Opinion ID: 2737139
Heading Depth: 1
Heading Rank: 3

Heading: Rights to Contribution

Text: We now turn to two related questions on the merits: whether the district court abused its discretion when it held Nos. 13-2447 et al. 19 on summary judgment that NCR was not entitled to contribution for any of its response costs at the Lower Fox River site; and whether the court correctly ruled that the recycling mills were entitled to 100% contribution from NCR for their own costs, as they asserted in counterclaims. We discuss these two points together, as they are just two different ways of asking whether NCR can be held responsible for all response costs, no matter who paid initially. We generally review a grant of summary judgment de novo. A party is entitled to summary judgment if, viewing the evidence in the light most favorable to the non-moving party, there are no genuine issues of material fact and the moving party is entitled to judgment as a matter of law. See Envtl. Transp. Sys., Inc. v. ENSCO, Inc., 969 F.2d 503, 507 (7th Cir. 1992); FED. R. CIV. P. 56(a). The equitable allocation of response costs in a CERCLA action, however, is for the district court to decide in its discretion, and we do not start from scratch in determining whether we would allocate every penny in the same way. See Browning-Ferris Indus. of Ill., Inc. v. Ter Maat, 195 F.3d 953, 957, 959 (7th Cir. 1999) (holding that district court “did not abuse [its] discretion”). Instead, this court has implicitly accepted, and some of our sister circuits have more explicitly stated, that we review the district court’s allocation for abuse of discretion, even when the issue comes to us on appeal from summary judgment. See ENSCO, 969 F.2d at 506, 509 (indicating district court decided case on summary judgment and discussing court’s discretion under CERCLA); United States v. R.W. Meyer, Inc., 932 F.2d 568, 573 (6th Cir. 1991) (applying abuse of discretion standard when evaluating summary judgment); see also Goodrich Corp. v. Town of Middlebury, 311 F.3d 154, 170 (2d Cir. 2002); Tosco Corp. v. Koch Indus., Inc., 216 F.3d 886, 894 20 Nos. 13-2447 et al. (10th Cir. 2000); Boeing Co. v. Cascade Corp., 207 F.3d 1177, 1187 (9th Cir. 2000). We begin with the text of section 113(f): Any person may seek contribution from any other person who is liable or potentially liable under section 9607(a) [CERCLA § 107(a)] of this title, during or following any civil action under section 9606 [CERCLA § 106] of this title or under section 9607(a) of this title. Such claims shall be brought in accordance with this section and the Federal Rules of Civil Procedure, and shall be governed by Federal law. In resolving contribution claims, the court may allocate response costs among liable parties using such equitable factors as the court determines are appropriate. Nothing in this subsection shall diminish the right of any person to bring an action for contribution in the absence of a civil action under section 9606 of this title or section 9607 of this title. 42 U.S.C. § 9613(f) (CERCLA § 113(f)). In a contribution action the court is not concerned with deciding whether a party is liable under CERCLA. That is a question for the enforcement action; the contribution action merely imports its conclusions. Even so, meeting a statutory liability trigger renders a party only potentially liable for contribution under CERCLA. ENSCO, 969 F.2d at 507. It is within the district court’s power to require all, none, or some intermediate share of contribution from a PRP, depending on the court’s weighing of the equities. We have described the district court’s authority in this area as “broad and loose.” Browning-Ferris, 195 F.3d at 957. Nos. 13-2447 et al. 21 CERCLA not only entrusts the district court to make the ultimate equitable allocation of costs, but it also grants the court the authority to decide which equitable factors will inform its decision in a given case. Kerr-McGee Chem. Corp. v. Lefton Iron & Metal Co., 14 F.3d 321, 326 (7th Cir. 1994). In that connection, “a court may consider several factors, a few factors, or only one determining factor … depending on the totality of circumstances presented to the court.” ENSCO, 969 F.2d at 509. The fact-intensive inquiry is “particularly suited” to case-by-case analysis, and we have resisted attempts to impose upon district courts a requirement to either include or to ignore any particular factors in its ultimate decision, even ones that might strike an unbiased observer as salient facts. Id. Even so, we have a responsibility to do more than rubber-stamp the district court’s decision, and so we begin by exploring how the court arrived at its decision to place 100% of the financial burden for cleaning up the Lower Fox River on NCR.
