The Effects of Short-Term, Prenatal and Postnatal Lead Exposure on Early Educational Outcomes:
Quasi-Experimental Evidence from NASCAR’s Deleading Policy

Ron Shadbegiana, Linda Buib, Heather Klemickc, Jennifer Tama, Anh Hoangd, Dennis Guignetea. San Diego State University; b. Brandeis University; c. US Environmental Protection Agency;
d. University of Notre Dame; e. Appalachian State University

Abstract
Lead (Pb), is a naturally occurring element, which can be toxic when absorbed by the bodythrough breathing, eating, or drinking. Exposure to any pollutant can have larger negativeeffects on children than adults, because their bodies are still growing and developing, whichputs them at increased risk. Moreover, children have higher exposures to certain pathways due
to behavioral patterns (e.g., hand-to-mouth). Lead poisoning can affect nearly every bodysystem; in particular, it can damage a child's central nervous system, kidneys, and reproductivesystem.
There is a rich and still-growing literature on the effects of early childhood lead exposure on
educational outcomes. There is consensus that early childhood lead exposure leads to deficits
in cognitive development (Miranda et al. (2007); Reyes (2015)), even at low levels of exposure(Bellinger et al. (1992); Lanphear et al. (2005); Miranda et al. (2007,2011); and Aizer et al.
(2018)). Adverse effects from low-level lead exposure on cognitive development have evenbeen shown to persist into later adolescence (Shadbegian et al. (2019)).
The link between early childhood lead exposure and cognitive development is well established,however the causal relationship between short-term, prenatal exposure to lead and cognitivedevelopment is less well understood. Various longitudinal cohort studies have established a link
between prenatal lead exposure and early cognitive development (Bellinger et al. (1987),
Schnaas et al. (2006)), though these studies often rely on relatively small cohorts of children.
It has been nearly 30 years since the U.S. EPA required the complete phaseout of leaded fuels in
automobile gasoline (1996). The National Association for Stock Car Racing (NASCAR), however,was granted an exemption for the use of leaded racing fuel under the 1990 Clean Air ActAmendments. How much lead emissions does a typical NASCAR race cause? For a single race,10,000 gallons are consumed during a race which includes practice and qualifying laps (Finney2006). Leaded gasoline content in racing fuels range from 2 – 6 grams/gallon. At 4grams/gallon, that suggests that if all of the lead is released, a single race could account for asmuch as 40kg of lead being emitted. NASCAR events usually involve several races of varying
types (stock cars, trucks, etc.) and distances during the same weekend. As a point ofcomparison, in 2005, the second largest emitter of lead emissions in the United States was aMissouri lead recycling facility, which released an average of 30.82 kg of lead per day.

Our study extends Bui et al. (2022), who exploit NASCAR’s voluntary switch to nonleaded racing
fuel in 2007, by linking individual births around the Charlotte Motor Speedway (CMS) in North
Carolina from 2004 to 2010 to their respective 3rd through 8th grade standardized math andreading exam scores. Our research design compares test scores of children born close to (e.g.,within 4 km) and far from (e.g., beyond 10 km) the CMS before and after the deleading of
NASCAR fuel, which allows us to causally estimate the relationship between short-term,prenatal and postnatal exposure to lead and educational outcomes. To minimize the likelihoodthat other potentially confounding factors will bias our estimates (i.e., our estimated effect ofprenatal lead exposure on educational outcomes is systematically incorrect), we include a set ofvariables that that can affect the educational outcomes (e.g., mother’s age, education, race;child’s gender). To further minimize the likelihood that our estimates are biased, we preprocess our data using a coarsened exact matching (CEM) algorithm prior to undertaking ourstatistical analyses (Iacus, King & Porro, (2012)). In our context, CEM is designed to match eachchild in the treatment group (i.e., those living near the CMS) with a child in the control group(i.e., those living far from the CMS), who has the same observable characteristic that could
affect educational outcomes. The variables we matched on were: child’s race; National Lunch
Program Participant; mother’s marital status, smoking behavior, and education level during
pregnancy; as well as grade-year indicators.
Our research is the first to exclusively investigate the effects of both prenatal and post-natal
exposure to lead on school performance. We find that prenatal exposure to lead has an
insignificant negative effect on both end-of-grade math and reading scores, whereas post-natal
exposure to lead has a significant negative effect on both end-of-grade math and readingscores. Importantly our previous research [Shadbegian et al. (2019)] showed that the negative
impact of lead exposure in early childhood on test scores persists through a child’s progression
from 3rd to 8th grade. This result indicates that physical maturation and additional schoolingare not sufficient to offset the damage caused by early childhood exposure to lead. Thus, ourresults highlight the need to develop effective public health interventions to continue to reduce
early childhood exposure to lead.