A "chorus" of groups are increasing pressure on Congress and the Obama administration to scale back the corn ethanol fuel mandate, pointing out their fears that higher blends of the alcohol fuel will damage vehicle engines and cause widespread economic harm.

On a Wednesday press call, the American Petroleum Institute joined with environmentalists and anti-hunger groups to outline why the mandate — the Environmental Protection Agency's Renewable Fuel Standard — does not mesh with reality and should be repealed, or at least significantly reformed.

"A chorus of concerned groups — from consumer groups to environmental groups to anti-hunger groups to industry groups — are calling for repeal or reform of the nation's ethanol mandates under the [standard]," said Bob Greco, director of the American Petroleum Institute's downstream group, which covers refining.

"API remains seriously concerned that increasing ethanol mandates under the RFS stand to harm consumers and our economy," Greco said.

He was joined by Environmental Working Group's government affairs vice president Scott Faber and ActionAid USA's biofuel policy analyst Kelly Stone.

Stone raised global hunger threats if the standard continues to divert corn for use in fuels production instead of food production, a claim that biofuel proponents in a counter press call on Wednesday said is not supported by the facts.

Faber added that the Renewable Fuel Standard has failed the advanced biofuel companies it was meant to support, while failing the environment and consumers.

Although biofuel groups are disappointed with EPA's management of the program, they do not support scrapping it or backing legislative efforts on Capitol Hill to roll back the mandate's corn ethanol requirements while leaving intact the much less damaging second-generation biofuel targets.

Greco and others who want the standard repealed endorsed a bipartisan bill introduce Feb. 26 in the Senate to roll back the corn ethanol mandate. The bill, introduced by California Democrat Diane Feinstein and Pennsylvania Republican Pat Toomey, is the Senate's attempt to rekindle the debate in the new Congress.

"The RFS requires us to squeeze more ethanol into a smaller amount of gasoline," especially as gasoline demand is waning, Greco said.

"This year we could hit what is called the ethanol blend wall, where the RFS would force more than 10 percent ethanol into each gallon of gas," he said. "This is concerning because most cars on the road today cannot tolerate these higher ethanol blends."

In an article published this month in Autoweek magazine, former "Tonight Show" host Jay Leno, who is an avid car collector, bashed the Renewable Fuel Standard and ethanol that he says will result in an uptick in vehicle fires and other problems.

The article forced ethanol trade groups to go on the offensive, publishing a number of counter points and articles in support of ethanol.