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Missteps in the Bunker

"We had a continuous workload in maintaining" warheads, said Scott Vest, a former Air Force captain who spent time in Minot's bunkers in the 1990s. "We had a stockpile of more than 400 . . . and some of them were always coming due" for service.

Among the many weapons and airframes, the AGM-129 cruise missile was well known at the base as a nuclear warhead delivery system carried by B-52s. With its unique shape and design, it is easily distinguished from the older AGM-86, which can be fitted with either a nuclear or a conventional warhead.

Last fall, after 17 years in the U.S. arsenal, the Air Force's more than 400 AGM-129s were ordered into retirement by then-Defense Secretary Donald H. Rumsfeld. Minot was told to begin shipping out the unarmed missiles in small groups to Barksdale Air Force Base near Shreveport, La., for storage. By Aug. 29, its crews had already sent more than 200 missiles to Barksdale and knew the drill by heart.

The Air Force's account of what happened that day and the next was provided by multiple sources who spoke on the condition of anonymity because the government's investigation is continuing and classified.

At 9:12 a.m. local time on Aug. 29, according to the account, ground crews in two trucks entered a gated compound at Minot known as the Weapons Storage Area and drove to an igloo where the cruise missiles were stored. The 21-foot missiles were already mounted on pylons, six apiece in clusters of three, for quick mounting to the wings of a B-52.

The AGM-129 is designed to carry silver W-80-1 nuclear warheads, which have a variable yield of between 5 and 150 kilotons. (A kiloton is equal to the explosive force of 1,000 tons of TNT.) The warheads were meant to have been removed from the missiles before shipment. In their place, crews were supposed to insert metal dummies of the same size and weight, but a different color, so the missiles could still be properly attached under the bomber's wings.

A munitions custodian officer is supposed to keep track of the nuclear warheads. In the case of cruise missiles, a stamp-size window on the missile's frame allows workers to peer inside to check whether the warheads within are silver. In many cases, a red ribbon or marker attached to the missile serves as an additional warning. Finally, before the missiles are moved, two-man teams are supposed to look at check sheets, bar codes and serial numbers denoting whether the missiles are armed.

Why the warheads were not noticed in this case is not publicly known. But once the missiles were certified as unarmed, a requirement for unique security precautions when nuclear warheads are moved -- such as the presence of specially armed security police, the approval of a senior base commander and a special tracking system -- evaporated.

The trucks hauled the missile pylons from the bunker into the bustle of normal air base traffic, onto Bomber Boulevard and M Street, before turning onto a tarmac apron where the missiles were loaded onto the B-52. The loading took eight hours because of unusual trouble attaching the pylon on the right side of the plane -- the one with the dummy warheads.

By 5:12 p.m., the B-52 was fully loaded. The plane then sat on the tarmac overnight without special guards, protected for 15 hours by only the base's exterior chain-link fence and roving security patrols.

Air Force rules required members of the jet's flight crew to examine all of the missiles and warheads before the plane took off. But in this instance, just one person examined only the six unarmed missiles and inexplicably skipped the armed missiles on the left, according to officials familiar with the probe.

"If they're not expecting a live warhead it may be a very casual thing -- there's no need to set up the security system and play the whole nuclear game," said Vest, the former Minot airman. "As for the air crew, they're bus drivers at this point, as far as they know."

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