The invention of the internal combustion engine is easily one of the more significant modern innovations of our time. However, early automobiles had a bit of a problem. Without going into too many boring details of how engines work, the basic problem was engine knocking, which is when compressed gasoline auto-ignites rather than getting set off by the spark plug. Engine knocking hurt fuel efficiency and could damage engines. About the only way to counter the problem was to use expensive higher octane fuels, which as one can imagine, did little to increase car sales. This all changed in 1921, when scientists with General Motors discovered that adding lead to gasoline completely removed the knocking problem, allowing for the increased use of cheaper and lower octane fuels. The industry was overjoyed. Car ownership in the United States slowly rose over the next several decades, but really took off after World War II thanks to the fact that the U.S. was the only major industrial power to come out of the war largely unscathed. The resulting economic boom allowed for the fulfillment of the American dream, part of which was everyone and their damn dog owning a car. Things were great, at least until a bunch of pesky scientists began pointing out a few problems.
Starting in the 1950’s, scientists began noticing elevated levels of lead in blood tests. Over times these levels continued to rise, quadrupling by the 1970’s. This was a bit concerning given that the dangers of lead exposure had been pretty well understood since the early twentieth century. Lead based paint had become widely popular in the U.S. at the time thanks to its cheap price, but growing warnings about its toxicity had led to a sharp decline in its use starting in 1920. For the scientists, the new source of lead seemed pretty obvious, what with every tail-pipe in the country belching it out, but it took years of studies to finally convince people that something had to be done. The clincher were studies done in the 1970’s showing that children exposed to lead were more likely to develop learning disabilities, have lower IQs, be more aggessive, and have less impulse control for the rest of their lives. Nothing fixes a problem quite like bringing the children into it. Under popular pressure, the U.S. government created new emission standards that over time forced the fuel and automobile companies to find alternative additives to stop engine knocking that weren’t so fucking terrible. Unleaded fuels were first introduced in 1979, leading to a rapid decrease in the use of leaded fuels, which were made outright illegal in 1996.
Now that might be very well the end of the story, but it’s not. For the rest, we also have to look at other things happening at the same time. Starting in the 1960’s, the violent crime rate in the United States began to rise rapidly, doubling by 1970, and then doubling again by 1980. The rapid rise in violent crime caused panic as people began to become convinced that society was coming apart at the seams. Those who were able to fled urban areas where crime rates were higher. Government officials and the public scrambled for answers; blaming counter cultural elements like hippies, drug use, and the collapse of the traditional American family and values. Vast amounts of money were spent creating and implementing new policies and strategies, but nothing worked. By 1990, violent crime rates were five times higher than they had been in 1960. It seemed as though nothing could be done, but then, for seemingly no reason whatsoever, crime rates began to drop, almost as fast as they had risen.
Of course a lot of eggheads and policy makers claimed various reasons why the crime rate dropped, but none of the explanations really held up to sustained analysis and the passage of time. It wasn’t until recently that the connection started to be made which hopefully you’ve already figured out. Studies have since shown that lead emission from automobiles can explain 90 percent of the variation in violent crime 20 years later. Generations of kids born into a world with air chocked full of lead particles led to problems that manifested when they became teenagers and young adults. It has been shown that children exposed to lead over their lives are more prone to behavioral problems as a child, pregnancy and aggression as a teen, and criminal behavior as a young adult. Similar correlations between lead exposure and crime have been shown to fit for state data, city data, and even neighborhood data. Though data is less available, some studies have also shown a connection between the rise in use of lead paint in the early twentieth century and the crime wave of the late 1920’s and early 1930’s. It wasn’t just a U.S. problem either. Every country in the world used lead in their gasoline, and though when it was phased out varies, the correlation holds true.
It is frightening to think about how much one thing can affect the world. The overexposure to lead during the mid-twentieth century did not create the world we live in, but it was certainly a factor, the effect of which we will undoubtedly debate and conjecture about for years to come. Pet theories about why crime rates increased abound; including drugs, poverty, the counterculture, and so much racist bullshit. Human behavior is caused by a broad swath of interconnecting inputs all affecting each other in real time, and while it might be fun to try to simplify a problem into a single issue, it just can’t be done. The world is far too complex for such things. However, that being said, how much more likely are issues to arise in a world where being dumb, mad, and impulsive is more likely? We may never fully know, but given the plethora of studies that have come out, it seems fair to say that the rise and fall in leaded gas did have an affect on the rise and fall in crime in the developed world in the late twentieth and early twenty-first centuries. If that holds true, it brings up an interesting question of what the future may hold. Though the developed world phased out leaded gas in the 1980’s, most of the developing world did not until the 1990’s and 2000’s. What does the future hold for them, not just in the area of crime, but also in terms of civil wars and terrorism? Only time will tell.