Editing Gasoline (section)

===Oxygenate blending===
[[Oxygenate]] blending adds [[oxygen]]-bearing compounds such as [[methanol]], [[Methyl tert-butyl ether|MTBE]], [[Ethyl tert-butyl ether|ETBE]], [[Tert-Amyl methyl ether|TAME]], [[Tert-Amyl ethyl ether|TAEE]], [[ethanol]], and [[biobutanol]]. The presence of these oxygenates reduces the amount of [[carbon monoxide]] and unburned fuel in the exhaust. In many areas throughout the U.S., oxygenate blending is mandated by EPA regulations to reduce smog and other airborne pollutants. For example, in Southern California fuel must contain two percent oxygen by weight, resulting in a mixture of 5.6 percent ethanol in gasoline. The resulting fuel is often known as reformulated gasoline (RFG) or oxygenated gasoline, or, in the case of California, California reformulated gasoline (CARBOB). The federal requirement that RFG contain oxygen was dropped on 6 May 2006 because the industry had developed [[Volatile organic compound|VOC]]-controlled RFG that did not need additional oxygen.<ref>{{cite web |date=22 February 2006 |title=Removal of Reformulated Gasoline Oxygen Content Requirement (national) and Revision of Commingling Prohibition to Address Non-0xygenated Reformulated Gasoline (national) |url=http://www.epa.gov/otaq/rfg_regs.htm#usage |url-status=live |archive-url=https://web.archive.org/web/20050920073346/http://www.epa.gov/otaq/rfg_regs.htm#usage |archive-date=20 September 2005 |publisher=[[U.S. Environmental Protection Agency]] |df=dmy-all}}</ref>

MTBE was phased out in the U.S. due to groundwater contamination and the resulting regulations and lawsuits. Ethanol and, to a lesser extent, ethanol-derived ETBE are common substitutes. A common ethanol-gasoline mix of 10 percent ethanol mixed with gasoline is called [[Ethanol fuel|gasohol]] or E10, and an ethanol-gasoline mix of 85 percent ethanol mixed with gasoline is called [[E85]]. The most extensive use of ethanol takes place in [[Brazil]], where the ethanol is derived from [[sugarcane]]. In 2004, over {{convert|3.4|e9U.S.gal|e9l|sp=us|order=flip}} of ethanol was produced in the U.S. for fuel use, mostly from [[Maize|corn]] and sold as E10. E85 is slowly becoming available in much of the U.S., though many of the relatively few stations vending E85 are not open to the general public.<ref>{{cite web |title=Alternative Fueling Station Locator |url=http://www.eere.energy.gov/afdc/fuels/stations_locator.html |url-status=dead |archive-url=https://web.archive.org/web/20080714060953/http://www.eere.energy.gov/afdc/fuels/stations_locator.html |archive-date=14 July 2008 |access-date=14 July 2008 |publisher=[[U.S. Department of Energy]] |df=dmy-all}}</ref>

The use of [[bioethanol]] and bio-methanol, either directly or indirectly by conversion of ethanol to bio-ETBE, or methanol to bio-MTBE is encouraged by the European Union [[Directive on the Promotion of the use of biofuels and other renewable fuels for transport]]. Since producing bioethanol from fermented sugars and starches involves [[distillation]], though, ordinary people in much of Europe cannot legally ferment and distill their own bioethanol at present (unlike in the U.S., where getting a [[BATF]] distillation permit has been easy since the [[1973 oil crisis]]).