The article states that the addition and later removal of lead in gasoline is responsible for a large part of the rise and decline of violent crime:
Put all this together and you have an astonishing body of evidence. We now have studies at the international level, the national level, the state level, the city level, and even the individual level. Groups of children have been followed from the womb to adulthood, and higher childhood blood lead levels are consistently associated with higher adult arrest rates for violent crimes. All of these studies tell the same story: Gasoline lead is responsible for a good share of the rise and fall of violent crime over the past half century.
On first glance, most of the cited data seems to be about finding a correlation between lead and violent crime, the causative link seems to be much weaker. While it might be plausible that lead poisoning has some effect on later violent behaviour, I find it hard to believe that a major part of the increased crime between 1960 and 1990 was caused by lead.
Is there strong evidence, preferably not only correlations, that show that lead poisoning is responsible for a large part of the rise and fall of violent crime in the United States?