The DEEP tool and user guide were developed as part of a project sponsored by Bureau of Ocean Energy Management (BOEM) to develop detailed estimates of the emissions associated with the future decommissioning of platforms in the Pacific Outer Continental Shelf (POCS) Region. DEEP is based on a series of phases associated with the future decommissioning of POCS Region facilities, including pre-abandonment, topside removal, jacket removal, debris removal and pipelines and power cable removal and provides emission estimates per facility for each of those decommissioning phases. Information used in DEEP was compiled based on past reports, interviews with equipment suppliers and current platform operators. DEEP generates the emissions estimates utilizing Excel spreadsheets. Some experience with Excel is useful to utilize DEEP. DEEP allows for the estimate of emissions for individual platforms as well as providing summary information for all the platforms located in the POCS.