How warheads made an unplanned flight

WASHINGTON — Just after 9 a.m. on Aug. 29, a group of U.S. airmen entered a sod-covered bunker on North Dakota's Minot Air Force Base with orders to collect a set of unarmed cruise missiles bound for a weapons graveyard. They quickly pulled out a dozen cylinders, all of which appeared identical from a cursory glance, and hauled them along Bomber Boulevard to a waiting B-52 bomber.

The airmen attached the gray missiles to the plane's wings, six on each side. After eyeballing the missiles on the right side, a flight officer signed a manifest that listed a dozen unarmed AGM-129 missiles. The officer did not notice that the six on the left contained nuclear warheads, each with the destructive power of up to 10 Hiroshima bombs.

That detail would escape notice for 36 hours, during which the missiles were flown to a Louisiana air base that had no idea nuclear warheads were coming. It was the first known flight by a nuclear-armed bomber over U.S. airspace, without special high-level authorization, in nearly 40 years.

The episode, serious enough to trigger a rare "Bent Spear" nuclear incident report that raced through the chain of command to Defense Secretary Robert M. Gates and President Bush, provoked new questions about the adequacy of U.S. nuclear weapons safeguards while the military's attention and resources are devoted to wars in Iraq and Afghanistan.

Three weeks after word of the incident leaked to the public, new details obtained by the Washington Post point to security failures at multiple levels in North Dakota and Louisiana, according to interviews with current and former U.S. officials briefed on the initial results of an Air Force investigation.

The warheads were attached to the plane in Minot without special guard for more than 15 hours, and they remained on the plane in Louisiana for nearly nine hours more before being discovered. The warheads slipped from the Air Force's nuclear safety net for more than a day without anyone's knowledge.

"I have been in the nuclear business since 1966 and am not aware of any incident more disturbing," retired Air Force Gen. Eugene Habiger, who served as U.S. Strategic Command chief from 1996 to 1998, said.

An error in a missile storage room led to missteps at every turn, as ground crews failed to notice the warheads, and as security teams and flight crew members failed to provide adequate oversight and check the cargo thoroughly. An elaborate nuclear safeguard system, nurtured during the Cold War and infused with rigorous accounting and command procedures, was utterly debased, the investigation's early results show.