Sensing a threat to the ethanol program, a bipartisan group of Midwestern U.S. senators, including Minnesota Democrats Amy Klobuchar and Tina Smith, have called on Pruitt to stop handing out ethanol waivers and reveal who has gotten waivers and why. U.S. Rep. Collin Peterson, D-Minn., ranking member on the House Agriculture Committee, sent a letter to President Donald Trump, asking him to stop Pruitt.

Farmers and ethanol producers in Minnesota say the waiver controversy is the latest battle in a long-running war for sales and market share between the oil and renewable fuel industries. The renewable fuel standard (RFS) has been controversial since its inception in 2005. Free marketers and the oil industry see it as an anti-competitive government mandate. Anti-poverty groups have charged that it encourages farmers to produce less food for people. Some environmentalists are skeptical of the ethanol industryís green credentials.

But Trumpís 2017 appointment of Pruitt to lead the EPA has brought things to a head, given Pruittís past ties to the oil industry and his criticism of the ethanol program.

The EPA will not confirm the total number of gallons of ethanol Pruitt has exempted from production so far this year. Trade groups for farmers and biofuel producers believe it could already be at least 1.6 billion gallons. If Pruitt continues on that pace, it could significantly undercut 2018ís 15 billion gallon national production mandate, ethanol producers say.