Nuclear security forces airmen use hand signals to direct personnel during an exercise at the Minot Air Force Base missile field complex near Minot, N.D., May 22, 2013. (Photo by Senior Master Sgt. David H. Lipp/ U.S. Air National Guard)

The U.S. Air Force has launched an investigation into illicit, off-duty drug use by troops who protect nuclear weapons, senior service officials said Friday, the latest black eye for a nuclear force that has suffered several scandals in recent years.

The probe centers on 14 enlisted troops between the ranks of airman and airman first class who serve with the 90th Security Forces Group at F.E. Warren Air Force Base in Cheyenne, Wyo., said Gen. Robin Rand, commander of Air Force Global Strike Command. He said the investigation focuses on “illegal drug activity,” but would not say whether the allegation focuses on use, sales or both. He also would not say what kind of drugs are involved, or whether the investigation could implicate more personnel.

“I’m not going to go into the specific details,” Rand said. “I will tell you that it came to light because of one airman who had suspected drug activity by another and he reported that to his chain of command. We’re going to stop at that point, and I’m not going to speculate on the others at this time because it is under investigation.”

The drug investigation comes as the service continues to make changes to the nuclear force following a cheating scandal involving missile launch officers that surfaced two years ago. Global Strike Command manages two of three “legs” of the U.S. nuclear arsenal, which includes bombers and intercontinental ballistic missiles operated by the Air Force and Navy submarines that can launch missiles at sea.