Project Summary Unconventional oil and gas development (UOGD), commonly referred to as hydraulic fracturing, has expanded rapidly over the past decade, leading to an estimated 4 million people living within one mile of a hydraulically fractured well. Despite the widespread nature of the industry, little is understood about the risks and exposures to individuals living near UOGD facilities. Due to the chemical- and water-intensive nature of UOGD, drinking water contamination by UOGD fluids and wastewater and the resulting potential for children living near UOGD to be exposed to chemical carcinogens are major public health concerns. Approximately 30 epidemiologic studies of UOG published to date, including two on childhood cancer, have relied on proximity-based spatial surrogates to ascertain exposure. While proximity-based metrics may serve as useful surrogates for collectively capturing numerous potential stressors of UOGD (e.g., air pollution, stress), their correlations with specific environmental measurements, such as concentrations of water contaminants, is unknown. In the proposed project, we will apply drinking water monitoring and epidemiological data to evaluate exposure to carcinogenic compounds related to UOG and improve our understanding of childhood cancer risk from UOGD. We will use measurements in drinking water samples we collected from >250 residences in Pennsylvania and Ohio to evaluate the relationship between commonly used spatial metrics as well as a newly developed water vulnerability model and drinking water concentrations of carcinogens. We will also examine whether the spatial surrogates are more strongly correlated with drinking water contaminant concentrations with the addition of other covariates, such as UOG well age, depth, and phase of development. Using these traditional and newly developed exposure metrics, we will then conduct a population-based case- control study investigating the association between UOGD exposure and risk of childhood leukemia in Pennsylvania and Ohio. My overarching hypothesis is that UOGD releases carcinogenic chemicals that may increase risk of childhood cancer. We expect that this work will provide important information on the potential health effects of exposure to carcinogenic compounds related to UOGD, as well as evaluate several available methods to assess this exposure. Such information can be used to guide public health policy and inform public health interventions, environmental monitoring, and future studies on UOGD exposure. This work will also support my development as an independent researcher conducting policy-relevant environmental health and exposure studies, with a focus on impacts to women and children.