the Rail-
roads leased the parcel in relation to B&B’s total operations,
45%;8 and (3) the fraction of hazardous products attributable
to the Railroad parcel, 66%.9 This calculation resulted in a
  6
     Quotations from and discussion of the district court’s ruling in this
opinion concern the district court’s Amended Findings of Fact and Con-
clusions of Law unless otherwise noted.
   7
     0.9 acres ÷ 4.7 acres = 0.191 (19.1%).
   8
     B&B began operations in 1960. The Railroad parcel was leased start-
ing in 1975. In 1988, B&B ceased its operations at Arvin. Thus, the Rail-
road parcel was part of the Arvin site for 13 of 29 years, or 45% of the
time B&B operated the facility.
   9
     There were three pertinent chemicals: D-D, Nemagon, and dinoseb.
The district court found that although there was some D-D contamination
3222 DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN
determination of 6% liability. Then, to account for any “cal-
culation errors,” the district court assumed 50% error and
raised the Railroads’ proportion of the total liability to 9%.

   For Shell, the district court approximated the percentages
of leakage from various activities attributable to Shell and
multiplied them together to set Shell’s proportion of the total
liability at 6%.10 Shell was also assigned, in the contribution
action, 6% of the costs incurred by the Railroads in their
cleanup effort.11

   DTSC and the EPA timely appealed the district court’s
judgment. Shell timely cross-appealed the finding that it was
liable as an “arranger” under CERCLA.

        II.   Standards of Liability Under CERCLA

   [1] CERCLA was enacted in 1980 to provide for effective
responses to health and environmental threats posed by haz-
ardous waste sites. See generally Mardan Corp. v. C.G.C.
Music, Ltd., 804 F.2d 1454, 1455 (9th Cir. 1986). Under
CERCLA, state and federal governments can first begin the
cleanup of toxic areas, see § 9604(a)-(d), and then sue poten-
tially responsible parties (PRPs) for reimbursement, see
§ 9607(a). A key purpose of this scheme is “shift[ing] the cost
of cleaning up environmental harm from the taxpayers to the
parties who benefitted from the disposal of the wastes that
caused the harm.” EPA v. Sequa Corp. (In the Matter of Bell

attributable to the Railroad parcel, that “slight contamination is offset by
the fact that the [Arvin] Site is graded towards the southeast pond [on the
B&B parcel] and the levels of chemical contamination on the B&B parcel
are substantially higher than the reported detections on the Railroad par-
cel.” On that reasoning, the district court removed all D-D from the equa-
tion.
   10
      B&B, albeit insolvent, was assigned 100% joint and several liability.
   11
      The Railroads do not challenge the percentage of liability assigned to
Shell.
        DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN 3223
Petroleum Servs., Inc.), 3 F.3d 889, 897 (5th Cir. 1993) (cit-
ing United States v. Chem-Dyne Corp., 572 F. Supp. 802,
805-06 (S.D. Ohio 1983)).

   [2] In accord with this purpose, CERCLA is a “super-strict”
liability statute. Under its provisions, parties can be liable for
cleaning up toxic chemicals if they fit into one or more of the
four PRP categories set out in § 9607(a):

       (1)   the owner and operator of . . . a facility,

       (2) any person who at the time of disposal of any
       hazardous substance owned or operated any facility
       at which such hazardous substances were disposed
       of,

       (3) any person who by contract, agreement, or oth-
       erwise arranged for disposal or treatment, or
       arranged with a transporter for transport for disposal
       or treatment, of hazardous substances owned or pos-
       sessed by such person . . . , and

       (4) any person who accepts or accepted any haz-
       ardous substances for transport to disposal or treat-
       ment facilities . . . .

A “facility” is defined in § 9601(9)(B) as “any site or area
where a hazardous substance has been deposited, stored, dis-
posed of, or placed, or otherwise come to be located; but does
not include any consumer product in consumer use or any ves-
sel.”12 The statute’s basic liability provision, in turn, provides
that “subject only to the defenses set forth in subsection (b)
of this section [PRPs shall be liable for] — (A) all costs of
removal or remedial action incurred by the United States
  12
    The district court found that the entire Arvin site, including the Rail-
road parcel, was a single facility for the purposes of § 9607. The Railroads
do not appeal that finding.
3224 DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN
Government or a State or an Indian tribe not inconsistent with
the national contingency plan . . . .” § 9607(a). Thus, PRPs
can be responsible for the costs of cleaning up hazardous
waste sites without any finding that they were negligent or
that they caused the contamination, unless they can make out
the third-party defense set out in § 9607(b)(3).13

  A.         Validity of Apportionment

   [3] CERCLA does not address the question whether, as
between PRPs who are liable for cleanup costs, liability is
joint and several — meaning that each PRP responsible for all
cleanup costs at a facility is liable for such costs — or sever-
able — meaning that cleanup costs at a single facility can be
apportioned among PRPs on some basis.
  13
    Section 9607(b) reads:
          There shall be no liability under subsection (a) of this section
       for a person otherwise liable who can establish by a preponder-
       ance of the evidence that the release or threat of release of a haz-
       ardous substance and the damages resulting therefrom were
       caused solely by—
       ...
          (3) an act or omission of a third party other than an employee
       or agent of the defendant, or than one whose act or omission
       occurs in connection with a contractual relationship, existing
       directly or indirectly, with the defendant (except where the sole
       contractual arrangement arises from a published tariff and accep-
       tance for carriage by a common carrier by rail), if the defendant
       establishes by a preponderance of the evidence that (a) he exer-
       cised due care with respect to the hazardous substance concerned,
       taking into consideration the characteristics of such hazardous
       substance, in light of all relevant facts and circumstances, and (b)
       he took precautions against foreseeable acts or omissions of any
       such third party and the consequences that could foreseeably
       result from such acts or omissions.
(Emphasis added). Section 9607(b) also provides defenses for “an act of
God” and “an act of war.” § 9607(b)(1), (2).
        DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN 3225
   In this circuit, liability is joint and several when the harm
is indivisible. Fireman’s Fund Ins. Co. v. City of Lodi, 302
F.3d 928, 945 (9th Cir. 2002); see also Carson Harbor Vill.,
Ltd. v. Unocal Corp., 270 F.3d 863, 871 (9th Cir. 2001) (en
banc). Thus, a defendant “may be held fully liable for the
entire clean-up costs at a site despite the fact that the defen-
dant PRP was in fact responsible for only a fraction of the
contamination.” Fireman’s Fund, 302 F.3d at 945.

   We have also referred in general terms to the possibility of
apportioning liability. See id. (noting the use of “federal com-
mon law principles” of apportionment); Carson Harbor Vill.,
270 F.3d at 871 (stating that once liability has been found,
“the defendant may avoid joint and several liability by estab-
lishing that it caused only a divisible portion of the harm”).
Yet, in none of our cases has there been an actual dispute
regarding whether liability should be apportioned among the
liable PRPs.14 This case squarely presents that question. To
determine whether the district court was correct to apportion
liability in this case, we thus must address, initially, the gen-
eral propriety of severability.15 In line with every circuit that
  14
      The major cases addressing division of PRP liability under CERCLA
in the Ninth Circuit instead have been contribution cases among PRPs,
decided after joint liability was established, see, e.g., Carson Harbor Vill.,
270 F.3d at 871; Pinal Creek Group v. Newmont Mining Corp., 118 F.3d
1298, 1301 (9th Cir. 1997), or have addressed a different issue entirely,
see, e.g., Fireman’s Fund, 302 F.3d at 945 (analyzing the possibility that
CERCLA preempts state laws).
   15
      DTSC argues that the apportionment question is not properly before
us because it was not properly raised in the pretrial order, but we do not
agree. To preserve a claim, a party must put forward a position in the pre-
trial statement in a manner sufficient to put the opposing party on notice
and allow the trial court to consider its merits. See Cripe v. City of San
Jose, 261 F.3d 877, 886 n.9 (9th Cir. 2001) (refusing to hold that defen-
dants had waived an affirmative defense by mislabeling it, because the
court and plaintiffs were on notice of the real issue); Arizona v. Compo-
nents Inc., 66 F.3d 213, 217 (9th Cir. 1995) (noting that argument must
be raised sufficiently for the court to rule on it). Notice to the district court
is not an issue in this case, as the final decision addresses apportionment.
3226 DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN
has addressed the issue, we hold that apportionment is avail-
able at the liability stage.

