32 CFR 2400.11: Duration of classification.
(a) Information shall be classified as long as required by national security considerations. When it can be determined, a specific date or event for declassification shall be set by the original classification authority at the time the information is originally classified.
(b) Automatic declassification determinations under predecessor Executive Orders shall remain valid unless the classification is extended by an authorized official of the originating agency. These extensions may be by individual documents or categories of information. The originating agency shall be responsible for notifying holders of the information of such extensions.
(c) Information classified under predecessor Executive Orders and marked for declassification review shall remain classified until reviewed for declassification under the provisions of Executive Order 12356.
(d) Information classified under predecessor Executive Orders that does not bear a specific date or event for declassification shall remain classified until reviewed for declassification. The authority to extend the classification of information subject to automatic declassification under predecessor Orders is limited to those officials who have classification authority over the information and are designated in writing to have original classification authority at the level of the information to remain classified. Any decision to extend this classification on other than a document-by-document basis shall be reported to the Director of the Information Security Oversight Office.