Many individuals are exposed to multiple toxic chemicals that contribute to the same adverse health impacts. However, these co-exposures and community vulnerability to exposures are not often considered in chemical assessments and regulations. In this study, we develop an approach to identify the potential co-exposures of chemicals causing similar adverse health effects and community vulnerability where these exposures occur. Co-releases of toxic chemical pairs in the same health endpoint groups were assessed from the U.S. Environmental Protection Agency’s Toxics Release Inventory (TRI). Comparative impacts from toxic chemical releases that occur in overburdened communities were conducted using the Climate Vulnerability Index (CVI). Analysis of variance (ANOVA) was used to determine if the magnitude of releases was significantly different between facilities releasing one or multiple chemicals, and ANOVAs with post hoc Tukey’s Honestly Significant Difference were performed to determine if CVI scores were significantly different depending on endpoint group or chemicals. This study found the occurrence of TRI co-releases of chemical pairs causing similar health effects ranges from 0% to 72%, with high co-releases in similar volatile organic compounds and metals. Facilities releasing multiple chemicals released statistically significantly higher amounts of these chemicals from 2017 to 2022 than facilities that release only one chemical—over 285,000 lbs. more on average ( p < 0.0001). Additionally, chemicals such as vinyl chloride and hexachlorobutadiene are released frequently in more vulnerable communities, with the CVI of communities near these chemical-releasing facilities being 8%–16% greater on average. This study provides an approach for identifying toxic chemical co-releases and community vulnerability where chemicals are released, which can aid state and federal agencies in prioritizing chemicals for assessment and regulation based on their potential for cumulative risks in overburdened communities, scoping for cumulative risk assessments, and identifying opportunities for co-benefits to at-risk communities.
Varner et al. (Wed,) studied this question.