Human error damaged nuclear-armed missile in Silo

Errors by three airmen troubleshooting a nuclear missile in its launch silo in 2014 triggered a "mishap" that damaged the missile, causing the Air Force to withdraw the airmen's nuclear certification and launch an accident investigation, officials said on Friday.

In a statement released to The Associated Press, the Air Force declined to provide key details or a copy of the report produced last year by an Accident Investigation Board, saying the information was classified as too sensitive to be made public.

Under the Air Force's own regulations, Accident Investigation Board reports are supposed to be made public. The Air Force did release a brief summary to the AP after it sought answers about the mishap. The summary said the full report was classified on November 9, 2015, by General Robin Rand, the four-star general who commands Air Force nuclear forces.

The accident happened May 17, 2014, but the Air Force only explained the consequences on Friday after repeated inquiries by the AP starting in January 2015.

The Air Force said the accident caused no injuries and did not risk public safety. The damaged missile was removed from its silo. The launch site is operated by the 320th Missile Squadron of the 90th Missile Wing in a remote area of northeastern Colorado.

The Air Force's brief summary said a Minuteman 3 intercontinental ballistic missile "became non-operational" during a diagnostic test on the evening of May 16, 2014.

The next morning a "mishap crew" chief, who was not identified, "did not correctly adhere to technical guidance" during troubleshooting efforts, "subsequently damaging the missile." The Air Force declined to specify how this happened.

It said the team chief "lacked the necessary proficiency level" to anticipate the consequences of his actions during the troubleshooting effort.

Repairs to the missile cost $1.8 million.