WASHINGTON — Lisa Jackson, the Environmental Protection Agency’s (E.P.A.) administrator, announced E.P.A. has finalized its RFS-2 rule, which will pave the way for increased use of corn-based ethanol in meeting the nation’s goal of 36 billion gallons of Renewable Fuel by 2022, the American Meat Institute said.

The new rule is a reversal of previous E.P.A. studies, which have found that due to land-use issues, corn-based ethanol would fail to meet the 20% threshold in greenhouse gas reductions, limiting its future use as a renewable fuel. This move was announced at a joint press conference highlighting the administration’s plan for developing sustainable biofuels following a meeting with President Obama. Participants also included the Secretaries of the Interior, Agriculture and Energy.

Numerous renewable fuels were examined by E.P.A. to ensure they achieve greenhouse gas emission reductions — compared to the gasoline and diesel fuels they displace — in order to be counted towards compliance with volume standards in the RFS-2 Rule. It found “ethanol produced from corn starch at a new natural gas, biomass, or biogas fired facility (or expanded capacity from such a facility) using advanced efficient technologies (ones that we expect will be most typical of new production facilities) will meet the 20 percent G.H.G. emission reduction threshold compared to the 2005 gasoline baseline.”

Ms. Jackson said during a question-and-answer session, after one reporter asked her how they could “change the science in the outcome where there was a lot of public pressure,” she didn’t agree with the premise of the question and that they stood by their research on corn-based ethanol. “Based on what we know now, including indirect land use, there is no basis to exclude these fuels,” she added.

“We listened to public comment and worked closely with the U.S.D.A.,” said Jackson, noting there were three major areas that changed the G.H.G. ratings for corn ethanol.

“On crop productivity, the data we used was not right,” she said. She explained after adding new yield information, the numbers changed. The E.P.A. also changed the indirect land-use modeling by broadening it beyond the initial 40 nations to include 120 nations, which also impacted the final emissions numbers.

Increasing renewable fuels will reduce dependence on oil by more than 328 million barrels a year and reduce greenhouse gas emissions more than 138 million metric tons a year when fully phased in by 2022, the Administration noted.

Clickhereto read a copy of RFS 2.