In the

United States Court of Appeals

For the Seventh Circuit ____________________ 

Nos. 20-1711 & 20-1793 

VON DUPRIN LLC, 

Plaintiff-Appellee, Cross-Appellant, 

v.

MAJOR HOLDINGS, LLC and

MAJOR TOOL AND MACHINE, INC., 

Defendants-Appellants, Cross-Appellees, 

and

MORAN ELECTRIC SERVICE, INC., 

Defendant, Cross-Appellee. 

____________________ 

Appeals from the United States District Court for the

Southern District of Indiana, Indianapolis Division.

No. 1:16-cv-01942 — Tanya Walton Pratt, Chief Judge. 

____________________ 

ARGUED MARCH 30, 2021 — DECIDED SEPTEMBER 3, 2021 

____________________ 

Before KANNE, BRENNAN, and SCUDDER, Circuit Judges. 

SCUDDER, Circuit Judge. This is a complex environmental 

cleanup case out of Indianapolis, Indiana. Over several 
2 Nos. 20-1711 & 20-1793 

decades, owners and operators of industrial facilities disposed of chemical solvents used in manufacturing processes. 

The solvents have degraded over time and have seeped into 

the groundwater and soil in the surrounding residential area. 

Investigations showed that vapors emitting from the underground contamination have intruded into homes and a local 

park. 

Von Duprin LLC, whose predecessor in interest manufactured security hardware and once owned property in the area, 

undertook cleanup efforts and then sought to recover some of 

those costs as well as future remediation costs. Von Duprin 

sued former and current owners and operators of adjoining 

properties under the Comprehensive Environmental Response, Compensation, and Liability Act—a federal environmental statute often shorthanded as CERCLA. Following a 

bench trial, the district court found that Von Duprin and two 

other former or current owners and operators in the area bore 

responsibility for portions of the environmental harm. The 

court then assigned liability among and between all three parties. Before us now are an appeal and cross-appeal from 

lengthy proceedings in the district court. 

While we see no error in many of the district court’s rulings, we vacate the court’s threshold determination under 

§ 107(a) of CERCLA that liability for remediating the environmental harm is divisible—capable of being apportioned on 

the basis of principles of causation—among and between the 

parties to this litigation. In the end, then, we affirm in part and 

vacate and remand in part for additional proceedings.
Nos. 20-1711 & 20-1793 3

I 

A. The Properties at Issue 

The environmental harm developed over at least the last 

50 years. The four relevant and adjacent properties, each in 

northeast Indianapolis, have changed hands over the years.

We start with the Von Duprin Property. Von Duprin LLC’s 

predecessor, Von Duprin Inc., owned the property for over 40 

years and during that time manufactured security hardware 

and safety products. The firm used degreasers and a variety 

of chemical products, including trichloroethylene (TCE) and 

perchloroethylene (PCE). Operations ceased in 1986, and a 

manufacturer named Threaded Rod Company, Inc. acquired 

the Von Duprin Property in 1987. 

Next up is the Moran Property. Moran Electric Service 

Inc., a company that used degreasers as well as TCE and other 

cleaning agents in connection with repairing electrical motors, owned and operated this property from 1946 to 1996. In 

2005, a company called Major acquired the Moran Property. 

Now the Ertel Property. Ertel Manufacturing, a manufacturer of automotive engine parts, owned this property from 

1917 to 1998. The firm used chlorinated solvents like TCE and 

PCE in its manufacturing processes. The Ertel Property 

changed hands in 1998, only later to be abandoned. In 2007 

Major leased the Ertel Property from the City of Indianapolis. 

Major acquired full ownership in 2013. 

The Zimmer Paper Property, itself subdivided into the 

Zimmer Paper Facility and the Zimmer Packaging Facility, is 

the fourth property. Zimmer Paper Products, Inc. owned the 

property from 1986 to 2006, during which time the company 

used and disposed of chemical solvents. These properties 
4 Nos. 20-1711 & 20-1793 

were owned and operated by Moran from 1967 to 1984. Major 

acquired the Zimmer Paper Facility in 2007 and later acquired 

the Zimmer Packaging Facility in 2013. 

Major, which we use for simplicity in referring to Major 

Holdings LLC and Major Tool & Machine, is the current 

owner of the Ertel Property, Moran Property, and Zimmer Paper Property. No one alleges that Major released any hazardous materials at any of its properties, but current owners or 

operators of a site where hazardous materials were released 

may be held liable under CERCLA without having caused a 

release. 

So the overall ownership history breaks down this way:

Properties Former Owner(s) Current 

Owner

Von Duprin Property Von Duprin LLC Threaded 

Rod

Moran Property Moran Electric 

Service

Major 

Ertel Property Ertel Manufacturing Major 

Zimmer Paper 

Property (divided into 

the Zimmer Paper 

Facility and the 

Zimmer Packaging 

Facility) 

Moran Electric 

Service

Zimmer Paper 

Products

Major

All agree that, at various times over the twentieth century, 

chlorinated solvents, including PCE and TCE, were dumped 

at and around the Von Duprin, Moran, Ertel, and Zimmer 

Properties. These solvents are toxic and over time they seeped 
Nos. 20-1711 & 20-1793 5

into the soil and groundwater, eventually commingling into a 

groundwater plume—a collection of groundwater mixed 

with hazardous contaminants underground—which flows 

from northeast (where the properties are located) to southwest, covering approximately three-quarters of a mile. Of particular concern is that vapor emissions from the plume can 

migrate upwards from the groundwater and through the soil, 

resulting in vapor intrusion into structures. About 40 homes 

and an indoor facility at the public park have experienced this 

intrusion. 

B. Von Duprin’s Lawsuit 

After several environmental assessments and investigations of the Von Duprin Property, the Indiana Department of 

Environmental Management or IDEM, determined in March 

2009 that soil and groundwater at and around the property 

had been contaminated by chlorinated solvents. In 2013 IDEM 

informed Von Duprin that it could be a potentially responsible party or PRP under Indiana law. Von Duprin then began 

its own investigation into the contamination. In time the company entered Indiana’s cleanup program and performed substantial remediation in the area. After it, too, received a potential liability notice from IDEM and began to take remedial action, Threaded Rod, the current owner of the Von Duprin 

Property, filed a suit against Von Duprin and others to recover costs. That case later settled. 

Von Duprin has continued to undertake remediation efforts at a cost of $3.2 million. In 2016 the company invoked 

§ 107(a) of CERCLA and turned to federal court to recover 

those costs from current and former owners of adjacent properties—Moran, Zimmer, and Major. 
6 Nos. 20-1711 & 20-1793 

Moran and Major responded by going on the offensive 

and filing counterclaims and crossclaims against Von Duprin 

under § 113(f) of CERCLA. Zimmer never appeared or replied to the original complaint, so the district court entered a 

default against the company under Federal Rule of Civil Procedure 55(a). 

