On January 21, 2011, the United States Environmental Protection Agency (EPA) granted a partial waiver to fuel and fuel additive manufacturers to allow the introduction of E15 fuel for use in model year 2001 and newer light duty motor vehicles. They previously granted a partial waiver for model year 2007 and newer vehicles. E15 is a blend of 15% ethanol and 85% gasoline. The previous ethanol limit was 10%.

The EPA has placed two types of conditions on the waiver for E15. Mitigating the potential for mis-fueling of E15 into vehicles, engines and equipment for which E15 is not approved, and addressing fuel and ethanol quality. All conditions must be met prior to the introduction of E15 for consumer use. The EPA is completing work on regulations that would make it more practical to meet the conditions.

The EPA lists the following vehicle types that will be able to use E15. •

• Flexible-fuel vehicles (FFVs). •
• MY2001 and newer cars. •
• MY2001 and newer light-duty trucks. •
• MY2001 and newer medium-duty passenger vehicles. (SUVs).

The following vehicles will not be able to use E15. •

• All motorcycles. •
• All vehicles with heavy-duty engines, such as school buses, transit buses, and delivery trucks. •
• All off-road vehicles, such as boats and snowmobiles. •
• All engines in off-road equipment, such as lawnmowers and chain saws. •
• All MY2000 and older cars, light-duty trucks, and medium-duty passenger vehicles (SUVs).

This waiver has been opposed by vehicle manufacturers and the American Petroleum Institute based on concerns of the adequacy of the testing, and their claims that the use of E15 could damage engines of vehicles not designed to use the higher ethanol content. There are also concerns that consumers will be confused by pump labeling which may lead to mis-fueling and damage to earlier vehicles. Both groups have filed lawsuits to stop the implementation of this waiver.

Several problems can happen when a vehicle not designed to run on E15 is fueled with it. Drive-ability problems such as lack of power, hard starting, hesitation, stalling at low speeds and others. Physical damage may include damage to metal, rubber and plastic parts of fuel system, corrosion of metal parts in fuel system and engine, wear and damage of internal engine parts. General problems with ethanol/gasoline fuel could include water contamination of the fuel due to absorption, drop in octane, vapor locking, decreased shelf life of the fuel, etc.

There are various methods of testing the percentage of ethanol in the fuel if you suspect this may be the cause of problems with your customer's vehicle. The simplest being a measured glass beaker where you start with a specific amount of water and then add fuel from the vehicle. You shake vigorously and then let this mixture stand for several minutes. The combined water and ethanol will separate from the gasoline and the percentage.