Although the scientific for using ethanol as a fuel additive to reduce pollution has been challenged, the politics of the subsidy are unassailable. For example, a major beneficiary of the subsidy in the United States is Archer Daniels Midland Company, a large corn processor. It is also a significant contributor to both major U.S. political parties. The fact that ethanol subsidies are concentrated in lowa is also politically significant, as that state hosts one of the earliest presidential primary races. Presidential hopefuls quickly see the wisdom of supporting subsidies. The 2005 energy bill included production subsidies and other policies (such as requiring more cars be built with engines flexible enough to use ethanol) intended to more than double ethanol use (to eight billion barrels per year) 2012.