Airmen from the 91st Missile Wing Security Forces team were traveling on gravel roads May 1 in North Dakota when the back hatch of their vehicle opened and a container filled with the explosive ammunition fell out, according to a statement from Minot Air Force Base.
On May 11, the Air Force sent more than 100 airmen to walk the entire six-mile route where the grenades were probably lost, according to a statement from the local Mountrail County sheriff. But two weeks after it was lost, the box of explosives still hasn't been found.
The missing ordnance is a belt of linked grenades for the MK 19 automatic grenade launcher, Sheriff Kenneth Halvorson said in the statement shared with The Washington Post. "This ammunition is specific to that launcher and will not operate in any other launching device without catastrophic failure," he said.
The security forces of the 91st Missile Wing are responsible for protecting the intercontinental ballistic missile silos that Minot Air Force Base operates across the Great Plains.
The weapons are manned by specially trained airmen known as missileers, who sit in the underground silos in the middle of North Dakota fields 24 hours a day and wait for an order from the president to launch the weapons of mass destruction. Associated security forces operate from a building above ground at each missile silo to protect the missileers and their equipment down below. The security forces are armed with weapons such as the MK 19 to fend off any attack on the installations and protect the dangerous nuclear warheads.
The Air Force said its Office of Special Investigations does not consider the incident a criminal matter and is seeking public assistance in ensuring the safe return of the explosives. The office has offered the number for an anonymous tip line for any information about the missing grenade rounds and a $5,000 reward for any information leading to their recovery.
Air Force Lt. Col. Jamie Humphries, a spokesman at Minot Air Force Base, said in a statement that the ammunition was in a green metal container weighing 42 pounds and is considered safe so long as the container remains intact.
Humphries warned that any damage to the container, however, could result in an explosion. If anyone locates the box and finds the ammunition in a damaged state, the area should be evacuated immediately, the statement said.
"We are hoping to get contacted by someone soon with information that leads to the can's return," Humphries said.
Humphries said the incident remains under investigation and that he couldn't speculate on whether any disciplinary action would be taken against the airmen who lost the explosives.
According to the statement from the sheriff, individuals living in the area were contacted by law enforcement authorities immediately and asked to keep an eye out for any explosives that have turned up on their property.
The sheriff's office also contacted many of the oil field vendors that operate in the area, as well as farmers, asking them to forward along any information about the box of grenade rounds, the sheriff said, describing the ammunition as very dangerous.
The sheriff's office wasn't notified until three days after the airmen lost the explosives, according to his statement. Agents from the Office of Special Investigations met with him a week after the incident to outline the status of their investigation and request assistance, resulting in a warning to the public.
Anyone with information should contact the Air Force Office of Special Investigations at (701)-723-7909.