Gasoline additives may increase gasoline's octane rating, thus allowing the use of higher compression ratios for greater efficiency and power, or act as corrosion inhibitors or as lubricants. Other additives include metal deactivators, oxygenates and antioxidants.
Some additives are harmful and are regulated or banned in some countries.
Ethyl tertiary-butyl ether (ETBE), also known as ethyl tert-butyl ether, is commonly used as an oxygenate gasoline additive in the production of gasoline from crude oil. ETBE offers equal or greater air quality benefits than ethanol, while being technically and logistically less challenging. Unlike ethanol, ETBE does not induce evaporation of gasoline, which is one of the causes of smog, and does not absorb moisture from the atmosphere.
The United States became the world's largest producer of ethanol fuel in 2005. The U.S. produced 15.8 billion U.S. liquid gallons of ethanol fuel in 2019, up from 13.9 billion gallons (52.6 billion liters) in 2011, and from 1.62 billion gallons in 2000. Brazil and U.S. production accounted for 87.1% of global production in 2011. In the U.S., ethanol fuel is mainly used as an oxygenate in gasoline in the form of low-level blends up to 10 percent, and, increasingly, as E85 fuel for flex-fuel vehicles. The U.S. government subsidizes ethanol production.
The ethanol market share in the U.S. gasoline supply grew by volume from just over 1 percent in 2000 to more than 3 percent in 2006 to 10 percent in 2011. Domestic production capacity increased fifteen times after 1990, from 900 million US gallons to 1.63 billion US gal in 2000, to 13.5 billion US gallons in 2010. The Renewable Fuels Association reported 209 ethanol distilleries in operation located in 29 states in 2011.