C. An Overview of CERCLA

Some background on CERCLA is essential to understanding the district court’s decision and issues before us on appeal. 

Over many decades, Congress has created legal mechanisms to encourage cleanup and continued stewardship of 

real property. A prime example came with the enactment of 

CERCLA in 1980. Congress designed the statute to “promote 

the timely cleanup of hazardous waste sites and to ensure that 

the costs of such cleanup efforts were borne by those responsible for the contamination.” Burlington Northern & Santa Fe 

Ry. Co. v. United States, 556 U.S. 599, 602 (2009) (cleaned up). 

The statute operates in part by encouraging, and directly 

providing the vehicle for, private parties to invest in environmental response, including remediation, and then to recover 

at least part of those response costs from other potentially responsible parties or PRPs.

In United States v. Atlantic Research Corporation, the Supreme Court held that § 107(a) of CERCLA, codified at 42 

U.S.C. § 9607(a), provides PRPs who incurred response costs 

with a cause of action to recover certain of those costs from 

other PRPs. See 551 U.S. 128, 131, 139 (2007). To establish a 

claim for cost recovery under § 107(a), a plaintiff must show 

that (1) the site in question is a “facility”; (2) the defendant 

qualifies as a PRP; (3) the facility experienced a release or 
Nos. 20-1711 & 20-1793 7

threatened release of hazardous substances; and (4) the plaintiff incurred costs consistent with the National Contingency 

Plan in responding to the release. See Env’t Transp. Sys., Inc., 

v. ENSCO, Inc., 969 F.2d 503, 506 (7th Cir. 1992). 

Congress defined PRPs to include four entities: current 

owners and operators of a site that experienced a disposal of 

hazardous material, past owners or operators at the time of 

the release, persons who arranged for disposal of a hazardous 

substance at a site, and parties who transported a hazardous 

substance to a site. See 42 U.S.C. § 9607(a)(1)–(4). Everyone 

agrees that each party to this litigation qualifies as a PRP under CERCLA. 

Joint and several liability is the norm for PRPs under 

§ 107(a). The exception is divisible liability—commonly called 

apportioned liability—where liability is assigned to PRPs according to the portion of the underlying environmental harm 

each caused. See Burlington Northern, 556 U.S. at 613. 

PRPs who find themselves sued under § 107(a) often file a 

counterclaim against the original plaintiff on the basis that the 

party is itself a PRP who caused part of the harm and thus 

should contribute to any ultimate remediation liability. These 

so-called contribution counterclaims proceed under § 113(f) 

of CERCLA, which authorizes the allocation of liability based 

on “such equitable factors as the court determines are appropriate.” 42 U.S.C. § 9613(f)(1). 

At this point, what is essential to recognize is that apportioned (divisible) liability and allocated liability are not one 

and the same under CERCLA. To the contrary, they are distinct, with apportioned liability imposed on the basis of 
8 Nos. 20-1711 & 20-1793 

principles of causation and allocated liability the product of 

an application of equitable factors. 

Two more background points help frame the issues on appeal. First, not all remediation costs are eligible for recovery 

under § 107(a). Rather, Congress has limited recovery costs to 

those incurred consistent with the National Contingency Plan 

or NCP. See 42 U.S.C. § 9607(a)(4)(B). The NCP establishes 

how private parties can best perform removal and remedial 

actions to ensure the achievement of CERCLA-quality

cleanup. See 40 C.F.R. § 300. 

Second, CERCLA provides an affirmative defense to remediation liability to PRPs who did not release hazardous materials themselves but remain potentially liable by virtue of being a current owner of a site where a prior release occurred. 

Added in 2002, Congress called this defense the “bona fide 

prospective purchaser” or BFPP defense. See 42 U.S.C. 

§ 9607(q)(1)(C). To qualify, a PRP must, in connection with the 

original purchase of the property in question, and among 

other things, make “all appropriate inquiries into the previous ownership and uses of the facility in accordance with generally accepted good commercial and customary standards 

and practices.” 42 U.S.C. § 9601(40). In that way, the BFPP defense shields from CERCLA liability those who invest in contaminated lands and exercise diligence, do not impede 

cleanup efforts, and meet ongoing obligations. 

D. Summary Judgment

After a period of initial discovery, the parties filed cross 

motions for summary judgment. The district court’s ruling on 

the divisibility of remediation liability—whether the norm of 

joint and several liability for PRPs should apply or instead 
Nos. 20-1711 & 20-1793 9

whether each PRP should bear responsibility to the degree 

they caused the underlying environmental harm—is a substantial issue on appeal. In granting in part Moran and Major’s motions for summary judgment, the district court determined that CERCLA liability was divisible and thus should 

be apportioned among and between the PRPs. 

The district court’s reasoning rested on two abbreviated 

observations. First, the court observed (without much accompanying explanation) that the harm caused by the PRPs (Von 

Duprin, Major, Moran, and Zimmer) was “theoretically capable of apportionment” and therefore divisible among them. 

From there, and second, the district court pointed to Moran’s 

expert witness, Dr. Adam Love, and, again without much 

elaboration, observed that there was a “reasonable basis for 

apportionment.” Who caused what harm and how much each 

PRP, including Von Duprin, should contribute to the overall 

remediation costs would, the district court concluded, be decided at a bench trial. 

At summary judgment the district court also concluded 

that Major was a BFPP and thus could not be held liable for 

response costs that Von Duprin (as the plaintiff) sought to recover relating to the Moran Property and Zimmer Packaging 

Facility. 

E. The District Court’s Bench Trial

A six-day bench trial ensued in the summer of 2019. A battle of competing experts—all offering different perspectives 

on which PRP caused what portion of the overall environmental harm—defined much of the trial. Other witnesses testified about methods for allocating liability and whether the 
10 Nos. 20-1711 & 20-1793 

remediation costs incurred by Von Duprin were consistent 

with the National Contingency Plan. 

The district court’s ultimate Findings of Fact and Conclusions of Law included these key rulings: 

Recoverable Costs. The district court evaluated what portion 

of Von Duprin’s costs were incurred consistent with the NCP 

and therefore recoverable under § 107(a) of CERCLA. The 

court concluded that $1.7 million of the $3.2 million Von 

Duprin originally sought was recoverable, excluding the $1.5 

million settlement with Threaded Rod from a previous lawsuit and $39,000 for the costs related to IDEM oversight. 

Apportionment of Liability. The district court began by renewing its prior observation (from summary judgment) that 

the environmental harm was “theoretically capable of apportionment.” It then found that, based on the evidence presented at trial, a “reasonable basis for apportionment exists.” 

The court did so by crediting Moran’s expert Dr. Adam Love’s 

testimony as to how the harm could be apportioned among 

the properties—even while noting that the nature of the contamination made it impossible to differentiate the chemical 

compounds once they enter the groundwater plume and 

eventually vaporize. 

