In the case of non-fissile or fissile-excepted uranium hexafluoride, the material must be classified under UN 2978. Uranium hexafluoride may be classified under this entry only if the conditions of §173.420 and §173.420 and §173.420 and §173.421 and §173.421, and, for fissile-excepted material, the conditions of §173.453 are met. In addition to the provisions applicable to the transport of Division 6.1 substances, the provisions of §173.421 and §173.443 apply. In addition, packages shall be legibly and durably marked with an identification of the consignor, the consignee, or both. No Class 7 label is required to be displayed. The consignor shall be in possession of a copy of each applicable certificate when packages include fissile material excepted by competent authority approval. When a consignment is undeliverable, the consignment shall be placed in a safe location and the appropriate competent authority shall be informed as soon as possible and a request made for instructions on further action. If it is evident that a package of radioactive material, or conveyance carrying unpackaged radioactive material, is leaking, or if it is suspected that the package, or conveyance carrying unpackaged material, may have leaked, the requirements of §173.443 apply.