Story at a glance
- In 2007, NASCAR traded leaded for unleaded fuel.
- Researchers studied academic performance at schools near two Florida racetracks before and after the switch.
- They found lead exposure yielded lower scores on a state-mandated exam in the early 2000s, but performance rose consistently after 2007.
Two researchers who like auto racing set out to learn whether leaded gasoline, which fueled NASCAR contests well into the 2000s, hurt academic performance at schools near racetracks.
Evidently, it did. Their study, centered on a pair of high-profile Florida speedways at Daytona and Homestead, found that test scores rose steadily in schools near the tracks after 2007, when NASCAR switched to unleaded gas.
“Lead damages the part of your brain that’s responsible for things like memory,” said Ivan Rudik, an assistant professor of environmental economics at Cornell, who co-wrote the paper with three colleagues. “You could imagine that’s super-important for performing well on tests.”
The study, published in October by the Journal of Human Resources, took advantage of a natural experiment that began with NASCAR’s decision to delead its fuel.
Researchers found that lead exposure lowered student proficiency rates by 4.4 percentage points on Florida’s state-mandated exam of the early 2000s, the Florida Comprehensive Assessment Test, or FCAT. They likened the effect to 16 weeks of lost instruction.
Test scores in schools near the Daytona and Homestead tracks rose consistently from the advent of lead-free NASCAR racing until 2014, when Florida changed its test.
The ill effects of lead on human brains is well-known. Another recent study estimates that leaded gasoline, alone, robbed Americans of a collective 824 million IQ points.
The Clean Air Act banned leaded gas in 1996 after two decades of declining use, a step now regarded as a public-health triumph. But the law exempted airplanes and race cars. Both industries depended on leaded fuel for engine performance.
“It’s hard to measure lead in planes, because they fly,” said Alex Hollingsworth, a health economist at Indiana University who co-authored the NASCAR study.
Racecars do not. The idea of studying them struck Hollingsworth in 2016. He went with a friend to the Teenage Mutant Ninja Turtles 400, a NASCAR event at the Chicagoland Speedway in Joliet, Ill.
“My friend had ‘hot passes,’ where you can go in the pit area,” Hollingsworth recalled. “I was picking pieces of tire off my sweater. I was just sitting there, breathing it in.”
From the track, Hollingsworth sent a text message to Rudik. They did an Internet search.
“And then we realized automotive racing had an exemption to the Clean Air Act,” Hollingsworth said. The researchers had found their next project.
“I was a really big NASCAR fan when I was a kid,” Rudik said. “My brother went to elementary school in Florida, and his school is in the data.”
The researchers found that a single NASCAR race emitted more than 10 kilograms of lead, as much heavy metal as a typical airport or factory might release in a full year.
The effect on test scores was strongest at schools within a few miles of the tracks, especially in areas with high poverty rates and large concentrations of Black students.
Students with more cumulative lead exposure suffered the steepest losses. Rudik and Hollingsworth estimate two years of lead exposure lowered average test scores by 17 points on the FCAT scale. Eight years of exposure lowered scores by 131 points.
The study found that lead exposure exacted a steep economic price. For a typical third-grader living within 50 miles of the track, researchers estimated a cost equivalent to a lifetime income reduction of $5,200. The figure draws on a well-established link between academic performance and future earning potential.
“Add up everything, you get a third of a billion in lost future income,” Rudik said. “This is relatively close to what people are estimating is the cost of the Flint crisis.”
When leaders in Flint, Mich., tapped the Flint River as a water supply in 2014 to save money, they exposed citizens to toxic levels of lead. Experts have estimated the lead poisoning that resulted could cumulatively cost $400 million in lost productivity and strains on the welfare and criminal justice systems.
Researchers have found childhood lead poisoning can haunt victims into adulthood. Children with elevated lead levels are more likely to fall behind in school, enter the juvenile justice system, be jailed as adults and/or to rely on public aid.
“People think this is a battle we fought and won, and it isn’t,” said Robert Fischer, an associate professor at the Jack, Joseph and Morton Mandel School of Applied Social Sciences at Case Western Reserve University, who has spent decades studying lead exposure.
Fischer said he admires the elegance of the NASCAR study.
“It’s a very clever natural experiment,” he said. “And to be able to tie it to children living nearby, and then thinking about kids’ exposure to these kinds of overwhelming amounts of lead in the air.”
The findings of the racetrack study are not unexpected. NASCAR abandoned leaded fuel under pressure from environmental groups. In a report at the time, the Environmental Protection Agency warned that leaded fuel “may pose a serious health risk to some subpopulations such as residents living in the vicinity of racetracks, fuel attendants, racing crew and staffs, and spectators.”
During the leaded-fuel days, doctors found excess lead in the blood of NASCAR crew members.
More than a decade later, researchers continue to study the echoing effects of lead in communities near the tracks.
In a 2020 study, Hollingsworth and Rudik linked leaded fuel to higher mortality rates in surrounding counties. They estimate the phaseout of lead at racetracks lowered mortality by 91 deaths per 100,000 people in counties with tracks.
Another group of researchers published a study this year that linked the Charlotte Motor Speedway in North Carolina to lower birth weights in babies born to mothers who lived near the track in the 2000s. Higher birth weights mean higher survival rates.
No one in Daytona Beach thought much about lead emissions from the racetrack in the old days, said Alycia Severson, who grew up there.
Severson attended Mainland High School, which sits along International Speedway Boulevard, just east of the track. She later taught English at the school.
“We went to the track,” she recalled. “Back in the day, they had a gate around the back. My dad would take us down there,” to patrol the gate in exchange for free admission.
“Maybe we all got poisoned a little bit. I don’t know.”
The Daytona Beach community greeted the NASCAR lead ban with little fanfare, Severson said. The speedway sparks many conversations in Daytona, but not about air pollution.
“There’s noise pollution from the track,” she said. “I think that bothers the locals more than anything.”
Greg Gimbert, a longtime Daytona resident, helps run a Facebook forum for Volusia County parents. He questions the validity of the NASCAR study, starting with its reliance on the FCAT.
Like many high-stakes tests, the FCAT became mired in the politics of academic accountability. Some principals pressured teachers to teach to the test. Some teachers cheated. Neither Gimbert nor Severson considers the abandoned test a particularly meaningful measure of student growth.
“To try to lay these gains at the foot of NASCAR, respectfully, seems laughable,” Gimbert said.
Of the researchers and their hypothesis, he quipped, “You might as well study the difference between people who use charcoal and gas grills.”
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