This report presents preliminary operational guidelines and supporting work products developed through the interagency Operational Guidelines Task Group (OGT). The report consolidates preliminary operational guidelines, all ancillary work products, and a companion software tool that facilitates their implementation into one reference source document. The report is intended for interim use and comment and provides the foundation for fostering future reviews of the operational guidelines and their implementation within emergency preparedness and response initiatives in the event of a radiological dispersal device (RDD) incident. The report principally focuses on the technical derivation and presentation of the operational guidelines. End-user guidance providing more details on how to apply these operational guidelines within planning and response settings is being considered and developed elsewhere. The preliminary operational guidelines are categorized into seven groups on the basis of their intended application within early, intermediate, and long-term recovery phases of emergency response. We anticipate that these operational guidelines will be updated and refined by interested government agencies in response to comments and lessons learned from their review, consideration, and trial application. This review, comment, and trial application process will facilitate the selection of a final set of operational guidelines that may be more or less inclusive of the preliminary operational guidelines presented in this report. These and updated versions of the operational guidelines will be made available through the OGT public Web site (http://ogcms.energy.gov) as they become finalized for public distribution and comment.