Biodiesel: A Fuel That Starts Low on the Food Chain: "A study financed by the Energy Department, published November 2001, suggested that expanded production of mustard seeds, combined with current soybean production and waste grease, could produce at least six billion gallons of biodiesel annually... 55 billion gallons of diesel fuel [are] used annually in the United States," in addition to gasoline.  Where air pollution is a factor, 100% biodiesel can be used; 20% biodiesel blends are commonly accepted, 5-10% is the most conservative.  4:06:27 PM