   In so ruling we rely, as have the other circuits that have
analyzed the issue, on a seminal case decided in 1983 in the
Southern District of Ohio, Chem-Dyne. After reviewing the
evolution of the statute, Chem-Dyne concluded that liability
under § 9607(a) may be joint and several even though the
statute does not expressly so provide. Chem-Dyne, 572 F.
Supp. at 810. Suggesting that Congress intended to leave the
matter to the usual common law rules, adjusted to CERCLA
as necessary, Chem-Dyne held that courts should look to the
Restatement (Second) of Torts, as well as to other indications
of federal common law, for the principles of joint and several
liability applicable under CERCLA. See id. at 809-10. Later,
circuit court cases endorsed this approach. See Chem-Nuclear
Sys., Inc. v. Bush, 292 F.3d 254, 259-60 (D.C. Cir. 2002);
United States v. Hercules, Inc., 247 F.3d 706, 717 (8th Cir.
2001); United States v. Township of Brighton, 153 F.3d 307,
318 (6th Cir. 1998); Bell Petroleum, 3 F.3d at 895-96; United
States v. Alcan Aluminum Corp. (Alcan-PAS), 990 F.2d 711,
721-22 (2d Cir. 1993); United States v. Alcan Aluminum
Corp. (Alcan-Butler), 964 F.2d 252, 268-69 (3d Cir. 1992);
United States v. Monsanto Co., 858 F.2d 160, 171-72 (4th Cir.
1988).

   [4] As Chem-Dyne persuasively recounts, the history of
§ 107(a) of CERCLA, 42 U.S.C. § 9607(a), indicates that

While the Governments claim to have been unaware that they needed to
address the apportionment issue, their assertion is not supported by the
record. Both the Railroads and Shell directly addressed the apportionment
issue in their pretrial orders. The Railroads “den[ied] that they are jointly
and severally liable for the response costs claimed by the Government”
but argued that, if liable, they should only be responsible for that fraction
of the total mass of groundwater contamination proven to be traceable to
their parcel. Shell noted that joint and several liability is not mandatory
and cited cases regarding apportionment. As a result, we conclude that the
issue of apportioning liability was not waived and is properly before us.
       DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN 3227
although Congress declined to mandate joint and several lia-
bility, it did not intend by doing so “a rejection of joint and
severable liability.” Chem-Dyne, 572 F. Supp. at 808. Instead,
recognizing the difficulties inherent “ ‘in prescribing in statu-
tory terms liability standards which will be applicable in indi-
vidual cases,’ ” id. at 806 (quoting 126 CONG. REC. S14964
(Nov. 24, 1980) (remarks of Sen. Randolph)), Congress meant
“to have the scope of liability determined under common law
principles, where a court performing a case by case evaluation
of the complex factual scenarios associated . . . will assess the
propriety of applying joint and several liability on an individ-
ual basis,” id. at 808. We agree with this account of Con-
gress’s intent and hold that apportionment can be appropriate
under CERCLA.

  B.   Standards for Apportionment

   Because we hold that apportionment is available at the lia-
bility stage in CERCLA cases, we must determine the appro-
priate standards for determining when apportionment is
available and, when it is, how to ascertain the proper division
of damages among defendants. Again, we draw on the experi-
ence of our sister circuits.

   [5] The circuits that have addressed these questions have
looked to common law principles of tort in general, and the
Restatement in particular, for guidance as to when and how
to impose joint and several liability under § 9607(a). We
agree that this approach is proper and adopt it here. We also
follow Chem-Dyne and all of the courts of appeals that have
addressed the question in holding that the resulting standard
must be a uniform federal rule. See, e.g., Aviall Servs., Inc. v.
Cooper Indus., Inc., 312 F.3d 677, 684 (5th Cir. 2002) (hold-
ing that apportionment of CERCLA liability “is . . . a matter
of federal common law”), reversed on other grounds by 543
U.S. 157 (2004); United States v. Burlington N. R. Co., 200
F.3d 679, 697 (10th Cir. 1999) (same); Township of Brighton,
153 F.3d at 329 (same); Monsanto Co., 858 F.2d at 172
3228 DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN
(same). As Chem-Dyne noted, the legislative history of CER-
CLA supports such an approach, as does its policy favoring
national uniformity so as to discourage “illegal dumping in
states with lax liability laws.” Chem-Dyne, 572 F. Supp. at 809.16

   [6] The question, then, is what the uniform federal law
should be. Once again, all the circuits that have addressed this
question have followed Chem-Dyne, holding that the appro-
priate source for a common law rule of apportionment is Sec-
tion 433A of the Restatement of Torts. See Hercules, 247
F.3d at 716 & n.9, 717 (noting that courts support the divisi-
bility doctrine as borrowed from the Restatement); Bell Petro-
leum, 3 F.3d at 895 (relying on the Restatement); Chem-Dyne,
572 F. Supp. at 810 (establishing this method). We concur in
this conclusion generally, although we borrow from the
Restatement with two important caveats, as there are two
areas where the Restatement approach is a somewhat poor fit
and requires slight modifications to ensure that our approach
comports with the liability and remediation scheme of CER-
CLA. First, there are important distinctions between causa-
tion as conceived in the Restatement and causation in the
context of CERCLA. We describe these and import a nexus
  16
     The parties here have assumed that the apportionment standard must
be one of uniform federal common law. As stated above, every federal cir-
cuit to address the issue, including those decided after O’Melveny &
Myers v. FDIC, 512 U.S. 79 (1994), and Atherton v. FDIC, 519 U.S. 213
(1997), has shared that understanding. Although Atchison, Topeka &
Santa Fe Ry. Co. v. Brown & Bryant, Inc., 159 F.3d 358, 362-64 (9th Cir.
1997), questioned whether O’Melveny & Myers and Atherton upset Ninth
Circuit law with regard to the adoption of uniform federal common law
regarding successor liability under CERCLA, very different considerations
govern with respect to apportionment. In Atchinson, resolution of the
question of successor liability would resolve who was liable under
CERLA, an inquiry with roots in state corporate law. Here, the inquiry
diverges from state law completely. As we explain in this section, the
“super-strict” nature of CERCLA liability is sui generis, so there is no
state law directly applicable. The resulting apportionment analysis there-
fore requires a similarly unique set of considerations, married to the stat-
ute’s functions and purpose.
         DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN 3229
concept that relates to the particular PRP provisions at issue.
And second, the concept of “harm” in the Restatement as
actual injury does not correspond easily to CERCLA’s priori-
ties. We conclude instead that contamination and the cost of
remediation are both relevant for the “harm” analysis under
CERCLA. The Restatement’s fundamental reliance on objec-
tive rather than equitable considerations, however, does com-
port well with the “super-strict” nature of CERCLA and with
the development of the statute, leaving us to conclude that
equitable considerations have no role at this stage in the appli-
cable standards.

       1.    Causation

   [7] Section 433A of the Restatement allows for apportion-
ment of damages where “(a) there are distinct harms,[17] or (b)
there is a reasonable basis for determining the contribution of
each cause to a single harm.”18 RESTATEMENT (SECOND) OF
  17
    Comment b of section 433A notes:
     Distinct harms. There are other results which, by their nature, are
     more capable of apportionment. If two defendants independently
     shoot the plaintiff at the same time, and one wounds him in the
     arm and the other in the leg, the ultimate result may be a badly
     damaged plaintiff in the hospital, but it is still possible, as a logi-
     cal, reasonable, and practical matter, to regard the two wounds as
     separate injuries, and as distinct wrongs. The mere coincidence
     in time does not make the two wounds a single harm, or the con-
     duct of the two defendants one tort. There may be difficulty in
     the apportionment of some elements of damages, such as the pain
     and suffering resulting from the two wounds, or the medical
     expenses, but this does not mean that one defendant must be lia-
     ble for the distinct harm inflicted by the other.
  18
     Comment d of section 433A notes:
       Divisible harm. There are other kinds of harm which, while not
       so clearly marked out as severable into distinct parts, are still
       capable of division upon a reasonable and rational basis, and of
       fair apportionment among the causes responsible. Thus where the
       cattle of two or more owners trespass upon the plaintiff’s land
3230 DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN
TORTS § 433A(1) (1965) (emphasis added). CERCLA, how-
ever, does not require causation as a prerequisite to liability
(except with regard to the third-party defense, see § 9607(b),
not at issue here). Nonetheless, most of the leading cases on
joint and several liability under CERCLA have addressed
divisibility under § 433A(1)(b) and thereby incorporated a
modified concept of causation.19 See, e.g., Bell Petroleum, 3
F.3d at 902-03; Monsanto, 858 F.2d at 172; Chem-Dyne, 572
F. Supp. at 810.