In a section of its Conclusions of Law labeled “Apportionment,” the district court held that Major was liable under 

§ 107(a) as the current owner of the Ertel Property and Zimmer Paper Facility. Von Duprin, the court further concluded, 

was liable as owner of the Von Duprin Property at the time of 

a hazardous release. Moran was liable too, because it owned 

the Moran Property at the time of a release. Since no party 
Nos. 20-1711 & 20-1793 11

offered evidence of a release when Zimmer owned the facility, the district court assigned no liability to it. 

Allocation of Liability. In a section labelled “Allocation,” the 

district court then performed what it called “equitable allocation” by applying a series of factors, including the distinguishability of each party’s hazardous waste, the amount of 

that waste, the toxicity of the contaminants at issue, the degree of involvement of the parties in generating the waste, the 

extent of each party’s cooperation with environmental authorities to mitigate harm, and the overall care taken by each 

party in handling the hazardous waste. These factors are commonly called the “Gore factors,” named after then-Congressman Albert Gore who proposed them as an amendment to a 

1980 Superfund bill. See Env’t Transp. Sys, 969 F.2d at 508. 

After listing these Gore factors, but without any explanation as to whether or how each factor played into its allocation 

analysis, the district court “apportioned” the response costs 

as follows: 50% to the Von Duprin Property, 10% to the Ertel 

Property, 20% to the Zimmer Paper Property, and 20% to the 

Moran Property. Each party was held responsible for 100% of 

the harm attributed to the property or properties that they 

once owned or now own. The district court then took those 

percentages and applied them to the total amount of Von 

Duprin’s recoverable costs—$1.7 million—and found that 

Von Duprin was responsible for $850,000, Major for $510,000, 

and Moran for $340,000. The district court considered the 

cross- and counterclaims filed by the parties to be resolved by 

these liability allocations. 

From there the district court ruled on Von Duprin’s request for a declaratory judgment entitling it to recover anticipated future remediation costs related to ongoing cleanup 
12 Nos. 20-1711 & 20-1793 

contamination at the adjoining properties. The court found an 

award of future costs warranted because the company had established its right to recover from the other PRPs for past response costs. The district court therefore awarded Von 

Duprin future costs in an amount to be determined based on 

the same allocation percentages of liability for past costs 

among the parties, conditioned on the company proving that 

subsequent costs were both incurred consistent with the NCP 

and related to contamination at the surrounding properties. 

Major’s BFPP Defense. The district court further considered 

Major’s request for a BFPP defense. At summary judgment, 

the district court had concluded that Major was a BFPP (and 

therefore shielded from liability under § 107(a)) for any harm 

arising from the Moran Property and Zimmer Packaging Facility. Based upon the evidence presented at trial, however, 

the district court reached the opposite conclusion for Major’s 

two other properties, the Ertel Property and Zimmer Paper 

Facility. Major was liable, the district court continued, for 

harm resulting from those two properties because the company could not show that it had satisfied the “all appropriate 

inquiries” requirement of the BFPP defense. 

Remaining State Law Claims. Finally, the district court summarily disposed of Von Duprin’s state law claims, observing 

that ruling in the company’s favor on those claims would 

amount to a prohibited double recovery. 

F. Major’s Appeal and Von Duprin’s Cross-Appeal 

Major appealed and Von Duprin filed its own cross-appeal. 

Major appeals the district court’s decision to deny it the 

benefit of the BFPP defense to liability for its ownership of the 
Nos. 20-1711 & 20-1793 13

Zimmer Paper Facility and the Ertel Property. Major also 

maintains that Von Duprin failed to prove its response costs 

were incurred consistent with the NCP. Finally, Major challenges the district court’s calculation of damages, contending 

that the district court conflated the allocation and apportionment processes, resulting in a damages award unsupported 

by the evidence. 

Von Duprin cross-appealed, arguing that the district 

court’s liability assignment erred at an earlier step: it should 

never have concluded that the harm was capable of apportionment. In Von Duprin’s view, the district court should 

have held the defendants jointly and severally liable. At a 

more granular level, Von Duprin also challenges the district 

court’s failure to exclude Dr. Love’s testimony as unreliable. 

For its part, Moran asks us to affirm the district court in 

full. 

II

We begin with a word on appellate jurisdiction. Upon 

docketing Major’s appeal and Von Duprin’s cross-appeal, we 

questioned whether the case had reached finality in the district court and directed the parties to brief the question. What 

concerned us was that the district court’s judgment made no 

mention of Zimmer’s default, how the court resolved Moran 

and Major’s counterclaims, and the amount of prejudgment 

interest owed Von Duprin as part of its damages award. In 

these ways, the district court’s judgment was deficient, as it 

invited the impression that the court had entered a partial 

judgment under Federal Rule of Civil Procedure 54(b) and 

thus not resolved all claims against all parties. See Gen. Ins. 

Co. of America v. Clark Mall Corp., 644 F.3d 375, 378–80 (7th Cir. 
14 Nos. 20-1711 & 20-1793 

2011) (explaining scenarios in which 54(b) judgments provide 

sufficient finality for purposes of appellate jurisdiction). 

Aided by the parties’ briefing of the finality question, we 

are confident in our jurisdiction. The district court’s final 

judgment order expressly accounted for 100% of the allocated 

liability by assigning amounts owed to the pertinent parties, 

thereby necessarily resolving Von Duprin’s primary claim 

under § 107(a) as well as Moran and Major’s counterclaims for 

contribution under § 113(f). We interpret the district court’s 

silence on Zimmer to mean—as everyone agrees—that Zimmer, despite its default, owes nothing under the terms of the 

judgment. To be sure, the district court should have entered 

formal default judgment against Zimmer under Rule 55. And 

while the district court also should have specified the prejudgment interest owed Von Duprin, the failure to do so does 

not indicate a lack of finality because the computation is 

“readily ascertainable from the record through only a ministerial calculation” and, even more, the docket shows that Moran has since paid the amount owed. Student Loan Marketing 

Ass’n v. Lipman, 45 F.3d 173, 177 (7th Cir. 1995). 

In these circumstances, then, we have no doubt the case 

reached finality in the district court and that we may proceed 

to the merits of the questions presented on appeal. 

III

On the merits, we start with Von Duprin’s challenge to the 

district court’s threshold determination at summary judgment that remediation liability should not be joint and several 

but instead apportioned among Major, Moran, and Zimmer 

as the PRPs according to the environmental harm caused by 

each company. Major challenges the district court’s resolution 
Nos. 20-1711 & 20-1793 15

of its counterclaim seeking contribution from Von Duprin under § 113(f) of CERCLA for its own share of the remediation 

liability. Major sees the district court’s ultimate allocation of 

liability as unsupported by the evidence presented at the 

bench trial. 

