WASHINGTON (Reuters) - In what officials admit is a major breach of security, a document describing design features intended to make a new Defense Departmentbuilding bomb-resistant has been posted on a public government website.

The document, comprising a 30-page narrative and hundreds of pages of technical data, describes bomb-proofing features which were incorporated in the structural design of the Mark Center, a new office complex inAlexandria, Virginia, Around 6,400 Defense Department personnel are scheduled to move into the building later this year.

One of the document's key points is raising eyebrows among some experts -- the building's level of bomb resistance.

According to the paper, the Mark Center is designed to resist threats posed by vehicle bombs detonated outside the building's security perimeter carrying the equivalent of 220 pounds (100 kg) of TNT.

That is far less than the amount of explosive used in recent attacks in the United States, including the 1993 bombing of New York's World Trade Center and 1995 bombing of the Alfred Murrah Federal building in Oklahoma City.

The top and bottom of every page of the 424-page document on the Mark Center is stamped "For Official Use Only" -- a label which is supposed to mean that the unclassified document will not circulate outside official channels.

But Reuters found a copy of the report posted on a public website maintained by theArmy Corps of Engineers. The Corps is responsible for the design and construction of a variety of government projects, ranging from office buildings to the flood defense structures meant to protect cities like New Orleans.

The report could be found on the Corps' public website nearly 24 hours after Reuters advised the Corps and top Pentagon officials that it had been publicly posted. Even after the Pentagon said the document had been taken down from the public website, a version could still be accessed in a Google cache.

A spokesman for the Corps, Ken Wells, said: "This should not have happened. We take it very seriously,"


Michael Greenberger, a former Justice Department lawyer who heads a Homeland Security institute at the University of Maryland, said the document is a "recipe for an attack. It should not be on the Internet."

The document would allow potential attackers to examine the building's bomb-proofing features to pinpoint weaknesses, according to Tom Thurman, a former FBI bomb disposal expert who now teaches security and emergency management at Eastern Kentucky University.

"If you know what all the defenses are, you plan the attack around those defenses," he said. The public posting of such a document is "inexcusable," he said, adding: "It's not something that should be on any unsecure government website whatsoever."

Another spokesman for Corps of Engineers Headquarters, Curry Graham, acknowledged the document had been mistakenly posted on a public website and that the government was doing all it could to take it down.

"You can pretty well tell it's an official document, 'for official use only,' from a contractor back to Corps officials," Graham said. "It looks like it was inadvertently published or put on our public site," he said, rather than on

password-protected sites the Corps uses to share sensitive information among contractors.

Graham said the document was dated 2009 and acknowledged it was possible the document has been openly posted on the web "since that time."

He said he did not know whether the document had been posted on the public website by a private contractor or by government employees. He said the Corps has "launched an inquiry into this to find out how it was posted."

The building whose design is examined in the publicly posted paper is a few miles south of the Pentagon, the Defense Department's headquarters. It was built alongside one of Washington's busiest highways, Interstate 395.

The building is comprised of 15-story and 17-story towers joined up to the 10th floor.


The Mark Center was meant to save money by consolidating Defense Department employees now scattered in office buildings around the Washington area. A publicly released fact sheet says the Army selected the Mark Center in part because it "provides the best resolution of security concerns."

The assessment said the building is designed to resist vehicle bombs carrying 220 pounds (100 kg) of TNT equivalent from outside the facility's security perimeter or a bomb of about 55 pounds (25 kg) of TNT-like material in a vehicle that gets inside the security zone.

Many bomb attacks involved much larger quantities of explosives.

An official report by the Federal Emergency Management Agency noted that the Oklahoma City bomb blast "was equivalent to the detonation of approximately 4,000 pounds (1,818 kg) of TNT."

A report posted on the website of the New York Police Department says that the vehicle bomb used to attack the World Trade Center in 1993 had the explosive power of 900 pounds (409 kg) of TNT, while the bomb used to blow up the U.S. MarineBarracks in Lebanon in 1983 had the power of 12,000 pounds (5,454 kg) of TNT.

Joanne Hensley, the Army Corps' deputy project manager for the building, said the decision to base the building's bomb-proofing design elements on the threat posed by a 220-pound bomb was a "judgment call by our experts."

She would not discuss further technical details.

(Editing by Kristin Roberts and Deborah Charles)

Source: Reuters US Online Report Technology News