Friends of the Earth, Inc. v. Laidlaw Environmental Services, Inc.

Friends of the Earth and other environmental groups (plaintiffs) sued Laidlaw Environmental Services (defendant) for violating its Clean Water Act discharge permit by emitting excess mercury; the district court found Laidlaw had come into compliance with its permit, and Laidlaw subsequently closed the facility responsible for the violations. On appeal, the court of appeals held the case moot, reasoning Laidlaw's compliance and facility closure amounted to a voluntary cessation of the violations, and the Supreme Court granted certiorari to address the mootness question.