1. What We Know, What We Don’t Know, and What We Need to Know about the Tradeoffs of Oil and Gas Development in the Western US AirWaterGas NSF Sustainability Research Network | www.airwatergas.org Mark Williams University of Colorado Boulder

2. AWG SRN Embedded Tech U Michigan UC Boulder Embedded Tech U Michigan UC Boulder Social-Ecological Systems Analysis UCB Water Quality CSPUP UCB Air Quality UCB NOAA NREL Water Quantity UCB CSU Health Effects CSPH Health Effects CSPH Analytical Laboratory UC Boulder Analytical Laboratory UC Boulder Policy and Practices UCB Oil and Gas Infrastructure CSM Outreach Education UCB UCAR Assessment UCB Data Management UCB Data Management UCB Water Treatment UCB CSM

3. Which compounds are of concern? hazardouspersistent mobile hazardous compounds that may reach drinking water Joe Ryan slide

4. What We Know  Small number of compounds of concern  a few dozen of concern, not a few hundred  Very low incidence of groundwater contamination  tens of thousands, a hundred thousand (?) oil and gas wells hydraulically fractured, only tens, hundreds (?) of water wells contaminated

5. What We Don’t Know  Unknown compounds  compounds from producing formations  proprietary compounds  efforts to reduce risk (e.g., CleanStim)  Contaminant properties at high temperature and pressure  up to 250  C (480  F), up to 10,000 psi  Flow paths  probabilities of the possibilities?

6. What We Don’t Know  Time  predictions less certain for longer time