This action arose out of the collapse of a salt mine owned by defendant Akzo Nobel Salt, Inc. (“Akzo”). Plaintiffs, who own property in the area surrounding the mine, seek to recover for, inter alia, diminution in the value of that property stemming from public fear of the mine collapse; some, but not all, plaintiffs also seek recovery for physical damage to their property. In a final order, the United States District Court for the Western District of New York (David G. Larimer, Chief Judge) granted summary judgment to Akzo as to the claims of those plaintiffs who alleged only diminution in property value, with no accompanying physical damage. See Mehlenbacher v. Akzo Nobel Salt, Inc.,
I
For many years, Akzo operated the largest salt mine in North America, in Retsof, New York. In March 1994, part of the mine collapsed, allegedly because Akzo used a risky small-pillar mining technique that did not provide enough surface support.
In June 1994, Terry Mehlenbacher and the other named plaintiffs brought this putative class action in New York state court, seeking to represent a class composed of all individuals and businesses who reside, work, or own property within a ten-mile radius of the mine and who suffered damages due to the collapse of the mine. Plaintiffs alleged that the mine collapse had resulted in physical damage to property and buildings, adverse effects on the quantity and quality of well water in the area, personal injuries (including emotional injuries), and economic losses, including “stigma” damages for diminution in the value of plaintiffs’ property due to public fear of the consequences of the mine collapse. The complaint stated claims sounding in negligence, strict liability due to an abnormally dangerous activity, nuisance, and gross negligence. It sought compensatory and punitive damages and injunc-tive relief “requiring the Defendant to take such action as to assure that the mine is shored up, the flooding ceased, and ... the mine is stabilized.” State complaint at 11-12. Plaintiffs did not specify the amount of damages sought.
Akzo filed a timely notice seeking to remove the case to the United States District Court for the Western District of New York. Akzo asserted that the district court could exercise jurisdiction pursuant to the diversity jurisdiction statute, 28 U.S.C. § 1332(a) (1994). It alleged that complete diversity existed between it and all the named plaintiffs, because Akzo was a New Jersey corporation and all the named plaintiffs, according to their complaint, were residents of New York. Akzo
In January 1995, plaintiffs filed an amended class action complaint, asserting the sarnie causes of action as had then-state complaint. In the new complaint, plaintiffs sought to represent a broader" class of all individuals and businesses who reside, work, or own property within a thirteen-mile radius of the mine and who suffered damages due to the mine collapse. That class, according to plaintiffs, was composed of four subclasses: (1) residential homeowners whose property values were adversely affected, who incurred physical damage to their property, or who lost the use and enjoyment of their property; (2) commercial property owners who suffered economic losses, including diminution in the value of their property or lost profits; (3) persons who live or work within the thirteen-mile radius who suffered economic losses, including “the expense of securing alternative water supplies,” the cost of remediating damage to their property, and lost wages; and (4) persons who suffered personal injuries or emotional distress due to the mine collapse or resulting water contamination. The parties conducted discovery limited to the class certification issue, and, in March 1998, plaintiffs filed a motion for class certification under Federal Rule of Civil Procedure 23(b)(3), which Akzo opposed.
Before the district court had ruled on the motion for class certification, Akzo moved for partial summary judgment dismissing all the plaintiffs’ claims for (1) stigma damages and (2) emotional distress unrelated to actual physical illness or injury, including emotional distress related only to property damage. The district court granted Akzo’s motion for summary judgment in part and denied it in part. See Mehlenbacher,
[T]he widely accepted if not universal view among the courts in this country is that causing the value of another’s property to diminish is not in and of itself a basis for tort liability. Something more — physical invasion or damage, or unreasonable interference with that person’s use and enjoyment of the property — is required. In order to recover damages for diminution in value, therefore, property owners must show (1) that their property has been physically damaged, or that their use and enjoyment of their property has been unreasonably interfered with, by the defendant’s actions, and (2) either that the trespass or nuisance thus created cannot be fully remediated, or that the cost of remediation would exceed the amount by which the value of the property has been diminished.
Id. at 188. Finding that those plaintiffs who alleged no physical damage to then-property could not satisfy the first prong of that test, the district court dismissed their claims for stigma damages. See id. at 190.
