Congressional debate over the use of ethanol has intensified in recent weeks, as rising food prices have caused some lawmakers to finger the increased growing of corn for fuel as a potential cause.
In the letter sent on Friday, Senate Republicans argue that the EPA has the power to waive or restructure an Energy Bill passed last December requiring a large increase in ethanol production by 2022.
"American families are feeling the strain of these food-to-fuel mandates in the grocery aisles and are growing concerned about the emerging environmental concerns of growing corn-based ethanol," the letter stated.
"It is essential for the EPA respond quickly to the consequences of these mandates."
The Energy Independence and Security Act of 2007 requires fuel companies to blend 15 billion gallons of ethanol into the fuel supply by 2015, however the law gives the EPA the authority to waive portions of the law at its discretion.
Sen. James Inhofe (R-Okla.), the top Republican on the Senate Energy and Natural Resources Committee, called the ethanol mandates "a policy blunder" and demanded "dramatic and necessary actions" to change the law.
Senate Democrats acknowledged the need for a conversation about the effects of ethanol on food prices, but cautioned against drastic changes.
"The volume on the food vs. fuel debate is getting louder by the day," said Bill Wicker, a spokesman for Sen. Jeff Bingaman (D-N.M.), the chairman of the Senate Energy and Natural Resources Committee.
"This is a complicated matter, with many moving parts, and we think it's best for folks to catch their breath and get better educated on the complexities before charging ahead with changes."