Methyl Tert-Butyl Ether is a gasoline additive that can leak into groundwater from storage tanks. It gives water an unpleasant taste and odor and may cause health issues.

Methyl Tert-Butyl Ether (MTBE) was widely used as a fuel oxygenate in gasoline from the 1980s to early 2000s to reduce air pollution. However, its high solubility and persistence in water led to widespread groundwater contamination, primarily through leaking underground storage tanks. MTBE is detected using gas chromatography. Even at low concentrations, it imparts a turpentine-like taste and odor to water. While its health effects are not fully understood, some studies suggest potential risks, leading many states to ban or limit its use in gasoline.