Section 211(k)(5) of the Clean Air Act describes the scope of the requirement to use RFG in the RFG covered areas:

(5) PROHIBITION. -- Effective beginning January 1, 1995, each of the following shall be a violation of this section:

(A) The sale or dispensing by any person of conventional gasoline to ultimate consumers in any
covered area.

This statutory prohibition on the sale or dispensing of conventional gasoline in RFG covered areas is not restricted to gasoline used to fuel motor vehicles, but rather applies to all gasoline sold or dispensed within an RFG covered area to any consumer, regardless of the use. The prohibition, therefore, would include gasoline sold or dispensed for use in motor vehicles, boats, construction equipment, recreational vehicles, lawn and garden equipment, etc.

As a matter of enforcement discretion, however, EPA will not enforce the requirement to sell or dispense RFG in the case of two categories of gasoline: aviation gasoline sold or dispensed for use in aircraft, including gasoline that has properties identical to motor vehicle gasoline that is sold or dispensed solely for use in aircraft; and racing gasoline sold or dispensed for use in racing vehicles during a sanctioned racing event. These exceptions would not apply if the aviation gasoline or racing gasoline is used other than in an aircraft, or in a racing vehicle in conjunction with a sanctioned racing event.

In the case of both aviation gasoline and racing gasoline, the gasoline must be clearly designated as such, and any person selling or dispensing these categories of gasoline must take appropriate steps to ensure the gasoline is used only in the limited circumstances described. In addition, EPA has strict guidelines as to what constitutes a racing vehicle, and the exception for racing gasoline applies only for gasoline used in such a vehicle. For further information on what constitutes a racing vehicle, contact EPA's Manufacturers Operations Division at (202) 233-9250.

The rationale for the exception for aviation gasoline used to fuel aircraft is based on safety considerations. Aviation gasoline must satisfy performance criteria that are relevant to the safe operation of aircraft, and this safety consideration outweighs the limited adverse environmental effect of conventional gasoline used in this manner. In addition, aircraft emissions normally would not be confined to the covered area where the aircraft is fueled, and could occur in significant part outside any RFG covered area. The rationale for the exception for racing gasoline is based on the special performance requirements for true race vehicles and the limited volumes of gasoline involved.(1/17/95)

This question and answer was posted at Consolidated List of Reformulated Gasoline and Anti-Dumping Questions and Answers: July 1, 1994 through November 10, 1997 (PDF)(333 pp, 18.17 MB, EPA420-R-03-009, July 2003, About PDF)