   Notably, these cases often dealt with simpler facts than
those we confront. Chem-Dyne, for instance, assumed a case
quite different from this one. There, the court stated that
“[t]ypically . . . there will be numerous hazardous substance
generators or transporters who have disposed of wastes at a
particular site.” 572 F. Supp. at 810. It was in that context —
that is, where the question was apportionment among defen-
dants who all disposed of wastes themselves — that Chem-
Dyne determined that courts could follow the divisibility prin-
ciples of the Restatement and remain true to CERCLA. In a
situation in which the several defendants are all polluters
themselves, divisibility under the Restatement standard is

      and destroy his crop, the aggregate harm is a lost crop, but it may
      nevertheless be apportioned among the owners of the cattle, on
      the basis of the number owned by each, and the reasonable
      assumption that the respective harm done is proportionate to that
      number. Where such apportionment can be made without injus-
      tice to any of the parties, the court may require it to be made.
   19
      The sections of the Restatement that courts have used to establish the
rules of joint and several liability under CERCLA are found in the negli-
gence division of the Restatement. As these courts recognize, CERCLA is
a strict liability statute. See, e.g., Hercules, 247 F.3d at 716; Township of
Brighton, 153 F.3d at 318. Because there is no comparable divisibility rule
in the strict liability portion of the Second Restatement, courts have
adapted the negligence rules to strict liability by declining to rely on the
portion of the Restatement section that places an initial burden as to causa-
tion on the plaintiff. Compare Hercules, 247 F.3d at 717, and Bell Petro-
leum, 3 F.3d at 896, with RESTATEMENT (SECOND) OF TORTS § 433B(1).
       DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN 3231
indeed a relatively straightforward analysis, and one in which
causation concepts are useful. If the court can estimate with
some confidence the amount of waste that each defendant dis-
posed of and has a basis for determining that the extent of
contamination of the site is proportional to the amount of
waste disposed of, then the Restatement approach to appor-
tionment works nicely.

   The situation here is different.20 The three “responsible”
parties are: the now-insolvent majority owner and operator of
the site; the mostly absentee landlord of a portion of the site;
and a seller of chemicals shipped to and stored at the site.
Each party had an entirely different role in the contamination
process, with overlapping effects, and not all “caused” con-
tamination in any meaningful sense.

   [8] Most notably, PRP status premised on ownership of a
facility does not require any involvement in the disposal of
hazardous substances. Thus, to speak of a PRP “causing” con-
tamination of its land simply by owning land on which some-
one else disposes of hazardous wastes is to indulge in
metaphor. At the same time, to allow CERCLA defendants,
especially landowner PRPs, to prove through traditional cau-
sation analysis that they were not entirely liable would be to
undermine the premise on which the statute designated them
as PRPs to begin with. CERCLA requires a connection — for
example, that the PRP be a landowner “at the time of dispos-
al,” see § 9607(a)(2) — but no further causation. We there-
fore adjust the application of the Restatement principles to the
current circumstance by abjuring the traditional “causation”
principles and substituting a nexus concept that depends upon
  20
    One commentator has noted that trying to apply the Restatement to
CERCLA in most cases is like “pushing a round peg through a square
hole. Traditional tort law principles falter in the CERCLA context because
CERCLA is so unlike a typical tort law cause of action.” Lynda J. Oswald,
New Directions in Joint and Several Liability Under CERCLA?, 28 U.C.
DAVIS L. REV. 299, 360 (1995).
3232 DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN
the particular PRP provision applicable. Where, as here, the
pertinent PRP status is as landowner, the landowner can
establish divisibility only by demonstrating that portions of
the contamination are in no respect traceable to the portion of
the facility that the landowner owned at the time of the dis-
posal. The arranger nexus is more straightforward, with a
focus not on ownership of the facility but rather on the rele-
vant, arranged disposals in light of other contamination at the
facility.

       2.   Harm

   [9] A second difficulty that results from relying on tort
principles in a scheme not based on tort law concerns the
application of the term “harm,” used in the Restatement, as
applied to CERCLA. See RESTATEMENT (SECOND) OF TORTS
§ 433A. The CERCLA cost recovery section does not focus
on “harm,” but rather on “costs of removal or remedial
action” and “necessary costs of response.”21 § 9607(a). Thus,
when applying the Restatement in the context of CERCLA,
the question becomes: What is the “harm” that we are
attempting to divide?

   There are three possible kinds of “harm” in actions for
remediation costs under CERCLA: the initial disposal, the
resulting contamination, and the costs of remediating the con-
tamination. Actual injury to individuals or to property, the
usual “harms” in a tort suit, are not a pertinent consideration;
the statute is concerned with averting future injury by
remediating contamination, not with compensation for past
injuries.
  21
    The statute also mentions “damages for injury to, destruction of, or
loss of natural resources” and “costs of any health assessment or health
effects study.” § 9607(a)(C), (D). These provisions may be informative
with regard to the nature of the harm in other cases but are not here appli-
cable.
       DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN 3233
   If the harm were the disposal, then divisibility based on
volume of discharge by operators or by parcel would always
make sense, because disposal occurs in specific amounts at
specific places. If the harm were contamination, then some
attempt would have to be made either to justify a direct corre-
lation between disposal and contamination under the specific
circumstances or to separate out the leakage that remained as
contamination from leakage that either evaporated, was ade-
quately diluted, or for other reasons did not remain on the
property in toxic form.22 If the harm is the cost of remediation,
then divisibility would have to be based on the pro rata cost
of cleaning up each defendant’s contribution to the contami-
nation. That pro rata cost will sometimes differ from the pro-
portion of contamination caused by each defendant, because
the cost of removing contamination can vary with geographi-
cal considerations, degree of toxicity, the means of extraction
used for different toxic substances, or other factors.

   [10] In light of a CERCLA liability suit’s central purpose
— recovering the cost of eradicating contamination — we
conclude that it is most useful for purposes of determining
divisibility to view the “harm” under CERCLA as the con-
tamination traceable to each defendant. Disposal itself is not
the focus of the statute, unless it results in contamination. And
the cost of cleaning up the contamination is most analogous
to the damages recovered in a tort suit, not to the injury on
which liability is based.23
  22
      In many instances, of course — as in Chem-Dyne — the various pol-
luters will dispose of the same substance in the same location, so there will
be a basis for assuming that each polluter’s pro rata share of the hazardous
waste disposed of and of the resulting contamination is the same. See also
Bell Petroleum, 3 F.3d at 903.
   23
      The cost of cleanup of different toxic substances or in different areas
of the facility will often be a useful measure of the proportion of the perti-
nent contamination allocable to each defendant. That cost will depend
upon factors such as which contamination was serious enough to merit
remediation and how thoroughly the soil was contaminated in various
areas. Thus, the “harm” allocation analysis may in some instances usefully
focus initially on the proportion of costs associated with remedying vari-
ous aspects of the contamination.
3234 DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN
       3.   Equity

   [11] Because this case is one in which the harms are not
distinct, apportionment must be under Restatement
§ 433A(1)(b) if it is to be allowed at all. That is, there must
be a reasonable basis for determining the contribution of each
PRP to the harm. While nothing in the statute directly
addresses the question whether equitable factors are appropri-
ate for purposes of apportioning liability among joint tortfea-
sors, all the other circuits that have addressed the issue have
held that they are not. We again follow their lead.

