Substantial confusion exists regarding the difference between the phrases “mass torts” and “class actions” and their relationship to “multidistrict litigation.” This brief article hopefully will provide clarity on these types of litigation, and examples of each.

Mass torts is a broad generic phrase that typically refers to tortious conduct committed by one or more defendants that causes widespread harm to many plaintiffs. An example of a mass tort is the conduct that gave rise to the multidistrict litigation In re Genetically Modified Rice Litigation, 4:06MD1811 CDP (E.D. Mo.). Bayer CropScience, L.P., negligently contaminated the United States long grain rice supply with unapproved, experimental genetically modified rice. The contamination resulted in the loss of important foreign markets and negative price impacts suffered by all U.S. rice farmers. Certain rice farmers who planted one or both of two contaminated rice seed varieties suffered additional losses. 1

A c lass action is a particular type of mass tort that meets the specific procedural requirements of federal or state law See, e.g., Rule 23, Fed.R. Civ. P., Rule 52.08, Mo.R.Civ.P. Those requirements typically include:

(1) numerosity (usually 30 or more class members);

(2) commonality (the plaintiffs’ claims raise questions of fact or law common to the class);

(3) typicality (the named plaintiffs’ claims are typical of those of the class);

(4) adequacy (the named plaintiffs and their counsel have no interests that are materially adverse to the class and are willing and able to vigorously and competently advance the interests of the class);

(5) Predominance (questions common to the class predominate over questions affecting only individual class members); and

(6) Superiority (a class action is superior to other available methods for fairly and efficiently adjudicating the controversy).

Some mass torts are suitable for certification as a class action and some are not. Recent case law indicates that mass torts causing personal injuries are less likely to be certified as a class action than those causing solely economic injury. Compare, e.g. In re Vioxx Products Liability Litigation, 239 F.R.D. 450 (E.D. LA. Nov. 22, 2006) (refusing to certify class claiming personal injury or wrongful death arising from ingestion of the pain reliever Vioxx) with Plubell v. Merck, 289 S.W. 3d 707 (May 22, 2009) (affirming certification of a class seeking economic loss only for Merck’s deceptive marketing of Vioxx.) This tendency is by no means a rigid rule. Some personal injury mass torts have been certified as class actions and some economic loss mass torts have been found to be unsuitable for class treatment ( See, e.g., In re Genetically Modified Rice Litigation, 251 F.R.D. 392 (E.D. Mo. Aug. 14, 2008).

Multidistrict litigation (“MDL”) occurs when numerous actions involving one or more common questions of fact are filed in multiple federal court districts. At one or more parties’ request, a panel of seven federal judges, known as the Judicial Panel on Multi District Litigation, considers whether all the actions should be coordinated or consolidated for pretrial purposes and, if so, the particular federal judge who should oversee the litigation. Mass torts that have spawned multiple actions in multiple federal court districts are strong candidates for MDL treatment without regard to whether those mass torts meet class certification requirements of federal or state law. Some MDLs include class actions, and some do not.


While this litigation certainly meets the definition of a mass tort, the court overseeing the litigation determined that it did not satisfy the federal procedural requirements necessary to be a class action. See In re Genetically Modified Rice Litigation, 251 F.R.D. 392 (E.D. Mo. Aug. 14, 2008).