Low-level ethanol fuel blends are sold in every state. In fact, nearly one-third of U.S. gasoline now contains up to 10% ethanol to boost octane or meet air quality requirements. All auto manufacturers approve the use of low-level ethanol blends because these fuels work well in gasoline engines and have no noticeable difference in vehicle performance.
The Clean Air Act Amendment of 1990 (and subsequent laws) mandated the sale of oxygenated fuels in areas with unhealthy levels of carbon monoxide. This kicked off the modern U.S. ethanol industry growth. Problems with groundwater contamination from the use of methyl tertiary butyl ether (MTBE)-the only other available oxygenate and principal octane booster-accelerated the use of ethanol in low-level blends.
The Energy Policy Act of 2005 established a nationwide renewable fuels standard requiring the use of 4 billion gallons of renewable fuel in 2006 and increasing to 7.5 billion gallons in 2012. The new standard gives fuel blenders flexibility to use ethanol or other renewable fuels and eliminates the previous 2% oxygen (5.7% ethanol) requirement for reformulated gasoline. Ethanol production was already well ahead of the new standard at the time of its enactment, with 2006 production of 4.9 billion gallons and use of 5.4 billion gallons.
