Leaded gasoline was gradually taken off the U.S. market
A combination of health and environmental concerns led to a ban on the sale of leaded gasoline for most uses in the United States.
Mid-grade gasoline was introduced in 1986 as the United States began phasing out leaded gasoline. Most gasoline stations already had pumps for leaded, unleaded, and unleaded premium (also called high-test) gasoline.
Because leaded gasoline use was in decline, mid-grade gasoline was offered as an additional choice for motorists who wanted a higher octane gasoline than regular unleaded. Offering mid-grade gasoline was also a way to continue using all three pumps to sell three grades of gasoline.
Health hazards associated with lead have been documented since the early 1920s. The U.S. Surgeon General set a voluntary standard for lead content in leaded gasoline. The standard was raised in the 1950s.
The U.S. Congress adopted the Clean Air Act in 1970 and created the U.S. Environmental Protection Agency (EPA). The Clean Air Act set air quality standards that included a timetable for phasing out leaded gasoline.
The Clean Air Act also regulated automobile emissions of carbon monoxide, nitrogen oxides, and hydrocarbons for the first time. The automobile industry responded to these new standards by devising ways to reduce emissions such as developing catalytic converters, which convert harmful emissions into water, carbon dioxide, and nitrogen gas. Leaded gasoline damages catalytic converters.
By 1975, unleaded gasoline was universally available. Effective January 1, 1996, leaded gasoline was banned by the Clean Air Act for use in new vehicles other than aircraft, racing cars, farm equipment, and marine engines.
Last reviewed: November 19, 2020