A prominent oil industry group came out swinging against the EPA’s decision to approve E15, a new blend of fuel comprised of 15 percent ethanol. Currently, most gasoline sold in the U.S. is 10 percent ethanol, so E15 represents a change.

For some in the industry, that change is unwelcome, according to the Des Moines Register’s Christopher Doering.

The American Petroleum Institute, which represents 500 oil and natural gas companies, told reporters the Environmental Protection Agency acted “prematurely” in approving E15 – a blend of 15 percent ethanol and 85 percent gasoline. The group has said more testing is needed.

In a study, the API estimates that “half of all gasoline equipment is not compatible with E15,” according to DTN. Agriculture Secretary Tom Vilsack doesn’t exactly buy that argument.

After API released its study, Agriculture Secretary Vilsack issued a release calling on petroleum companies to help increase the percentage of ethanol in America's gas tanks in order to reduce dependence on foreign oil, boost job creation and promote development of renewable energy from farm-produced feedstocks.

In March, our Field Notes podcast dove into the middle of the oil-ethanol spat. “The ethanol industry says its product is good for domestic security; oil says ethanol hasn’t been tested enough, and is thus unsafe for American consumers,” our Jesssica Naudziunas said then. “Ask anyone which group is right, and you get a different answer.”

Clearly, the E15 battle is just heating up.