Abstract: The Department of Energy’s Environmental Management (DOE-EM) program manages approximately $6B/year in decommissioning, environmental restoration, and waste management projects. The DOE-Environmental Management Consolidated Business Center (EMCBC) Office of Cost Estimating & Project Management Support (EMCBC-OCE&PMS) has developed ECAS into a comprehensive, web-accessible database that includes actual costs, waste generation, and other parametric data on over 278 projects from sites across the country. The data is normalized and applies the Environmental Cost Element Structure (ECES) to make project data generally applicable, with standard project types, code of accounts (to differentiate types of work), cost elements, and additional descriptive information to better support a variety of applications. OCE&PMS uses the data to support it cost estimating and analysis functions. ECAS provides a system with detailed reporting of data to enable users to develop estimates for future projects, establish benchmarks, and promote improved cost control and cost management. We discuss how this approach can be used for application in other industries.