ABSTRACT Children from underserved racial/ethnic backgrounds may have elevated exposures to flame retardant chemicals in their environments that threaten health and development from an early age. Although state governments have passed laws which ban polybrominated diphenyl ethers (PBDEs) due to neurotoxicity, children from underserved racial/ethnic groups may still encounter PBDEs, and preliminary evidence suggests that they may be exposed to larger quantities of PBDEs than White children (for example through older homes, secondhand and discarded furniture, clothing, and mattresses). Moreover, children’s exposure to chlorinated organophosphates (OPFRs) as flame retardants, and their developmental effects remains largely unknown. The proposed study will examine both the individual and cumulative effects of PBDEs and OPFRs. Additionally, relational and community factors such as social support and connectedness are predictive of health and wellness, especially for those from underserved racial/ethnic groups that experience daily isolation and discrimination. Research that examines joint influences of social and biological factors on cognitive development specifically with regard to environmental toxin exposure is essential. The overall objective in this supplementary grant is to examine racial/ethnic disparities in flame retardant exposures, and to quantify the effects of both flame retardant exposure and protective factors (relational and community) on children’s cognitive skills (executive function or EF) during preschool. The central hypothesis is that children with underserved race/ethnicity will experience higher levels of exposure to both PBDEs and OPFRs, which will be predictive of lower EF skills in preschool. Furthermore, relational and community protective factors among children and their parents will predict higher EF for children from underserved race/ethnic groups, controlling for flame retardant exposure. This study will be conducted within the parent study through additional literature review, analysis, and mentoring. The aims of this study expand upon those of the parent study. The expected outcomes are to have quantified racial/ethnic disparities in PBDE and OPFR exposure, and advanced understanding of potentially neurotoxic effects of such exposures, as well as supportive influences of relational and community protective factors among young children from racial/ethnic groups that have historically been underserved by society. Moreover, this project will prepare the candidate for an independent career to conduct research on protective factors that ameliorate potentially deleterious effects of environmental exposures among children from underserved racial/ethnic groups, such as cultural socialization and cultural identity.