Mother Jones Jamaica started replacing leaded gasoline with unleaded in 1990 and banned leaded gasoline completelyin 2000. That's a pretty steep drop (it took the United States a full two decades to go from introduction to complete ban). So what you'd expect is a fairly steep drop in violent crime with a lag of 20 years—i.e., starting around 2010. What we got was a 40% drop in murder between 2009 and 2013. Pretty remarkable, no? It fits the lead hypothesis like a glove. Again: this is just murder, not violent crime in general. And all I have here is a horseback estimate of how quickly leaded gasoline was phased out in Jamaica. What I don't have is a time series of blood lead levels in small children going back to 1990. So don't take this too seriously. But don't dismiss it either. It's yet another data point that suggests leaded gasoline really does have a significant impact on violent crime.
