Leaded Gasoline: Convenience, Profit, and Forty Years of Denial

On 9 December 1921, General Motors engineer Thomas Midgley Jr. added a new compound to an engine that was knocking. Tetraethyl lead stopped the noise and allowed a higher compression ratio. Car makers received cheap fuel that made engines more powerful. Cities received a poison that would be released in exhaust for most of the century.

General Motors, DuPont and Standard Oil formed the Ethyl Gasoline Corporation to manufacture and market the additive. In 1923, “Ethyl” fuel was promoted as a technical breakthrough. The three leading drivers in the Indianapolis 500 used it, turning speed into a public safety advertisement. Because the name “Ethyl” kept the word “lead” away from the pump, drivers saw speed before they saw the poison. That combination of profit, branding and missing warnings made the product a public-health conspiracy before most drivers knew what they were breathing.