Gasoline Standards

Reformulated Gasoline

Reformulated gasoline (RFG) is gasoline blended to burn more cleanly than conventional gasoline and to reduce smog-forming and toxic pollutants in the air we breathe. The RFG program was mandated by Congress in the 1990 Clean Air Act amendments. The first phase of the RFG program began in 1995 and the second (current) phase began in 2000.

RFG is required in cities with high smog levels and is optional elsewhere. RFG is currently used in 17 states and the District of Columbia. About 30 percent of gasoline sold in the U.S. is reformulated.

The air quality benefits RFG has achieved represent a significant part of the country's smog reduction strategy. The RFG program, combined with other industrial and transportation controls aimed at smog reduction, is contributing to the long-term downward trend in U.S. smog levels. About 75 million people breathe cleaner air because of RFG.

Phase II Reformulated Gasoline: The Next Major Step Toward Cleaner Air (PDF) (2 pp, 152 K, EPA-420-F-99-042, November 1999, About PDF)

Learn more about RFG federal standards

The table below provides the RFG areas with county listings by state. 

Clean Air Act Required Areas:
All counties implement a version of the California Reformulated Gasoline Program, not just those listed here as Clean Air Act-required areas. Standards differ from federal RFG requirements, and compliance periods vary by air basin. Please refer to the California Air Resources Board website for additional details: Exit

El Dorado County (partial) 1
Fresno County 2
Kern County (partial) 2
Kings County 2
Los Angeles County
Madera County 2
Merced County 2
Orange County
Placer County (partial) 1
Riverside County (partial)

Sacramento County 1
San Bernardino County (partial)
San Diego County
San Joaquin 2
Solano County (partial) 1
Stanislaus County
Sutter County (partial) 1
Tulare County
Ventura County
Yolo County 1
1 Sacramento, CA area was reclassified from Serious to Severe ozone nonattainment effective June 1, 1995. RFG was required as of June 1, 1996.
2 San Joaquin Valley, CA area (excluding East Kern County) was reclassified as Severe ozone nonattainment effective December 10, 2001. RFG was required as of December 10, 2002.
Fairfield County
Hartford County (partial)
Litchfield County (partial)
Middlesex County (partial)
New Haven County (partial)
New London County (partial)
Tolland County (partial)
New Castle County
Kent County
District of Columbia
Entire District of Columbia
Cook County
Du Page County
Grundy County (partial)
Kane County
Kendall County (partial)
Lake County
McHenry County
Will County
Lake County
Porter County
Anne Arundel County
Baltimore County
Calvert County
Carroll County
Charles County
Cecil County
Frederick County
Harford County
Howard County
Montgomery County
Prince George's County
The City of Baltimore
New Jersey

Bergen County
Burlington County
Camden County
Cumberland County
Essex County
Gloucester County
Hudson County
Hunterdon County
Mercer County

Middlesex County
Monmouth County
Morris County
Ocean County
Passaic County
Salem County
Somerset County
Sussex County
Union County
New York
Bronx County
Kings County
Nassau County
New York County
Orange County
Queens County
Richmond County
Rockland County
Suffolk County
Westchester County
Bucks County
Chester County
Delaware County
Montgomery County
Philadelphia County
Brazoria County
Chambers County
Fort Bend County
Galveston County
Harris County
Liberty County
Montgomery County
Waller County
Arlington County
Fairfax County
Falls Church
Loudoun County
Manassas Park
Prince William County
Stafford County
Kenosha County
Milwaukee County
Ozaukee County
Racine County
Washington County
Waukesha County

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"Opt-In" Areas:
Connecticut (Entire State)
Litchfield County (partial)
Hartford County (partial)
Middlesex County (partial)
New London County (partial)
Tolland County (partial)
Windham County
New Haven (partial)
Delaware (Entire State)
Sussex nonattainment area
Sussex County
Illinois (effective opt-in date is July 1, 2007)
Jersey County
Madison County
Monroe County
St. Clair County
Boone County
Bullitt County (partial)
Campbell County
Jefferson County
Kenton County
Oldham County (partial)
Kent County Queen Anne's County
Androscoggin County
Cumberland County
Kennebec County
Knox County
Lincoln County
Sagadahoc County
York County
Barnstable County
Berkshire County
Bristol County
Dukes County
Essex County
Franklin County
Hampden County
Hampshire County
Middlesex County
Nantucket County
Norfolk County
Plymouth County
Suffolk County
Worcester County
Missouri (Effective Opt-In Date is June 1, 1999)
St. Louis County
St Louis (city)
Franklin County
Jefferson County
St. Charles County
New Hampshire
Hillsborough County
Rockingham County
Merrimack County
Strafford County
New Jersey
Atlantic County
Cape May County
Warren County
New York
Dutchess County
Essex County (partial)
Rhode Island
Bristol County
Kent County
Newport County
Providence County
Washington County
Collin County
Dallas County
Denton County
Tarrant County
Charles City County
Chesterfield County
Colonial Heights
Hanover County
Henrico County
James City County
Newport News
Virginia Beach
York County

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"Opt-Out" Areas:
Phoenix, AZ nonattainment area
Maricopa County (partial)
  • Phoenix opted in the RFG program in 1997; retail stations were
    required to supply RFG by August 4, 1997
  • In September 1997, the Governor of Arizona submitted an RFG
    opt-out petition for purposes of adopting a more stringent state
    RFG program in Phoenix.
  • EPA approved the opt-out petition which became effective on June
    10, 1998.

Androscoggin County
Cumberland County
Hancock County
Kennebec County
Knox County

Lincoln County
Sagadahoc County
Waldo County
York County
5 These "Opt-Out" areas withdrew from the federal RFG program before it went into effect on January 1, 1995. However, on January 23, 2015, the Administrator signed a final rule approving Maine’s request that seven of these counties (Androscoggin, Cumberland, Kennebec, Knox, Lincoln, Sagadahoc, and York counties) opt into the RFG program beginning on May 1, 2015.

Adams County
Allegheny County
Armstrong County
Beaver County
Berks County
Blair County
Butler County
Cambria County
Carbon County
Columbia County
Cumberland County
Dauphin County
Erie County
Fayette County

Lackawanna County
Lancaster County
Lebanon County
Lehigh County
Luzerne County
Mercer, PA
Monroe County
Northampton County
Perry County
Somerset County
Washington County
Westmoreland County
Wyoming County
York County
New York
Albany County
Erie County
Greene County
Jefferson County
Montgomery County
Niagara County
Rensselear County
Saratoga County
Schenectady County
  • A proposed rule to remove the above "opt-out" areas from the requirements of the reformulated gasoline program was published June 14, 1995. [On January 1, 1995, a temporary exemption of the RFG requirements in these areas went into effect. On July 1, 1995 this stay was extended until the Agency took final action].
  • The final rule, published July 8, 1996 [61 FR 35673], formally removed these areas from the list of RFG covered areas and provided states with general opt-out procedures.
  • The July 8 final rule was superseded by a final rule published October 20, 1997 [62 FR 54552], revising the opt-out procedures.

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