In technical terms, biodiesel is a liquid fuel made up of fatty acid alkyl esters, fatty acid methyl esters (FAME), or long-chain mono alkyl esters. In everyday terms, biodiesel is a better fuel for diesel engines. It is 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. It is nontoxic and biodegradable. Biodiesel has energy properties similar to those of petroleum diesel, but without the pollution qualities and without the dependence on foreign oil.