Agriculture Secretary Tom Vilsack says the conflict between agriculture and petroleum interests over the Renewable Fuels Standard shows no signs of slowing. Vilsack told Bloomberg last week “you’re going to have constant litigation.” Oil and biofuel industry advocates alike have filed numerous lawsuits over the RFS volume targets issued by the Environmental Protection Agency last November. Valero Energy, the third largest ethanol producer and the largest U.S. petroleum refiner, is the latest to file suit against the EPA. In November, EPA announced refiners must use 14.5 billion gallons of corn-based ethanol this year, below the 15 billion gallon mark as set within the RFS. The oil industry says that is above levels considered safe to use in engines while biofuel proponents say that is below the target required by law. The EPA maintains it has the authority to set the volume targets based off the current market situation.