Studies suggest that lead exposure may be to blame for an increase in violent criminal activity that began in the 1960’s. Leaded gasoline in particular has been suggested as the culprit.
In 1994, Rick Nevin, a consultant working for the US Department of Housing and Urban Development, began studying the correlation between lead exposure in young children, and problems later in life. Evidence was emerging that exposure to lead could cause children to suffer from behavioral issues, hyperactivity, and learning disabilities.
As reported by Mother Jones, further studies at the time explored the possibility that early exposure to lead may also be related delinquent behavior later in life. This possibility led Nevin to explore the correlation between lead exposure and violent crime.
Although the exploration began with paint, it later became clear to Nevin that the majority of lead exposure was not caused by paint, but rather leaded gasoline. Recorded atmospheric lead levels rose and fell dramatically along with the increased use of and the eventual discontinued use of leaded gasoline.
Interestingly, rates of violent crime follow the same pattern — almost exactly. Crime rates in the US rose and fell with the introduction and discontinuation of leaded gasoline. In 2000 Nevin released the results of the correlation between leaded gasoline and violent criminal activity:
“If you add a lag time of 23 years, lead emissions from automobiles explain 90 percent of the variation in violent crime in America. Toddlers who ingested high levels of lead in the ’40s and ’50s really were more likely to become violent criminals in the ’60s, ’70s, and ’80s.”
Nevin continued his research, and in 2007 released a study of crime trends around the world. It was Nevin’s intention to rule out coincidence in his previous study. In the second study, Nevin compared crime rates in the US with crime rates internationally, then compared those results with leaded gasoline exposure. The results confirmed the conclusion of his earlier work:
“Nevin collected lead data and crime data for Australia and found a close match. Ditto for Canada. And Great Britain and Finland and France and Italy and New Zealand and West Germany. Every time, the two curves fit each other astonishingly well.”
As reported by wired.com, the criminal activity of those exposed to lead is related to impulse control. Studies conducted over a period of decades have concluded that many adults who were exposed to lead as children lack impulse control and tend to act without considering consequences. The lack of control may lead to an increase in criminal activity or behavior.