Ethyl gasoline first goes on sale, at roadside gas station Dayton, Ohio

“Unleaded Gasoline” is one of those ubiquitous signs that we all read but never pay any attention to. Yet almost every gas station carries some sign or sticker on a pump calling their gas “unleaded.” The changeover is still new enough to warrant the sign: before its total phaseout in the mid-80s, lead was in fact a gasoline additive to prevent “engine knock” — improper combustion in the engine cylinders that wore out engines and caused poor fuel efficiency. One of the longest trends in automotive history – one that continued for the better part of six decades – began with the first test sales at a small gas station in Dayton, Ohio.

On this day, February 2nd, in 1923, a new brand of reddish-looking gasoline called “ehtyl,” for the tetra-ethyl lead compound it contained, went on sale at the Refiners Oil Company, owned by a friend of one of ehtyl’s inventors, on the corner of sixth and main streets. Several years later, DuPont began mass-producing it for General Motors.

Subsequent ads promoted lead gasoline’s superiority to regular gasoline in increasing durability of car engines and improving fuel efficiency. What they did not mention was the active ingredient, lead, was widely known to be toxic to humans. In fact the engineer that first started working on lead alcohol in December 1921 had to greatly curtail his activities a year later because of ill health due to lead poisoning. Nevertheless, leaded ethyl alcohol was used nationwide until 1986.