Richard M. Frank, Attorney General’s Office of State of California, Sacramento, CA, Kimberly P. Massicotte, Matthew I. Levine, Attorney General’s Office of State of Connecticut, Hartford, CT, Donna M. Murasky, Senior Assistant Attorney General, Edward Eugene Schwab, Deputy Attorney General, Office of Attorney General for the District of Columbia, Office of the Solicitor General, Joseph Mendelson, III, Kimbrell & Mendelson, David G. Bookbinder, Sierra Club, David D. Doniger, Natural Resources Defense Council, Julie M. Anderson, Union of Concerned Scientists, Washington, DC, Gary S. Feinerman, Attorney General’s Office for the State of Illinois, Gerald T. Karr, Office of the Illinois Attorney General, Chicago, IL, Thomas Edward Davis, Attorney General’s Office of State Of Illinois, Environmental Bureau, Springfield, IL, William Lyon Pardee, Assistant Attorney General, James R. Milkey, Attorney General’s Office of Commonwealth of Massachusetts, Environmental Protection Division, Boston, MA, William Rowe Phelan, Jr., City of Baltimore Department of Law, City Hall, Baltimore, MD, Gerald D. Reid, Attorney General’s Office of State of Maine, Augusta, ME, Stefanie A. Brand, Attorney General’s Office of State of New Jersey, Division of Law, Trenton, NJ, Stuart Michael Bluestone, Attorney General’s Office of State of New Mexico, Santa Fe, NM, J. Jared Snyder, Peter Hans Lehner, Attorney General’s Office of State of New York, The Capitol New York State, Department of Law, Albany, NY, James Todd Baldwin Tripp, Environmental Defense Fund, Mark Pomeroy McIntyre, Corporation Counsel’s Office of City of New York, New York City Law Department, New York, NY, Philip Schradle, Attorney General’s Office of State of Oregon, Office of General Counsel, Salem, OR, Trida K. Jedele, Attorney General’s Office of State of Rhode Island, Providence, RI, William H. Sorrell, Erick Titrud, Kevin O. Leske, Attorney General’s Office of State of Vermont, Montpelier, VT, David K. Mears, Environmental and Natural Resources, Law Clinic, Olympia, WA, Fiti A. Sunia, Attorney General’s Office of American Samoa, Pago Pago American Samoa, for Petitioners., Jeffrey Bossert Clark, Kirkland & Ellis LLP, Jon M. Lipshultz, Attorney, U.S. Department of Justice, Environment and Natural Resources, Ann R. Klee, General Counsel, Nancy A. Ketcham-Colwill, John Thomas Hannon, Attorney, U.S. Environmental Protection Agency, Office of General Counsel, Washington, DC, for Respondent.