Tetraethyl lead is an ingredient that was once commonly added to gasoline (also called petrol) to improve the performance of engines. Its widespread use exposed people around the world to toxic lead. Today, gasoline is almost always sold without tetraethyl lead.
Tetraethyl lead is considered an antiknock additive because it reduces the “knocking” or “pinging” sound that an engine makes. Knocking occurs when portions of the fuel in an engine cylinder ignite too soon, causing all of the fuel to burn too quickly. The same conditions that cause knocking also reduce an engine’s power and can damage the cylinders.
An engine that burns leaded gasoline (gasoline containing tetraethyl lead) gives off exhaust that includes chemical compounds containing lead. These compounds pollute the environment and expose people to lead. Exposure to lead causes dangerous lead poisoning.
In the 1970’s, automobile manufacturers in the United States began making cars with catalytic converters. A catalytic converter reduces the pollutants produced by the car’s engine. Because cars with catalytic converters required unleaded gasoline, governments and manufacturers began phasing out leaded gasoline.
By 2021, countries around the world had stopped using leaded gasoline in cars and trucks. However, fuel for certain vehicles, such as small aircraft, may still contain tetraethyl lead.
See also Gasoline; Gasoline engine; Lead; Lead poisoning; Octane number; Patterson, Clair Cameron.
