20 MISHAPS THAT MIGHT HAVE STARTED ACCIDENTAL NUCLEAR
by Alan F. Phillips, M.D.
Ever since the two adversaries in the Cold War, U.S.A. and U.S.S.R.,
realized that their nuclear arsenals were sufficient to do disastrous
damage to both countries at short notice, the leaders and military
commanders have thought about the possibility of a nuclear war starting
without their intention or as a result of a false alarm. Increasingly
elaborate accessories have been incorporated in nuclear weapons and
their delivery systems to minimize the risk of unauthorized or
accidental launch or detonation. A most innovative action was the
establishment of the "hot line" between Washington and Moscow in 1963 to
reduce the risk of misunderstanding between the supreme commanders.
Despite all precautions, the possibility of an inadvertent war due
to an unpredicted sequence of events remained as a deadly threat to both
countries and to the world. That is the reason I am prepared to spend
the rest of my life working for abolition of nuclear weapons.
One way a war could start is a false alarm via one of the warning
systems, followed by an increased level of nuclear forces readiness
while the validity of the information was being checked. This action
would be detected by the other side, and they would take appropriate
action; detection of that response would tend to confirm the original
false alarm; and so on to disaster. A similar sequence could result
from an accidental nuclear explosion anywhere. The risk of such a
sequence developing would be increased if it happened during a period of
increased international tension.
On the American side many "false alarms" and significant accidents
have been listed, ranging from trivial to very serious, during the Cold
War. Probably many remain unknown to the public and to the research
community because of individuals' desire to avoid blame and maintain the
good reputation of their unit or command. No doubt there have been as
many mishaps on the Soviet side.
Working with any new system, false alarms are more likely. The
rising moon was misinterpreted as a missile attack during the early days
of long-range radar. A fire at a broken gas pipeline was believed to be
enemy jamming by laser of a satellite's infrared sensor when those
sensors were first deployed.
The risks are illustrated by the following selection of mishaps. If
the people involved had exercised less caution, or if some unfortunate
coincidental event had occurred, escalation to nuclear war can easily be
imagined. Details of some of the events differ in different sources:
where there have been disagreements, I have chosen to quote those from
the carefully researched book "The Limits of Safety" by Scott D. Sagan.
Sagan gives references to original sources in all instances.
1956, Nov.5: Suez Crisis coincidence.
British and French forces were attacking Egypt at the Suez Canal. The
Soviet Government had suggested to U.S. that they combine forces to stop
this by a joint military action, and had warned the British and French
governments that (non-nuclear) rocket attacks on London and Paris were
being considered. That night the U.S. military HQ in Europe received
(i) unidentified aircraft were flying over Turkey and the Turkish
air force was on alert
(ii) 100 Soviet MIG-15's were flying over Syria
(iii) a British Canberra bomber had been shot down over Syria
(iv) the Russian fleet was moving through the Dardanelles.
It is reported that in U.S.A. General Goodpaster himself was concerned
that these events might trigger the NATO operations plan for nuclear
strikes against U.S.S.R.
The 4 reports were all shown afterwards to have innocent explanations.
They were due, respectively, to:
(i) a flight of swans
(ii) a routine air force escort (much smaller than the number
reported) for the president of Syria, who was returning from a visit to
(iii) the Canberra bomber was forced down by mechanical problems
(iv) the Russian fleet was engaged in scheduled routine exercises.
BMEWS communication failure.
On the night of 24 November, 1961, all communication links went dead
between SAC HQ and NORAD, and so cut SAC HQ off from the three Ballistic
Missile Early Warning sites (BMEWS) at Thule (Greenland), Clear
(Alaska), and Filingdales (England). For General Power at SAC HQ, there
were two possible explanations: either enemy action, or the coincidental
failure of all the communication systems which had redundant and
ostensibly independent routes including commercial telephone circuits.
All SAC bases in U.S.A. were therefore alerted and B-52 nuclear bomber
crews started their engines, with instructions not to take off without
further orders. Radio communication was established with an orbiting
B-52 on airborne alert which was near Thule. It contacted the BMEWS
station by radio and could report that no attack had taken place.
[NOTE: Long after I wrote this, a reader informed me that he was a
technician at Plattsburgh Air Force Base at the time. The order reached
that Base as an "Alpha" alert, the highest level, at which nuclear-armed
bombers were to fly direct to their targets and bomb, without waiting at
the fail-safe point for further orders. Before any bomber could take
off the correction arrived making it a third-level "Cocoa" alert, at
which the bombers stayed on the runway with engines running and waited
for further orders.]
The reason for the "coincidental" failure was that the redundant routes
for telephone and telegraph between NORAD and SAC HQ all ran through one
relay station in Colorado. At that relay station a motor had overheated
and caused interruption of all the lines.
THE CUBAN MISSILE CRISIS LASTED FOR THE TWO WEEKS 14-28 OCTOBER 1962.
