Research Links Lead Exposure, Criminal Activity - washingtonpost.com

Apparetnly, the biggest weapon in the fight against crime is banning lead, a neurotoxin. Research shows that "lead poisoning accounts for much of the variation in violent crime in the United States. [Studies have linked] children's exposure to lead with violent behavior later in their lives" and this association between lead poisoning and crime rates can be seen across decades and in nine different countries. Lead poisoning (typically from paint or gasoline fumes) leads to greater impulsivity and aggression that can lead to criminal activity.