Cruz, speaking on behalf of a group of eight GOP senators, wrote in a Tuesday letter to Reynolds that they do not wish to up-end the market for corn ethanol produced in her state, which is the nation's top producer of the fuel.
Instead, Cruz argued that the senators' real problem with the Renewable Fuel Standard is refiners being required to buy expensive renewable identification number credits, or RINs, to meet the EPA's ever-increasing biofuel targets.
The RFS requires refiners to blend ethanol and other biofuels in the nation's fuel supply.
"Surely, we can agree that our nation's RFS policy should benefit corn farmers and hardworking refinery workers on Main Street, not fast-talking bankers on Wall Street."
Cruz noted in the letter that Iowa senators had placed similar holds on EPA nominees to block their confirmations because of a furor over the RFS.