Criminal contaminant? Research suggests link between lead and crime rates
by Tim Lockette
For years, Ruth Ann Norton has been crusading against lead paint in old houses, an all-but-forgotten environmental hazard that still plagues poor communities.

Lately, though, Norton's work has developed a new twist. She's getting calls from public defenders representing young men accused of violent crimes.

"Lead is linked to the destruction of reasoning faculties, to a quick fuse and lower tolerance for frustration, " said Norton, director of the Maryland-based nonprofit Coalition to End Childhood Lead Poisoning.

Norton is one of a growing number of people who see a link between the amount of lead in the environment and the amount of crime in society. Armed with studies that draw on years of environmental and law enforcement data, lead-and-crime theorists say that the known effects of lead poisoning — lower intelligence, inability to regulate emotion and increased aggression — are the unrecognized force behind America's surge and decline in violence over the last century.

The theory has plenty of skeptics. But if it's true, it would have sobering implications for parents with young children in lead-contaminated housing. And for Anniston, it would be a hopeful sign. For decades, the city was contaminated with lead no one even knew about — and today, the city has a higher crime rate than the state as a whole.

With the cleanup of Anniston's lead sites now finished, can the city expect a decline in violent crime?

A link, but a cause?

Some scientists see the lead-and-crime connection as plausible but unproven. Others see it as strong and increasingly obvious.

"If you want to clean up the community, over time, you want to clean up the environment," said Howard Mielke, a research professor at the Tulane University School of Medicine.

Years ago, Mielke read one of the early studies linking crime in the U.S. to the use of leaded gasoline. Lead was introduced as an additive in gasoline to improve engine performance beginning in the 1920s. Lead gas use peaked in the early 1970s, then tapered off by the mid-1980s after its use was banned.

Rates of violent crime in America surged in the middle of the 20th century, with a peak in the early 1990s. It's been tapering off ever since.

Mielke was intrigued by studies that saw a connection between the two trends. Put lead in the atmosphere — damaging the developing brains of toddlers who ingest it — and two decades later, crime increases. Or so the theory goes.

Mielke took the studies down to the city level, looking at atmospheric lead levels and crime statistics for six major American cities, including Atlanta and New Orleans. In every city, he found that peaks and troughs in lead matched with peaks and troughs in arrests for aggravated assault 22 years later.

Mielke's not alone. He got the idea from people such as Rick Nevin, a government consultant who mapped not just violent crime but teen pregnancies nationwide in a similar way.

Nevin later looked at international numbers on leaded gas and crime and found the same trend. Another researcher, Jessica Wolpaw Reyes of Harvard, looked at crime trends in different states — some of which banned leaded gasoline before others — and found a link between the time of those bans and later drops in violent crime in each state.

"What we've found is that as much as 90 percent of the variation in the crime rate can be explained by the presence of lead," Mielke said. The idea isn't that lead causes most crime, he said — it's that most of the change in crime, from the rise in the turbulent 1960s, through the decline the country has seen since the 1990s, is due to lead poisoning.

Toxic town, crime city

Over the last 20 years, Alabama as a whole has enjoyed the same sharp decline in crime researchers are finding across the United States. In Anniston, though, the news isn’t quite as good.

According to FBI statistics, violent crime in Alabama peaked in 1992, with 36,052 violent crimes reported. Most were assaults; 455 were homicides. In 2010, there were only 18,052 violent crimes, including 322 homicides. That decrease happened while the state's population grew from 4.1 million to 4.8 million. That's roughly one violent crime per 114 people in 1992, and one per 265 people in 2010.

Those numbers match closely with nationwide numbers that show violent crime peaking in 1994.

Things in Anniston are a little different. Violent crime peaked here in 1993, with 984 violent crimes. In 2009, the last year for which the FBI has solid numbers, there were 584 violent crimes. But during that time, the city's population declined significantly, from 27,436 residents to 23,598. That's one violent crime per 28 residents 1993 and one per 40 residents in 2009. It's higher than the statewide rate, with less of a drop over the last 20 years. (Numbers were sharply lower in 2010, but the FBI says those numbers are underreported.)

And the city's homicide numbers have hardly moved. Eighty-four Model City residents died by violence in the 1990s, compared to 77 in the following decade.

The FBI warns against using its numbers to rank cities against one another, but it's clear that the city has a higher rate of violent crime than is typical of the state. Neighboring Oxford, with roughly the same number of residents, had only 135 violent crimes and no homicides in 2009, according to the FBI’s numbers.

Anniston has also, historically, had an abnormal amount of lead in its soil, a threat that remained even after leaded gasoline went away. That lead came from the foundries that were part of the core of the city's economy in the middle of the 20th century. Lead escaped from the smokestacks of foundries before emissions controls were put into place, environmental officials say. The lead spread beyond the range of those smokestack plumes when foundries unwittingly gave away ton after ton of lead-contaminated soil to local residents for use as fill dirt.

No one knew about the lead until residents began taking legal action against the chemical company Monsanto, which polluted the town with carcinogenic PCBs made at a plant in western Anniston. In testing 7,842 local properties for PCBs, environmental officials found that 675 of them had lead levels above the Environmental Protection Agency's acceptable threshold of 400 parts per billion. Most of those properties were clustered in western Anniston.

Much of that lead is gone now. For years, a group called the Foothills Community Partnership, funded by a legal settlement with the foundries that produced much of the lead, conducted a cleanup of the properties with 400 parts per billion or more. The partnership finished its work in 2010, and Foothills spokesman Tom Potts said the city is probably cleaner now than most industrial towns.

