DES MOINES, Iowa (AP) — Iowa leaders are criticizing a proposal from the Obama administration that would reduce the amount of ethanol blended in U.S. gasoline. Iowa leads the nation in producing ethanol, a fuel additive made mostly from corn. Under the proposal released Friday by the Environmental Protection Agency, the amount of ethanol blended in to gasoline will increase, but not by as much as originally required by law.

Still, the agency didn’t decrease the standards as much as it had proposed in 2013. Iowa Gov. Terry Branstad — who has lobbied aggressively for maintaining a strong standard — says in a statement that he was disappointed, but noted that the EPA made slight increases from a previous proposal. Sen. Joni Ernst says in a statement that “we can and must do better.”