The Environmental Information Management Plan provides an overview of the integrated approach to managing the Hanford Site environmental data. The Environmental Data Management Center has been established to ensure that all environmental information is retrievable throughout the lifetime of the environmental programs. Part I of this Environmental Information Management Plan addresses the methods by which environmental information is processed into a working file management system with an emphasis on retrievability. File categories have been established to accommodate compilation of Administrative Records and to provide a central reference file location for all environmental information. The Environmental Data Management Center coordinates the Administrative Record activities, ensuring distribution of Administrative Record Indices and Administrative Record documents to the US Environmental Protection Agency, Washington Department of Ecology, and four information repositories. Part II addresses the long-range plan for management of scientific and technical environmental data. The planning and control activities affecting data are discussed. These activities include data collection, analysis, integration, transfer, storage, retrieval, and presentation. The tasks described in Part II will result in definition of policies, procedural systems, and automation components necessary to ensure that environmental data are accessible, traceable, and sufficiently qualified to meet future needs. 4 figs., 9 tabs.