   Although CERCLA is not explicit on this issue, there is a
statutory provision concerning the separate question of contri-
bution actions among PRPs once liability to the plaintiffs
seeking to recover cleanup costs has been determined. That
provision, § 9613(f), added to CERCLA in 1986, is silent as
to initial divisibility. It only describes, quite generally, the
considerations applicable in a contribution action for deter-
mining whether one PRP can collect from another a portion
of the costs for which it has been held liable: “In resolving
contribution claims, the court may allocate response costs
among liable parties using such equitable factors as the court
determines are appropriate.” § 9613(f) (emphasis added).24 In
contrast, § 433A(1)(b) of the Restatement and the appended
commentary concerning divisibility are silent as to equitable
considerations.25
  24
      Among the equitable factors used in CERCLA contribution cases are
the so-called “Gore factors.” See Hercules, 247 F.3d at 718. Those factors
are derived from the amendment that then-Representative Gore introduced
in 1980 to alleviate the harshness of mandatory apportionment, which at
that time was a part of the bill. See 126 CONG. REC. 26782 (1980) (state-
ment of Rep. Gore). Although these factors are appropriate in contribution
cases, they are not, for the reasons suggested in the text, appropriate con-
siderations at the liability stage.
   25
      The only mention of equity in Restatement § 433A is in comment h,
regarding “[e]xceptional cases.” Comment h suggests that in cases of
insolvent defendants, when an “innocent plaintiff would be forced to bear
       DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN 3235
   Although, as noted, this circuit heretofore has not addressed
divisibility analysis, the implication from our cases deciding
§ 9613(f) contribution issues is that the proper time to focus
on such factors is at the contribution phase, not the liability
phase. See, e.g., Carson Harbor Vill., 270 F.3d at 871 (noting
that the “contribution provision aims to avoid a variety of sce-
narios by which a comparatively innocent PRP might be on
the hook for the entirety of a large cleanup bill”); Pinal Creek,
118 F.3d at 1301 (“A PRP’s contribution liability will corre-
spond to that party’s equitable share of the total liability and
will not be joint and several.”).

   Other circuits have been careful to delineate the difference
between the equitable considerations pertinent under
§ 9613(f) and the objective considerations pertinent under
§ 9607(a). See Hercules, 247 F.3d at 718; Township of Brigh-
ton, 153 F.3d at 318; Bell Petroleum, 3 F.3d at 901. As the
Sixth Circuit has noted, divisibility analysis has the potential
to eviscerate the strict liability principles of CERCLA
entirely, “because defendants who can show that the harm is
divisible, and that they are not responsible for any of the
harm” could whittle their liability to zero. Township of Brigh-
ton, 153 F.3d at 318. Additionally, as Township of Brighton
also noted in rejecting a fairness-based approach, divisibility
analysis is not an invitation to “split the difference” and come
up with a “compromise amount.” Id. at 319.

   While it may seem unfair to hold a partial owner liable for
all the contamination cleanup costs, that perceived unfairness
is the result of the statutory “super-strict” liability scheme.
Assuring fairness among PRPs is the proper subject of the

the share of the loss due to the defendant from whom he could not collect
damages,” courts may refuse to allocate harm to avoid “injustice to the
plaintiff.” Because we determine that there is no reasonable basis for
apportioning the defendants’ harm, we do not reach the question of
whether the considerations of comment h are applicable here.
3236 DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN
contribution stage, not of apportionment at the liability stage.
See United States v. Rohm & Haas Co., 2 F.3d 1265, 1280-81
(3d Cir. 1993), overruled on other grounds by United States
v. E.I. Dupont de Nemours & Co., 432 F.3d 161, 162-63 (3d
Cir. 2005) (en banc). At the liability stage, CERCLA simply
assigns liability to statutorily responsible parties so as to
assure that, as between those with some connection to the
contamination — and who have, it may be assumed, benefit-
ted from the contamination-causing process — and those with
none, such as the taxpayers. Any court-created structure that
would allow PRPs to whittle their share to little or nothing
and leave the taxpayers holding the bag may seem more equi-
table to some PRPs but would violate the basic structure of
the CERCLA statutory scheme. Because of such concerns,
courts have generally refrained from using an equity-based
allocation analysis, so as not to weaken further the strict lia-
bility principle basic to CERCLA.

   [12] We agree that while joint and several liability need not
be universally applied, see Bell Petroleum, 3 F.3d at 897, the
inquiry as to whether such liability is appropriate must focus
strictly on whether there is a reasonable basis for apportion-
ment, see, e.g., id. at 901-04. Consequently, in an action under
§ 9607(a), a court is not to look to equitable considerations,
such as relative fault, in determining whether liability is to be
joint and several or apportioned.

    III.   Analysis of Railroads’ and Shell’s CERCLA
                          Liability

   We now proceed to apply these fairly straightforward prin-
ciples to the circumstances of this case. Here, the Railroads
were found to be PRPs under § 9607(a)(2), as the owners of
a “facility at which . . . hazardous substances were disposed
of,” and Shell was found to be a PRP under § 9607(a)(3), as
a person who “arranged for disposal . . . of hazardous sub-
stances owned or possessed by such person.” The first ques-
tion we address is whether the Railroads and Shell are liable
       DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN 3237
for all the cleanup costs at the Arvin site, or, as the district
court held, only some of them. The second question,
addressed later, is whether Shell is liable for any of the harm,
as an “arranger.”

  A.     Apportionment of Liability

    1.    Standard of Review and Burden of Proof

   Because we have not heretofore faced a CERCLA appor-
tionment issue directly, there is no Ninth Circuit precedent
concerning the standard of appellate review for such an issue.
Three circuits have addressed the question, and two separate
approaches have emerged.

   The Fifth and Eighth Circuits look first to whether there is
a reasonable basis for apportioning the harm, an inquiry they
consider a question of law reviewed de novo. See Hercules,
247 F.3d at 718-19; Bell Petroleum, 3 F.3d at 896, 902. These
two circuits then examine, as a question of fact reviewed
under the clearly erroneous standard, precisely how damages
are to be divided. See Hercules, 247 F.3d at 718 (holding that
“actual apportionment” of damages is a question of fact); Bell
Petroleum, 3 F.3d at 896 (same).

   In contrast, the Sixth Circuit considers divisibility as a
whole a factual matter of causation, reviewed entirely under
the clearly erroneous standard. Township of Brighton, 153
F.3d at 318 n.13. This view, however, disregards a distinction
between conceptual divisibility and actual allocation that we
find both persuasive and useful. The latter inquiry can involve
the resolution of credibility issues and of conflicting evidence,
while the former ordinarily does not.

   We believe the most appropriate approach, and the one we
therefore adopt here, is the one adopted in Hercules and Bell
Petroleum, with a refinement suggested by Judge Parker’s
dissent in Bell Petroleum. Judge Parker thought that the
3238 DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN
majority confused the distinction between the “legal burden
that the single harm at issue caused is of a type capable of
apportionment, and the factual burden of proving the amount
of harm attributable to a particular party.” Bell Petroleum, 3
F.3d at 909 (Parker, J., concurring in part and dissenting in
part). We are not sure that there was any such confusion.
Rather, an aspect of clear error review is the legal determina-
tion whether the party with the burden of proof met that bur-
den; if the party did not and the district court nonetheless
ruled for it, then the district court clearly erred. See Lloyd v.
Schlag, 884 F.2d 409, 415 (9th Cir. 1989) (reviewing
“whether the district court committed clear error by holding
that [plaintiff] had not met his burden of proof”). Thus,
although the harm may be capable of apportionment, the
harm may not actually be apportionable in the particular case
as a factual matter, given the evidence produced, because the
party advocating apportionment has not come forward with
the minimum showing needed to meet its burden of proof as
to the proper division of liability.

   We therefore proceed as follows: We inquire, first, whether
the particular harm at issue in the case is theoretically capable
of apportionment — i.e., whether it could ever be apportioned
or whether it is, by nature, too unified for apportionment. That
question is one of law, reviewed de novo. Cf. Taisho Marine
& Fire Ins. Co. v. M/V Sea-Land Endurance, 815 F.2d 1270,
1274 (9th Cir. 1987). Second, we review for clear error
whether the defendant submitted evidence sufficient to estab-
lish a reasonable basis for the apportionment of liability, tak-
ing into account that the burden of proof is on the party
seeking allocation, as well as the district court’s actual divi-
sion of liability.

