No. 06-1023. Argued March 15, 2007. Decided June 1, 2007. On Petition for Review of a Final Action of the Environmental Protection Agency. Emma E. Garrison argued the cause for petitioner. With her on the briefs was Hope M. Babcock. Steven E. Rusak, Attorney, United States Department of Justice, argued the cause for respondent. With him on the brief were John C. Cruden, Deputy Assistant Attorney General, and Michael W. Thrift, Counsel, U.S. Environmental Protection Agency. David A. Berg, Mac S. Dunaway