After the court sorted out the questions of cost-recovery and contribution, it held a scheduling conference under Rule 26(f) and asked the parties to lay out a discovery plan. NCR and Appvion proposed that the court set a firm trial date and permit full discovery into all relevant matters at once. The defendants countered with the suggestion that the court limit initial discovery to “(1) when each party knew, or should have known, that recycling NCR-brand carbonless paper would result in the discharge of PCBs to a waterbody, thereby risking environmental damage; and (2) what, if any, action each party took upon acquiring such knowledge to avoid the risk of further PCB contamination.” Defendants 22 Nos. 13-2447 et al. argued that actual or constructive knowledge of the risk and any failure to take immediate action to prevent the risk would be the key factors in determining the equitable allocation of costs. The court adopted the defendants’ proposal for targeted discovery. It explained that, in the relatively wide-open world of equitable-contribution actions, “fairness would seem to dictate that those who were in the best position to know about possible contamination … should bear more responsibility than parties further down the stream (so to speak)” and that “under some circumstances, joint tortfeasors having substantially greater culpability can be denied contribution altogether.” A ruling reached on this basis, the court hoped, would obviate the need for much of the discovery that NCR and Appvion were seeking. The parties undertook discovery in accordance with this plan, and both sides filed motions for summary judgment. Their efforts yielded a hefty record, with some 900 exhibits, covering expert and government reports; deposition testimony; laboratory notes; corporate records; and correspondence. Based on these materials, the court distilled the undisputed material facts. The court began by finding that NCR used Aroclor 1242, a solvent containing PCBs and manufactured by Monsanto, from 1954 until it found an adequate alternative in 1971. During this time, which it called the “production period,” roughly 30 million pounds of the PCB-laden emulsion were used. Though it had not yet called for discovery into the quantities that were discarded into the River, the court noted that the WDNR calculated that 98% of the PCBs in the Lower Fox River entered it during the production period. WDNR Nos. 13-2447 et al. 23 estimated that 39% of the PCBs entered the river as a result of NCR’s own manufacturing process, and 56% entered as a result of the recycling operations of the defendants during the 1954 to 1971 period. The remainder, it said, was dumped by recycling mills continuing to recycle carbonless copy paper after the production period ended in 1971. These estimates, however, were outside the scope of the discovery plan, and NCR did not concede their accuracy. We therefore disregard this data for present purposes. The court next considered evidence about knowledge: what did each party know about the environmental dangers posed by PCBs, and when did it acquire this knowledge. For this purpose, the court relied heavily on correspondence by the British company Wiggins Teape, which was NCR’s exclusive licensee for carbonless copy paper production in Europe. The Wiggins Teape documents showed that the company was aware as early as 1964 that Aroclor was toxic, and that it knew that recycled NCR paper could not be used for food packaging unless it was sufficiently cleansed. There were also records of scientific tests beginning in 1965 demonstrating the toxicity of Aroclor 1242. NCR’s own studies showed that PCBs had a “defatting effect” when they came into contact with skin, and indicated that the company was searching for a replacement. (In other words, PCBs are an irritant that chemically dissolves the fats in the skin and leaves it cracked and vulnerable to infection.) An independent study published by the Swedish scientist Soren Jensen in 1966 called PCBs “as poisonous as DDT,” and said they were harmful to the liver and the skin. NCR scientists were aware of this report by February 1967 at the latest. 