Prior to the lead phase-out in gasoline, the total amount of lead used in gasoline was over , tons per year. Congress passed the Clean Air Act in , setting in motion the formation of the EPA and, ultimately, the removal of lead from gasoline.
EPA estimates that between and , 68 million children were exposed to toxic levels of lead from leaded gasoline alone. The phase-out of lead from gasoline subsequently reduced the number of children with toxic levels of lead in their blood by 2 million individuals a year between and The EPA is formed and given the authority to regulate compounds that endanger human health. Lead damages the catalytic converters used in these new vehicles to control tailpipe emissions. Catalytic converters are still used in vehicles today.
Lead is still used in some aviation fuels. Thanks to coordinated efforts, lead is now absent from gasoline in most of the world. Following the lead phase-out in the United States, the oil refining industry chose to construct additional refining capacity to produce octane from other petroleum products, rather than from renewable sources such as ethanol.
RFG has an increased oxygenate content, which helps it burn more completely. As a result, RFG lowers the formation of ozone precursors and other air toxics during combustion. Petroleum refiners were not required to use any particular oxygenate in RFG, but by the late s, a petroleum product, methyl tertiary butyl ether MTBE , was used in 87 percent of RFG due to its ease of transport and blending.
In the Midwest, ethanol was a more common component of RFG. Despite its success at reducing ozone precursors, MTBE was phased out of the gasoline pool due to concerns over its solubility in water, which resulted in the contamination of water resources in numerous states. Currently, 30 percent of gasoline sold in the United States is reformulated gasoline. Ethanol is providing the additional octane required by RFG.
At the time, the U. At the same time, EPA and the U. The BTEX complex is a hydrocarbon mixture of benzene, toluene, xylene and ethyl-benzene. Commonly referred to as gasoline aromatics, these compounds are refined from low-octane petroleum products into a high-octane gasoline additive.
While some volume of BTEX is native to gasoline, it is also added to finished gasoline to boost its octane rating. The total volume of BTEX aromatics in finished gasoline depends on the desired octane value and other desired fuel properties. Leaded gasoline was the primary fuel type produced and sold in America until The use of catalytic converters became necessary to meet stricter emissions regulations outlined in the Clean Air Act of , and leaded gasoline proved damaging to these devices.
In , catalytic converters were in and lead was out. New cars were sold with cats, hardened valve seats, and Unleaded Fuel Only labels. Eventually, leaded gas became illegal in roadgoing vehicles, first in California in and then nationwide four years later. The US didn't tax lead in petrol until the s, then finally banned it as part of clean air legislation, as the country moved down the far side of the environmental Kuznets curve.
Two decades later, in the s, rates of violent crime started to go down. There are many reasons why this might have happened, but the economist Jessica Reyes had an intriguing thought. Children's brains are especially susceptible to chronic lead poisoning. Is it possible that kids who didn't breathe leaded petrol fumes grew up to commit less violent crime? Reyes could test her hypothesis: different US states phased out leaded petrol at different times.
Other researchers have found similar links between lead water pipes and urban homicide. You can put a dollar figure on the value of crime reduction, Reyes found. It's about 20 times higher than the cost of de-leading petrol - and that's before you count other downsides of children breathing lead, like worse performance in school. It's a tale of disputed science and delayed regulation, much like you could tell about asbestos, or tobacco, or other products we now know slowly kill us.
The problem is that people who want to ban things aren't always disinterested visionaries like Hamilton. Sometimes they're obstructive cranks. The only way to tell the difference is by conducting studies. And, as Gerald Markowitz and David Rosner point out, "For the next four decades, all studies of the use of tetraethyl lead were conducted by laboratories and scientists funded by the Ethyl Corporation and General Motors".
How Diesel's engine changed the world. Battery bonanza: From frogs' legs to mobiles and electric cars. Why the falling cost of light matters. How a razor revolutionised the way we pay for stuff. And what of the scientist who first put lead in petrol? By all accounts, Midgley was a genial man who may even have believed his own spin about the safety of a daily tetraethyl lead handwash. But, as an inventor, his inspirations seem to have been cursed.
His second major contribution to civilisation was the chlorofluorocarbon, or CFC, which improved refrigerators, but destroyed the ozone layer. In middle age, afflicted by polio, Midgley applied his inventor's mind to lifting his weakened body out of bed. He devised an ingenious system of pulleys and strings. After World War II, economic growth, population growth, rapid suburbanization, and the closing of some public transit systems led to more reliance on personal vehicles for transportation.
The number of cars and trucks in the United States increased dramatically, as did the number of highways. One result of the rapid increase of motor vehicles was air pollution, especially in cities, that had serious impacts on public health and the environment. Congress passed the landmark Clean Air Act in and gave the newly-formed EPA the legal authority to regulate pollution from cars and other forms of transportation. EPA and the State of California have led the national effort to reduce vehicle pollution by adopting increasingly stringent standards.
The U. Reducing pollution from transportation sources has led to healthier air for Americans. In cities, smog has been visibly reduced. Just compare the images of New York City below.
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