Image Credit: Ricardo Levins Morales

Researchers have known for decades that polluting facilities and waste sites are more likely to be located in low-income communities and communities of color, which makes these areas extra vulnerable to the environmental health impacts of pollution. However, we lack a clear understanding of how these disparities come to exist. Do the demographics in areas surrounding hazardous waste sites shift over time, or are polluting facilities placed disproportionately in low-income communities?

Researchers at the University of Michigan recently published two papers that attempt to answer this question. Their first paper is a review of previous studies on environmental injustice. According to Mohai and Saha, the study authors, previous research racial and socioeconomic environmental hazards have lead to contradictory findings. However, they also noted a major gap in the research. Most of the studies have been what they call “snapshot studies,” looking only at hazardous waste facilities and the populations that surround them at a single point in time, rather than looking at demographic change over longer time spans.

They used these longitudinal methods in their second paper, which was unique in a second way. Previous national-level environmental justice studies have used a method of assessment called the ‘unit-hazard coincidence’ approach. This means that demographics are analyzed within geographic units, like a census tract or zip code area, which also contains a hazardous waste site. “Not taken into account by this approach is the precise location of the hazard within the host unit,” Mohai and Saha write. Under this approach, effects on neighboring areas are ignored, which Mohai and Saha believe may lead to underestimating the degree of racial and socioeconomic disparities. Their study used a more precise distance-based method, rather than just looking at effects within arbitrary boundaries.

By analyzing a database of commercial hazardous waste facilities sited between 1966 and 1995, the researchers found strong evidence supporting the ‘disparate-siting’ hypothesis – that polluting facilities are disproportionately placed in low-income communities and communities of color. The researchers concluded that racial discrimination and sociopolitical factors are strongly at play in the siting of hazardous waste facilities. In other words, industries and governments are likely to take advantage of vulnerable areas lacking economic resources and political power, choosing the “path of least resistance” for deciding where our waste goes.

Mohai and Saha recommend more research to strengthen our understanding of these processes. Overall, their work highlights the political and social factors that proliferate patterns of environmental injustices, and asks us to take a closer look at how our government policies and industry practices reinforce racial discrimination.

Read the studies here and here.