Science & Technology

Why Did We Ever Use Lead In Gasoline?

Sometimes, you look back in time and say "What were people thinking?!" From townspeople executing "witches" to surgeons failing to wash their hands, 20/20 hindsight tells us that human history is full of moments when we really should have known better. Leaded gasoline is a perfect example. Why did we ever think dosing car fuel with a potent neurotoxin was a good idea? In fact, we did it to make cars safer.

Lesser of Two Evils

Long before the days of snazzy push-to-start ignitions, cars started via hand crank. To start your car, you had to attach a crank handle to the engine crankshaft, then turn it repeatedly until the engine got the energy it needed to run on its own. The only problem, besides the obvious physical effort required, was that crank engines were incredibly dangerous. If the engine kicked back while you were cranking, the handle could kick back, too — pummeling you in the process.

That's just what happened to auto manufacturer Byron Carter on one fateful April day in 1908. A woman's car broke down on a busy Detroit bridge, leaving her stranded. Carter kindly stopped to help the driver, but when he cranked the engine, it kicked. The crank shattered his jaw, and complications from the injury led to his death days later. Henry M. Leland, the founder of Cadillac, had been a close personal friend of Byron and swore that his company would build a crankless car to prevent tragedies like that from ever happening again.

Gulf Refining Company (later Gulf Oil) opened the first “drive-in” gas station in Pittsburgh in December 1913.

But that promise was slow going. With the help of inventor Charles Kettering, Leland made the 1912 Cadillac the first car to use an electric starter. But its engine was deafening. If you've ever heard the sputter of a car in an old cartoon, you know the sound of engine knock. It's the sound of pockets of air and fuel igniting when they aren't supposed to, and it's not only loud; it's also inefficient. It's usually caused by quirks of fuel chemistry, so Kettering and a scientist named Thomas Midgley Jr. set out to find the perfect fuel additive to stop the knocking.

Nearly a decade passed — and many additives failed — from the introduction of the first automatic-start automobile before experts found their solution in 1921. Tetraethyl lead, when mixed with kerosene fuel, made the engine purr.

A Known Risk

Soon, companies began manufacturing the new "ethyl" gasoline, and nearly as soon, workers in factories began hallucinating (at best) and dropping dead (at worst). How could they have known, you might ask? Science in the early 1920s was hardly primitive — Einstein had already published his famous theories on relativity, after all. To put it bluntly, they knew. They just didn't make it public. Scientists looked into the risks associated with lead in gasoline, but their industry funders required approval of their findings before they were published.

In 1925, Dr. Alice Hamilton testified at a government conference that when it came to lead, any amount was too much. "Where there is lead," she said, "some case of lead poisoning sooner or later develops, even under the strictest supervision." And this wasn't new information: In the first century, Pliny the Elder wrote that lead-sweetened wine cause "paralytic hands." Academics have cited lead poisoning as a cause of the fall of Rome. And all around the world, cities with lead pipes experienced more infant mortality than neighbors that used another metal.

It wasn't until the 1970s — after half a century of a country full of cars sputtering lead-laced fumes into the air — that lead was finally banned from gasoline in the U.S. It's made a big difference. The average blood lead level in the U.S. has dropped to barely detectable levels. One study found that preschool children in the 1990s had IQs up to 4.7 points higher than children in the 1970s. In the 1960s, more than 100 countries used leaded gasoline; today, only three do. Mistakes can be devastating, but sometimes, we bounce back.

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Learn more about the discovery of and fight against this toxic enemy in "Toxic Truth: A Scientist, a Doctor, and the Battle over Lead" by Lydia Denworth. We handpick reading recommendations we think you may like. If you choose to make a purchase, Curiosity will get a share of the sale.

Written by Ashley Hamer September 18, 2017

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