Each individual radiation source (or container, if appropriate) shall be labeled with an identification tag clearly indicating the date, radionuclide (if applicable), quantity, and radiation or contamination level.  Labels are available from the Radiation Safety Office.  All tags or labels should be removed / replaced when the information on them is no longer applicable. Radioactive materials meeting the exemption criteria of 10 CFR 30 Appendix B and 105CMR129.297 do not need to be labeled.  Call the Radiation Safety Office for questions on the labeling of radiation sources.