The U.S. government classifies information that it determines could damage the national security of the United States if disclosed publicly. Currently, all classified information falls under two authorities, one for national defense and foreign relations, the other for nuclear weapons and technology. Beginning in 1940, classified national defense and foreign relations information has been created, handled, and safeguarded in accordance with a series of executive orders. Executive Order 12958, Classified National Security Information, as amended, is the most recent. It establishes the basis for designating National Security Information (NSI). It demarcates different security classification levels, the unauthorized disclosure of which could reasonably be expected to cause exceptionally grave damage (Top Secret), serious damage (Secret), or damage (Confidential). It also lists the types of information that can be classified and describes how to identify and mark classified information. In 2005, about one quarter of DOE classification decisions concerned NSI. The advent of nuclear weapons during World War II, led to a new category of classified information. In 1946, the Congress enacted the Atomic Energy Act, which established a system for governing how U.S. nuclear information is created, handled, and safeguarded. Nuclear information categorized as Restricted Data (RD) or Formerly Restricted Data (FRD) is not governed by Executive Order 12958. RD is defined as data concerning the design, manufacture, or utilization of atomic weapons; production of special nuclear material; and use of special nuclear material in the production of energy. This includes information about nuclear reactors that produce plutonium and tritium, radioactive isotope separation techniques, and the quantities of nuclear materials involved in these processes. FRD relates primarily to data regarding the military use of nuclear weapons. Examples of FRD include weapons stockpile data, weapon yields, the locations of nuclear weapons, and data about weapons safety and storage. Like NSI, classified nuclear information also has three classification levels: Top Secret, Secret, or Confidential. Naval Nuclear Propulsion Information (NNPI) is an exceptional category, which may fall under either of the two classification authorities. NNPI is deemed by both DOE and the Department of Defense (DOD) to be sufficiently sensitive to merit special protections and may be classified under the Atomic Energy Act or Executive Order 12958, depending on its subject and details. Two categories of nuclear information can be withheld from the public without being classified: Unclassified NNPI and Unclassified Controlled Nuclear Information (UCNI). Unclassified NNPI and UCNI are information the government considers sufficiently sensitive to withhold from public release, but not so sensitive as to warrant designation as RD, FRD, or NSI. UCNI is a category created under the authority of the Atomic Energy Act, which enables DOE officials to share information with state and local law enforcement and emergency services personnel who, while lacking security clearances, may have a legitimate need to know operational details about, for example, planned shipments of special nuclear materials. According to the current executive order, documents containing only NSI must be “portion marked,” for instance, classified paragraph-by-paragraph. For example, a document containing NSI may have paragraphs classified as Top Secret, Secret, or Confidential, along with others that are unclassified. However, documents containing any RD or FRD are classified in their entirety at the level of the most sensitive information in the document. Portion marking of documents containing RD and FRD is not required by the Atomic Energy Act and is discouraged by DOE policy. Executive Order 12958, as amended, states that NSI shall be declassified as soon as it no longer meets the standards for classification. The point at which information is to be declassified is set when the decision is made to classify it, and it is linked to an event, such as a completed mission, or to a period of time. Classified records that are older than 25 years and have permanent historical value are automatically declassified unless an exemption is granted because their contents still remain sensitive and their release could harm national security. Agencies have adopted processes to facilitate declassification in compliance with the executive order. Unlike documents containing NSI, documents containing RD or FRD are not reviewed automatically for possible declassification. The reason for this is that these two categories are mostly scientific and technical and may not become less sensitive with the passage of time. In fact, such data may be useful to nations and terrorist groups that are trying to build nuclear weapons. At a time of increased concern about nuclear proliferation, some of the oldest and simplest nuclear technology can be useful for making weapons of mass destruction. For this reason, documents about nuclear weapons and technologies from the 1940s and 1950s remain especially sensitive and worthy of protection. DOE implements the executive order and classification statutes by issuing departmental regulations, directives, and extensive use of classification guides. DOE’s directive, Identifying Classified Information, is the department’s comprehensive guide to classifying, declassifying, marking, and