Editing Methyl tert-butyl ether (section)

===As anti-knocking agent===
In the U.S. MTBE has been used in gasoline at low levels since 1979, replacing [[tetraethyllead]] (TEL) as an antiknock (octane rating) additive to prevent [[engine knocking]].<ref>{{Cite web |title=Overview {{!}} Methyl Tertiary Butyl Ether (MTBE) {{!}} US EPA |url=https://archive.epa.gov/mtbe/web/html/faq.html |access-date=2021-04-07 |website=archive.epa.gov |language=en}}</ref> Oxygenates also help gasoline burn more completely, [[Automobile emissions control|reducing tailpipe emissions]]. Oxygenates also dilute or displace gasoline components such as aromatics (e.g., [[benzene]]). Before the introduction of other oxygenates and octane enhancers, refiners chose MTBE for its blending characteristics and low cost.