Both Von Duprin and Major are right to find fault with the 

district court’s liability determinations. We see two errors. 

First, the district court applied incorrect substantive and procedural standards in concluding at summary judgment that 

the environmental harm and attendant CERCLA liability 

could be apportioned. Second, after the bench trial, the district 

court conflated the concepts of apportionment and allocation 

and left unexplained the factors guiding its ultimate assignments of liability. These two errors interrelate in ways that 

leave us no choice but to vacate the district court’s judgment 

and to remand for further proceedings.

A. Apportionment at Summary Judgment

Section 107(a) of CERCLA imposes “strict liability” on 

PRPs for response costs resulting from a release of hazardous 

materials. Burlington Northern, 556 U.S. at 608. While the statutory text is silent on the scope of liability, the Supreme Court 

has explained that Congress intended that question to “‘be 

determined from traditional and evolving principles of common law.’” Id. at 613 (quoting United States v. Chem-Dyne 

Corp., 572 F. Supp. 802, 808 (S.D. Ohio 1983)). 

The primary guideposts come from the Restatement (Second) of Torts. And we know from the Restatement that 

“where two or more persons cause a single and indivisible 

harm, each is subject to liability for the entire harm.” ChemDyne, 572 F. Supp. at 810 (citing Restatement (Second) of 
16 Nos. 20-1711 & 20-1793 

Torts, § 875). The imposition of joint and several liability 

holds each party responsible for the entirety of the harm. See 

id. 

The Restatement explains that liability may be divided—

or apportioned—“when two or more persons acting independently caused a distinct or single harm for which there is 

a reasonable basis for division according to the contribution 

of each,” with each responsible party being “subject to liability only for the portion of the total harm that he has himself 

caused.” Id. (citing Restatement (Second) of Torts § 433A). Because “[n]ot all harms are capable of apportionment,” the Supreme Court has emphasized that “CERCLA defendants 

seeking to avoid joint and several liability bear the burden of 

proving that a reasonable basis for apportionment exists.” 

Burlington Northern, 556 U.S. at 614. The facts and evidence 

must permit a “reasonable basis” for dividing liability among 

PRPs, as “arbitrary apportionment for its own sake” is inconsistent with CERCLA’s liability scheme. See id. at 614 (citations omitted). 

As a practical matter, joint and several liability often reflects the norm in complex environmental cleanup cases because most circumstances reveal numerous disposers of waste 

over long periods of time where after-the-fact identification of 

who contributed what and thus who caused what portion of 

the present-day harm at issue is exceptionally difficult to ascertain with reliability. A leading case in this area—ChemDyne, from which the Supreme Court took direction in Burlington Northern—reinforced this precise reality. See ChemDyne, 572 F. Supp. at 810–11 (declining at summary judgment 

to determine that liability could be apportioned because the 

evidence, when viewed in the light most favorable to the non-
Nos. 20-1711 & 20-1793 17

moving party, showed that multiple parties had contributed 

to the contamination and over time much of the waste had 

become commingled, making the divisibility determination 

all the more complex). Our cases, too, have recognized that 

joint and several liability is the norm in complex CERCLA

cases. See Metro. Water Reclamation Dist. v. N. Am. Galvanizing 

& Coatings, Inc., 473 F.3d 824, 827 n.3 (7th Cir. 2007) (“The only 

exception to joint liability is when the harm is divisible, but 

this is a rare scenario.”); United States v. Capital Tax Corp., 545 

F.3d 525, 535 (7th Cir. 2008) (“Divisibility is the exception, 

however, not the rule.”).

The apportionment inquiry proceeds in two steps. See 

Burlington Northern, 556 U.S. at 614 (laying out the two-step 

process); United States v. NCR Corp., 688 F.3d 833, 838 (7th Cir. 

2012) (applying that process) (“2012 NCR Corp.”). The threshold question is whether the harm is even capable of apportionment. See Burlington Northern, 556 U.S. at 614. Making 

that determination requires an initial look at the underlying 

facts to determine “what type of pollution is at issue, who 

contributed to that pollution, how the pollutant presents itself 

in the environment after discharge, and similar questions.” 

2012 NCR Corp., 688 F.3d at 838. If the preliminary review of 

the facts suggests that the harm can be apportioned, the inquiry then must take the second step of asking with even 

more factual particularity whether the evidentiary record 

provides a reasonable basis for actually apportioning the liability among the PRPs. See id. 

Although the case law has described these inquiries as 

proceeding in two distinct steps, it is often easier and more 

practical to think of them as blending together and interrelated. Whether undertaken in one or two steps, the 
18 Nos. 20-1711 & 20-1793 

overarching question is whether, as a matter of record evidence, the environmental harm (and responsibility for the response costs at issue) can be apportioned by applying principles of causation. 

Whether the evidence permits the apportionment of remediation liability is itself often a contested question. Some parties may insist the answer is yes, while others will urge the 

district court to say no. That is what happened here: Major 

and Moran contended that the evidence in the summary judgment record allowed the district court to make findings as to 

which PRP caused what environmental harm. Von Duprin 

took the opposite position, arguing that the same record evidence provided no reliable basis for making the findings necessary to apportion the liability. The district court’s responsibility at summary judgment was to ensure that Major and Moran, as both the moving parties and the parties with the burden of showing that cost-recovery liability is divisible, had 

identified materially uncontested record evidence allowing 

that question to be resolved in the affirmative without a trial. 

See Burlington Northern, 556 U.S. at 614 (explaining that the 

burden for showing divisibility is on the moving party); Fed. 

R. Civ. P. 56(a) (identifying the burden on the party moving 

for summary judgment). 

The point of this observation is to recognize and reinforce—as the district court did in Chem-Dyne—the complexity 

and intersection of the substantive liability question with the 

procedural posture at which the question is being asked. The 

apportionment inquiry must be answered at summary judgment in a manner consistent with both the standards (and protections) of Rule 56 and the substantive burden imposed by 

§ 107(a) of CERCLA on the party requesting that cost-
Nos. 20-1711 & 20-1793 19

recovery liability be divided among the PRPs instead of joint 

and several. 

The district court did not approach the apportionment 

question this way at summary judgment. In granting Moran’s 

motion for partial summary judgment on the apportionment 

question, the district court determined that the harm was 

“theoretically capable of apportionment” based on the opinion offered by Moran’s expert, Dr. Adam Love. He opined 

that there were distinct sites of pollution at each property that 

could be used to effectively account for how much of the harm 

emanated from each property. This was possible, Dr. Love explained, by examining the chemical composition of soil samples from those source sites to ascertain the concentration of 

certain chemicals at each site and to compare those respective 

concentrations to the chemical composition of the groundwater plume. In Moran’s view, Dr. Love’s analysis established 

that the Von Duprin Property’s contributions to the total 

harm were distinct from that of the other properties. This was 

so, according to Dr. Love, because soil samples from the Von 

Duprin Property showed a larger presence of PCE, whereas 

the soil samples from the other properties—which sit upgradient from Von Duprin, meaning that the groundwater flows 

down toward the Von Duprin Property—show a larger presence of TCE. Thus, in Dr. Love’s opinion, responsibility for 

the environmental harm at issue was reasonably apportionable based on the chemical composition at the source sites visà-vis the composition of the plume. 

