Dr. DiGiulio is a senior research scientist at PSE Healthy Energy and an affiliate at the University of Colorado. He completed a BS in environmental engineering at Temple University, a MS in environmental science at Drexel University, and a PhD in soil, water, and environmental science at the University of Arizona. During his 31 years with the US Environmental Protection Agency (EPA), he conducted research on gas flow-based subsurface remediation, groundwater sampling methodology, soil-gas sampling methodology, gas permeability testing, intrusion of subsurface vapors into indoor air, subsurface methane and carbon dioxide migration, and solute transport of contaminants in soil and groundwater including that associated with hydraulic fracturing and pits used to dispose of oil and gas waste. He assisted in the development of EPA’s original guidance on vapor intrusion and the EPA’s Class VI Rule on geologic sequestration of carbon dioxide. The focus of his current work is on understanding the environmental impact from oil and gas development, especially in regard to surface and groundwater resources. He has served as an expert witness in litigation relevant to oil and gas development, has testified before state oil and gas commissions on proposed regulation, and has testified before Congress on the impact of oil and gas development on water resources.