A mass tort is a civil lawsuit that involves hundreds or thousands of plaintiffs and one or a few defendants in which the plaintiffs have the same or similar claims against the defendant or defendants. Mass tort lawsuits are often filed as class action lawsuits (a procedural mechanism for joining the plaintiffs in one lawsuit), and are typically based on alleged wrongful acts (torts) such as exposure of the plaintiffs to harmful substances (asbestos or benzene), or defective products (pharmaceuticals or medical devices), or invasions of privacy (data breaches).

In Missouri, mass torts are handled similarly to other states, where they involve a large number of plaintiffs against one or a few defendants. These cases often arise from common issues such as exposure to harmful substances, defective products, or privacy violations like data breaches. Missouri courts may consolidate these cases for pretrial proceedings to manage the litigation more efficiently. While mass torts can be filed as class actions, they must meet certain criteria under Rule 52.08 of the Missouri Rules of Civil Procedure, which include commonality, adequacy, numerosity, and typicality of the claims and defenses. If the case is certified as a class action, it allows for a representative plaintiff to sue on behalf of all members of the class. It's important to note that mass torts differ from class actions in that each plaintiff in a mass tort may have individualized claims and potential damages, whereas class actions involve plaintiffs with nearly identical claims and damages. An attorney specializing in mass torts or class actions can provide specific guidance on the intricacies of these legal proceedings in Missouri.