   There is no dispute here on the first, purely legal question
— whether the harm is capable of apportionment. See Bell
Petroleum, 3 F.3d at 896; Chem-Dyne, 572 F. Supp. at 810.
Some of the contamination on the B&B site occurred before
the Railroads’ parcel became part of the facility, and the origi-
      DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN 3239
nal B&B site is distinct from the portion leased from the Rail-
roads. Only some of the toxic substances were stored on the
Railroads’ parcel, and only some of the water on the facility
washed over the Railroads’ site. As to Shell, only some of the
toxic substances spilled on the facility were sold by the com-
pany. The different toxic substances vary in their likelihood
to leak and in the manner and speed in which they dissemi-
nate in ground water. So, conceptually, the contamination
traceable to the Railroads and Shell, with perfect information,
would be allocable, as would be the cost of cleaning up that
contamination.

   The questions, then, are whether the district court clearly
erred in finding that the Railroads and Shell established a
“reasonable basis” for apportionment, Bell Petroleum, 3 F.3d
at 901, and whether, having so found, the district court prop-
erly apportioned the harm.

   We recognize that the district court at one point stated that
the Railroads failed to “meet their burden of proof” as to
divisibility. But its overall ruling was necessarily to the con-
trary, as the court also stated that it “independently found [in
the record] a reasonable basis for apportionment in spite of
the parties[’] presentations.” Thus, while the district court
rejected both defendants’ theories as to divisibility, it used
record evidence it found persuasive to determine apportion-
ment. Whether the district court was correct in this regard is,
as we have noted, part of the review of the factual decision
regarding apportionment, discussed hereafter. The burden of
proof issue thus melds with the merits of the apportionment
issue, rather than barring us from considering it.

    2.   The Railroads

  As we have established, if apportionment is to be allowed
under the Restatement approach, there must be a reasonable
basis for calculating the connection between the Railroads’
PRP status and the relevant harms. Again, the harm we con-
3240 DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN
sider is the contamination on the Arvin site. Where, as for the
Railroads, the PRPs’ responsibility under the statute derives
solely from their status as landowner, the PRPs can establish
divisibility by demonstrating that discrete portions of the con-
tamination are in no respect traceable to land they owned at
the time of the toxic disposal.

   Here, the district court’s severability analysis — after 191
pages of an amended opinion that included over 80 pages of
factual findings — ultimately relied on the simplest of consid-
erations: percentages of land area, time of ownership, and
types of hazardous products. Although we do not fault the dis-
trict court’s factfinding — its numbers are mostly correct —
its legal conclusion that these three factors alone suffice to
support apportionment cannot stand.26 We address each factor
below to show why.

        a.    Land Area

   The only court of appeals case that has fully addressed
divisibility of landowner liability takes a relatively strict
approach to apportionment on the basis of land area. In
United States v. Rohm and Haas Co., 2 F.3d 1265 (3d Cir.
1993), the most analogous CERCLA divisibility case to this
one, the Third Circuit held, as do we, that “simply showing
that one owns only a portion of the facility in question is [not]
sufficient to warrant apportionment.” Id. at 1280.

  Like this case, Rohm and Haas concerned a landowner PRP
and changes in landownership over time. Although the Third
Circuit’s divisibility analysis is fairly cursory, its reluctance to
  26
     We emphasize that our conclusion does not rest simply on the fact that
the district court’s calculation of the Railroads’ share of liability was, as
the court recognized, “rough[ ].” It is neither unusual nor fatal to the valid-
ity of the resulting allocation that an apportionment determination includes
estimates of contribution to contamination based on extrapolation of
record facts, as long as the basis for the extrapolation is explained, is logi-
cal, and does not disregard other record facts.
       DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN 3241
apportion landowner liability on the basis of land boundaries
is informative. Rohm and Haas indicates that the mere per-
centage of land owned by one PRP relative to the entire facil-
ity cannot alone be a basis for apportionment, as it does not
provide a minimally reliable basis for tracing the proportion
of leakage, contamination, or cleanup costs associated with
the entire parcel.

   Contrary to Rohm and Haas, the district court’s analysis
gave star billing to the percentage of land ownership, even in
a unified facility.27 We agree with Rohm and Haas that this
approach, seemingly straightforward though it is, fails in most
circumstances to comport with the “reasonable basis” test, as
the facts of this case illustrate.

   [13] The Arvin site was a single facility. CERCLA prem-
ises landowner liability on ownership of a facility, not on
ownership of a certain parcel of land that is part of a facility.
The operations on the site were dynamic, with fertilizer rigs
stored on the Railroad parcel and filled up on the B&B parcel.
Empty pesticide cans were stored on the Railroad parcel
before they were crushed and disposed of. After the 1978
windstorm, tanks were stored all over the facility, including
on the Railroad parcel. A simple calculation of land owner-
ship does not capture any data that reflect this dynamic, uni-
tary operation of the single Arvin facility.

   In addition, the synergistic use of different parts of the
Arvin site makes division based on percentage of land owner-
ship particularly untenable. The record shows that B&B
leased the Railroad parcel to accommodate its expanding
  27
    Judge Moore, concurring in the result in Township of Brighton,
asserted that a court can never apportion liability for contamination at a
single facility on the basis of geography. Township of Brighton, 153 F.3d
at 331 n.12 (Moore, J., concurring in result). We do not go as far as Judge
Moore. We do note, however, that purely geographic apportionment of a
single facility is unlikely to be appropriate if operations on the two por-
tions are intertwined to the extent present in this case.
3242 DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN
operations. The Railroad parcel added an unquantifiable and
perhaps exponential amount to B&B’s soil contamination.
Were the Railroad parcel not part of the facility, there would
have been less overall storage capacity. One can assume that
a smaller amount of toxic chemicals would have been deliv-
ered to, and spilled on, the Arvin site. The fertilizer rigs, for
example, were stored almost exclusively on the Railroad par-
cel. Had that parcel not been available, less fertilizer might
have been delivered to — and leaked onto — the Arvin par-
cel. As these descriptions suggest, nothing in the record sup-
ports a conclusion that the leakage of contaminants that ended
up on the B&B parcel occurred on each parcel in proportion
to its size.

   [14] Instead, given the circumstances of this case, more
pertinent comparisons would be the proportion of the amount
of chemicals stored, poured from one container to another, or
spilled on each parcel. For example, were adequate records
kept, it would be possible to estimate the amount of leakage
attributable to activities on the Railroad parcel, how that leak-
age traveled to and contaminated the soil and groundwater
under the Arvin parcel, and the cost of cleaning up that con-
tamination.

   [15] But none of this data is in the record. It may well be
that such information is, as a practical matter, not available
for periods long in the past, when future environmental
cleanup was not contemplated. Unlike records concerning the
amount of toxic chemicals produced by a given operator of a
facility, records that separate out, with any precision, the
amount of toxic chemicals stored on one part of a facility as
opposed to another would have had little utility to B&B, the
operator of the facility, and none to the Railroads, the owners
of the parcel. This observation is true in spades for the more
directly pertinent data, such as the amount of leakage on the
Railroad parcel, the amount of that leakage that flowed onto
the B&B parcel, and the amount of that residue that remained
      DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN 3243
as contamination under the B&B parcel when the cleanup
began.

