Information Security Oversight Office (ISOO)

Frequently Asked Questions on Identifying and handling Classified Records in Private Papers


It is not uncommon for non-governmental repositories to discover classified records among their manuscript collections. The accessioned papers of former federal employees as well as those of prominent scientists and research entities who interacted with the U. S. government occasionally contain information marked CONFIDENTIAL, SECRET, or TOP SECRET. Archivists in universities and colleges, research institutions, state archives, and historical societies frequently uncover these records and are unsure—even afraid—of how to handle them. Fortunately, there are established means, codified in the Code of Federal Regulations, for non-governmental repositories to properly safeguard and to obtain the declassification of these records, as appropriate. This information paper will help you recognize classified material in your collection and deal with it in the right way.

Question #1 - What is Classified National Security Information?

Classified national security information is information created or received by an agency of the federal government or a government contractor that would damage national security if improperly released. Since 1940, the President has managed the system of classifying information by executive order (E.O.); the most recent order concerning classified national security information is E.O. 13526, signed by President Obama on December 29, 2009.

Information can only be classified if an official determination is made that its unauthorized release would damage the national security. Levels of classification correspond to levels of supposed damage. E.O. 13526 specifies that information whose release would cause “exceptionally grave damage to the national security” is classified TOP SECRET; information whose release would cause “serious damage” is classified SECRET; CONFIDENTIAL is the lowest category of classified information currently in use. RESTRICTED is an obsolete category that was discontinued in 1953.

Classified information may take any form. Though paper documents are most common, there are classified photographs, maps, motion pictures, videotapes, databases, microfilms, hard drives, CDs, etc. Regardless of medium, classified information requires protection until it is formally declassified.

The Federal Government's current system of marking and controlling security-classified information dates from World War II. Very little pre-1941 information still meets the criteria for continued classification. Only very specific information dating from before 1942 controlled by the National Security Agency regarding signals intelligence, by the United States Secret Service regarding the protection of the President, and by the U.S. Mint concerning the gold bullion depository at Fort Knox remains classified.

Question #2- How does Classified Information end up in Private Collections?

Former government officials and contractors have been known to retain papers containing classified national security information and to eventually donate them to private archives. Often, it is not until these records are formally processed that archivists realize a collection contains classified information. If an archives or a library has not received Federal approval to store classified materials, continuing to store the records in an unapproved area could be endangering national security. In these instances, the institution should contact the Information Security Oversight Office (ISOO) at the National Archives and arrange for these records to be securely stored. ISOO will maintain temporary custody of the records through the declassification process.

By contacting ISOO you will be respecting the access restrictions placed on that information by the U.S. government. ISOO, in turn, will respect the rights of your institution to maintain the integrity of collections of donated personal papers.

Question #3- How can I identify Classified National Security Information?

There are three basic tests which you can apply to determine whether a document contains classified information:

  • The information should concern the national security of the U.S. government. If the document was created by a private organization or a state government agency, it may contain classified national security information only if the organization or agency was serving as an agent of the Federal Government. Defense contractors and research laboratories are obvious examples. Also, the information should not concern personal, private, or purely political issues. Over the decades many documents have been stamped “Confidential” not because they would damage national security if released, but to indicate some other type of sensitivity. When in doubt, though, consider the document as classified.
  • There should be a classification marking on the top and bottom of every page of the document. Very old documents may have the markings only on the top of the first page. In more recent documents, individual paragraphs may also be marked with markings like “(S)” for Secret or “(C)” for Confidential.
  • The document should not be marked as declassified. A declassification marking should look like an official stamp that indicates the name and office of the person who authorized the declassification action. A copy of a declassified document from the National Archives and Records Administration should include a marking that includes a project number starting with “NND” or “NW.”

While these are the primary means of identifying classified information, those who suspect they have classified materials in their collections should also be careful to examine documents for:

  • “Restricted Data” and “Formerly Restricted Data” markings. These designations refer to categories of classified information concerning nuclear weapons design and utilization. Despite the misleading nature of the phrase “Formerly Restricted Data,” documents with this marking remain sensitive and must be protected.
  • Unmarked Classified National Security Information. Records of national security officials should be reviewed and handled carefully, as the classification marking requirements were not always executed on informal records such as handwritten notes. In all cases, it is the sensitivity of the information that determines classification. An unmarked, handwritten page can just as easily contain classified national security information as a document containing classification markings. When in doubt, treat handwritten notes concerning intelligence, military, diplomatic, or emergency planning matters as classified national security information.
  • Declassification Dates. Some documents may have been originally marked with a date on which the document may be declassified. These dates are useful in determining the relative sensitivity of the information contained in the document, but occasionally these markings are erroneous or invalid. Remember that regardless of markings, only a U.S. government declassification authority can declassify classified information.
  • Foreign Government Information. Foreign governments routinely share classified information with the U.S. government. Foreign government information received by a U.S. government agency with a promise of non-disclosure should remain protected, but in some cases information may be declassified and released. Many foreign markings resemble U.S. markings.
  • Controlled Unclassified Information. Federal agencies have designated some types of information as requiring a degree of control that does not rise to the level as that for information that would damage national security if released. These types of markings include “For Official Use Only,” “Limited Official Use,” or “Sensitive but Unclassified.” These types of markings do not designate classified national security information. Archivists processing papers containing U.S. Government information should not release out for social security numbers for living people, health care information, and other personal information collected from private citizens.
  • Closed Congressional Information. Archivists processing the papers of former congressmen should be aware that the rules of the U.S. Senate and the House of Representatives restrict public access to certain types of closed committee and investigative records, regardless of whether they contain classified national security information, for up to 50 years.
  • Codeword Information. Since World War II, when the British used the word “Ultra” to designate intelligence obtained by cracking the German Enigma encryption machine, the most sensitive types of information of the U.S. government has been identified by special codewords. These include intercepts of encoded enemy radio signals, information about satellite reconnaissance programs, and human intelligence programs. If you see words like “Umbra,” “Talent-Keyhole,” “Ruff,” or “Gamma” on records also carrying a “Secret” or “Top Secret” classification marking, you should realize that you have in your collections something particularly damaging to national security if improperly released, regardless of the age of the records.

