Midwestern senators are calling on the Obama administration to stop delaying testing that would allow an increase in the blend rate of ethanol in gasoline to 15 percent.

In a letter to President Obama, U.S. Senator Amy Klobuchar (D-MN) and six other senators expressed concern that the Department of Energy (DOE) has not yet completed testing higher blends of ethanol gasoline, which would allow the Environmental Protection Agency (EPA) to issue a waiver for gasoline with blends of ethanol higher than 10 percent.

“In the wake of the worst oil spill in our nation’s history, we believe our government should operate with a great sense of urgency to utilize more homegrown biofuels,” the senators wrote in the letter. “We urge you to use all available means to ensure that the DOE’s testing is completed as soon as possible so that both consumers and our biofuels industry are not further harmed by this delay.”

In addition to Klobuchar, the letter was signed by Democratic senators from Iowa, South Dakota, Nebraska, Illinois and Indiana.