MTBE is a Four Letter Word

The Clean Air Act of 1990 started the ball rolling with regard to reformulated and oxygenated gasolines and their impact on air quality. These requirements were area- and seasonal-specific. Reformulated and oxygenated gasolines were intended to reduce hydrocarbon emissions that contributed to smog. Oxygenated gasoline was also intended to reduce carbon monoxide emissions during the winter. Reformulated and oxygenated gasolines were generally confined to urban areas while conventional gasoline was sold in the rest of the nation. On top of these Federal requirements, states could impose their own limits, creating a gasoline boutique in the United States where gasoline specifications varied by location and season.