Find out why leaded gasoline is no longer widely used.
Tetraethyl lead has been used for more than 40 years to improve the combustion characteristics of gasoline. It reduces or eliminates knocking (pinging caused by premature ignition) in high performance large engines and in smaller high compression engines. It provides lubrication to the extremely close fitting engine parts where oil has a tendency to wash away or burn off.
However, lead will ruin and effectively destroy the catalyst used in emission control devices installed in cars produced to use unleaded gasoline, so lead-free gasoline must be used.