24 Nos. 13-2447 et al. Monsanto apparently began to worry about the environmental effects of Aroclor in the late 1960s: on March 12, 1969, it circulated an internal memo with advice about how to deal with customers’ concerns about Aroclor’s safety. It essentially advocated silence, except with NCR—which by itself comprised 40% of the market for Aroclor 1242 in 1968. Monsanto decided to follow NCR’s approach toward the increasing worries about PCBs in crafting its own response. When Monsanto employees visited NCR headquarters in late March 1969, NCR officials told them that it wanted to stay informed about new developments, but it was not going to make any changes unless another article appeared specifically naming NCR as a source of the pollution. Samples taken by Monsanto in late 1969 and early 1970 showed that the effluent from NCR’s emulsion plants had “quite high” levels of Aroclor 1242. Wiggins Teape documents from 1970 show that it was becoming acutely aware of the problem and that British regulators were zeroing in on Aroclor as an environmentally toxic substance. Nevertheless, documents from that year reveal that NCR pushed Wiggins Teape not to disclose that NCR was the source of the Aroclor-coated paper. This request made Wiggins Teape executives uncomfortable. An internal memo from the latter written on February 13, 1970, indicated that although no study had definitely established a causal link between PCBs and health problems at that point, Wiggins Teape had known about potential toxicity since 1955. The memo also said that the Jensen report in 1966 awoke a “sleeping tiger.” It worried that a comparison could be drawn between the PCB threat and the evolving public knowledge of the health dangers of cigarettes. Nos. 13-2447 et al. 25 Monsanto stopped selling Aroclor 1242 in 1970, explaining to its customers that PCBs’ “use in synthetic resin compositions may be a source of … alleged environmental contamination.” NCR decided to draw down its remaining stock of Aroclor; it ceased using Aroclor to make carbonless copy paper in April 1971. The following year, NCR circulated an internal memorandum stating, “In the late 1960’s accumulative evidence began to show that PCBs may have adverse effects on certain forms of animal life. … The resistance to breakdown—such as thermal and biodegradation—was shown to lead to accumulations in the environment.” The authenticity of these documents was not contested, and in light of them the district court concluded that it could draw certain inferences that could not be disputed. First, it concluded that NCR knew that PCBs posed a risk of environmental harm by the late 1960s. This is not to say that NCR knew definitively that PCBs were harmful, but it was aware that there was a danger that they were toxic to human and animal life when released in waterways, and that they did not break down in the environment. At the latest, said the court, NCR knew this much when Monsanto sent its letter about environmental concerns in early 1970. The court next concluded that none of the defendants knew about the risks of PCBs until after NCR had ceased to produce carbonless copy paper in 1971. It noted that NCR had produced no evidence that any defendant knew that NCR’s paper contained PCBs at all, or that the paper could lead to environmental damage, in the period before April 1971. In drawing this inference, the court discounted three pieces of evidence that NCR now highlights: 1) an industrywide report stating that the presence of PCBs in paper prod26 Nos. 13-2447 et al. ucts and mill effluents had been recognized since the late 1960s; 2) testimony from a Menasha purchasing agent that it was instructed not to buy carbonless copy paper broke as early as 1950 because it might contain PCBs; and 3) testimony by a Fort Howard employee that Monsanto’s decision to stop selling Aroclor 1242 in 1970 was “well known.” The court discounted the industry report because it was prepared in 1976 and did not show that the mills were specifically alerted to PCBs in NCR’s products; it found the Menasha agent’s testimony unhelpful because he later repudiated it and the plaintiffs themselves rejected it in a different document before the court; and it found the Fort Howard employee’s testimony to be beside the point, because the deponent dated the knowledge to 1974, not 1970. In the district court’s view, the record left no doubt that NCR and Appvion knew long before others that PCBs posed a long-term risk to the environment. The importance of this early knowledge, it thought, drowned out all other equitable factors. It added that NCR actually increased its production of PCB-laden carbonless copy paper even as its knowledge of the risks increased in the late 1960s, and NCR’s response to the evidence was sluggish at best. It also reasoned that NCR was in a far better position to learn about the risks, even if it was not fully aware of them. Finally, it found that the equities strongly favored the defendants even in the period from 1954 until the mid-1960s, when all parties were ignorant of the risks posed by PCBs, because “between parties who produced the product and those who merely processed it and recycled it along with all other paper products or water sources, these latter parties are significantly less blameworthy.” The court recognized that this was not a claim for indemnification