Von Duprin disagreed, maintaining that liability should 

be joint and several because the complexity of the underlying 

facts showed that the harm was incapable of reliable apportionment. The company supported this view by attacking Dr. 
20 Nos. 20-1711 & 20-1793 

Love’s opinion and raising larger questions about the feasibility of dividing the harm given the complexity of the underlying facts. Dr. Love’s methodology, Von Duprin contended, relied on soil samples collected well after large quantities of soil 

had been removed from the properties and decades after releases of hazardous waste. Von Duprin further offered its own 

expert, John McInnes, who opined that the four properties all 

played a part in releasing chlorinated solvents over many decades. Von Duprin also urged that apportionment was inappropriate because the toxic chlorinated solvents became indistinguishable once they commingled in the groundwater 

plume. These observations and facts, Von Duprin advanced, 

precluded a finding of divisibility at summary judgment. 

The district court reacted by seeing Von Duprin’s position 

as a “concern [that] highlights a practical problem, not a theoretical one.” Indeed, the district court went even further, observing that Von Duprin’s concerns with the reliability of Dr. 

Love’s apportionment analysis are “irrelevant to the question 

of whether harm is divisible.” 

Therein lies the misstep. The district court’s approach reflects two errors—one substantive and one procedural—that 

interrelated in a way that sent the incorrect question to trial 

and had the effect of relieving Major of its burden of showing 

that liability should be apportioned instead of imposed jointly 

and severally on each PRP. 

The errors were the product of the district court approaching the divisibility question at too high a level of generality, 

taking too literally the use of the word “theoretically” in our 

decision in 2012 NCR Corp. See 688 F.3d at 838. There we restated the Burlington Northern test in terms of two steps. We 

described the first step as one at which “we must determine 
Nos. 20-1711 & 20-1793 21

whether the harm at issue is theoretically ‘capable of apportionment.’” Id. (quoting Burlington Northern, 556 U.S. at 614). 

The district court overread the adverb’s importance to the 

test. After all, nearly everything in theory is capable of division if examined at a high enough level of generality. But seeing the question in theoretical—rather than factual and evidentiary—terms robs the necessary apportionment inquiry of 

any meaningful content and leads to an analysis divorced 

from the Supreme Court’s instructions in Burlington Northern

and the guiding principles in the Restatement (Second) of 

Torts.

Indeed, we made much the same observation in 2012 NCR 

Corp. itself. We emphasized that whether the environmental 

harm at issue was capable of apportionment depended—at 

the first step of the analysis—on many findings of fact. See 688 

F.3d at 838. Here, however, the district court seemed to conclude that the remediation liability was divisible—at least at 

the theoretical level—because Moran’s expert Dr. Love offered that view. But stopping with that observation effectively 

transformed the norm of joint and several liability in CERCLA 

cost-recovery cases to divisible liability. Put another way, our 

review of the summary judgment record leaves us of the view 

that the district court stopped short of grappling with the 

complexity inherent in a CERCLA cost-recovery case as wideranging as this one. We do not read the Supreme Court’s Burlington Northern decision as intending every asserted apportionment defense to so easily clear the evidentiary hurdle demanded by the standard embodied in § 433A of the Restatement. 

Consider the complexity of the environmental harm at issue. At least three different owners of four different properties 
22 Nos. 20-1711 & 20-1793 

released hazardous waste in different quantities and concentrations at different times over several decades, at least from 

the 1960s to well into the 1980s. What is more, the record does 

not establish when or in what amounts any of this pollution 

occurred. And, as the district court acknowledged in its 

posttrial findings of fact, once the hazardous chemicals entered the groundwater, commingled, and vaporized, the individual molecules that make up the plume became indistinguishable. Layer this reality onto the burden a party seeking 

apportionment faces and the district court’s error becomes 

clear. Rather than recognizing the rarity of divisible liability 

in CERCLA cases, the district court instead treated the stepone inquiry as satisfied by a threshold proffer of expert testimony by Moran that the harm could be apportioned. 

The district court’s error also manifests as a closely-related 

procedural misstep. The error had the effect of all but eliminating Moran and Major’s burden at summary judgment under the substantive law of CERCLA. Federal Rule of Civil Procedure 56 permits entry of summary judgment only “if the 

movant shows that there is no genuine dispute as to any material fact and the movant is entitled to judgment as a matter 

of law.” Here that was the defendants, Moran and Major, as 

the parties that sought summary judgment on the question 

whether the remediation liability was divisible. Recall too 

that, as a substantive matter under CERCLA, the party contending that the court should abandon joint and several liability in favor of divisible liability bears the burden of proving 

that a reasonable basis for apportionment exists. See Burlington Northern, 556 U.S. at 614. 

The critical takeaway is to recognize that the substantive 

law governing the parties’ claims (here, § 107(a) of CERCLA) 
Nos. 20-1711 & 20-1793 23

and the procedural rule controlling whether summary judgment is appropriate work in tandem. The Supreme Court underscored this precise point in Anderson v. Liberty Lobby, Inc.: 

“in ruling on a motion for summary judgment, the judge must 

view the evidence presented through the prism of the substantive evidentiary burden.” 477 U.S. 242, 254 (1986). Stated 

most succinctly, district courts, in deciding “whether a given 

factual dispute requires submission to a jury[,] must be 

guided by the substantive evidentiary standards that apply to 

the case.” Id. at 255. 

The district court charted a different course, one that did 

not account at summary judgment for the substantive burden 

Major and Moran would face at trial on the apportionment 

question. The district court even seemed to require Von 

Duprin to affirmatively disprove that the harm was capable 

of apportionment. That was error, especially at the summary 

judgment stage. 

On the summary judgment record as we see it, there appears to have been a genuine dispute over material facts that 

bore on the question whether the harm was capable of apportionment. The district court should have viewed the trial as 

the vehicle for resolving—as a definitive matter of evidence—

that question. By proceeding otherwise, the district court displaced the norm of joint and several liability in favor of apportionable harm, a subversion of the substantive law at odds 

with CERCLA’s central design. 

