Boutique Fuels Reduction Act of 2004

Boutique Fuels Reduction Act of 2004 - Amends the Clean Air Act (CAA) to authorize the Administrator of the Environmental Protection Agency to temporarily waive controls or prohibitions on the use of a fuel or fuel additive regulated under specified provisions of that Act or prescribed in an applicable State Implementation Plan (SIP) if the Administrator determines that: (1) extreme and unusual circumstances exist in a State or region that prevent distribution of an adequate supply of the fuel or fuel additive to consumers; (2) such circumstances are the result of a natural disaster, an Act of God, a pipeline or refinery equipment failure, or another unforeseeable event; and (3) it is in the public interest to grant the waiver.

Permits such a waiver only if it: (1) applies to the smallest necessary geographic area; (2) is effective for 20 days or the shortest practicable time period; (3) permits a transitional period after the termination of the temporary waiver to allow wholesalers and retailers to blend down their inventory; (4) applies to all persons in the motor fuel distribution system; and (5) is preceded by public notice to all parties in the distribution system, local and State regulators, public interest groups, and consumers in the State or region covered by the waiver.

States that the Administrator shall have no authority, when considering a SIP or SIP revision regarding State controls or prohibitions on motor vehicle fuel or fuel additives, to approve any fuel: (1) if doing so would increase the total number of approved and fully implemented fuels as of September 1, 2004, in all SIPs; and (2) unless that fuel was approved and fully implemented in at least one SIP in the applicable Petroleum Administration for Defense District (with the exception of fuels with a specified summertime Reid Vapor Pressure).

Requires the Administrator and the Secretary of Energy jointly to study and report to Congress on the effects on air quality, number of fuel blends, fuel availability, fuel fungibility, and fuel costs of SIPs adopted pursuant to CAA provisions regarding State controls or prohibitions on motor vehicle fuel or fuel additives.