by the defendants, but it felt that Nos. 13-2447 et al. 27 such actions provided a useful analogy. The principles behind indemnification—particularly when one party provides another with a defective product—argued for denying contribution to NCR. The district court decided that no equitable adjustment was needed for the period when the defendant recycling plants continued to use broke from NCR’s carbonless copy paper after the product was discontinued in April 1971, and indeed past the point where the court concluded that all parties had knowledge of the harmfulness of PCBs. There was little that would have alerted the recyclers to the danger of this use. In 1976, Wisconsin approved the continued use of wastepaper containing PCB in recycling operations. See Wis. Stat. § 144.50(3)(c) (1976). The EPA promulgated a regulation in 1979 that allowed the continued use of PCB-containing carbonless copy paper, 44 Fed. Reg. 31,514 (May 31, 1979), and in 1984 it granted an express exemption for the use of “recycled PCBs,” 49 Fed. Reg. 28,172, 28,175 (July 10, 1984). A further amendment to allow the “safe level” of recycled PCBs to be measured in a more flexible way (to benefit the paper recyclers) followed in 1988, 53 Fed. Reg. 24,206 (June 27, 1988). For the interim periods when the defendants continued to recycle PCB-contaminated paper before these express authorizations, the district court used a WDNR study to conclude that the amount of PCBs dumped into the River during this period was less than two percent of the total (although it did not conduct discovery on this point). It would be a “Herculean task,” the court feared, to try to isolate and apportion responsibility for such a small portion of the overall PCBs in the River. At any rate, said the court, there was no evidence that these additional releases contributed significantly to the cleanup costs, and they did not put a dent in 28 Nos. 13-2447 et al. NCR’s overall greater equitable responsibility for the cleanup. The court also pointed to policy reasons in support of its conclusions. It worried that encouraging “manufacturers of a toxin” to continue using it until an economically feasible replacement can be found, and then allowing the manufacturer to recover contribution from “innocent processors” of the toxin, created a moral hazard. Finally, it thought that an approach that encourages producers of toxic materials to act “swiftly and proactively” as soon as the data begin to suggest the potential for environmental damage was more compatible with CERCLA.
NCR attacks the district court’s grant of summary judgment on two fronts. Its main thrust, to which we will return in a moment, is that it was an abuse of discretion to determine at this stage that the equities so clearly favored the defendants as to make NCR responsible for 100% of the costs of response—both its own costs and the costs initially borne by the defendant recycling mills. It also makes the procedural argument that the district court impermissibly resolved disputed questions of fact on the way to reaching summary judgment. We reject the latter contention. The district court faithfully applied the appropriate standard for summary judgment, and the conclusions it reached about the parties’ relative knowledge and awareness of the risks of PCBs were consistent with the undisputed evidence in front of it. NCR’s contention that the district court resolved disputed questions about when the company knew about the dangerousness of PCBs is based on a misunderstanding or a Nos. 13-2447 et al. 29 mischaracterization of the conclusions that the district court drew. If the district court had determined, without qualification, that NCR knew how dangerous PCBs were in the mid1960s, NCR might have a point. NCR presented evidence showing that it did not believe that Aroclor 1242 was toxic because the initial evidence of toxicity related to Aroclor products with higher amounts of chlorine. (Aroclors were numbered based on their chlorine content; the “42” in Aroclor 1242 indicates that the product was 42% chlorine.) An expert retained by NCR produced a report stating that earlier studies focused on higher-chlorinated Aroclors, and that the toxicity of PCBs was “poorly known” even through the early 1970s. NCR also presented some evidence showing that the company internally felt that PCBs were not an environmental risk. For example, notes taken from a meeting between NCR and Monsanto employees showed that the parties discussed an incident of mass bird deaths in the Irish Sea in November 1969; those notes indicate that the investigation “cleared PCBs.” On the same document, the employee taking the notes wrote, “We think it degrades.” The record also contains a letter sent from Monsanto to its