Ethanol, Reformulated Gasoline


Maine Law repealed the requirement to sell only reformulated gasoline (RFG) in the Southern Maine area of York, Cumberland, Sagadahoc, Androscoggin, Kennebec, Knox and Lincoln Counties as of November 1, 2020. In order to opt-out of the federal RFG program, Maine was required to petition U.S. EPA and submit a State Implementation Plan (SIP) revision. Maine DEP's technical analysis demonstrated that emissions in these counties will continue to decline after the requirement is lifted. EPA has approved Maine's petition and determined that the removal of the federal RFG program for the Southern Maine Area is consistent with the applicable provisions of the Clean Air Act (CAA) and EPA's regulations. As a result, RFG will no longer be required in the Southern Maine Area as of September 30, 2021.


Ethanol is an alcohol-based fuel made by fermenting and distilling the simple sugars found in agricultural crops and wood fibers. Ethanol is blended with gasoline when used as a motor fuel. It cannot be blended at the refinery and shipped by pipeline. Ethanol must be shipped and stored separately and blended with gasoline at the terminal.

Nearly all gasoline distributed in Maine is now blended with 10% ethanol. The introduction of ethanol in gasoline is not a state requirement. For more information, see our FAQs and the history behind the increase in blended gasoline.

Because of the increase of ethanol-blended gasoline in Maine, the Department has received questions regarding the use of ethanol in their vehicles, boats, and other gasoline powered equipment. Below are several documents and links about ethanol and its use:

Additional Information

  • Special Airworthiness Information Bulletin (SAIB) - This Special Airworthiness Information Bulletin (SAIB) alerts you of an airworthiness concern where you could have alcohol (ethanol or methanol) present in the automobile gasoline on any General Aviation airplane type certificated (TC) to use automobile gasoline or with automobile gasoline supplemental type certificates (STCs).
  • Converting to Ethanol (PDF file) This document created by Central Illinois Manufacturing Co. offers information for the conversion of retail service station tanks to ethanol-blended gasoline. Note: Mention of any trade names does not imply endorsement by DEP.
  • FAME Finance Authority of Maine website describing low-interest, fixed-rate financing for the removal, disposal and replacement of aboveground and underground commercial storage tanks, piping and related equipment associated with the tank, as well as the purchase and installation of vapor recovery systems.
  • EPA Renewable Fuel Standard Program: This page also contains notices, regulations and analyses regarding the Renewable Fuel Standard.
  • American Coalition for Ethanol
  • DOE Alt Fuels Department of Energy's Alternative Fuels and Advanced Vehicles Data Center.
  • Report by the National Renewable Energy Laboratory - " Effects of Intermediate Ethanol Blends on Legacy Vehicles and Small Non-Road Engines", Report 1 updated February 2009 : The report discusses the effect of E15 to E20 on Small Non-road Engines etc.
  • Ethanol Promotion and Information Council Frequently Asked Questions


Ethanol is available in the Maine market for several different reasons. Those reasons include federal and state regulatory changes and current fuel market forces.

Maine Legislative Changes

MtBE Ban. Methyl Tertiary Butyl Ether (MtBE) was added to conventional gasoline to enhance combustion and octane levels and to meet the federal Clean Air Act mandate requiring 2% oxygen in Reformulated Gasoline (RFG). The Maine Legislature banned MtBE as a gasoline additive in the state after January 1, 2007. With the MtBE ban in Maine and other states ethanol has been blended with gasoline in place of MtBE. However, Maine has no requirement to blend gasoline with any oxygenate such as ethanol.

Maine also provides tax incentives for the manufacturing and distributing of biofuels.

Federal Energy Policy Acts

EPACT 2005. While Maine withdrew from the Reformulated Gasoline (RFG) program in 1999, some states are still part of the RFG program. The Energy Policy Act of 2005 (EPACT 2005) removed the federal Clean Air Act mandate requiring 2% oxygen in RFG as of May 5, 2006. MtBE was the refiners' primary fuel oxygenate to comply with the RFG oxygen requirement. Although EPACT 2005 did not ban the use of MtBE, the elimination of the federal oxygenate requirement led to a rapid phase-out of MtBE and a significant increase in the use of ethanol. While RFG can be produced without oxygenates, the industry uses ethanol to provide performance (octane enhancement), help achieve the lower air toxics requirements of RFG, and to make up the lost volume from MtBE.

Refiners and distributors are choosing to blend gasoline with ethanol due to a federal tax incentive (in the case of E-10 the blenders credit is 5.1¢ per gallon of ethanol) which has created an industry incentive to use higher volumes of ethanol. However, the market is fluid and could change at any time should blending with ethanol prove to be less cost effective than other fuel formulations.

Energy Independence and Security Act 2007. In addition, Congress passed in 2007 the Energy Independence and Security Act which mandated an increase in the amount of renewable fuels nationally to 9 billion gallons of ethanol to be blended in the gasoline fuel supply in 2008 increasing to 36 billion gallons in 2022. Maine has no renewable fuel standard requirement.

Market Forces

Due to its chemical properties (particularly its affinity for water), ethanol cannot be blended into the gasoline at the refinery and shipped by pipeline. It must be shipped separately by barge, rail or truck, stored separately, and then blended with gasoline at the terminal. Some gasoline terminals in Maine have started to blend ethanol with conventional fuel here in Maine.