In 1999, the Governor of California released Executive Order D-55-99 that ordered the removal of Methyl Tertiary- Butyl Ether (“MTBE”) from California gasoline at the earliest possible date, but no later than December 31, 2002. In March 2002, the Governor extended the phase out for another year, until March 2003. MTBE is a chemical made of oxygen, but often is added to gasoline to boost its octane content, specifically to meet clean fuel requirements. The oxygen content in gasoline helps the gasoline burn more completely and reduce the harmful emissions from automobiles. MTBE has been used by the United States in different forms since 1979, and is a volatile clear liquid that dissolves easily into water. MTBE poses a health risk when it enters the drinking water supply from leaking underground storage tanks, pipelines, spills, emissions from marine engines into lakes and reservoirs, and minimally from air deposition.
Rao, Rekha. "Facing Arbitration for Environmental Regulation: Arbitration Under Chapter 11 of the North American Free Trade Agreement Between Methanex Corporation and the United States of America." Sustainable Development Law & Policy, Winter 2005, 66-67.