The Air Force cheating scandal at Malmstrom Air Force Base in Montana has resulted in the firing of nine commanders and the disciplining of 79 nuclear launch officers.

The disciplinary action is the latest in a string of negative incidents that have occurred over the past year involving the officers charged with overseeing the Air Force's fleet of 450 intercontinental ballistic missiles.

Col. Robert Stanley, the senior officer in charge of the 341st Missile Wing, was not disciplined but submitted his resignation Thursday because the nine senior officers worked directly under his command. Stanley had been nominated earlier this year for promotion to brigadier general but will retire from the Air Force instead.

The nine senior officers included colonels, lieutenant colonels, and a major who held key positions in the 341 st Missile Wing. They have been removed from their posts due to a lack of confidence in their leadership mainly for not being aware that the cheating on proficiency tests was taking place. They will also receive administrative punishments that will in effect end their opportunities for career advancement.

The Air Force's investigation into cheating at Malmstrom ultimately looked at 100 nuclear launch officers, or missileers as they are known, for possible involvement or knowledge of the cheating on regular tests. That number is half the 200 missileers based at Malmstrom and higher than the 92 the Air Force said in January were being investigated.

The investigation determined that 79 of the missileers, mostly lieutenants and captains, were involved in the cheating at one point or another. They will receive disciplinary action including letters of counseling, letters of reprimand, non-judicial punishment or possible court martial.

The cheating probe was launched last fall by an unrelated investigation of drug use involving junior Air Force officers, including three officers at Malmstrom. A review of their cellphones uncovered photographs and text messages about the regular proficiency tests given to missileers.

The Air Force investigation found that a ring of four missileers was behind the cheating which may have begun as early as November, 2011 and lasted through November, 2013.

Air Force Secretary Deborah Lee James and Lt. Gen. Stephen Wilson of Air Force Global Strike Command told reporters at a Pentagon briefing to announce the results of the investigation that they were initiating changes to the missileer force.

In January both James and Wilson blamed the cheating on a culture among missileers that saw perfect test scores as the only way they could get promoted. They also said that the emphasis on perfection led missileer commanders to micromanage their force.

James reiterated Thursday that though there were "systemic" problems within the missileer force she still had confidence that they could get the job done. She said changes are being implemented that will change "dramatically" how the missileer testing is done while maintaining high standards.

But she was also realistic that the issues in the missileer force have "been years in the making. They're not going get solved overnight."

Wilson said that the review of the missile force concluded that senior leaders micromanaged their missileers and had an "unhealthy" focus on testing "with the goal of eliminating all human error." Wilson said "this approach is unrealistic" given all the redundancies in the ICBM force.

Wilson said there would now be a focus on training and field evaluations that he said "better assess crew performance in the operational environment." Instead of numbered test results, the tests will also be switched to a Pass/Fail system.

The cheating scandal was the latest in a series of incidents involving missileers over the past year that included failed inspections and disciplinary action for some missileers who had fallen asleep during their 24-hour shifts.

In October, Maj. Gen. Michael Carey was fired from his job as commander of the 20 th Air Force that had direct oversight for the three wings responsible for the Air Force's ICBM fleet. An investigation determined that he had engaged in drunken behavior last summer while attending a nuclear security conference in Russia.

James said Thursday that Carey has requested retirement and a review panel will determine whether he should retain his current rank.

Also on Thursday, a senior commander at the 90th Missile Wing at F.E. Warren AFB in Wyoming was relieved of duty for a loss of confidence.

Col. Tracey Hayes, commander of the 90th Missile Wing, relieved Col. Donald Holloway, commander, for what she said was a loss of confidence in his ability to lead. Hayes said Holloway's dismissal had nothing to do with the cheating scandal at Malmstrom.