   [16] So the failure to keep these records is quite under-
standable. But these practical considerations cannot justify a
“meat-axe” approach to the divisibility issue, premised on
percentages of land ownership, as a means of adjusting for the
difficulties of proving divisibility with precision when PRP
status is based on land ownership alone. Such an approach
would be tantamount to a disagreement with the imposition of
no-fault land ownership liability. Congress, however, created
precisely such liability, placing the responsibility to pay for
environmental cleanup on parties, such as the Railroads, that
profited from the circumstances giving rise to the contamina-
tion so that the taxpayers are not left holding the tab. The risk
of lack of adequate information for meaningful division of
harm therefore must rest on the responsible parties, even
when that information is extremely hard to come by.

       b.   Period of Ownership

   [17] Just as the district court’s land area calculations did
not correspond to the harms in this case, its simple fraction
based on the time that the Railroads owned the land cannot be
a basis for apportionment. The fraction it chose assumes cons-
tant leakage on the facility as a whole or constant contamina-
tion traceable to the facility as a whole for each time period;
no evidence suggests that to be the case. Again, if adequate
information were available, it would make sense to eliminate
the Railroads’ liability for the period before B&B leased the
Railroad parcel. See, e.g., Rohm and Haas, 2 F.3d at 1280.
The evidentiary vacuum concerning the amount of contamina-
tion traceable to the pre-lease period, however, precludes any
such calculation here.

       c.   Types of Hazardous Products

   [18] While many of the district court’s calculations were
factually correct but legally insufficient, its decision to assign
3244 DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN
a two-thirds fraction to represent the present types of hazard-
ous products contains a basic factual error. All three chemi-
cals were on the Railroad parcel at some time. There is no
evidence as to which chemicals spilled on the parcel, where
on the parcel they spilled, or when they spilled. Yet, there is
evidence that there may well have been leakage on the Rail-
road parcel of D-D, the chemical the district court excluded
in its calculations. Given the record, the district court clearly
erred in its attempt to rely on the proportion of hazardous
products present on the Railroad parcel.

       d.   Conclusion

   It will often be the case that a landowner PRP will not be
able to prove in any detail the degree of contamination trace-
able to activities on its land. A landowner PRP need not be
involved at all in the disposal of hazardous chemicals and so
will often have no information concerning that disposal or its
impact. The net result of our approach to apportionment of
liability, consequently, may be that landowner PRPs, who
typically have the least direct involvement in generating the
contamination, will be the least able to prove divisibility. And
contribution “is not a complete panacea since it frequently
will be difficult for defendants to locate a sufficient number
of additional, solvent parties.” O’Neil v. Picillo, 883 F.2d 176,
179 (1st Cir. 1989).

   While the result may appear to fault a landowner PRP for
failing to keep records proving the minor connection of its
land to the contamination on the facility as a whole, CERCLA
is not a statute concerned with allocation of fault. Instead,
CERCLA seeks to distribute economic burdens. Joint and
several liability, even for PRPs with a minor connection to the
contaminated facility, is the norm, designed to assure, as far
as possible, that some entity with connection to the contami-
nation picks up the tab. Apportionment is the exception, avail-
able only in those circumstances in which adequate records
were kept and the harm is meaningfully divisible.
      DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN 3245
   [19] In sum, although most of the numbers the district court
used were sufficiently exact, they bore insufficient logical
connection to the pertinent question: What part of the contam-
inants found on the Arvin parcel were attributable to the pres-
ence of toxic substances or to activities on the Railroad
parcel? We therefore reject the district court’s apportionment
calculation and hold that the Railroads have failed to prove
any reasonable basis for apportioning liability for the costs of
remediation.

    3.   Shell

   Shell’s contribution to the contamination of the Arvin site
is easier to isolate than that of the Railroads’, as it involved
ascertainable pollutants entering the soil in a specific way.
Shell thus had a greater prospect of succeeding on divisibility
than did the Railroads, as there is some volumetric basis for
comparing its contribution to the total volume of contamina-
tion on the Arvin site.

   Nonetheless, the evidence actually produced was insuffi-
cient to allow even a rough approximation of the contamina-
tion remaining on the facility, either directly or through the
presumption that the pro rata cost of remediating contamina-
tion is likely to be equivalent to a PRP’s pro rata share of con-
tamination. Indeed, Shell produced only evidence concerning
leakage.

   [20] Such leakage or disposal evidence cannot suffice in
the present circumstances as a basis for apportioning the harm
in question. As we have explained, contamination — as dis-
tinct from leakage — is the necessary consideration. Where
there is disposal of multiple contaminants, courts have
demanded a “showing [of] a relationship between waste vol-
ume, the release of hazardous substances, and the harm at the
site.” Monsanto, 858 F.2d at 172. Factors such as “relative
toxicity, migratory potential, and synergistic capacity of the
hazardous substances” are relevant to demonstrating this rela-
3246 DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN
tionship. Id. at 172 n.26. Alternatively, volumetric calcula-
tions of contaminating chemicals — those remaining in the
environment and requiring cleanup — could be sufficiently
specific for apportionment. See Hercules, 247 F.3d at 719;
Bell Petroleum, 3 F.3d at 903. But Shell provided no evidence
regarding such factors. It thus failed to prove whether its
leaked chemicals contaminated the soil in any specific propor-
tion as compared to other chemicals spilled at the site. See
United States v. Agway, Inc., 193 F. Supp. 2d 545, 549
(N.D.N.Y. 2002) (noting that defendants whose products have
become commingled in the soil “face an uphill battle in
attempting to demonstrate that volumetric contribution is a
reasonable basis for apportioning liability of a single harm”).

   To fill these evidentiary gaps, the district court assumed
equal contamination and cleanup cost from all the chemicals’
leakage. This methodology entirely failed to account for the
possibility that leakage of one chemical might contribute to
more contamination than leakage of another, because of their
specific physical properties. Similarly, the cost of cleanup
depends upon which contaminants are present; some contami-
nants are more expensive than others to extract from the soil.

   Moreover, even as an approximation of leakage, the district
court’s calculations were too speculative to support apportion-
ment. Chem-Nuclear is informative in this regard. In Chem-
Nuclear, the defendant disposed of drums of hazardous waste
at several facilities. 292 F.3d at 255. At least eighty drums
found at a single site were attributable to the defendant. Id.
The defendant could not prove, however, that it was responsi-
ble only for those eighty drums, and therefore was not entitled
to apportionment. Id. at 259-61. Although the defendant pro-
vided evidence supporting inferences regarding where its
drums went, the court refused to accept these inferences as
sufficient proof. Id. at 260.

   Here, the court estimated the volume of Shell’s chemicals
that leaked from each transfer based on data samples that do
       DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN 3247
not readily extrapolate to total leakage over the entire twenty-
three-year period that Shell supplied B&B with D-D. The
court used figures from only six years of B&B’s purchases of
Shell D-D to calculate the average D-D transferred at the
Arvin site each year, yet provided no basis for assuming equal
purchases each year. The court then based its estimate of the
amount of D-D spilled during each transfer on guesses by wit-
nesses.28 Also, although D-D was known to leak when sight
gauges on D-D rigs broke, the court had no evidence of how
much D-D leaked under these circumstances and, therefore,
did not add any quantity for sight gauge leakage into the cal-
culation. Even if each of these estimates alone might have
been reasonable, the resulting combined estimate is too specu-
lative to serve as an accurate basis for ascertaining leakage,
let alone contamination or the costs of cleaning up the contami-
nation.29
  28
      For the quantity of D-D that spilled during transfer from Shell’s carri-
ers’ trucks to the D-D rigs, for example, the court relied on estimates of
witnesses that the spill was between a cup and a quart. It then calculated
“3 cups x 23 years = 2,691 cups => 168 gallons of D-D.”
   29
      There is something of a circuit split on the degree of specificity of
proof necessary to establish the amount of liability apportioned to each
PRP. According to some courts, proving up the precise proportion attribut-
able to each PRP is a “very difficult proposition,” Control Data Corp. v.
S.C.S.C. Corp., 53 F.3d 930, 934 n.4 (8th Cir. 1995), requiring “concrete
and specific” evidence in support of any proposed apportionment, Hercu-
les, 247 F.3d at 718. The defendant cannot rely on a “chain of possible
inferences.” Chem-Nuclear, 292 F.3d at 260. In contrast, other courts have
permitted informal estimates or data rather than more exact calculations.
See Bell Petroleum, 3 F.3d at 903-04 (allowing estimation of the propor-
tion of contamination produced by each of a series of successive operators
of a facility, where reliable approximations were simple because there was
a single chemical produced by the successive operators each of whom
operated the facility similarly); see also Hercules, 247 F.3d at 719 (relying
on Bell Petroleum, 3 F.3d at 895-96, and holding that the defendant need
not show that there was no possibility that it contributed to the harm,
because certain approximations can suffice). Aside from noting, as we
have, supra n.27, that logical, supportable inferences from the record facts
are, as always, permissible, we need not weigh in on this dispute, as the
district court’s extrapolations could not be upheld under even a forgiving
standard.
3248 DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN
   Again, Shell’s harm was capable of apportionment. Shell
could have provided data showing the volume of chemicals
shipped to B&B every year, or more precise estimates of the
average volume of leaked chemicals during the transfer pro-
cess. Data connecting the properties of the various chemicals
leaked at the site to the likelihood that they contributed to the
contamination could have been presented and considered. But
the record before us provides none of that information, most
likely because Shell put its eggs in the no-liability basket.

