Diesel Fuel is a crude-oil distillate fuel oil used in compression-ignition engines. Alternative types of diesel can also be obtained from alternatives sources that are not derived from petroleum, such as biodiesel, biomass to liquid (BTL) or gas to liquid (GTL) diesel which are increasingly being developed and adopted. To avoid confusion, petroleum-derived diesel is also called petrodiesel. Diesel fuel is similar to home heating oil, but must meet a cetane number specification of 40 or more.
In the US the new standard for highway diesel fuel, as of December 2010, is the Ultra Low Sulfur Diesel (ULSD), a cleaner-burning diesel fuel that contains 97% less sulfur than low-sulfur diesel (LSD).