protecting information, documents, and material. The directive also establishes policies and procedures, such as departmentwide training and certification requirements for staff authorized to classify or declassify information, and for periodic self-assessments. Classification guides are manuals specifying precisely which DOE information must be classified, how it should be categorized (NSI, RD, or FRD), and at what level (Top Secret, Secret, or Confidential) it should be protected. DOE has a detailed and comprehensive set of classification guides that are integral to efficient functioning of the department’s classification activities. The department limits the use of “source documents” for the purpose of making classification decisions. Source documents may be used to classify documents containing NSI, but only when there is no guidance available. For example, if a DOE classifier is evaluating a new document with the same information found in another document already classified as Secret, then this new document may also be classified as Secret. RD and FRD documents can never be used as source documents. DOE’s Office of Classification’s systematic training, comprehensive guidance, and rigorous oversight programs had a largely successful history of ensuring that information was classified and declassified according to established criteria. DOE’s training requirements and classification guidance are essential internal controls that provide a strong framework for minimizing the risk of misclassification. However, since responsibility for classification oversight was shifted from the Office of Classification to the Office of Security Evaluations in October 2005, the pace of oversight was interrupted—creating uncertainty about how oversight will be performed and whether it will continue to be effective. Systematic training requirements are an important element of DOE’s framework for maximizing the proper classification of documents. Only staff that have successfully completed training are authorized to classify or declassify documents. Staff must be recertified as classifiers and/or declassifiers every 3 years, in order to retain their authority. Staff are typically trained as “derivative classifiers” and, in some cases, as “derivative declassifiers” as well. They are limited in their authority to those areas in which they have special knowledge and expertise and are only authorized to classify (or declassify) documents “derivatively”—that is, only if the document in question contains information a DOE or other U.S. government agency classification guide specifically requires be classified or declassified. There are currently about 4,600 derivative classifiers in DOE, nearly all of whom do classification work only as a collateral duty. For example, most derivative classifiers in DOE are scientists, engineers, or other technically trained people who work in programs or areas involving classified information that need staff who can properly classify the documents these programs produce. Relatively few DOE staff (just 215 as of May 2006) are authorized to declassify documents. Because a declassified document may become publicly available, derivative declassifiers are among the most experienced derivative classifiers. Only original classifiers, of which there are currently 25 throughout the DOE complex, are authorized to classify previously unclassified information. All DOE original classifiers are either very senior, full-time classification professionals, such as the director and deputy director of the Office of Classification, or one of the department’s top-level political appointees, such as the Administrator, National Nuclear Security Administration. DOE has developed an extensive collection of more than 300 classification guides, or manuals, specifying precisely which DOE information must be classified, how it should be categorized, and at what level (Top Secret, Secret, or Confidential) it should be protected. The Office of Classification oversees the regular updating of all classification guides used in DOE and must ultimately approve the use of every guide. DOE prohibits classification decisions based on source documents for documents containing RD and FRD and permits their use only when no guidance is available for documents containing NSI from other federal agencies. The Information Security Oversight Office considers the use of classification guides to be a best practice because they provide a singular, authoritative voice that is less open to individual interpretation or confusion than source documents and so using these guides are less likely to result in errors. According to the Information Security Oversight Office, DOE’s use of classification guides is among the most extensive in the federal government. Classification guides are integral to the efficient functioning of the department’s classification program. Some classification guides are more general in nature, such as those dealing with physical security, and are used widely throughout DOE. Others, known as “local guides,” are used at a few or even a single site because they provide guidance specific to a single DOE program or project. For example, a classification guide used by contractors working on a decontamination and clean-up project at a site in Oak Ridge, Tennessee, provides specific guidance on nuclear waste and storage unique to this site. DOE has also implemented an extensive and rigorous oversight program.