America experienced a massive increase in levels of violent crime, ranging from 1960, to its peak in 1990, then steadily declining. Though many theories are in place to explain this peak and decline in crime, Kevin Drum of Mother Jones has provided compelling evidence and statistics; all of which points to one simple idea: violent crime rose as a result of lead poisoning because of leaded gasoline.
The chemistry and neuroscience of lead gives us good reason to believe the connection. Decades of research has shown that lead poisoning causes significant and probably irreversible damage to the brain. Not only does lead degrade cognitive abilities and lower intelligence, it also degrades a person’s ability to make decisions by damaging areas of the brain responsible for emotional regulation, impulse control, attention, verbal reasoning, and mental flexibility.
It is scientifically noted that children exposed to high levels of lead in early childhood are more likely to have lower IQs, higher levels of aggression, and lower impulse-control. All those factors point to crime when children reach their teens if not earlier.
Between 1976 and 1986, the Environmental Protection Agency required oil companies to phase out leaded gasoline. In 1978, lead in residential paint was banned (though most pre-1978 buildings still have lead paint, which children can absorb).
Tests have shown that the amount of lead in Americans’ blood fell by four-fifths between 1975 and 1991. A 2007 study by the economist Jessica Wolpaw Reyes contended that the reduction in gasoline lead produced more than half of the decline in violent crime during the 1990s in the U.S. and might bring about greater declines in the future. Another economist, Rick Nevin, has made the same argument for other nations. He collected lead data and crime data for Australia and found a close match; same for Canada, Great Britain, Finland, France, Italy, New Zealand and West Germany.
As Drum reports in his article, leaded gasoline, though totally banned, still lurks and still has adverse affects on our children. The fact of the matter is that the leaded gasoline fumes settled into soil, especially in heavy traffic areas. And, the issue we’re faced with is that lead in soil doesn’t stay in the soil. Every summer, like clockwork, as the weather dries up, all that lead gets kicked back into the atmosphere in a process called resuspension.
And just like gasoline lead, a lot of that lead in old housing is still around. Lead paint chips flaking and old windows whose friction surfaces generate lots of dust as they’re opened and closed.
Drum’s conclusion is that solving our lead problem will do more than any prison could do to reduce our crime problem—it would produce smarter, better-adjusted kids in the bargain.
Cleaning up the rest of the lead that remains in our environment could turn out to be the cheapest, most effective crime prevention tool we have. And we could start doing it tomorrow.