Who would have thought that getting lead out of gasoline would have had such an apparently positive impact on reducing crime?
According to a WSJ article, rising levels of lead in the environment from the 1950s through 1970s, in large part due to leaded gasoline, was correlated with rising crime 20 years later. This is because toddlers, who often put their fingers in their mouths, ingested dirt contaminated by air pollution. By the time they were in their late teens and early twenties – the age when violence tends to peak – crime had risen.
Then in the 1970s came the prohibition of leaded gasoline. The article states, “As lead in the environment fell in the ’70s and ’80s—thanks in large part to the regulation of gasoline—violence fell correspondingly. No other single factor can account for both the inexplicable rise in violence in the U.S. until 1993 and the precipitous drop since then.”
It would be interesting to find out if the scientists and policymakers back then knew of the correlation between lead and crime. Probably not. Little did they know of the unintended positive effects of their actions.