An Air Force Minuteman III intercontinental ballistic missile was damaged in May 2014 during maintenance work inside its launch silo, Air Force officials revealed today.The damage to the missile cost $1.8 million and led to the re-certification of the three airmen involved in the incident, officials said."On May 16, 2014, at approximately 11:15 p.m. MDT, a Minuteman III intercontinental ballistic missile assigned to the 90th Missile Wing at F.E. Warren AFB, Wyoming, became non-operational during a diagnostic test," said a statement provided to ABC News by Air Force Global Strike Command."While maintenance personnel were troubleshooting the issue, a mishap occurred that resulted in approximately $1.8 million of damage to the missile. The incident did not result in any injuries, prevent the Air Force from meeting its ICBM requirements, or create a hazard to public safety," the Air Force Global Strike Command added.The incident led the command to launch an Accident Investigation Board to look at the circumstances that led to the incident. That investigation "found that although the maintenance team chief was properly trained for the task he was performing, he mistakenly performed an action not directed by the technical guidance," according to the Air Force.In the wake of the incident, the maintenance team chief and two other airmen on his team were de-certified from working with the missiles, officials said, noting they returned to duty after they had been retrained and certified again.Lt. Col. John Sheets, a spokesman for the Air Force Global Strike Command, could not confirm whether the ICBM was armed at the time of the incident "since it is DOD policy to neither confirm nor deny the presence of nuclear weapons at any particular location when the public's safety is not at risk."The Associated Press first reported the incident today after making inquiries to Air Force Global Strike Command.To prevent a similar incident in the future, "the Air Force has strengthened technical guidance, modified training curriculum, and shared information with the other missile wings regarding the conditions that led to the mishap," the Global Strike Command said."In accordance with Air Force policy, further details related to this mishap and its associated investigation are classified," the Air Force said.