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Reformulated Gasoline Program

Purpose of Reformulated Gasoline and the Texas counties required to use it.


The Clean Air Act Amendments of 1990 required reformulated gasoline (RFG) to be used in nine major metropolitan areas of the United States with the worst ozone air pollution. In addition, the U.S. Environmental Protection Agency expanded the RFG Program at the request of many state governors to allow areas with a history of ozone problems to voluntarily become part of the program. The RFG Program is federally implemented year-round in these areas as an emission-reduction program to control ozone and air toxic emissions.

RFG is designed to reduce air toxins and emissions of volatile organic compounds by decreasing the amount of toxic compounds, such as benzene, and lowering the evaporation rate of the fuel. The RFG Program began Jan. 1, 1995.

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Texas Counties Required to Use RFG

The Houston-Galveston-Brazoria nonattainment area is required by the Clean Air Act Amendments of 1990 to use RFG. This eight-county area includes Brazoria, Chambers, Fort Bend, Galveston, Harris, Liberty, Montgomery, and Waller Counties.

The Dallas–Fort Worth nonattainment area voluntarily opted into the RFG Program. This four-county area includes Collin, Dallas, Denton, and Tarrant Counties. Reclassification of the Dallas-Fort Worth area to severe nonattainment for the 2008 ozone National Ambient Air Quality Standards was effective on November 7, 2022, and resulted in the prohibition of the sale of conventional gasoline throughout the entire 10-county nonattainment area effective November 7, 2023. Ellis, Johnson, Kaufman, Parker, Rockwall, and Wise Counties are now also subject to the federal RFG program.

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The Difference Between Oxygenated Gasoline and RFG

Oxygenated fuel is conventional gasoline that has been blended with an oxygenate to achieve a certain concentration of oxygen in the fuel by weight.

RFG is a formulation of gasoline that has lower amounts of certain chemical compounds that contribute to the formation of ozone and air toxins. It does not evaporate as readily as conventional gasoline during the summer months. It may contain oxygenates, which increase the combustion efficiency of gasoline and reduce carbon monoxide emissions.

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Using RFG

The exhaust emissions of vehicles using RFG will have less air toxins and ozone-forming pollutants, and the use of RFG should have no adverse effects on vehicle performance or the durability of engine and fuel system components.

RFG may be purchased at any gasoline-dispensing facility within the Houston-Galveston-Brazoria and Dallas–Fort Worth nonattainment areas.

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Contact Information

For more information about reformulated gasoline, visit the EPA’s Web page on RFG .

For additional information about RFG in Texas, contact:

Michael Regan
Air Quality Division, TCEQ

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