The Environmental Protection Agency’s (EPA) long process to set the volume requirements for calendar years 2014, 2015, and 2016 under the Renewable Fuel Standard (RFS) was completed with the recently published final rule. The final RFS rule reduces the volume requirements for renewable fuels from the statutorily-mandated levels. EPA argues that it has the authority to reduce the mandate based on a specific waiver provision in the statute and its interpretation of the three words ‘inadequate domestic supply’ in that provision. Whether the rule and EPA’s arguments for the waiver authority will withstand a court challenge is an open question.