The court declined, however, to grant summary judgment as to the plaintiffs who sought to recover both for physical surface damage and for diminution in the market value of their property. The court noted (1) that “[t]he general rule in New York is that the measure of damages for injury to real property is the lesser of the repair costs or the diminution in market value,” but that “[t]here is also authority that both
Finally, the court declined, for the time being, to certify the proposed class under Rule 23(b)(3), noting that it had dismissed the claims of potential class members seeking to recover only for stigma damages and that this dismissal changed the contours of the numerosity and typicality issues, making them difficult to decide on the current record. Accordingly, it denied the motion for class certification without prejudice. See id. at 193.
Appellants then moved for an order pursuant to Rule 54(b) entering a final judgment, so that they could immediately appeal the dismissal of the stigma claims.
The plaintiffs whose claims for stigma damages were dismissed now appeal, arguing that New York law does allow them to recover such damages.
II
Neither party has raised the issue of whether this case was properly removed from state court to the federal district court. Nevertheless, because “a challenge to subject matter jurisdiction cannot be waived,” Alliance of Am. Insurers v. Cuomo,
The diversity jurisdiction statute in effect at the time this action was begun in state court, and at the time it was removed, required that “the matter in controversy exceedf ] the sum or value of $50,000, exclusive of interest and costs, and [be] between,” inter alia, “citizens of different States.” 28 U.S.C. § 1332(a)(1)
The record indicates, and Akzo noted in its removal petition, that all of the named plaintiffs are domiciled in New York, while Akzo is a citizen of New Jersey. Moreover, if the district court certifies this suit to proceed as a class action, diversity would not be defeated even if some members of the class who are not named plaintiffs are citizens of New Jersey, since a class action may be maintained in federal court so long as the representative parties are completely diverse. See Snyder v. Harris,
Satisfaction of the amount in controversy requirement is far more problematic, however. Akzo “has the burden of proving that it appears to a reasonable probability that the claim is in excess of the statutory jurisdictional amount.” United Food,
Such an assumption was unwarranted. The Supreme Court has long held that separate and distinct claims raised by different plaintiffs may not be aggregated to satisfy the jurisdictional amount in controversy. See Snyder,
A more complicated question arises when we consider whether, if at least one of the named plaintiffs meets the jurisdictional threshold of $50,000, the district court can exercise supplemental jurisdiction over the remaining members of the plaintiff class. In Zahn v. International Paper Co.,
Our court has not spoken as to the continuing viability of Zahn after the enactment of § 1367, and other courts of appeals have reached different conclusions on the issue. Compare Free v. Abbott Labs. (In re Abbott Labs.),
It would, however, be premature for us to address this vexing question of statutory interpretation. For, not only was it not briefed or argued by the parties, neither of whom recognized the potential jurisdictional impediment, but the facts that would
Because, on this record, we are unable to determine whether any or all of the plaintiffs met the required $50,000 amount in controversy, we must remand to the district court to give Akzo an opportunity to make that showing. See, e.g., Squibb,
We note that in Lupo v. Human Affairs Int’l, Inc.,
If, on remand, Akzo can show to a reasonable probability that each of the plaintiffs’ claims — including those of absent class members — met or exceeded $50,000 when the case was brought, then diversity jurisdiction was proper.
Ill
Because subject-matter jurisdiction is not established, we cannot and do not reach the merits of the question of New York tort law presented to us on this appeal. See Steel Co. v. Citizens for a Better Environment,
The district court held that New York nuisance law does not allow plaintiffs to recover for diminution in the value of their property caused by public fear of a dangerous event such as a mine collapse, unless they can show “that their property has been physically damaged, or that then-use and enjoyment of their property has been unreasonably interfered with, by the defendant’s actions.” Mehlenbacher,
This latter is an issue on which the New York courts have not spoken. In support of their argument to the contrary, plaintiffs rely primarily on cases involving the measure of just compensation for a taking. See, e.g., Criscuola v. Power Authority,
Under these circumstances, we might be inclined to certify the issue to the New York Court of Appeals. Cf. Scribner v. Summers,
Because federal jurisdiction over this action is not yet established, we make these comments merely to indicate to the district court some of the problems that would remain, were it, on remand, to conclude that it had subject-matter jurisdiction. Accordingly, we intimate no view on the correct resolution of these issues, which are, in the first instance, for the district court to consider, should it find that it has jurisdiction. ‘
* * *
The judgment of the district court is Vacated and the case is Remanded for further proceedings consistent with this opinion.
