8:48 p.m. EDT March 27, 2014 WASHINGTON   The Air Force announced Thursday it is relieving nine nuclear missile commanders in connection with a widespread test cheating scandal that implicated dozens of missile crewmen under their charge.

The commanders, most of them colonels and lieutenant colonels, were not involved in the cheating, but were relieved for failing to provide proper supervision and leadership, the Air Force said. An additional commander submitted his resignation and will retire.

Air Force Secretary Deborah Lee James said the investigation found a range of problems in the nuclear missile community, including the micromanagement of subordinates and some morale problems.

The scandal has raised troubling questions about the Air Force's nuclear missile force. The missile crews were at the heart of the nation's defense during the Cold War years.

Since then their mission has slipped into the shadows, as the threat of nuclear war has receded. Yet every day missile crewmen continue to descend into underground command centers at remote bases.

The price of making a mistake, however, hasn't changed and crews must undergo regular testing and inspections.

The investigation, which focused on crewmen at Malmstrom Air Force Base in Montana, determined that commanders created a climate where relentless pursuit toward perfect test scores led to an "unhealthy" environment.

"They sought to ensure that the zero defect standard was met by personally monitoring and directing daily operations ... with the goal of eliminating all human error," said Lt. Gen. Stephen Wilson, commander of the Air Force Global Strike Command.

The Air Force said it will change how it trains and tests missile crewmen. The crewmen serve in underground command centers where they remain for 24-hour shifts, and are responsible for launching missiles when ordered.

The Air Force said the system was never compromised by the allegations of cheating. The airmen would have passed the tests but felt pressure to get a perfect scores to improve their chances of advancement.

The investigation was initially launched to look into allegations of drug use among missile crewmen. The investigation uncovered that officers were sharing the answers to monthly tests through text messages.

The investigation determined that 79 officers participated in the cheating or knew about it and did nothing to stop it. Another 10 officers remain under investigation for more serious charges, including allegations of misusing classified material.

The cheating is alleged to have taken place between November 2011 and November 2013.