The UN reported this week that the world recently reached a major milestone: by ending use of leaded gasoline, which has been a major threat to the environment and public heath.
But why were countries using it the in first place, and why did it take so long to phase out?
Tetraethyl lead was added to gasoline beginning in 1922 to help engines run better. However, lead is poisonous to humans. Exposure can cause severe neurological damage, something that was known about the entire time that leaded gasoline was in use.
Nonetheless, leaded gasoline was the standard in the United States for decades. As with tobacco, companies with a stake in continued lead use—including General Motors—funded studies to create the false impression that leaded gasoline was safe, according to a BBC News story. Competition with leaded fuel was also one of the reasons E10 (a mix of 10% ethanol and 90% gasoline) failed to take off in the 1930s, only to come back decades later.
The U.S. began phasing out leaded gasoline in 1975 not for health reasons, but because it fouled catalytic converters, which were just then being mandated to reduce emissions.
Last holdouts for transition from leaded gas - March 2018 - UN Environment Programme
Leaded gas could be sold in the U.S. until January 1996—although by that time it was extremely rare and limited to classic-car and marine uses. Yet it remained available in other countries until July of this year, when Algeria ended sales of the fuel, according to the United Nations Environment Program (UNEP).
In all, 217 countries were still using leaded gas in 2002 when the UN started its campaign, focusing largely on Africa and developing countries. Africa has a long pattern of getting some of the world's filthiest fuel.
In addition to Algeria, Yemen and Iraq were among the last holdouts, according to a 2018 UN map.
Now that the world has finally said goodbye to leaded gasoline, perhaps we can envision a day when the last gallon of gasoline itself is sold. How long do you think that will take?