Link: "America's Real Criminal Element: Lead"
If it spreads along lines of communication, he says, the cause is information. Think Bieber Fever. If it travels along major transportation routes, the cause is microbial. Think influenza. If it spreads out like a fan, the cause is an insect. Think malaria. But if it’s everywhere, all at once—as both the rise of crime in the ’60s and ’70s and the fall of crime in the ’90s seemed to be—the cause is a molecule.
– Kevin Drum for Mother Jones quoting Karl Smith in http://m.motherjones.com/environment/2013/01/lead-crime-link-gasoline