A mass tort is a civil action involving numerous plaintiffs against one or a few defendants in state or federal court. The lawsuits arise out of the defendants causing numerous injuries through the same or similar act of harm (e.g. a prescription drug, a medical device, a defective product, a train accident, a plane crash, pollution, or a construction disaster). Law firms sometimes use mass media to reach potential plaintiffs. The main categories of mass torts include: * Medical device injuries * Prescription drug injuries * Product liability injuries * Toxic contamination