Ethanol producers are asking the federal Environmental Protection Agency to to remove the 10 percent limit on ethanol in gasoline.
Right now, about 70 percent of the gas in the U.S. contains ethanol, mostly a 10-percent blend. Corn farmers and ethanol producers want to boost the blend to 15 percent.
Minnesota Agriculture Commissioner Gene Hugoson says opposition is coming from the same sectors that earlier fought the 10-percent rule.
"There were critics that said it was causing everything from flat tires to who-knows-what, and yet time showed that no, in fact it wasn't a problem," he said.
Hugoson says recent tests, including tests on small engines, are showing no problems with higher blends.
He says the 15-percent blend would cut greenhouse gas emissions, create jobs in rural areas, and reduce dependence on foreign oil.
Minnesota is working toward a 20-percent blend mandate, but that also requires a waiver from the EPA.
The federal agency must respond to the request by November.