1352753 (Pinder). A credible quantitative assessment of the risk of hydrofracking fluids used for gas production impacting the environment does not exist. Rather, there are a few ?worst case scenario? evaluations obtained using mathematical models. However, this approach provides no estimate of the probability of a potable aquifer being impacted by hydrofracking fluids. To fill this knowledge gap the PI proposes to create and apply, through a proof of concept example, a new risk-assessment methodology that allows for the specific calculation of the probability that potable water supplies above a selected area of the Marcellus shale will be impacted by hydrofracking fluids. He will use a fault tree, and to a lesser degree an event tree, in his analysis because the system failure criterion is known and therefore of interest are the events that could contribute to its occurrence. Through a formal risk assessment he will provide a quantitative statement, for the proof of concept geological site addressed, of the probability of an unacceptable impact of hydrofracking on potable water supplies. The result will inform the debate regarding this environmental risk and bring it to a more intellectually informed level. Moreover, by examining those factors that impact the risk, such as geological formation integrity, strategies can be formulated to minimize that risk. This project will provide an objective, quantitative assessment of this environmental risk that can form a basis for discussion. There will be disagreements about whether one probability value or another is appropriate for some steps in the fault tree analysis, but if the research community agree on the methodology, significant progress will have been made. The PI can subsequently look at the sensitivity of the selected probabilities on the risk, and this will provide one possible basis to propose appropriate investments for gathering more complete information as needed. Relative to broader impacts, the PI initiated a new program at the University of Vermont (UVM) for minority recruitment in engineering which has been very successful. This program is designed to attract outstanding undergraduates from historically black high schools to UVM to increase the ethnic diversity in engineering. Students selected for this program spend one week on the UVM campus where lectures are provided on various aspects of engineering. One broader impact goal of this project is to create and deliver a stand-alone unit for the on-campus program on the role of engineering in the debate on hydrofracking; one lecture will be dedicated to the science and engineering of hydrofracking and the other to the analysis of the environmental risk of this process. The students will be asked to provide an assessment of the project. A form will be provided to each student to evaluate how beneficial the lecture was. Additionally, the general public seeks to know the risk to potable water supplies of hydrofracking. The calculations that will be made using this approach will, for the first time, allow for an actual quantification of the risk of hydrofracking fluids reaching potable aquifers. A non-technical lecture will be designed to bring hydrofracking in general, and the risk concepts developed by this project in particular, to college students that are non-engineers.