[1][2] Petroleum containing higher levels of sulfur is called sour crude oil.
[3] Sweet crude oil contains small amounts of hydrogen sulfide and carbon dioxide.
High-quality, low-sulfur crude oil is commonly used for processing into gasoline and is in high demand, particularly in industrialized nations.
Nineteenth-century prospectors would taste and smell small quantities of oil to determine its quality.
[4] Producers of sweet crude oil include: The term "price of oil", as used in the U.S. media, generally means the cost per barrel (42 U.S. gallons) of West Texas Intermediate Crude, to be delivered to Cushing, Oklahoma during the upcoming month.