Environmental Protection Agency (EPA) Administrator Stephen Johnson is sworn in on Capitol Hill in Washington, Thursday, Jan. 24, 2008, prior to testifying before the Senate Environment and Public Works Committee's hearing on California' request for a greenhouse gas waiver. (AP Photo/Dennis Cook)

Environmental Protection Agency (EPA) Administrator Stephen Johnson testifies on Capitol Hill in Washington, Thursday, Jan. 24, 2008, before the Senate Environment and Public Works Committee's hearing on California' request for a greenhouse gas waiver. (AP Photo/Dennis Cook)