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 Michigan, mass torts are civil actions that involve a large number of plaintiffs against one or a few defendants. These plaintiffs generally have similar legal claims resulting from actions such as exposure to hazardous substances, defective products, or privacy violations. Michigan courts handle mass torts in a manner consistent with federal law and other states, often consolidating cases through a class action or multidistrict litigation (MDL) to manage the complex and numerous claims efficiently. Class actions in Michigan are governed by Michigan Court Rules, which are similar to the Federal Rules of Civil Procedure. These rules allow plaintiffs with common issues of law or fact to sue collectively, provided they meet certain criteria such as numerosity, commonality, typicality, and adequacy of representation. Defendants in mass tort cases can include manufacturers, corporations, or other entities alleged to have caused harm through negligence, strict liability, or other tortious conduct. It's important for plaintiffs to consult with an attorney experienced in mass torts to navigate the complexities of these cases and to ensure their rights are adequately represented.