The military is investigating a recent incident in which a missile launch crew fell asleep on the job.
It occurred at Minot Air Force Base in North Dakota.
Officials say the missile launch codes were outdated and remained secure at all times.
"This was just a procedural violation that we investigated," said Air Force Col. Dewey Ford, a spokesman at Peterson Air Force Base in Colorado Springs, Colo. "We determined that there was no compromise."
The lapse was serious enough to prompt an investigation by the 91st Missile Wing, in conjunction with codes experts at the 20th Air Force, U.S. Strategic Command and the National Security Agency.
No one has been punished yet in the latest Minot incident involving sleeping crew members. A continuing review by Minot commanders will determine what, if any, actions will be taken against them.
The untimely nap is the latest in a series of problems that has placed the Air Force under scrutiny.
Last month, Defense Secretary Robert Gates forced two top Air Force leaders to step down. Gates blamed them for not fully addressing a series of nuclear-related mishaps.
Two replacements were confirmed this week in the Senate.
Source: The Associated Press