Diesel fuel is refined from oil
Diesel fuel is used in the diesel engines found in most freight trucks, trains, buses, boats, and farm and construction vehicles, and in some cars and small trucks. Diesel fuel is also used in diesel engine generators to generate electricity, such as in remote villages in Alaska, among other locations around the word. Many industrial facilities, large buildings, institutional facilities, hospitals, and electric utilities have diesel generators for backup and emergency power supply.
Diesel fuel is a type of distillate fuel. On average, about 12 gallons to 13 gallons of distillate are produced from each 42-gallon barrel of crude oil in U.S. refineries, with the majority sold as diesel fuel.
Before 2015, diesel fuel sold in the United States contained high quantities of sulfur. Sulfur in diesel fuel produces air pollution emissions that are harmful to human health. In 2006, the U.S. Environmental Protection Agency issued requirements to reduce the sulfur content of diesel fuel. The requirements phased in over time, beginning with diesel fuel sold for vehicles used on roadways and eventually covering all diesel fuel. All diesel fuel now sold in the United States must have a sulfur content of no more than 15 parts per million.