Olive oil quality is judged by its overall flavor and by its content of “free fatty acids,” or fatty carbon chains that should be bound up in intact oil molecules but instead are floating free, and that are evidence that the oil is damaged and unstable. Under the regulations of the European Economic Community, “extra virgin” olive oil must contain less than 0.8% free fatty acids, “virgin” oil less than 2%. (To date, quality labeling of U.S. oils is not regulated.) Oils with higher free fatty acid levels are usually processed to remove nearly all impurities from the remaining intact oil molecules—including desirable flavor molecules. Producers usually blend such refined or “pure” oil with some virgin oil to give it flavor.