A trip to the gasoline pump in the 1970s and 1980s was a choice between leaded or unleaded. Nearly 40 years later, we’ve learned that choosing unleaded not only made the environment cleaner but also the streets safer.
Researchers have made a link between the growing violent crime rates of the 1960s, ‘70s and ‘80s and exposure to the gasoline additive tetraethyl lead. Tetraethyl was introduced by General Motors in the 1920s to prevent pinging in automobile engines.
There are a host of theories attempting to explain the last half century’s surge and decline in crime. Some researchers suggest the decline in the demand for crack cocaine had an impact on crime. As young men saw how their families and communities were ravaged by crack, the drug fell out of vogue and the accompanying violence subsided.
Some attributed the decline to improved police strategies that rely heavily on innovative technology and evidence-based crime analysis. Others say soaring incarceration rates, along with longer sentences, have kept more criminals from plying their trade. America locks up more people for longer periods of time than any other industrialized nation.
Still others argue the graying of America means offenders are aging out of crime; legalized abortion has wiped out an entire generation of criminals; or the “Obama effect”— young African-American men see hope and opportunity now that America has elected, and re-elected, a black president.
Recently researchers have latched on to another possibility — cars. According to Karen K. Wolf in Chemical & Engineering News, automobiles exclusively burned leaded gasoline until 1973, when the Clean Air Act mandated that tetraethyl be removed from fuel. The phase out resulted in the introduction of unleaded gasoline and the catalytic converter.
Five years later lead based paint was banned. As a result, children born in the late 1970s and early 1980s grew up with less lead in their bodies than children born earlier. Children who reached adulthood in the 1990s have healthier brains and less of a penchant for violence than their predecessors.
According to Kevin Drum in Mother Jones Magazine, researcher Rick Nevin reviewed detailed data on lead emissions and violent crime rates in an effort to unearth a correlation. In research published in 2000, Nevin concluded that 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 1940s and ‘50s were more likely to become violent criminals in the 1960s, ‘70s and ‘80s.
Researchers were worried that the very broad connection between lead and violent crime could not be proven. There was no question that increasingly stringent Environmental Protection Agency rules, steadily reduced the amount of leaded gasoline used in America, but the reduction was not uniform. According to Drum, researcher Jessica Wolpaw Reyes of Amherst College dug into an analysis of the variation in the use of leaded gasoline among states.
Page 2 of 2 - Using state-specific reductions in lead exposure, states that removed lead quickly saw quicker reductions in crime and states that removed lead more slowly saw slower reductions in crime. In 2007, she concluded that the reduction in childhood lead exposure in the late 1970s and early 1980s is responsible for significant declines in violent crime in the 1990s, and continues to have an impact on crime rates.
If the lead theory is accurate — considering lead rates are down significantly — crime rates should have stabilized. A look at national crime rates over the last few years seems to support that hypothesis. According to the FBI, crime rates have moved an average of little more than three percentage points, up or down, in the last half dozen years.
Matthew T. Mangino is of counsel with Luxenberg, Garbett, Kelly & George P.C. His book, “The Executioner’s Toll, 2010,” is due out this summer. You can reach him at www.mattmangino.com and follow him on Twitter at @MatthewTMangino.