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 Maine, as in other states, a mass tort is a type of civil action that involves numerous plaintiffs against one or several defendants. These plaintiffs usually have similar legal claims resulting from the defendant's conduct, such as exposure to hazardous substances, defective products, or privacy violations. Mass torts in Maine can be filed as class action lawsuits if they meet certain criteria, such as commonality, adequacy, typicality, and numerosity, which are required to certify a class under Rule 23 of the Maine Rules of Civil Procedure. These cases often involve complex litigation and are managed in a way that balances the efficiency of handling many similar individual claims together while also recognizing the unique aspects of each plaintiff's case. Mass torts are governed by both state and federal laws, and in some instances, they may be consolidated into multidistrict litigation (MDL) to streamline pretrial proceedings when cases are filed in federal court. It's important for plaintiffs in mass tort cases to consult with an attorney experienced in this area of law to understand their rights and the specific procedures that apply to these types of lawsuits in Maine.