List of U.S. Nuclear Sites Inadvertently Posted Online

A U.S. document containing sensitive details about hundreds of civilian nuclear sites across the country was posted online Monday, an apparently inadvertent security breach that had federal officials scrambling yesterday to remedy the mistake.

The document, a draft declaration of U.S. nuclear facilities to the U.N. nuclear watchdog agency, contained descriptions of sensitive civilian sites, including the locations of facilities that store enriched uranium and other materials used in nuclear weapons. It was available for about a day on a Government Printing Office Web site before inquiries by news organizations prompted its hasty removal.

Nuclear experts said it was theoretically possible that the document could benefit terrorists contemplating an attack on one of the facilities. Still, because the information was unclassified and most of it is publicly available through other sources, the release generally was deemed more embarrassing than harmful.

"It is probably not that dangerous, but it is a violation of the law," said David Albright, a former U.N. nuclear inspector and president the Institute for Science and International Security, a nonprofit research group in Washington. "You don't want this information out there, any more than you would want a thief to know the location of a vault in your house."

The 267-page draft document was intended as a formal declaration to the International Atomic Energy Agency as part of U.S. obligations under the nuclear Non-Proliferation Treaty. The Obama administration submitted the document last month to the House Committee on Foreign Affairs for technical review.

In a cover letter to Congress that accompanies the document and is posted on the White House's Web site, President Obama states that measures had been taken to "ensure that information of direct national security significance will not be compromised at any such site, location, facility, or activity" as a result of IAEA oversight of U.S. facilities.

The document does not contain information about the U.S. nuclear weapons stockpile, but it does divulge restricted information such as interior design features of nuclear facilities where fissile materials are stored.

The online appearance of the document was first reported on the blog Secrecy News, written by Steven Aftergood, a senior research analyst at the Federation of American Scientists. He noted that much of the draft's contents were designated "sensitive but unclassified."