U. S. Department of Energy (DOE) prepared this draft Environmental Assessment (EA) to evaluate the potential environmental consequences of providing financial assistance in a cooperative agreement with Big Sky Regional Carbon Sequestration Partnership (BSCSP). If DOE decides to provide funding, in accordance with the terms of the cooperative agreement, BSCSP plans to test the injection of 1 million metric tons of carbon dioxide (CO2) over a four year project injection period into the Duperow formation in Kevin Dome. BSCSP would drill up to five production wells, one injection well, and four wells for monitoring. The project would also involve construction of a compressor station, five miles of roads, and six to ten miles of stainless steel pipeline, as well as various monitoring activities. Two activities, a three dimensional, nine-component seismic survey and some air and water baseline sampling, were allowed to proceed before this document was completed under an interim action request. However, the seismic survey work ceased after the seismic crews caused inadvertent adverse effects to cultural resources, and inclement weather caused postponement of the environmental monitoring. Under the terms of the financial assistance agreement, BSCSP has also initiated some desktop studies and administrative work that would have no effect on the environment (BSCSP, 2012a). DOE's proposed action evaluated in this draft EA is to provide approximately $63.8 million in financial assistance in a cost-sharing arrangement to BSCSP. The total cost of the proposed project would be approximately $81.4 million. This EA evaluates the environmental resource areas DOE commonly addresses in its EAs and identifies no significant adverse environmental impacts for the proposed project after mitigation.