Is a liquid fuel produced from renewable sources, such as new and used vegetable oils and animal fats, and is a cleaner-burning replacement for petroleum-based diesel fuel. Biodiesel is nontoxic and biodegradable and is produced by combining alcohol with vegetable oil, animal fat, or recycled cooking grease. Like petroleum-derived diesel, biodiesel is used to fuel compression-ignition (diesel) engines. Using biodiesel as a vehicle fuel increases energy security, improves air quality and the environment, and provides safety benefits. It meets both the biomass-based diesel and overall advanced biofuel requirement of the Renewable Fuel Standard. Biodiesel can be blended with petroleum diesel in any percentage, including B100 (pure biodiesel) and, the most common blend, B20 (a blend containing 20% biodiesel and 80% petroleum diesel).