President Trump chalked up his announcement on boosting ethanol for farmers in Iowa to his record of "promises made, promises kept," while speaking in Iowa Tuesday night.

"I made that promise to you during the campaign," Trump said. "I made that promise to you during the primaries. Promises made, promises kept."

"We're going with E15 year-round," Trump said early in his speech, admitting that the full announcement would come later in his remarks.

The plan would relax Environmental Protection Agency rules that restrict the sale of 15-percent ethanol fuel blends to eight months of the year. The EPA waiver for the E15 fuel would allow it to be sold year-round, which corn farmers and ethanol producers have been pushing the administration to do for months.

Later in the speech, Trump warned that ethanol production and E15 will be in jeopardy if Democrats take back Congress in November.

"The Dems will end ethanol, you know that," Trump said. "They're not going to approve ethanol. They will find a way to take it away. ... You better get out there and vote."

The second part of Trump's E15 plan seeks to reform the market that refiners use to buy ethanol credits in order to comply with EPA's Renewable Fuel Standard. The Renewable Identification Number credits, or RINs, have been a hot topic of debate among the oil industry.

The Trump plan is an attempt to settle a feud between the ethanol industry and refiners over the direction of the nation's renewable fuel program until Congress can agree on substantive reforms.

The refiners don't want to be subject to the high costs associated with the price of buying RINs. One company in Philadelphia said the high cost of RINs forced it to declare bankruptcy last year.

But the ethanol industry argues that blending more ethanol into the gasoline supply via E15 would solve both sides' problems. More ethanol blended means more RINs are produced, which increases the supply of the credits and the prices comes down.

The oil industry and refiners don't agree with that logic, saying E15 is dangerous to consumers to be allowed to be sold year-round. They argue that only a small number of vehicles can use the fuel, raising the possibility of misfueling that can damage engines not equipped to use the fuel.

The top group representing refiners in Washington called Trump's actions illegal, saying it will only make problems worse for the industry.

“The President’s proposal to waive the rules for E15 is unlawful and could actually make the problems of the Renewable Fuel Standard worse," said Chet Thompson, president and CEO of the American Fuel and Petrochemical Manufacturers.

"The President has promised to broker a deal to reform the RFS that works for all stakeholders. This isn’t it," Thompson said. "We are disappointed to see that despite good-faith efforts by refiners to find potential solutions, the Administration has unilaterally embraced a one-sided approach that only serves the ethanol community, which has shown little interest in finding common ground."