Under a microscope, scientists could see the lead-laden particles flecking the blades of grass, pine needles, and even animals’ fur. All bore traces of lead pollution, much of it from car exhaust in San Francisco and Los Angeles. Patterson, a geochemist, trekked to a site about 10,000 feet up in California’s Yosemite National Park to collect samples. That same year, just a few hours’ drive from Meyer Elementary and Reid-Hillview, a pioneering scientist named Clair Patterson at CalTech was raising the alarm about how pervasive lead was in the environment. Amid heavy industry lobbying, the panel concluded that the absence of acute poisoning offered “no good grounds for prohibiting the use of gasoline” while admitting the possibility of “chronic degenerative disease of a less obvious character.”īy 1970, more than 200,000 tons of lead were pumped into the atmosphere annually, settling like a metallic mist over the surface of the Earth. In 1925, the US surgeon general convened a committee to render a verdict about its safety.
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The additive was so toxic, even a splash on the skin could be lethal.īut it solved the engine-knocking problem. But humanity didn’t enter uncharted territory until the first gallon of gasoline was sold with tetraethyl lead in 1923. Modern humans carried levels of lead about thousands of times higher than their prehistoric ancestors by the 20th century.
Lead pollution had been rising for millennia. “It’s not worth entering, but it’s not worth giving up.” “It’s a nice business,” says the former executive. Profit margins on avgas are around 80 cents per gallon, roughly 20 times more than conventional gasoline, says a former oil executive involved in its production. The avgas market is dominated by about eight US refineries and one (troubled) UK company producing the world’s supply of tetraethyl lead. Although the oil industry sells only a small volume each year-less than a day’s worth of automobile gasoline-leaded fuel is far more profitable. But getting lead out of avgas turned out to be more than a technical challenge.įor refineries, avgas is a lucrative product. Solving the lead problem in aircraft meant solving detonation, something Braly was uniquely positioned to do. The most powerful aircraft, which burn the majority of avgas and emit the most lead, still need the higher octane that lead provides to fly safely. The average piston-engine aircraft in the US is around 50 years old very few are retired each year.
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