"Where we are right now, we're blessed with one of the cleaner environments in the U.S.," Potts said.

'Provocative' but more data needed

David Baker doesn't doubt that lead and other forms of contamination are affecting the behavior of young people in his neighborhood. Still, he thinks it would be hard to prove that lead is linked to the crime rate.

"It does cause a behavior problem, when you've got lead and these other things in your blood," said Baker, a leader of Citizens Against Pollution, a group that represents people affected by PCBs and lead left behind by Anniston's industries. "That's a study that's been out for years."

Baker said some people are going to be criminals in any neighborhood. And he said it's almost impossible to separate the effects of lead from western Anniston's other big problem: poverty. Polluting industries were located in Anniston because the people there were poor, he said. And the departure of many of those foundries left the city without economic hope.

"Once they moved out it left us desolate," he said.

UAB epidemiology professor Paul Muntner echoed some of Baker's sentiments.

"Is it a crazy idea? No," Muntner said of the lead-and-crime theory. "It's provocative. But I think I'd need stronger data."

The Star found Muntner by cold-calling Alabama epidemiologists. Muntner has done studies that found links between lead and diabetes, but hadn't delved into the lead-and-crime research until The Star sent him some of Mielke's work.

While the studies show that lead and crime seem to appear together, Muntner said, that doesn't prove that one causes the other.

But it's a finding that scientists find hard to ignore.

"It is rather compelling, and it's biologically plausible," said Mary Jean Brown, chief of the lead poisoning prevention division of the Centers for Disease Control in Atlanta.

Both Brown and Muntner said there's one piece of the puzzle still missing — research that follows individual children over a long period and compares their blood lead level to their actual criminal involvement. There is one study, which followed 250 Cincinnati children from early childhood through their teens and found that high blood lead predicted run-ins with the law later. Brown said she'd like to see more evidence.

There may not be enough data to map the lead-and-crime theory onto Alabama's landscape. Lead tests are commonly done on children whose families are on Medicaid, and high lead levels from those tests are reported to the Alabama Department of Public Health. Asked for county-by-county numbers, the department provided The Star with data going back to only to 2009 — not far enough in the past to weigh the numbers against current crime data. The department also tracks factors in each county that can cause high lead levels in kids — issues such as old housing stock painted with lead paint, industrial sources of lead and high numbers of rental housing units. (A homeowner in a lead-contaminated house could poison his own children; a lead-contaminated rental could poison multiple families in a single generation.)

Calhoun County had three risk factors. There were industrial sources of lead; more than half of the county’s houses were built before 1980, when lead paint was common; and more than one-sixth of houses were built before 1955, when lead content in paint was heavier.

But a number of counties had four or five risk factors, and some of those counties — such as Lamar and Franklin — didn't have high levels of violence.

Another problem with the theory is that Anniston isn't the only Calhoun County city with lead contamination. Anniston and Oxford are nearly the same size, and Oxford had about one-third as many violent crimes as Anniston in 2009. Yet Oxford didn't entirely escape Anniston's lead problem, with lead-contaminated properties clustered around a foundry there, said Pam Scully, a former EPA site administrator for the Anniston area.

No safe level

If a link between lead and crime does hold up, anti-lead campaigners say, it could change the way people think about the social problems of some of America's poorest, most polluted cities. If lead poisoning leads to a noticeable change in levels of crime, could it also be a cause of poor academic performance in schools? Norton, the anti-lead campaigner, thinks it's worth looking at.

"In the education community, this should be a concern," Norton said.

Officially, there were only 13 cases of lead poisoning among Calhoun County children in 2011, according to the Alabama Department of Public Health. That's compared to 47 lead-poisoned Anniston kids found in a Department of Health study conducted in association with the lead cleanup in 2000. That 2000 study found that Anniston's lead-contaminated sites posed "no apparent public health hazard" to the city.

But there's been a change in the way health officials look at lead levels. Until last year, health officials considered someone lead-poisoned if they had 10 micrograms of lead in every deciliter of their blood. In recent years, they cut that number in half. They also started calling the new 5-microgram limit a "reference level" — because their old system had people with fewer than 10 micrograms per deciliter thinking they were "safe."

Brown said the most recent research suggests that kids show evidence of cognitive problems well before they reach the 10-microgram level.

"We've never been able to find a safe level of lead," Brown said.

Of the entire population, 97.5 percent of people would have a blood lead level below the 5-microgram mark, Brown said.

"It's common to use that upper 2.5 percent limit for toxins that have no known safe threshold," she said.

It's not clear how many people in Anniston have blood lead levels above the new 5-microgram limit. In 2000, researchers took blood samples from 37 people living on Anniston's lead-contaminated properties. Not a single one was considered lead-poisoned by the standards of the time. But seven of the 37 had blood lead above the 5-microgram mark.

The new CDC standards have researchers such as Mielke calling for the EPA to tighten its standards for cleanup of lead-contaminated sites. He said people can suffer serious lead contamination from living on land with lead levels well below the 400-parts-per-billion used in Anniston's cleanup and other EPA projects.

"You should see change in crime over time if your cleanup is really successful," Mielke said. "But it probably isn't. The EPA hasn't changed their numbers, even though the CDC says no level of exposure to lead is acceptable."

Capitol & statewide reporter Tim Lockette: 256-294-4193. On Twitter @TLockette_Star.
© 2013