14 CFR 1203.407: Duration of classification.

(a) At the time of original classification, the original classification authority shall establish a specific date or event for declassification based on the duration of the national security sensitivity of the information. Upon reaching the date or event, the information shall be automatically declassified. Except for information that should clearly and demonstrably be expected to reveal the identity of a confidential human source or a human intelligence source or key design concepts of weapons of mass destruction, the date or event shall not exceed the timeframe established in paragraph (b) of this section.

(b) If the original classification authority cannot determine an earlier specific date or event for declassification, information shall be marked for declassification 10 years from the date of the original decision, unless the original classification authority otherwise determines that the sensitivity of the information requires that it be marked for declassification for up to 25 years from the date of the original decision.

(c) An original classification authority may extend the duration of classification up to 25 years from the date of origin of the document, change the level of classification, or reclassify specific information only when the standards and procedures for classifying information under this Order are followed.

(d) No information may remain classified indefinitely. Information that is marked for an indefinite duration of classification under predecessor orders, for example, information marked as “Originating Agency's Determination Required,” or classified information that contains either incomplete or no declassification instructions, shall have appropriate declassification information applied in accordance with part 3 of this order.