   [21] In the end, the district court’s apportionment analysis
with regard to Shell came closer to meeting the legal standard
than the method it used with respect to the Railroads. We
hold, nonetheless, that on the facts of this case as the district
court found them, there was no reasonable basis for appor-
tioning the pertinent harm caused by Shell.

  B.   “Arranger” Liability

   [22] Under CERCLA, “any person who by contract, agree-
ment, or otherwise arranged for disposal or treatment, or
arranged with a transporter for transport for disposal or treat-
ment, of hazardous substances owned or possessed by such
person” is liable. § 9607(a)(3). Shell claims that (1) the dis-
trict court applied the wrong legal standard in determining
whether Shell was an “arranger” under § 9607(a); (2) the
“useful product” doctrine precludes imposition of “arranger”
liability on Shell; (3) Shell lacked ownership and control over
the chemicals at the time of the transfers and thus the district
court could not find that it had arranged them; and (4) because
D-D evaporates or disperses rather than remaining in toxic
form in the soil, the district court erred when it determined
that Shell contributed to the groundwater contamination. We
reject these contentions and affirm the district court’s ruling
on the “arranger” issue.

  We review the district court’s interpretation of CERCLA to
determine the legal standard for arranger liability as a ques-
      DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN 3249
tion of law, reviewed de novo. Carson Harbor Vill., 270 F.3d
at 870. We review the district court’s factual determinations
regarding Shell’s operations for clear error. W. Prop. Serv.
Corp. v. Shell Oil Co., 358 F.3d 678, 685 (9th Cir. 2004).

    1.   Requirements for “Arranger” Liability

   CERCLA does not define “arrange[ ].” We have avoided
giving the term “arranger” too narrow an interpretation to
avoid frustrating CERCLA’s goal of requiring that companies
responsible for the introduction of hazardous waste into the
environment pay for remediation. Pakootas v. Teck Cominco
Metals, Ltd., 452 F.3d 1066, 1081 (9th Cir. 2006); Cadillac
Fairview/Cal., Inc. v. United States, 41 F.3d 562, 565 n.4 (9th
Cir. 1994) (per curiam) (citing with approval United States v.
Aceto Agric. Chems. Corp., 872 F.2d 1373, 1380 (8th Cir.
1989)); see also Jones-Hamilton Co. v. Beazer Materials &
Servs., Inc., 973 F.2d 688, 694-95 (9th Cir. 1992) (discussing
Aceto, 872 F.2d at 1390). Accordingly, we have recognized,
in addition to “direct” arranger liability, a “broader” category
of arranger liability, see United States v. Shell Oil Co., 294
F.3d 1045, 1054-55 (9th Cir. 2002), in which disposal of haz-
ardous wastes is a foreseeable byproduct of, but not the pur-
pose of, the transaction giving rise to PRP status.

   “Direct” arranger liability — also referred to as “ ‘tradi-
tional’ direct” arranger liability — involves transactions in
which the central purpose of the transaction is disposing of
hazardous wastes. See id.; see, e.g., Cadillac Fairview, 41
F.3d at 563-65 (involving rubber companies that transferred
contaminated styrene to Dow Chemical for reprocessing);
Catellus Dev. Corp. v. United States, 34 F.3d 748, 749-50
(9th Cir. 1994) (involving a company that sold used automo-
tive batteries to a lead reclamation plant). In contrast, “broad-
er” arranger liability involves transactions that contemplate
disposal as a part of, but not the focus of, the transaction; the
“arranger” is either the source of the pollution or manages its
disposal. See Shell Oil, 294 F.3d at 1058. In the “broader”
3250 DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN
arranger liability cases, such as Shell Oil, we examined the
connection between the alleged arranger transaction and the
disposal and decided whether the transaction necessarily con-
stituted an arrangement for disposal of hazardous substances,
whatever immediate form it may have taken.

   These broader arranger cases can involve situations, like
the present one, in which the alleged arrangers did not con-
tract directly for the disposal of hazardous substances but did
contract for the sale or transfer of hazardous substances,
which were then disposed of. See, e.g., Fla. Power & Light
Co. v. Allis Chalmers Corp., 893 F.2d 1313, 1315, 1318 (11th
Cir. 1990) (involving purchaser and recycler that sued manu-
facturer of transformers for cleanup costs from later disposal);
Mathews v. Dow Chemical Co., 947 F. Supp. 1517, 1519-20
(D. Colo. 1996) (involving neighbors of chemical company
who sued manufacturer of paint thinner for contamination
resulting from packaging paint thinner); Courtaulds Aero-
space, Inc. v. Huffman, 826 F. Supp. 345, 347-48, 353-54
(E.D. Cal. 1993) (involving neighbor of smelting plant who
sued companies that contracted with plant for burning and
smelting of copper wire for resulting contamination). There
are no Ninth Circuit cases in this category.30

  [23] The inclusion of such circumstances within the “ar-
ranger” concept, however, accords with the statutory language
and structure as a whole. To be an “arranger,” one must “ar-
   30
      Although Shell Oil involved “broader” arranger liability, it concerned
“arranger” liability of a customer, rather than a producer, of hazardous
materials. 294 F.3d at 1056. There, the State of California sought to hold
the United States liable as an “arranger” because the federal government
had purchased large quantities of high octane fuel for military use; the pro-
cess used by the oil companies to refine the fuel resulted in toxic waste
that the oil companies later dumped at a site in California. Id. Because the
United States was the end purchaser, never owned the intervening toxic
products used in the refining process, and did not contract out the crucial,
waste-producing intermediate step, we held that it was not an arranger
under § 9607(a)(3). Id. at 1056-59.
      DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN 3251
range[ ] for disposal or treatment, or arrange[ ] with a trans-
porter for transport for disposal or treatment, of hazardous
substances . . . .” § 9607(a)(3). CERCLA’s definition of “dis-
posal,” in turn, includes “the discharge, deposit, injection,
dumping, spilling, leaking, or placing of any solid waste or
hazardous waste into or on any land or water so that such
solid waste or hazardous waste or constituent thereof may
enter the environment or be . . . discharged into any waters,
including ground waters.” § 6903(3) (referred to by
§ 9601(29)). That “disposal” includes such unintentional pro-
cesses as “leaking” indicates that “disposal” need not be pur-
poseful. See Carson Harbor Vill., 270 F.3d at 880 (holding
that “leaking” may not “require affirmative . . . conduct”
(internal quotation marks omitted) (quoting and adopting
interpretation of United States v. CDMG Realty Co., 96 F.3d
706, 714 (3d Cir. 1996))). Thus, an entity can be an arranger
even if it did not intend to dispose of the product. Arranging
for a transaction in which there necessarily would be leakage
or some other form of disposal of hazardous substances is suf-
ficient.

    2.   “Useful Product” Doctrine

   [24] While adopting a generally expansive view of arranger
liability, we have refused to hold manufacturers liable as
arrangers for selling a useful product containing or generating
hazardous substances that later were disposed of. See, e.g.,
3550 Stevens Creek Assocs. v. Barclays Bank of Cal., 915
F.2d 1355, 1362-65 (9th Cir. 1990). As Stevens Creek and
other “useful product” cases recognize, liability cannot extend
so far as to include all manufacturers of hazardous substances,
on the theory that there will have to be disposal of the sub-
stances some time down the line, after it is used as intended.
See, e.g., Stevens Creek, 915 F.2d at 1362-65 (refusing to hold
manufacturer liable for costs of removing asbestos from
building); Fla. Power & Light, 893 F.2d at 1318-19 (refusing
to hold manufacturer of transformers liable for subsequent
release of chemicals upon disposal of transformers). Also, the
3252 DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN
asserted liability in “useful product” cases generally involved
only the normal use of those chemicals. See, e.g., Jordan v.
S. Wood Piedmont Co., 805 F. Supp. 1575, 1577 (S.D. Ga.
1992) (involving the sale of chemicals to treat wood and the
contamination from the wood treatment process); Edward
Hines Lumber Co. v. Vulcan Materials Co., 685 F. Supp. 651,
653 (N.D. Ill. 1988) (same).

