approved fuel blends in State implementation plans with 
the blends included on the Federal Fuels List and shall 
promulgate implementing regulations for this plan not 
later than 18 months after enactment of this subclause. 
This harmonization shall be fully implemented by the 
States by December 31, 2008.’’. 
(b) STUDY.—Section 1541(c)(2) of the Energy Policy 
Act of 2005 is amended to read as follows: 
‘‘(2) FOCUS OF STUDY.—The primary focus of 
the study required under paragraph (1) shall be to 
determine how to develop a Federal fuels system 
that maximizes motor fuel fungibility and supply, 
preserves air quality standards, and reduces motor 
fuel price volatility that results from the prolifera-
tion of boutique fuels, and to recommend to Con-
gress such legislative changes as are necessary to 
implement such a system. The study should include 
the impacts on overall energy supply, distribution, 
and use as a result of the legislative changes rec-
ommended. The study should include an analysis of 
the impact on ozone emissions and supply of a man-
datory reduction in the number of fuel blends to 6, 
including one Federal diesel fuel, one alternative die-
sel fuel blend, one conventional gasoline for ozone 
attainment areas, one reformulated gasoline (RFG)
meeting the requirements of subsection (k), and 2 
additional gasoline blends with Reid vapor pressure 
(RVP) controls for use in ozone nonattainment areas 
of varying degrees of severity.’’. 
SEC. 109. ATTAINMENT DATES FOR DOWNWIND OZONE 
NONATTAINMENT AREAS. 
Section 181 of the Clean Air Act (42 U.S.C.7511) 
is amended by adding the following new subsection at the 
end thereof: 
‘‘(d) EXTENDED ATTAINMENT DATE FOR CERTAIN 
DOWNWIND AREAS.— 
‘‘(1) DEFINITIONS.— 
‘‘(A) The term ‘upwind area’ means an 
area that— 
‘‘(i) affects nonattainment in another 
area, hereinafter referred to as a downwind 
area; and 
‘‘(ii) is either— 
‘‘(I) a nonattainment area with a 
later attainment date than the down-
wind area, or 
‘‘(II) an area in another State 
that the Administrator has found to 
be significantly contributing to non-
attainment in the downwind area in
violation of section 110(a)(2)(D) and 
for which the Administrator has es-
tablished requirements through notice 
and comment rulemaking to eliminate 
the emissions causing such significant 
contribution. 
‘‘(B) The term ‘current classification’ 
means the classification of a downwind area 
under this section at the time of the determina-
tion under paragraph. 
‘‘(2) EXTENSION.—Notwithstanding the provi-
sions of subsection (b)(2) of this section, a down-
wind area that is not in attainment within 18 
months of the attainment deadline required under 
this section may seek an extension of time to come 
into attainment by petitioning the Administrator for 
such an extension. If the Administrator— 
‘‘(A) determines that any area is a down-
wind area with respect to a particular national 
ambient air quality standard for ozone; 
‘‘(B) approves a plan revision for such 
area as provided in paragraph (3) prior to a re-
classification under subsection (b)(2)(A); and 
‘‘(C) determines that the petitioning down-
wind area has demonstrated that it is affected