Should US oil refiners pay the cost of mixing ethanol in fuel?
Oil firms that are forced to carry the cost of blending ethanol, when refining gasoline or petrol, say the industry is skewed in favour of biofuel producers.
Refiners are unhappy about a complex mechanism that requires them to buy credits known as Renewable Identification Numbers (RIN), to prove they are mixing ethanol, a biofuel made from corn, when they produce fuel.
Wayne Lee, the chief executive of Lee Enterprises Consulting, in Sherwood, Arkansas, tells the BBC's Russell Padmore why Big Oil and Big Corn are at odds.
(Picture: A fuel service station in Mill Valley, California. Getty Images.)