Section 211(k)(1) of the Clean Air Act (CAA) requires that the Administrator of the Environmental Protection Agency promulgate regulations establishing requirements for reformulated gasoline (RFG) to be used in gasoline-fueled vehicles in specified ozone nonattainment areas. The CAA mandates RFG use in certain nonattainment areas, based on ozone air quality and population criteria. Other ozone nonattainment areas are allowed to opt into the RFG program. Within the state of Connecticut, RFG is mandated in the Connecticut State portion of the Hartford-New Haven-Springfield Consolidated Metropolitan Statistical Area (CMSA) and the Connecticut State portion of the New York City CMSA. Parts or all of Litchfield, Hartford, Middlesex, New London, Tolland, and Windham Counties, Connecticut are an opt-in area. Section 211(k)(2)(B) of the Act, 42 U.S.C. § 7545(k)(2)(B), establishes an oxygen content requirement for federal RFG, but allows EPA to waive compliance with the requirement under certain circumstances. Section 211(k)(2)(B) provides that: The oxygen content of the gasoline shall equal or exceed 2.0 percent by weight (subject to a testing tolerance established by the Administrator) except as otherwise required by this Act. The Administrator may waive, in whole or in part, the application of this subparagraph for any ozone nonattainment area upon a determination by the Administrator that compliance with such requirement would prevent or interfere with attainment by the area of a national primary ambient air quality standard. In a letter dated April 22, 2002 from Connecticut Governor John G. Rowland to then Administrator Whitman, Connecticut expressed intent to submit a waiver request under CAA Section 211(k)(2)(B) from the federal RFG oxygen content requirement. In a letter dated September 29, 2004 from Connecticut Department of Environmental Protection (DEP) Commissioner Arhtur J. Rocque, Jr., to Assistant Administrator Jeff Holmstead, Connecticut officially submitted such a request for the Connecticut RFG area. The submission stated that because MTBE was banned in the State of Connecticut beginning January 1, 2004, and because of the Act’s oxygen requirement for RFG, ethanol would be used as an oxygenate in the RFG areas in the State of Connecticut. DEP asserted that the use of ethanol as a replacement for MTBE in RFG would result in an increase in Volatile Organic Compounds (VOCs), and oxides of nitrogen (NOx) during the summer ozone season. DEP further argued that “increases in these pollutants will immediately interfere with Connecticut’s ability to attain the National Ambient Air Quality Standard (NAAQS) for both one-hour and eight hour ozone and fine particulates in its RFG areas.