Quantifying sociodemographic inequities in exposure to point source carcinogenic industrial pollution emissions across the United States

Abstract

Background/Aim: Few studies have investigated how carcinogenic environmental exposures are distributed among the general population. We described recent cross-sectional relationships between carcinogenic industrial emissions and sociodemographic characteristics across the United States (US). Methods: We linked US Environmental Protection Agency’s 2018 Toxics Release Inventory to sociodemographic characteristics in 2010 Census tracts. Using chemical abstract service registry numbers, we identified onsite emissions (e.g., air, landfill, surface) of known and probable carcinogens as classified by the International Agency for Research on Cancer. Tract characteristics included total population, median household income, Yost neighborhood deprivation index, poverty, and percentages of Black, Hispanic, and white populations. We used linear regression to investigate the relation between quintiles of emissions in each census tract and distributions of these characteristics. Results: 5,209 (7%) tracts with an estimated 23.2 million population contained 7,028 facilities emitting known (n=22) or probable (n=33) carcinogens, including 1 billion pounds of these emissions in total (median: 226; IQR 7-5970 pounds/tract). Compared to tracts without emissions (all p-values <0.01), those with the highest quintile of emissions had higher proportions of rural (44% vs. 19%) and white (71% vs. 62%) populations, lower median household income ($45,000 vs. $55,000), and a higher deprivation score (62 vs. 49). Tracts with the highest emissions had a higher proportion of population with a high school education or less (53% vs. 44%). Overall, the proportions of families below the poverty level did not differ; however, greater numbers of black and white families below poverty lived in the tracts with the highest emissions. We observed similar demographic patterns in analyses restricted to air emissions. Conclusions: Our novel assessment demonstrates that carcinogenic emissions are not homogeneously distributed among the US population. It may be important to consider joint distributions of sociodemographic characteristics when describing environmental exposures and associated health disparities. Keywords: carcinogens, health disparities