Planning and executing the safe shipment of radioactive materials is a complex process. The shipper must first have a thorough understanding of the material being shipped and must consider not only the isotopic makeup of the material but also the process that generated the material and the reason for the shipment. Physically identical materials may be regulated differently based solely on their source. The shipper’s knowledge of the material will also figure heavily in the selection of a package for the material, and the shipper may find that packaging requirements for transportation do not allow shipment in a package that was deemed perfectly acceptable for storage. Further, packaging requirements sometimes vary based on the mode of transportation selected, be it truck, rail, or vessel.