By Ayesha Rascoe
WASHINGTON (Reuters) - The U.S. Environmental Protection Agency has not complied with federal requirements to study the effects of the nation's biofuel use mandate, an agency watchdog said on Thursday.
EPA's Inspector General concluded that the agency has not issued a report to Congress on the environmental impacts of the Renewable Fuel Standard (RFS) since 2011, even though federal law requires that the agency provide a report every three years.
The RFS, which is administered by EPA, sets the amounts of biofuels, such as ethanol, that must be blended into U.S. gasoline and diesel supplies annually.
The IG report also said the agency has not evaluated whether the program is causing any harm to air quality and it has no formal process to initiate an update of its data on the life cycle greenhouse gas emissions of biofuels.
"Not having required reporting and studies impedes the EPA's ability to identify, consider, mitigate and make policymakers aware of any adverse impacts of renewable fuels," the report said.
EPA said it mostly agreed with the report's findings. The agency said it has "agreed to a set of corrective actions and timelines" to address the report's conclusions.
The agency estimated that it would complete a report on the impact of the biofuel mandate by the end of 2017.
The renewable fuel program has faced intense opposition in recent years from oil companies, who argue that the program places undue financial burdens on refiners.
A spokesman for the American Petroleum Institute said the oil and gas trade group is still reviewing the IG report.
Some environmental groups have also questioned whether EPA has properly evaluated the life cycle greenhouse gas emissions of corn ethanol to calculate its global warming potential. They say land-use change associated with its production outweighs the environmental benefits of replacing gasoline.
But, biofuel backers have strongly pushed back against these claims.
"We are confident that once EPA conducts these required studies, they will show that biofuels like ethanol are significantly reducing greenhouse gas emissions, even above the threshold reductions," said Renewable Fuels Association President Bob Dinneen in a statement.
(Reporting by Ayesha Rascoe; Editing by Cynthia Osterman)