Disparities in demographic and health indicators among communities by frequency of hazardous waste sites in Indiana, USA: differences by Superfund vs. brownfield classification.

Background: The location of hazardous sites is a known environmental justice issue, but impact of site classification (Superfund vs. brownfield) is less clear. The objective of this study is to determine whether demographic and health indicators are correlated with the prevalence of brownfield and/or Superfund sites in Indiana, USA. Methods: This is a cross-sectional, ecologic study using publicly available data on hazardous waste sites, demographics, and self-reported health status. Complete data were available for 1252 census tracts, with 2251 brownfield and 2264 Superfund sites. Adjusted Poisson and linear regression models were used to determine associations between hazardous site frequency with demographic and health characteristics. Results: Approximately 24% of census tracts had >3 Superfund or brownfield sites. Higher brownfield frequency was significantly associated with a higher nonwhite population (adjusted β=0.004, 95% confidence interval (CI): 0.002, 0.006); in contrast, more Superfund sites were significantly associated with a lower nonwhite population (adjβ=-0.006, 95% CI:-0.008, 0.004). Lower income was significantly associated with higher Superfund or brownfield site frequency. Results were consistent when limited to urban areas. Self-reported health measures were not associated with Superfund frequency. Census tracts with a higher number of brownfields were associated with a higher proportion of the population reporting poor general health (adjβ=0.057, 95% CI:0.010, 0.104) and poor mental health (adjβ=0.046, 95% CI:0.017, 0.075) compared to tracts without brownfield sites. Conclusions: These results concur with existing evidence on disparities related to the location of hazardous site; they additionally suggest these disparities may extent to how hazardous sites are classified.