Question #4- How is Classified National Security Information stored and protected?

If you discover classified materials in your collection and your institution does not have federally approved secure storage, immediately remove the records from public review and restrict access to as few staff members as possible. Until they are ready for transmittal to ISOO, the records should be locked in a safe, filing cabinet, or other secure area.

Question #5- How is Classified National Security Information transmitted?

Transmittal requirements for classified materials vary depending on the classification level of the information they contain. In all instances, the use of street side mailboxes is prohibited.

CONFIDENTIAL materials may be sent via U.S. Postal Service certified, first class, express, or registered mail or government courier service.

SECRET materials may ONLY be sent via U.S. Postal Service express or registered mail or government courier service.

When mailing materials to ISOO, please adhere to the following guidelines:

  • Wrap the body of records in opaque paper. Heavy brown paper or brown mailing envelopes are best. CONFIDENTIAL and SECRET materials may be wrapped together.
  • Seal all seams with filament tape.
  • Address the package to:

Director, Information Security Oversight Office
National Archives and Records Administration
700 Pennsylvania Avenue NW, Room 100
Washington, DC 20408

  • Provide a return address.
  • Label the front and back of the package with the highest classification marking of the documents it contains.
  • Wrap the entire package ONCE MORE in opaque paper.
  • Again, address the package to the Director of ISOO as indicated above and provide a return address.
  • On this outer wrapper, do NOT write the classification level of the materials contained within.
  • Again, seal all seams with filament tape.

TOP SECRET materials may NOT be sent via U.S. mail and may only be transmitted by authorized government courier service. ISOO can make the necessary arrangements on your institution’s behalf.

ISOO staff will give more detailed instructions regarding the shipment of classified records and regarding the temporary retention of records by ISOO pending declassification.


Government policies dictate that any piece of classified information is “owned” by the Executive agency which created it, even if the record itself is no longer (or never was) in the custody of that agency. Agencies determine the ongoing sensitivity of their information, or “equity,” and mandate its protection accordingly. Declassification is a determination that information would no longer damage national security if released, and no longer warrants withholding from the public.

The issue of multiple equities complicates the declassification process. The minutes of an interagency meeting, for example, can contain the equities of several agencies. Declassifying such a document requires the review and concurrence of all equity-holding agencies. Often these equities are not immediately discernible to non-specialists in declassification.

It is generally unwise for private archival institutions to attempt to contact what they believe to be the equity-holding agencies directly. By contacting agencies directly, archival institutions may encounter agency staff unfamiliar with the declassification process and with the rights of institutions whose collections contain donated personal papers.

As the Federal office responsible for overseeing the classification and declassification actions of the Government, ISOO is experienced at evaluating classified records, identifying agency equities, and coordinating declassification on behalf of non-governmental repositories. For this reason, the Code of Federal Regulations designates the Director of ISOO as the point of contact for classified information in the custody of private organizations or individuals. Section 2001.36, “Classified information in the custody of private organizations or individuals,” of 32 Code of Federal Regulations (C.F.R) Part 2001 details this responsibility.

Question #6- How do I file a Mandatory Declassification Review (MDR) request?

If ISOO determines that the records provided require declassification review by equity-holding agencies, a non-governmental repository will be encouraged to file a Mandatory Declassification Review (MDR) request. The request should come in the form of a formal letter to the Director of ISOO explaining that the institution is filing an MDR for those records furnished to ISOO for temporary custody. ISOO will then contact all equity-holding agencies and provide them with copies of the records for their review.

Question #7- How do I find out the MDR Results and Appeal Options?

ISOO will communicate the results once all agencies have completed their reviews or after one year’s time, whichever comes first. If an institution is not satisfied with the results of an agency’s review, it may appeal the agency’s initial determination. If an agency or agencies fail to review the records within a year, ISOO will notify the requesting institution of its right to appeal directly to the Interagency Security Classification Appeals Panel for a final determination on the records’ classification status.

Contacting the Information Security Oversight Office (ISOO)

Phone: 202-357-5250
Mailing Address: Information Security Oversight Office
National Archives and Records Administration
700 Pennsylvania Ave., NW, Room 100
Washington, DC 20408

Updated March 8, 2013