customers in 1970 saying that Aroclors with a chlorine content below 54% “appear to present no potential problem to the environment.” This evidence of NCR’s subjective beliefs would call into dispute any conclusion that NCR knew for a certainty about the impact its PCB use would have on the environment in the mid-1960s. But the district court did not say that NCR had such perfect knowledge. Instead, it concluded that NCR was beginning to see the warning signs about PCBs in the mid-1960s. This is indisputably true; Wiggins Teape docu30 Nos. 13-2447 et al. ments showed awareness of PCBs’ toxicity in 1964, and NCR had the Jensen Report by early 1967 at the latest. The court’s point was that by the mid-1960s NCR was aware that Aroclor posed a risk of being harmful to the environment. Evidence had begun to accumulate that PCBs might cause severe damage. The recycling mills, in contrast, had not seen that evidence, and even if they had seen it, they had no apparent way of knowing that NCR’s broke contained PCBs. Whether NCR was given different information about higherchlorinated Aroclors, or whether some of its fears about PCBs were allayed during a meeting with Monsanto employees, does not change the fact that it was on alert by then. Given the district court’s caution in drawing its factual conclusion about NCR’s knowledge in the period between 1964 and 1971, we find nothing in the record to bring its findings into dispute. NCR’s argument could be taken to suggest that the district court should not have settled for such a modest conclusion; once it chose to decide the case based on knowledge, NCR might say, it should have proceeded (perhaps after more discovery) to resolve in full what each party knew and when. This is just another way of putting the question whether it was an abuse of discretion to decide contribution shares based on the facts as they stood— the issue to which we now turn.
The ultimate question on this part of the appeal is whether the district court abused its discretion by allocating 100% of the Lower Fox River response costs to NCR at this juncture. In the past, we have stressed that the district court’s discretion is broad, both when it determines how much weight to place on any given equitable factor before the Nos. 13-2447 et al. 31 court, and also when it chooses which factors are pertinent at all for the case before it. Firms that have failed to secure contribution have come to us looking for greater certainty. Some have argued that fidelity to volumetric shares is required, see Browning-Ferris, 195 F.3d at 958–59, and others have urged that fault must play the leading role, ENSCO, 969 F.2d at 507 n.4. We have rejected these pleas for a onesize-fits-all bright-line rule. Courts may permissibly make the equitable allocation based on “several factors, a few factors, or only one determining factor … depending on the totality of circumstances presented to the court,” as long as the factors chosen are rational. ENSCO, 969 F.2d at 509. See also Litgo N.J. Inc. v. Comm’r N.J. Dep’t of Envtl. Prot., 725 F.3d 369, 387 (3d Cir. 2013) (courts have “tremendous discretion”). Yet discretion has limits. Even if some factors are not outcome-determinative on their own, the district court’s decision must reflect its consideration of the particulars of the case, lest the outcome become too divorced from the purposes underlying CERCLA. For example, in Kerr-McGee Chemical Corp. v. Lefton Iron & Metal Co., we found an abuse of discretion when the district court allocated cleanup costs based on the erroneous belief that an indemnification agreement between the parties did not apply to the costs at issue. 14 F.3d 321, 326 (7th Cir. 1994). While acknowledging that the indemnification agreement was “not necessarily determinative” of the contribution question, we held that it should have been considered when allocating costs and that one party’s responsibility for producing most of the waste at the cleanup site did not justify “ignor[ing] other relevant considerations.” Id. 32 Nos. 13-2447 et al. The Eighth Circuit confronted a similar problem in K.C.1986 Ltd. P’ship v. Reade Mfg., 472 F.3d 1009 (8th Cir. 2007). The district court there had refused to consider pretrial settlement credits obtained by one of the parties in its contribution decision, despite CERCLA’s explicit policy against double recovery. See 42 U.S.C. § 9614(b). Reasoning that the district court “failed to consider a relevant factor that should have been given significant weight,” the appellate court found an abuse of discretion. Id. at 1017. It explained that “[i]n determining which equitable factors are appropriate, the policies articulated in CERCLA cannot be ignored.” Id. In one significant way, this case is unlike the earlier