https://en.wikipedia.org/wiki/Tetraethyllead https://en.wikipedia.org/wiki/Tetraethyllead > It is a fuel additive, first being mixed with gasoline beginning in

https://en.wikipedia.org/wiki/Tetraethyllead https://en.wikipedia.org/wiki/Tetraethyllead > It is a fuel additive, first being mixed with gasoline beginning in the 1920s as a patented octane rating booster that allowed engine compression to be raised substantially. This in turn increased vehicle performance and fuel economy.