Superfund Sites, Community Education, and Population Migration: An Econometric Analysis

Since its approval in 1980, the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), more commonly known as the Superfund Act, has been an important legal force in the effort to clean up toxic waste sites in the United States. However, hazardous waste remains a serious threat to human health and the environment. In some cases, the prospect of exposure to such hazards is enough to induce migration of residents away from a site and/or prevent others from moving in.

Several recent studies have used census data to investigate the relationship between population demographics and the presence of environmental health hazards, finding that certain demographic groups are more likely than others to move away from Superfund sites. Additionally, a recent study by Bennear et al. (2010) provides evidence that the form in which information about environmental health hazards is presented is important in determining the actions people take to protect themselves.

The following study explores the related questions of (a) whether migration patterns of people living in census tracts that contain Superfund sites differ across groups of residents with different educational backgrounds, and (b) if migration rates within these education groups depend on site characteristics such as the number of contaminants found on-site, the types of contaminants, and the severity of hazard that a site poses, as measured by a site’s Hazard Ranking System (HRS) score. In an econometric analysis of census data and site evaluation reports from the EPA, I find strong evidence of migration away from Superfund sites in all education groups, with slightly elevated rates among individuals with at least a college degree.

However, there is little evidence of responsiveness to site characteristics such as HRS score, number of contaminants present, and the proportion of contaminants at a site that are high-profile and recognizable. These results suggest that simply adding a site to the National Priorities List has a more significant impact on the characteristics of the surrounding population than specific details about the site’s contamination do, constituting a first step towards understanding how diverse communities respond to various types of information about Superfund sites.