ones, or nearly any other CERCLA contribution action. Usually, a litigant dissatisfied with its contribution share will assert that the district court assigned impermissible weight to certain factors based on evidence in the record, or discounted facts that it should not have. In those situations, it is relatively easy to evaluate whether the district court neglected to consider an important factor or placed unacceptable weight on some factors while failing to accord due respect to others. Here, however, we are asked to decide whether the district court is authorized to preselect the equitable factor that it believes most likely to determine the outcome, and then conduct limited discovery into that factor to see if it can reach an equitable determination. We do not dismiss phased discovery out-of-hand as an unacceptable way to manage CERCLA contribution actions. Questions of cause and culpability surrounding an environmental cleanup can be tremendously complex, and discovery into every matter that anyone deems relevant—no matNos. 13-2447 et al. 33 ter how unlikely it is to sway a court’s equitable allocation of costs—could be prohibitively expensive and wasteful of the time of the court and parties alike. If one factor, such as knowledge, will so clearly overwhelm all others such that inquiry into other matters is unnecessary, there is no reason to force parties to bear additional costs just for the sake of appearances. Nonetheless, the court’s ultimate decision must reflect CERCLA’s equitable principles. We have always drawn a distinction between determining an action based on a single factor, and considering only certain factors on the way to the decision. The former practice is what ENSCO approved. See 969 F.2d at 509. The latter showed up in Kerr-McGee, in which we reversed because the district court failed to show its awareness of certain relevant factors before arriving at its equitable conclusion. Similarly, in Beazer East, Inc. v. Mead Corp., the Third Circuit found an abuse of discretion when the district court “prioritize[d] a priori the parties’ relative contributions of waste over their contractual intent to allocate environmental liability among themselves.” 412 F.3d 429, 447 (3d Cir. 2005). These cases demonstrate that the district court must decide what is relevant based on the record as a whole; an allocation based on otherwise permissible factors will not be rescued if it does not explain why the court has chosen to disregard other apparently relevant information. Kerr-McGee, 14 F.3d at 326; cf. R.W. Meyer, 932 F.2d at 573 (“Congress intended the court to deal with these situations by creative means, considering all the equities and balancing them in the interests of justice.”) (emphasis added). NCR argues that the district court here made the same error that we criticized in Kerr-McGee: that it preselected 34 Nos. 13-2447 et al. knowledge as the determinative factor and permitted discovery into only that aspect of the case, thus depriving NCR and Appvion of the opportunity to develop evidence of other potentially relevant factors. NCR is not suggesting (or at least it should not be suggesting) that it necessarily is entitled to a different result based on the additional evidence it would have presented. Instead, it contends that the allocation decision could not have been made based on the totality of the circumstances because the district court did not have the totality of the circumstances before it. At least three equitable factors that the court put to one side would have been relevant to the question of cost allocation, it urges: the parties’ relative volumes of PCB discharges; sources of PCBs in the river other than carbonless copy paper; and the parties’ levels of voluntary cooperation with the government’s cleanup effort. We agree with NCR that these points are potentially relevant to an understanding of who should contribute to the costs of the Fox River cleanup. For us to evaluate the district court’s allocation decision, therefore, we would need to see either that it evaluated and rejected these considerations as bases for allocation, or that it explained why one or more of them were so immaterial when compared with the ones on which it chose to rely as to make it fruitless for a party to develop evidence on those points. Unfortunately, the court did not record its thinking in this respect. We are thus unable confidently to say that the court chose knowledge as the deciding factor because undisputed facts showed that the relative volumes of discharge, alternate sources, and voluntary cooperation paled in comparison to knowledge. When explaining why it chose Nos. 13-2447 et al. 35 to proceed solely on the basis of the parties’ knowledge of the dangers posed by PCBs