Montana Power Company, a Corporation v. Environmental Protection Agency, and Northern Cheyenne Tribe and Northern Plains Resource Council, Intervenors. Montana Power Company, a Corporation v. Environmental Protection Agency, and Northern Plains Resource Council and Northern Cheyenne Tribe, Intervenors-Appellants. The Montana Power Company, Washington Water Power Company, Puget Sound Power and Light Company, Portland General Electric Company and Pacific Power and Light Company v. Environmental Protection Agency · Ninth Circuit Court of Appeals · 1979 | Caselegis