Withdrawal of Records from Public Access at the National Archives and Records Administration for Classification Purposes [open pdf - 201KB]
"Under the provisions of Executive Order (E.O.) 12958, as amended, 'Classified National Security Information' (the Order) and in response to a request from the Archivist of the United States as well as a group of concerned individuals and organizations, the Information Security Oversight Office (ISOO) performed an audit of all re-review efforts undertaken since 1995 by agencies in their belief that certain records at the National Archives and Records Administration (NARA) had not been properly reviewed for declassification, but had been made available to the public. The audit found a total of ten unrelated efforts to identify such records, which resulted in the withdrawal of at least 25,315 publicly available records; approximately 40 percent were withdrawn because the reviewing agency purported that its classified information had been designated unclassified without its permission and about 60 percent were identified by the reviewing agency for referral to another agency for declassification or other public disclosure review."
The National Archives: http://www.archives.gov