Historical Redlining and Cumulative Environmental Impacts across the United States

Environmental regulation of single pollutants likely underprotects communities disproportionately burdened by multiple, overlapping environmental hazards. We investigate whether historically redlined neighborhoods across the US are exposed to cumulative environmental inequities today. We overlaid 1930s-40s Home Owners’ Loan Corporation maps of 202 US cities from the Mapping Inequality project onto EPA EJScreen data to analyze whether a collective, simultaneous, IQR increase in 12 environmental hazards (various air pollutants and toxic facility proximities) was significantly associated with higher odds of a neighborhood having been historically redlined (D-grade) using a boosted regression tree model. Controlling for neighborhood socioeconomic status, a collective, simultaneous, IQR increase in 12 environmental hazards was associated with 1.30 (95%CI: 1.17–1.46) times higher odds of a neighborhood having been historically redlined. Proximity to hazardous waste and wastewater discharge sites, traffic volume, and diesel particulate matter were the most pervasive environmental hazards in historically redlined neighborhoods. Cumulative environmental inequities were largest in the Western US by region and in Oklahoma City, Cincinnati, and Detroit by city. We find that historically redlined neighborhoods may be disproportionately impacted by cumulative environmental impacts. Environmental regulation of single pollutants may not be sufficiently protective of historically marginalized communities, which may help us understand why contemporary environmental health disparities persist today.