The U.S. Air Force revealed that an unnoticed fire in an unmanned
Minuteman III missile silo burned itself out, and then went unnoticed for five
days. The fire occurred when a battery charger overheated in an equipment room
adjacent to the silo chamber containing the missile. The fire burned itself out
after an hour or two, but there were no sensors in the sealed room to report
the incident. Because the fire never got outside the room to where there were
sensors, like in the silo itself, the distant missile command center had no way
of knowing about it.
later, a sensor in the silo did report a possible problem with electrical
wiring, and a repair crew was sent in. They discovered the fire. Among the
items burned up in the equipment room was a shotgun and box of shotgun shells.
These were standard items in the equipment room, in the event of a security
problem. The air force checked out the entire silo, and found no other damage.
But they promptly replaced all the battery chargers in silos. An investigation
of the incident criticized the design of the silo, and recommended changes in
the ventilation system for the silo, among other things. Apparently nothing like
this had ever happened before, and none of the engineers who created
simulations for potential mishaps, considered this one. It cost the air force
over a million dollars for the investigation, replacement of equipment and