The Environmental Protection Agency (EPA) has mandated that all consumers in the United States must purchase at least 4 gallons of gasoline when they go to the gas station, if they are getting fuel from a pump that also offers a new E15 ethanol-gasoline blend.

The Obama administration wants consumers to use more of the E15 fuel - a blend that contains 15 percent ethanol - but the problem is that many gas stations use blender pumps, which offer several types of fuel and, after pumping, there always is a residual amount of fuel in the hose. E15 fuel can potentially damage engines made prior to 2000 and it cannot be used in motorcycles, ATVs, and many other engines, such as lawn mowers and boat engines.

So, to circumvent the potential problems, the EPA is requiring a 4-gallon minimum from blender pumps to ensure that any E15 fuel residue is diluted. (Stations that provide a completely separate, single hose for E15 only are exempt from the rule.)

But many lawmakers, as well as motorcycle and off-road specialists, say the EPA rule is not a viable solution and that requiring people to buy a minimum of 4 gallons of gasoline is not acceptable.

The Obama administration announced in April that it had begun issuing waivers to allow for the sale of gasoline that contains 15 percent volume ethanol (E15), a product previously not approved for the market.

"To enable widespread use of E15, the Obama Administration has set a goal to help fueling station owners install 10,000 blender pumps over the next 5 years," stated an EPA press release on April 2.

The issue has drawn criticism on Capitol Hill, with two members of the House Committee on Science, Space and Technology demanding answers from the EPA.

"The EPA has no business telling Americans how much fuel they must purchase," wrote Representatives James Sensenbrenner (R-Wis.) and Chip Cracaack (R-Minn.) in a letter to the EPA on Sept. 10.

The congressmen have asked EPA Administrator Lisa Jackson what authority the agency had to issue the policy since it was not present in the final rule issued in July 2011, but first appeared in sample letters the department sent to companies approving "Misfueling Mitigation Plans" this year.

"EPA's first-ever fuel purchase requirement appears to have been made outside the normal rulemaking process, seems antithetical to free markets, and highlights the flaws in the Agency's hasty decision to grant partial waivers for E15 prior to comprehensive scientific assessment and evaluation," the lawmakers said.

"EPA's requirement that consumers purchase a minimum of 4 gallons of E15 is an absurd solution to a defective policy," said Senator James Inhofe (R-Okla.).  "Simply put, this is a thinly veiled attempt to mitigate a bad policy that was defective from the start and the latest example of a bureaucracy forcing unnecessarily burdensome regulations on the already-suffering consumer."

"Oklahomans have always been adamantly opposed to E15 not only because of its bad fuel economy but because of the detrimental effects E15 has on engines," he said.

"EPA's latest move proves they are correct," said Inhofe.

Currently, only a small handful of retailers are selling E15.  However, the large number of blender pump locations in the Midwest could lead to more retailers selling the fuel and more consumers having to face the minimum 4-gallon purchase rule.