The district court’s error is not one we can correct on appeal. Having taken our own fresh look at the summary judgment record, we see the question whether remediation liability is capable of apportionment as both contested and difficult. It was hotly contested by Von Duprin and Major and 
24 Nos. 20-1711 & 20-1793 

Moran—each presented evidence bearing on the questions 

underlying the apportionment inquiry. And it is difficult because the overarching apportionment question that the parties disagree over begets even more questions. The open questions include what role some variables—such as the length of 

time between the actual discharge of the hazardous chemicals 

and the chemical analysis of the soil on the properties, the removal of soil on the properties as part of past remediation efforts, and the commingling of the solvents once they entered 

the groundwater—might play in deciding the feasibility of 

determining who caused what harm with any remote confidence. Determining whether liability can be apportioned requires wrestling with these and other questions presented by 

the complexity of the underlying facts. 

Given how fact and context-specific the apportionment inquiry is—even at step one—we think it wiser to provide these 

observations and give the district court another opportunity 

to evaluate the question. In approaching this question anew, 

the district court should analyze the facts and record evidence 

at a higher level of particularity under the standards articulated in the Restatement (Second) of Torts and the pertinent 

case law. 

Do not overread our conclusions. We break no new 

ground on the law of apportionment in CERCLA cases. We 

merely restate the high bar for parties arguing that apportionment is appropriate in a given CERCLA cost-recovery action. 

The district court did not take that into account and otherwise 

failed in its summary judgment ruling to support its decision 

to depart from the norm of joint and several liability with factual findings rooted in the record. 
Nos. 20-1711 & 20-1793 25

B. Assignment of Liability After Trial

Our reversal of the divisibility determination at summary 

judgment compels us to vacate the damages award for a fresh 

liability calculation as a whole. But we need to address an additional error by the district court. After determining that apportionment was appropriate, the district court proceeded to 

Major and Moran’s request for contribution under § 113(f) 

and allocated the liability among the parties. While we can see 

the ultimate liability awards, we cannot tell how the district 

court weighed the equitable factors. The error, as we see it, 

resulted from the district court treating apportionment and 

allocation interchangeably—so much so that we cannot be 

sure how the court arrived at its determinations of liability. 

We are not quibbling with word choice. The distinction between apportioned liability and allocated liability is substantive and important under CERCLA. These terms are far from 

synonymous. Indeed, they refer to altogether separate statutory provisions. Apportionment operates in a § 107(a) action 

for the recovery of response costs, but only where the harm is 

divisible. See Burlington Northern, 556 U.S. at 614. Allocated 

liability, on the other hand, arises by operation of § 113(f). See 

Atl. Rsch., 551 U.S. at 140. That provision authorizes PRP defendants to seek contribution toward the liability from the 

party seeking cost recovery in the first instance or from other 

PRP defendants. As happened here, the defendants in a 

§ 107(a) cost-recovery action typically bring a counterclaim 

under § 113(f) for contribution from the plaintiff. 

Allocation refers to the way liability is assigned in a contribution claim. See NCR Corp. v. George A. Whiting Paper Co., 

768 F.3d 682, 689 (7th Cir. 2014) (“2014 NCR Corp.”). Unlike 

apportionment, which is guided by principles of causation, 
26 Nos. 20-1711 & 20-1793 

§ 113(f) of CERCLA provides that courts allocate liability 

among PRPs “using such equitable factors as the court determines are appropriate.” 42 U.S.C. § 9613(f)(1). It seems easiest 

to think of the allocation analysis as more flexible and softer 

than the apportionment analysis under § 107(a), which requires more an application of principles of causation and a 

form of contributory negligence. One court has described the 

distinction more colorfully: “To apportion is to request separate checks, with each party paying only for its own meal. To 

allocate is to take an unitemized bill and ask everyone to pay 

what is fair.” Yankee Gas Servs. Co. v. UGI Utilities, Inc., 852 

F. Supp. 2d 229, 241–42 (D. Conn. 2012). 

The district court exercises substantial discretion when allocating liability. As Congress put it, district courts must allocate response costs using “such equitable factors as the court 

determines are appropriate,” 42 U.S.C. § 9613(f)(1), a level of 

discretion we have described as “broad.” 2014 NCR Corp., 768 

F.3d at 700. But that discretion is not without limits, and the 

“court’s ultimate decision must reflect CERCLA’s equitable 

principles.” Id. at 701. We have previously vacated a district 

court’s allocation of damages where the district court did not 

adequately explain its rationale for evaluating some relevant 

equitable factors and not others. See id. at 702. Just as we observed in 2014 NCR Corp., we must vacate the judgment 

where “we cannot be sure either that the court did, or that it 

did not, adequately consider all of the circumstances before 

makings its decision.” Id. at 703. Just so here. 

After reaffirming its view that the harm was capable of apportionment at summary judgment, the district court proceeded to a bench trial to conduct what it called “equitable 

allocation.” To be sure, the district court mentioned equitable 
Nos. 20-1711 & 20-1793 27

factors that it considered, including listing the Gore factors, 

but the court went into no detail as to how or why it considered certain factors or discounted others. Instead, the district 

court seemed to rely solely on Dr. Love’s expert testimony on 

how the harm could be apportioned based on the four distinct 

sources of contaminants. Without an explanation from the 

district court, we cannot conduct our own evaluation of its exercise of discretion. 

In many ways, we find ourselves stuck. We cannot discern 

how the district court determined how much to award each 

party and on what basis. Even more, though, our review of 

the district court’s posttrial opinion leaves us of the firm conviction that the court merged and conflated its consideration 

of apportionment and allocation. We do not know what portions of the liability awards reflect apportionment and what 

aspects reflect allocation. The Supreme Court cautioned 

against this error in Atlantic Research, emphasizing that treating “contribution as if it were synonymous with apportionment of expenses among PRPs” too “confuses the complimentary yet distinct nature of the rights established in §§ 107(a) 

and 113(f).” 551 U.S. at 138 (internal citation and quotation 

omitted). The Court sounded similar caution in Burlington 

Northern, emphasizing that “[e]quitable considerations play 

no role in the apportionment analysis; rather, apportionment 

is proper only when the evidence supports the divisibility of 

the damages jointly caused by the PRPs.” 556 U.S. at 615 n.9. 

We see no path forward other than to vacate the judgment 

and allow the district court to revisit the entirety of its liability 

analysis. On remand and with the legal framework now clarified, the district court must first revisit the apportionment 

question it previously resolved at summary judgment on Von 
28 Nos. 20-1711 & 20-1793 

Duprin’s § 107(a) cost-recovery claim. Our review of the summary judgment record, as we have explained, leaves us persuaded that resolving the apportionment inquiry at the very 

least requires consideration of the evidence presented at trial 

and perhaps even additional evidence. The district court has 

the discretion to fashion the remand proceedings in ways that 

position the evidentiary record to allow for the findings necessary to resolve the apportionment question. The court will 

have the same flexibility in revisiting the allocation of liability 

when it resolves Major and Moran’s counterclaims under 

§ 113(f). 