   [25] The useful product cases have no applicability where,
as here, the sale of a useful product necessarily and immedi-
ately results in the leakage of hazardous substances. In that
circumstance, the leaked portions of the hazardous substances
are never used for their intended purpose. See Zands v. Nel-
son, 779 F. Supp. 1254, 1262 (S.D. Cal. 1991) (stating that
“gasoline is no longer a useful product after it leaks into, and
contaminates, the soil”); see also Aceto, 872 F.2d at 1381
(rejecting application of the useful product doctrine where
“waste is generated and disposed of contemporaneously with
the process” (emphasis added)).

   Here, although Shell sold B&B a useful product, leakage of
some of that product before B&B could use it was both inher-
ent in the transfer process arranged by Shell and contempora-
neous with that process.31 Shell arranged for delivery of the
substances to the site by its subcontractors; was aware of, and
to some degree dictated, the transfer arrangements; knew that
some leakage was likely in the transfer process; and provided
advice and supervision concerning safe transfer and storage.
Disposal of a hazardous substance was thus a necessary part
of the sale and delivery process.
   31
      For this reason, we also reject Shell’s argument that, because manu-
facturers are taxed to provide money for the Superfund, Congress could
not, without more, have intended for them to be subject to liability as
arrangers. See 26 U.S.C. §§ 4661, 4662. Shell’s liability derives not from
its role as a manufacturer of a useful product but rather from its role in
leakage prior to use. The Superfund tax is wholly irrelevant to the latter
imposition of liability and certainly does not bar it.
      DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN 3253
   Put another way, the district court did not assign arranger
liability to Shell for contamination resulting from the applica-
tion of Shell’s useful products to the soil as fertilizers or fumi-
gants, or for disposal of contaminated soil after the products
were used. Instead, the district court assigned arranger liabil-
ity on the portion of product that never made it to the fields
for its intended use but was disposed of prior to use. Because
Shell’s liability here stems from the leaked chemicals rather
than the fertilizer that was used as fertilizer, the useful prod-
uct doctrine is not applicable.

    3.   Control and Ownership

   Much of the district court’s analysis relies on the factual
determination that spills would necessarily occur during the
transfer of Shell’s chemicals to B&B. Shell maintains that this
finding was inadequate, because Shell did not itself transport
the chemicals or participate in transferring the chemicals to
B&B’s containers. Central to this contention is Shell’s insis-
tence that it lacked ownership and control of the chemicals at
the time of transfer and so could not be an “arranger.” We do
not agree that the district court’s findings about Shell’s
involvement were insufficient to support “arranger” liability.

   There was evidence before the district court that: (1) Spills
occurred every time the deliveries were made; (2) Shell
arranged for delivery and chose the common carrier that
transported its product to the Arvin site; (3) Shell changed its
delivery process so as to require the use of large storage tanks,
thus necessitating the transfer of large quantities of chemicals
and causing leakage from corrosion of the large steel tanks;
(4) Shell provided a rebate for improvements in B&B’s bulk
handling and safety facilities and required an inspection by a
qualified engineer; (5) Shell regularly would reduce the pur-
chase price of the D-D, in an amount the district court con-
cluded was linked to loss from leakage; and (6) Shell
distributed a manual and created a checklist of the manual
3254 DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN
requirements, to ensure that D-D tanks were being operated
in accordance with Shell’s safety instructions.

   The parties vigorously dispute whether, given these facts,
Shell owned the pesticide during the transfer and controlled
the transfer process. Although the district court addressed
these questions and resolved them against Shell, we do not
enter this controversy. The text of the statute does not require
that the arranger own the hazardous wastes, either at the time
the “arranger” arranged for the transaction or at the time of
transfer of ownership. See Pakootas, 452 F.3d at 1081.
Indeed, to require ownership at the time of disposal “would
make it too easy for a party, wishing to dispose of a hazardous
substance, to escape by a sale its responsibility to see that the
substance is safely disposed of.” Catellus, 34 F.3d at 752. Nor
is control a statutory requirement, Cadillac Fairview, 41 F.3d
at 565, although it has been viewed as a pertinent consider-
ation in cases quite different from this one.

   Where an owner of hazardous substances directly “ar-
ranges” for disposal — by, for example, using a hazardous
substance disposal company — that owner is plainly an “ar-
ranger” even if it has nothing more to do with disposal. See,
e.g., Catellus, 34 F.3d at 752. In “broader” arranger liability
cases, however, we have tended to view control as a “crucial
element” in determining whether the party arranged for dis-
posal. Shell Oil, 294 F.3d at 1055. We also have viewed own-
ership of hazardous substances at the time of disposal as an
important factor in nontraditional, indirect arranger liability
cases. See Jones-Hamilton, 973 F.2d at 695 (relying on Aceto,
872 F.2d at 1380).

   None of these cases, however, indicates that ownership or
control at the time of transfer are the sine qua non of nontradi-
tional arranger liability. Instead, ownership and control at
time of disposal are useful indices or clues toward the end of
“look[ing] beyond defendants’ characterizations to determine
whether a transaction in fact involves an arrangement for the
      DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN 3255
disposal of a hazardous substance.” Aceto, 872 F.2d at 1381.
In Shell Oil, for example, the government never owned the
chemicals before disposal occurred, so control over the sub-
stances was an important factor in determining whether or not
the government could have “arranged” for disposal. Shell Oil,
294 F.3d at 1057-59.

   [26] Here, ownership at the time of disposal is not an infor-
mative consideration, and control is informative only in light
of additional considerations. Unlike in Shell Oil, where the
absence of any ownership or control was a clue concerning
whether the sales transaction necessarily contemplated dis-
posal as an inherent part of the transaction, Shell here owned
the chemicals at the time the sale was entered into. The statute
requires nothing more in terms of ownership. We therefore
need not determine the precise moment when ownership
transferred to B&B. As to the control question, the district
court’s findings, recited above, demonstrate that Shell had
sufficient control over, and knowledge of, the transfer process
to be considered an “arranger,” within the meaning of CER-
CLA, for the disposal of the chemicals that leaked.

    4.   Groundwater Contamination

   Shell, finally, contends that the court erred when it deter-
mined that it contributed to the groundwater contamination,
maintaining that D-D evaporates or disperses rather than
remaining in toxic form in the soil. The district court’s analy-
sis on this issue is factually complex and based on several
weeks of testimony. The district court made specific findings
that D-D can indeed enter groundwater. Those findings are
based on the testimony of experts whom the court found per-
suasive. In light of the complexity of the science and the sub-
stantial expert evidence supporting the finding, the district
court’s determination was not clearly erroneous.

                      IV.   Conclusion

  The district court erred in determining that the harm in this
case could be apportioned on this record. Given the district
3256 DEP’T OF TOXIC SUBSTANCES v. BURLINGTON NORTHERN
court’s erroneous approach and the paucity of record evi-
dence, there is no reasonable basis for apportioning the dam-
ages attributable to the Railroads’ activity. Shell’s liability is
a closer call, but the evidence on the record in that regard is
also insufficient to support apportionment.

   The district court followed the proper analysis in finding
that Shell is liable as an arranger. Shell arranged for the sale
and transfer of chemicals under circumstances in which a
known, inherent part of that transfer was the leakage, and so
the disposal, of those chemicals.

   We therefore reverse as to the district court’s finding on
apportionment. We affirm the district court’s findings regard-
ing both the Railroads’ and Shell’s liability. The Railroads
and Shell are jointly and severally liable for the harm at the
Arvin site. We remand for further proceedings not inconsis-
tent with this opinion.

  REVERSED in part and AFFIRMED in part.
