The judgment is affirmed by an equally divided Court.
MR. JUSTICE POWELL took no part in the decision of this case.
* Briefs of amici curiae urging reversal were filed by Mark Wilmer, Rex E. Lee, Gary K. Nelson , Attorney General, J. A. Hughes, John Conway, William Duncan, Gordon Pearce, Richard G. Campbell, Lawrence V. Robertson, Jr. , and Donald E. Dickerman for the State of Arizona and Ten Named Public Utilities; by Andrew P. Miller , Attorney General, and C. Tabor Cronk , Assistant Attorney General, for the Commonwealth of Virginia; by Milton A. Smith and Stanley W. Schroeder for the Chamber of Commerce of the United States; by Cameron F. MacRae, G. S. Peter Bergen , and Henry V. Nickel for the Edison Electric Institute; and by Edward A. McCabe, Laurence P. Sherfy , and David W. Miller for the American Mining Congress.
Briefs of amici curiae urging affirmance were filed by Evelle J. Younger , Attorney General, pro se, Robert H. O'Brien , Assistant Attorney General, and Nicholas C. Yost, Anthony M. Summers , and C. Foster Knight , Deputy Attorneys General, for the Attorney General of California; by William J. Scott , Attorney General, Fred F. Herzog , First Assistant Attorney General, and Harvey M. Sheldon , Assistant Attorney General, for the State of Illinois; by Frank J. Kelley , Attorney General, Robert A. Derengoski , Solicitor General, and Jerome Maslowski, Stewart H. Freeman , and Charles S. Alpert , Assistant Attorneys General, for the State of Michigan, joined by Warren Spannaus , Attorney General, and Curtis D. Forslund , Solicitor General, for the State of Minnesota; by Louis J. Lefkowitz , Attorney General, Samuel A. Hirshowitz, First Assistant Attorney General, and Philip Weinberg and James P. Corcoran , Assistant Attorneys General, for the State of New York; by John L. Hill , Attorney General, Larry F. York , First Assistant Attorney General, and Mike Willatt, Phil Maxwell , and Troy C. Webb , Assistant Attorneys General, for the State of Texas; by David L. Norvell , Attorney General, for the State of New Mexico, joined by the Attorneys General for their respective States as follows: William J. Baxley of Alabama, Robert Killian of Connecticut, Robert L. Shevin of Florida, Vern Miller of Kansas, William J. Guste, Jr. , of Louisiana, Jon A. Lund of Maine, Robert H. Quinn of Massachusetts, Louis J. Lefkowitz of New York, Robert Morgan of North Carolina, William J. Brown of Ohio, Lee L. Johnson of Oregon, Israel Packel of Pennsylvania, Kermit A. Sande of South Dakota, John L. Hill of Texas, and Kimberley B. Cheney of Vermont; by Norman Redlich for the cities of New York and Boston; by Alfred S. Forsyth for the Association of the Bar of the city of New York; by David H. Getches for the Jicarilla Apache Tribe of Indians et al.; and by Neal A. Jackson , and James F. Bromley for Natural Resources Defense Council, Inc., et al.