IV

Beyond the assignment of liability, the parties raise a host 

of other issues on appeal. Though none is outcome determinative, we address them to provide as much clarity as possible for the proceedings on remand. On these remaining issues, we see no errors and indeed affirm each of the district 

court’s challenged rulings. 

A. Major’s Bona Fide Prospective Purchaser Defense 

To encourage investment in and restoration of contaminated lands, Congress provided a complete defense to liability for parties who would otherwise face liability solely by virtue of acquiring and thus owning or operating on contaminated land. CERCLA calls this the bona fide prospective purchaser or BFPP defense. See 42 U.S.C. §§ 9601(40), 

9607(q)(1)(C). The district court determined that Major qualified for the BFPP defense for two properties (the Moran Property and the Zimmer Packaging Facility) but not for two others (the Ertel Property and the Zimmer Paper Facility). Major 

appeals the district court’s ruling on the latter two properties. 
Nos. 20-1711 & 20-1793 29

To qualify for the BFPP defense, PRPs must meet certain 

requirements, including that—in connection with acquiring 

the property in question—they make “all appropriate inquiries into the previous ownership and uses of the facility in accordance with generally accepted good commercial and customary standards and practices.” 42 U.S.C. § 9601(40). 

Zimmer Paper Facility. The district court was right to conclude that Major was not entitled to the BFPP defense for the 

Zimmer Paper Facility. To be sure, Major did complete a 

Phase 1 Environmental Assessment according to the provisions of ASTM International Standard E1527-05, and, complying with that standard, did at the time satisfy parts of the “all 

appropriate inquiries” requirements set forth in portions of 

CERCLA’s implementing regulations. See 40 C.F.R. §§ 312.23-

312.31. But CERCLA’s regulations—in particular 40 C.F.R. 

§§ 312.21 and 312.22—required more, and that more is where 

Major fell short. Those provisions include requiring certain 

attestations about the professional qualifications of the environmental professionals conducting the inquiry for the prospective purchase. See 40 C.F.R. § 312.21(d). These required 

attestations appear nowhere in Major’s Phase 1 Environmental Assessment, however. Try as Major does to point to nonbinding agency guidance, it cannot show full compliance with 

all requirements in the “all appropriate inquiries” regulation. 

Ertel Property. The district court was equally right to conclude that Major did not qualify for the BFPP defense for the 

Ertel Property. Here, too, Major failed to make all appropriate 

inquiries, though its missteps related more to timing than 

substance. Major leased the Ertel Property from the City of 

Indianapolis in November 2007, purchasing it outright several years later in 2013. Major completed all appropriate 
30 Nos. 20-1711 & 20-1793 

inquiries only at the time it acquired title to the property in 

2013. We agree with the district court’s conclusion that the 

BFPP defense, by its terms, applies to “owner[s] and operator[s],” and Major became an operator in November 2007, 

when it commenced its 99-year lease. See 42 U.S.C. 

§ 9607(a)(1). Major therefore had to complete the required inquiries by performing or updating an environmental assessment within 180 days of becoming an owner or operator. The 

company failed to do so, for the only environmental assessment that could satisfy the BFPP’s substantive requirements 

comes from September 6, 2006—a date not within 180 days of 

the commencement of the lease in November 2007. 

Moran Property. Von Duprin, in its combined reply and 

cross-appeal brief, adds that the district court erred at summary judgment when it allowed Major to assert the BFPP defense for the Moran Property. That position lacks merit. The 

evidence presented at trial established that Major completed 

the necessary inquiries in a complete and timely fashion in 

connection with acquiring the Moran Property. 

B. Von Duprin’s Compliance with the National 

Contingency Plan

We turn now to Major’s challenges to the district court’s 

determinations that certain costs incurred by Von Duprin 

were recoverable under § 107(a) of CERCLA. 

The parties disagree about the applicable standard of review. Major invites us to review the district court’s determination of NCP compliance de novo while Von Duprin urges 

application of the clear error standard. Our decision in NutraSweet suggests (without expressly stating) that our review 

is only for clear error. See 227 F.3d 776, 791 (7th Cir. 2000) 
Nos. 20-1711 & 20-1793 31

(explaining that “the district court did not clearly err in concluding that NutraSweet had satisfied the NCP”). But we do 

not need to resolve the question because the district’s conclusions satisfy either standard. We see no errors in the district 

court’s findings that Von Duprin incurred most of the challenged costs in substantial compliance with the NCP. We 

therefore reject Major’s cross-appeal on this point.

Congress permitted the recovery of necessary response 

costs incurred “consistent with” the National Contingency 

Plan or NCP, a federal regulation that establishes standards 

and obligations for remediation and cleanup efforts. 42 U.S.C. 

§ 9607(a)(4)(B); see also NutraSweet, 227 F.3d at 791. “A private 

party response action will be considered ‘consistent with the 

NCP’ if the action, when evaluated as a whole, is in substantial compliance with the applicable requirements ... and results in a CERCLA-quality cleanup.” 40 C.F.R. 

§ 300.700(c)(3)(i). The requirements are numerous and task 

specific. See, e.g., id. § 300.700(c)(5)–(6). The ultimate and controlling inquiry is whether the expenses in question were incurred in “substantial compliance” with the NCP. Id.

§ 300.700(c)(3)(i). Perfect compliance is not the measuring 

stick. 

When considering whether the costs Von Duprin sought 

to recover were incurred consistent with the NCP, the district 

court evaluated the relevant provisions of the regulations for 

the specific types of costs Von Duprin sought to recover. It 

concluded that Von Duprin’s remedial efforts, on the whole, 

reflected substantial compliance with the NCP. This finding, 

in turn, resulted in the district court determining that Von 

Duprin incurred the following costs consistent with the NCP: 

$750,000 for preliminary investigation and site assessment, 
32 Nos. 20-1711 & 20-1793 

$120,000 for remediation of the public park, $465,000 for residential vapor intrusion remediation, and $365,000 for bench 

and pilot testing. The only contrary finding came with respect 

to the $1.5 million settlement Von Duprin paid to Threaded 

Rod and about $39,000 in IDEM oversight costs. The district 

court found those costs were not incurred consistent with the 

NCP. 

Major contends that the district court erred in concluding 

that Von Duprin’s $750,000 in investigation and site assessment costs were recoverable. As best we can tell, Major seems 

to take issue with the district court’s finding that these costs 

relate to site assessment and other investigative work undertaken by Von Duprin. But the position is difficult to follow 

and not advanced with the clarity and evidentiary support to 

convince us to reverse. Going further, though, we see no legal 

infirmity in the district court’s observation that § 107(a) permits a company to recover due diligence costs incurred in 

connection with the investigation of a contaminated site. It 

stands to reason, the district court sensibly explained, that 

such initial inquiries are necessary to enable subsequent 

measures to ensure a CERCLA-quality cleanup, as CERCLA 

and the NCP both contemplate. See CNH Am., LLC v. Champion Envt’l Servs., 863 F. Supp. 2d 793, 809 (E.D. Wis. 2012) (collecting district court cases within our Circuit likewise finding 

that these preliminary investigative costs are recoverable under CERCLA). 