Notes
. This appeal was consolidated with another appeal of an action for damages from the mine collapse, Integrated Waste Servs., Inc. v. Akzo Nobel Salt, Inc., No. 99-9317,
. Until shortly before the collapse, Akzo had employed the “large-pillar” method, which supported the surface with large pillars of salt. The small-pillar method involved harvesting some of the salt from the large pillars in areas where it was thought that other geological features would provide adequate surface support.
. The district court also declined to grant summary judgment on these plaintiffs’ claims for emotional distress unrelated to physical illness or injury. The court noted that this claim could be construed as a claim sounding in nuisance and seeking to recover for invasion to the plaintiffs’ interest in the quiet use and enjoyment of their property. See Mehlenbacher,
In addition, the district court denied summary judgment as to the plaintiffs' second cause of action, which alleged that Akzo was strictly liable to them because it conducted an ultrahazardous activity, saying that although it ”harbor[ed] serious doubts about the viability of this claim,” there would be no harm in allowing it to proceed, since plaintiffs could go forward with discovery on their nuisance claim in any event. Id.
. Rule 54(b) provides that "[w]hen more than one claim for relief is presented in an action, ... or when multiple parties are involved, the court may direct the entry of a final judgment as to one or more but fewer than all of the claims or parties only upon an express determination that there is no just reason for delay and upon an express direction for the entry of judgment.” Fed.R.Civ.P. 54(b).
. The jurisdictional threshold has since been raised to $75,000. See 28 U.S.C. § 1332(a) (amended 1996).
. Nor did plaintiffs' amended complaint filed in federal court assert any specific amount of damages.
. Because this suit was brought as a class action, we treat it as such even though the district court has not yet granted the plaintiffs' motion for class certification. See City of Inglewood v. City of Los Angeles,
.Section 1367 provides, in pertinent part, as follows:
(a) [I]n any civil action of which the district courts have original jurisdiction, the district courts shall have supplemental jurisdiction over all other claims that are so related to claims in the action within such original jurisdiction that they form part of the same case or controversy under Article III of the United States Constitution. Such supplemental jurisdiction shall include claims that involve the joinder or intervention of additional parties.
(b) In any civil action of which the district courts have original jurisdiction founded solely on section 1332 of this title, the district courts shall not have supplemental jurisdiction under subsection (a) over claims by plaintiffs against persons made parties under Rule 14, 19, 20, or 24 of the Federal Rules of Civil Procedure, or over claims by persons proposed to be joined as plaintiffs under Rule 19 of such rules, or seeking to intervene as plaintiffs under Rule 24 of such rules, when exercising supplemental jurisdiction over such claims would be inconsistent with the jurisdictional requirements of section 1332.
28 U.S.C. § 1367.
. The circuits have also disagreed over whether § 1367 allows supplemental jurisdiction over plaintiffs joined under Federal Rule of Civil Procedure 20, which, like Rule 23, is not among the listed exceptions in § 1367(b). Compare Stromberg Metal Works, Inc. v. Press Mechanical, Inc.,
. Of course, such a disposition has no precedential effect. See Neil v. Biggers,
., In this regard, we note that, while the record as to the amount of loss sustained by each plaintiff is sparse, what evidence there is suggests that Akzo may not be able to meet that burden. One of the arguments put forward by plaintiffs’ counsel for certifying this suit as a class action was that the individual losses sustained by the plaintiffs were likely to be less than $50,000. At oral argument before the district court, plaintiffs' counsel maintained that "for most of these people the cost of trying their cases would be more than their damages. It would not be economically feasible for them to go forward on a case by
. The issue of whether, when a jurisdictional defect exists at the outset of an action but is subsequently cured (for example, by dismissal of dispensable parties), the relevant amount in controversy is that in effect at the outset, or that in effect at the time the jurisdictional defect is cured, is currently sub judice in this Court. See E.R. Squibb & Sons, Inc. v. Accident & Cas. Ins. Co., No. 97-9468(L) (2d Cir. argued Oct. 4, 1999).
