WASHINGTON — An Air Force unit that operates one-third of the nation’s land-based nuclear missiles has failed a safety and security inspection, marking the second major setback this year for a force charged with the military’s most sensitive mission, the general in charge of the nuclear air force said Tuesday.
Lieutenant General James M. Kowalski, commander of Air Force Global Strike Command, said a team of ‘‘relatively low-ranking’’ airmen failed one exercise as part of a broader inspection, which began last week and ended Tuesday. He said that for security reasons he could not be specific about the team or the exercise.
‘‘This unit fumbled on this exercise,’’ Kowalski said by telephone from his headquarters at Barksdale Air Force Base, La., adding that this did not call into question the safety or control of nuclear weapons at Malmstrom Air Force Base in Montana.
‘‘The team did not demonstrate the right procedures,’’ he said, and as a result was rated a failure.
To elaborate any more on the problem ‘‘could reveal a potential vulnerability’’ in the force, Kowalski said.
Without more details it is difficult to reliably judge the extent and severity of the problem uncovered at Malmstrom, home of the 341st Missile Wing, which is one of three nuclear missile wings. Each wing operates 150 Minuteman 3 intercontinental ballistic missiles, or ICBMs, on alert for potential launch against targets around the globe.
On Capitol Hill, a spokesman for Representative Howard ‘‘Buck’’ McKeon, Republican of California and chairman of the House Armed Services Committee, said that ‘‘two troubling inspections in a row at two different missile wings is unacceptable.’’
‘‘It is his sense that the Air Force must refocus on the nuclear mission,’’ spokesman John Noonan said.
Asked whether the Air Force intends to take disciplinary action against anyone for the failure, Kowalski said the Air Force is ‘‘looking into it.’’ Overall, the 341st wing ‘‘did well,’’ he said, earning ratings of excellent or outstanding in the majority of the 13 areas in which it was graded by inspectors.
The 341st also failed a safety and security inspection in 2008.
A different type of inspection of the 91st Missile Wing at Minot Air Force Base, N.D., in March of this year led the deputy commander of the wing’s operations group to complain of ‘‘rot’’ in the force. Technically, the wing passed that inspection but its missile crews earned the equivalent of a ‘‘D’’ grade when tested on their mastery of Minuteman 3 launch operations using a simulator. The following month the 91st temporarily removed 17 officers from launch control duty — the first time such a large number had been removed.
In June, the commander in charge of training and proficiency of missile crews at Minot, Lieutenant Colonel Randy Olson, was relieved of duty, citing a ‘‘loss of confidence’’ in his leadership.
The troubles are the latest in a longer series of setbacks for the Air Force’s nuclear mission, highlighted by a 2008 Pentagon advisory group report that found a ‘‘dramatic and unacceptable decline’’ in the Air Force’s commitment to the mission.
Following a series of nuclear embarrassments in 2008 — including the inadvertent transport of six nuclear-tipped missiles on a B-52, whose pilot did not know they were aboard when he flew from Minot to Barksdale Air Force Base, La. — then-Defense Secretary Robert Gates fired the top two Air Force officials.
Kowalski’s command was created in late 2009 as part of an effort to fix what was broken in the nuclear force.