Nor are we convinced by Major’s insistence that the challenged costs are not recoverable because they are not expressly recognized in the NCP. It would be one thing if Von 

Duprin incurred costs proscribed by the NCP, as such costs 

would not be recoverable under the plain terms of § 107(a). 
Nos. 20-1711 & 20-1793 33

But we see nothing inconsistent—lacking substantial compliance—with the NCP to permit Von Duprin to recover due diligence site-assessment costs. It seems difficult to call such 

costs inconsistent with the NCP, to say nothing of CERCLA’s 

broader objectives. 

On this record, and especially against Major’s undeveloped argument on appeal, we cannot conclude that the preliminary assessment and investigative costs—those not expressly addressed by the NCP—were not incurred consistent 

with the NCP. We therefore see no error in the district court’s 

finding that the $750,000 Von Duprin spent on preliminary 

investigative measures and site-assessment was recoverable 

under § 107(a). 

Major also challenges Von Duprin’s recovery of certain 

other costs. These costs included the remediation of the public 

park, residential vapor intrusion remediation, and various 

tests. The district court took considerable care reviewing the 

testimony offered by Major and Von Duprin on these costs 

against the backdrop of the pertinent NCP regulations. While 

noting that Von Duprin’s compliance was not perfect, the district court concluded these challenged costs were incurred in 

substantial compliance with the NCP. 

We agree. Von Duprin substantially complied with the relevant components of the NCP dealing with documentation, 

health and safety protocols, site investigation, and public input for that set of challenged costs. And throughout the effort, 

the company worked with IDEM. See NutraSweet, 227 F.3d at 

791 (citing with favor the cooperation with regulatory agencies in discussing compliance with the NCP). To be sure, the 

district court correctly observed that Von Duprin failed to 

comply to the letter with certain NCP prescriptions. But to 
34 Nos. 20-1711 & 20-1793 

reverse the district court on this front would require a level of 

perfection at odds with Congress’s more limited requirement 

that recoverable costs only be incurred in “substantial compliance” with the NCP. 

C. District Court’s Admission of Dr. Adam Love’s 

Expert Testimony

We come in closing to Von Duprin’s challenge to the district court’s denial of its motion to exclude the testimony of 

Dr. Adam Love, Moran’s expert who offered opinions pertinent to the apportionment of liability under § 107(a) of 

CERCLA. 

“We review de novo whether a district court properly followed the framework for determining the admissibility of expert testimony.” Schultz v. Akzo Nobel Paints, LLC, 721 F.3d 426, 

430–31 (7th Cir. 2013); see also Fed. R. Evid. 702; Daubert v. 

Merrell Dow Pharm., Inc., 509 U.S. 579 (1993). If it did, “we review its decision to admit or exclude expert testimony only 

for an abuse of discretion.” Schultz, 721 F.3d at 431. 

In Daubert, the Supreme Court explained that Federal Rule 

of Evidence 702 imposes a gatekeeping responsibility on district courts to ensure that any proposed expert testimony “is 

not only relevant, but reliable.” 509 U.S. at 589. We afford district courts substantial latitude in making the findings necessary to fulfill this gatekeeping role. See Jenkins v. Bartlett, 487 

F.3d 482, 489 (7th Cir. 2007). Latitude is not a blank check, 

however, and the court must provide more than just conclusory statements of admissibility to show that it adequately 

performed its gatekeeping function. See Naeem v. McKesson 

Drug Co., 444 F.3d 593, 608 (7th Cir. 2006). 
Nos. 20-1711 & 20-1793 35

We start with two points of agreement among all parties. 

First, Dr. Love offered a relevant opinion. Indeed, he opined 

on whether and the extent to which each property contributed 

to the commingled plume—the question at the epicenter of 

whether liability could be apportioned. To our mind, it would 

be difficult to identify a question more relevant to the entire 

litigation. Second, nobody questions Dr. Love’s qualifications, 

as he plainly has the training and experience necessary to offer an opinion pertinent to whether responsibility for the contamination can be divided among the PRPs. 

What the parties tangled over was whether Dr. Love 

reached his opinions by applying a methodology that inhered 

with sufficient reliability to satisfy the requirements of Rule 

702. He came to his opinions by relying on soil and groundwater data collected during site investigations that occurred 

primarily from 2005 to 2017. Using this data, he analyzed soil 

samples at each property and then compared that to the 

chemical makeup of the groundwater plume. Dr. Love 

claimed that the distinct chemical compounds in the contaminated soil he tested at each site provided a way to apportion 

each property’s contributions to the total environmental harm 

that is the commingled groundwater plume. At no point did 

Dr. Love opine on which party was responsible for what 

amount of the harm. Instead, he offered a view on the proportion of the total contamination that was attributable to each 

property. 

Von Duprin insists that the district court should have excluded Dr. Love’s opinions because his underlying analysis 

failed to account for a range of confounding variables that 

prevented him from making reliable findings. While Von 

Duprin advances some sound observations about the 
36 Nos. 20-1711 & 20-1793 

limitations of Dr. Love’s ultimate opinions, we cannot say the 

district court abused its discretion in admitting the opinions 

in the first instance. Right to it, Von Duprin’s challenge goes 

more to the weight (or lack thereof) the district court should 

have afforded Dr. Love’s ultimate opinions. See Burton v. E.I. 

du Pont de Nemours and Co., Inc., 994 F.3d 791, 826 (7th Cir. 

2021) (“Although Rule 702 places the judge in the role of gatekeeper for expert testimony, the key to the gate is not the ultimate correctness of the expert’s conclusion but rather the 

soundness and care with which the expert arrived at her opinion.”) (cleaned up). Cross-examination, the presentation of 

contrary evidence, and an instruction on the burden of proof 

are the appropriate methods through which Von Duprin 

could have attacked Dr. Love’s opinions. See Schultz, 721 F.3d 

at 431. 

Be careful not to confuse what we are saying here. To conclude, as we have, that the district court did not abuse its discretion in admitting and considering Dr. Love’s opinions is 

not to say that those same opinions were sufficient as an evidentiary matter to establish the divisibility of cost-recovery liability under § 107(a) of CERCLA. Admissibility and evidentiary sufficiency are not one and the same. 

* * * 

This is a difficult case involving many decades, many parties, and many millions of dollars. We see no merit to much of 

the challenges to the district court’s rulings. But we do agree 

with Von Duprin that the district court’s summary judgment 

determination on apportionment requires remand. And we 

agree with Major that the district court’s ultimate allocation 

of liability necessitates a remand as well. For these reasons, 

we AFFIRM in part and VACATE and REMAND in part.