While not considered a security threat, the accidental public posting of a confidential listing of U.S. stores of nuclear material is considered a breach of information. Even though some of the information is already public:
David Albright, president of the Institute for Science and International Security, said that the information could "provide thieves or terrorists inside information that can help them seize the material."
"Somebody screwed up," Federation of American Scientists' Steven Aftergood, an advocate of open government who described the document's disclosure as a "net plus" from a public policy standpoint, said in an e-mail. "When the president declares a document to be sensitive on May 5, it is not supposed to show up on a government Web site on May 22. But that's what happened."
The breached document is described in CSO Magazine as:
is titled The List of Sites, Locations, Facilities, and Activities Declared to the International Atomic Energy Agency, and contains detailed information on hundreds of civilian nuclear sites in the country, including those storing enriched uranium. The report lists details on programs at nuclear weapons research labs at Los Alamos, Livermore and Sandia.
An interesting comment from the CSO Magazine article:
"Upon being informed about potential sensitive nature of the attachment in this document, the Public Printer of the United States removed it from GPO's website pending further review," the statement said. "After consulting with the White House and Congress, it was determined that the document including the sensitive attachment [should] be removed from the website," it added.
As noted, this isn't the first time that sensitive information has come out, and it probably won't be the last. But it also illustrates one of the reasons that "insider threats" represent dangers.