What constitutes proper labeling for CUI in a physical environment?

• A. Mark only the exterior packaging.
• B. Labels are optional.
• C. Clear CUI designation on all containers/files and appropriate protective markings and handling instructions.
• D. Use generic labels with no designation.

Answer: (C)

Labeling for CUI in a physical environment requires making the designation and protection requirements visible on every item that contains or stores CUI. The best approach is to apply a clear CUI designation on all containers and files, and to include the appropriate protective markings and handling instructions. This ensures anyone handling, transporting, or storing the material knows its sensitivity and the safeguards that must be followed, reducing the risk of improper disclosure.

Marking only exterior packaging misses internal containers and contents, so it doesn’t guarantee protection once the item is opened or redistributed. Optional labeling leads to inconsistent safeguarding, and generic labels without a clear designation or specific handling instructions do not communicate the required controls.