California Air Resources Board

SACRAMENTO – The California Environmental Protection Agency's Air Resources Board (ARB) today approved a regulatory change that increases the amount of ethanol that can be used in California's cleaner-burning gasoline.

       "California is committed to providing refiners with alternatives to the use of the additive MTBE in our state's gasoline," ARB Chairman Barbara Riordan said.  "This is a small but noteworthy action that provides refiners with additional flexibility if they decide to use ethanol instead of MTBE in cleaner-burning gasoline."

       The board's action allows California gasoline to contain up to 10 percent ethanol by volume.  Previously, ARB had limited ethanol to 6.5 percent by volume in gasoline.  The board's action requires gasoline with the higher ethanol levels to provide the same air-quality benefits as other cleaner-burning gasoline formulations.  The board also encouraged ARB staff to work with the ethanol industry to find new ways to utilize ethanol in California's cleaner-burning gasoline program.

       MTBE and ethanol are the two most widely used oxygenated additives that help gasoline burn more cleanly.  Federal law requires gasoline in Southern California and the greater Sacramento area to contain oxygenates.  In other parts of the state, ARB regulations allow refiners to reduce or eliminate their use of oxygenates as long as their gasoline provides the required clean-air benefits.  Refiners can choose MTBE, ethanol or several other oxygenates, but most California gasoline contains MTBE.

       ARB's cleaner-burning gasoline requirements, which took effect in 1996, require all California gasoline to produce 15 percent fewer smog-forming emissions and to be about 40 percent less toxic than conventional gasoline.  While providing flexibility on the use of oxygenates, ARB regulations also require gasoline to evaporate less readily and contain reduced levels of high-polluting fuel components, including sulfur, benzene, aromatic hydrocarbons and olefins.

       The board's action is the latest in a series of steps ARB is taking to increase options for the use of non-MTBE gasoline.  In August, the board eliminated special wintertime oxygenated gasoline requirements for much of the state.  In 1999, ARB staff will conduct a comprehensive review of the cleaner-burning gasoline program and will look for opportunities to provide greater flexibility on oxygenate use.  ARB is also supporting elimination of the federal requirement for oxygenated gasoline in California.