in the first instance, the court said that its “premise was that parties who knew, or should have known, about the dangers of PCBs should bear the brunt, or even the entirety, of any cleanup costs resulting from PCB contamination.” Its analysis of the parties’ relative knowledge was thorough and thoughtful, and reasonable as far as it went. The problem is that the court’s reasons for rejecting consideration of other factors leave us unable to say whether the record adequately supported the court’s decision to select knowledge as the decisive factor. All the court said was that apportionment on factors apart from knowledge “would require additional phases of the trial” in which the parties could prove other disputed facts like volume. It then reiterated its conclusion about knowledge, both that NCR was “not completely ignorant” of the dangers of PCBs during at least some of the period when they were producing carbonless copy paper, and that it was in the “best position” to learn of the dangers before it was fully aware. It added that in the period before any party could have been aware of the dangers, the equities favored the recycling mills because NCR actually produced the product, whereas the recycling mills “merely processed it”; it analogized the recycling mills to “innocent end-users.” It added that NCR bore more responsibility because the “defect” in its product—the PCBs— was the key to its profitability and not “incidental,” and that NCR was “sluggish” in its response to the mounting data about PCBs. As compelling a picture as this is on the knowledge issue, it does not explain why other factors, such as cooperation in 36 Nos. 13-2447 et al. the cleanup or relative volumes dumped, are so wholly irrelevant to the equitable determination that information about them need not even be gathered or presented by the parties. Without a more complete record, we are unable to endorse the court’s decision to resolve the case on the basis it chose. As a practical matter, the district court was unable to avoid mentioning basic facts such as the relative volumes of PCBs discharged by the parties, even though it qualified those references with the acknowledgment that the figures had not been subject to discovery. Other factors that NCR proposes, such as cooperation, might have influenced the court’s conclusions about NCR’s slow responses to data. We hasten to say, however, that further information may just as easily point in the other direction and have the effect of reinforcing the district court’s present conclusions. It is impossible to know at this juncture what the likely effect will be. We understand that a party’s knowledge that it is either doing something wrong or running an undue risk that it is doing something wrong can be a compelling basis for deciding who should contribute to the costs of clean-up. But we do not want, either advertently or inadvertently, to privilege that factor above all others. Knowledge may be the point that tips the scale, but only after other plausible relevant factors have been considered and either added to the balance or discarded as inappropriate for the case at hand. We also note that some of the reasons the court gave for allocating all of the costs to NCR do not appear to be consistent with its stated rationale, particularly for the period of “general ignorance” preceding the existence of any serious evidence about the dangers of PCBs. Regardless of whether NCR produced the carbonless copy paper and the defendant Nos. 13-2447 et al. 37 mills merely recycled it, the fact remains that it was used in in all of their businesses. At least for that period, the court gave no reason to fault one party more than another for producing something that it did not realize was environmentally toxic. The court also did not explain why it was important whether the harmful material was essential or collateral to the product’s main purpose. We do not lightly impose the burden on either the parties or the court of additional complex and time-consuming discovery, and we appreciate the effort that the district court has made to manage this case. Nonetheless, in the equitable realm where CERCLA contribution actions exist, we must remain vigilant to ensure that the financial responsibility for this huge project is properly allocated. On the summary judgment record before us, we cannot be sure either that the court did, or that it did not, adequately consider all of the circumstances before making its decision. We therefore vacate the judgment of the district court denying any contribution to NCR and imposing the response costs of the recycling mills on NCR, and remand so that the district court can decide which factors will guide its decision on the basis of a more complete record.