Clean Power Act : hearings before the Subcommittee on Clean Air, Wetlands, and Climate Change and the Committee on Environment and Public Works, United States Senate, One Hundred Seventh Congress, first and second sessions on S. 556, a bill to amend the Clean Air Act, to reduce emissions from electric powerplants, and for other purposes, July 26, 2001, November 1, 2002, November 15, 2001, January 29, 2002, June 12, 2002.