Background <p>Proximity to coal-fired plants exposes children to neurotoxic metals, which can negatively impact their behavioral health. Our research team previously reported an association between coal fly ash exposure and depression. However, other neurobehavioral outcomes have not been assessed. We hypothesized that the presence of fly ash would be associated with increased externalizing behaviors in children aged 6–14 years old.</p> Methods <p>This was a community-basedcross-sectional study. To investigate the association between externalizing behaviors and fly ash, five externalizing behavior scales and the composite Externalizing Problems scale from the Child Behavior Checklist (CBCL) were examined. Air samplers were placed in children’s homes to collect fly ash which was determined by scanning electron microscopy. Generalized linear regression with a negative binomial distribution and logistic regression were conducted to assess the association between fly ash and the results from the CBCL.</p> Results <p>Approximately 43% of children had detectable levels of fly ash in their homes. The odds of exhibiting clinically significant externalizing problems (t-score ≥ 65) after being exposed to fly ash was 2.66 times higher (95% confidence interval (CI) 1.08 to 6.57) compared to children who were not exposed. Though not statistically significant, Conduct Problems were 34% higher (95% CI: 0.885, 2.021) and Rule-Breaking Behavior was 22% higher (95% CI: 0.872, 1.696) among children exposed to fly ash compared to those who were not exposed.</p> Conclusions <p>Based on our findings, fly ash may be a potential risk factor for externalizing behaviors in children living near coal-fired power plants. While a cross-sectional study design does not provide the opportunity to prove a causal relationship, it can generate hypotheses that inform more rigorous epidemiological studies for further investigation of the observed associations.</p>