MANY DANGEROUS EVENTS TOOK PLACE IN RELATION TO THE CRISIS, SOME OF THEM
BECAUSE OF CHANGES MADE TO ENHANCE MILITARY READINESS. ELEVEN HAVE BEEN
1962, Aug.23: B-52 Navigation Error.
SAC Chrome Dome airborne alert route included a leg from the northern
tip of Ellesmere Island, SW across the Arctic Ocean to Barter Island,
Alaska. On 23 August,1962, a B-52 nuclear-armed bomber crew made a
navigational error and flew a course 20 deg. too far north. They
approached within 300 miles of Soviet airspace near Wrangel island,
where there was believed to be an interceptor base with aircraft having
an operational radius of 400 miles.
Because of the risk of repetition of such an error, in this northern
area where other checks on navigation are difficult to obtain, it was
decided to fly a less provocative route in future. However, the
necessary orders had not been given by the time of the Cuban missile
crisis in October 1962, so throughout that crisis the same northern
route was being flown 24 hours a day.
Aug.-Oct.62: U2 flights into Soviet airspace.
U2 high altitude reconnaissance flights from Alaska occasionally strayed
unintentionally into Soviet airspace. One such episode occurred in
August 1962. During the Cuban Missile Crisis in October 1962 the U2
pilots were ordered not to fly within 100 miles of the Soviet airspace.
On the night of 26 October, for a reason irrelevant to the crisis, a U2
pilot was ordered to fly a new route, over the north pole, where
positional checks on navigation were by sextant only. That night the
aurora prevented good sextant readings and the plane strayed over the
Chukotski Peninsula. Soviet MIG interceptors took off with orders to
shoot down the U2. The pilot contacted his U.S. command post and was
ordered to fly due east towards Alaska. He ran out of fuel while still
over Siberia. In response to his S.O.S., U.S. F102-A fighters were
launched to escort him on his glide towards Alaska, with orders to
prevent the MIG's from entering U.S. airspace. The U.S. interceptor
aircraft were armed with nuclear missiles. These could have been used
by any one of the F102-A pilots at his own discretion.
1962, Oct.24: Russian satellite explodes.
On 24 October a Russian satellite entered its parking orbit, and shortly
afterwards exploded. Sir Bernard Lovell, director of the Jodrell Bank
observatory wrote in 1968: "the explosion of a Russian spacecraft in
orbit during the Cuban Missile Crisis... led the U.S. to believe that
the USSR was launching a massive ICBM attack." The NORAD Command Post
logs of the dates in question remain classified, possibly to conceal the
reaction to this event. Its occurrence is recorded, and U.S. space
tracking stations were informed on 31 October of debris resulting from
breakup of "62 BETA IOTA".
1962, Oct.25: Duluth intruder.
At around midnight on 25 October, a guard at Duluth Sector Direction
Center saw a figure climbing the security fence. He shot at it, and
activated the "sabotage alarm". This automatically set off sabotage
alarms at all bases in the area. At Volk Field, Wisconsin, the alarm
was wrongly wired, and the Klaxon sounded which ordered nuclear-armed
F-106A interceptors to take off. The pilots knew there would be no
practice alert drills while DEFCON 3 was in force, and they believed
World War III had started.
Immediate communication with Duluth showed there was an error. By this
time aircraft were starting down the runway. A car raced from the
command center and successfully signalled the aircraft to stop.
The original intruder was a bear.
1962, Oct.26: ICBM Test Launch.
At Vandenberg Air Force Base, California, there was a program of
routine ICBM test flights. When DEFCON 3 was ordered all the ICBM's
were fitted with nuclear warheads except one Titan missile that was
scheduled for a test launch later that week. That one was launched for
its test, without further orders from Washington, at 4 a.m. on 26
It must be assumed that Russian observers were monitoring U.S. missile
activities as closely as U.S. observers were monitoring Russian and
Cuban activities. They would have known of the general changeover to
nuclear warheads, but not that this was only a test launch.
Unannounced Titan missile launch.
During the Cuba Crisis, some radar warning stations that were under
construction and near completion were brought into full operation as
fast as possible. The planned overlap of coverage was thus not always
A normal test launch of a Titan-II ICBM took place in the afternoon of
26 October, from Florida towards the S.Pacific. It caused temporary
concern at Moorestown Radar site until its course could be plotted and
showed no predicted impact within the United States. It was not until
after this event that the potential for a serious false alarm was
realized, and orders were given that radar warning sites must be
notified in advance of test launches, and the countdown be relayed to
1962, Oct.26: Malmstrom Air Force Base.
When DEFCON 2 was declared on 24 October, solid-fuel Minuteman-1
missiles at Malmstrom Air Force Base were being prepared for full
deployment. The work was accelerated to ready the missiles for
operation, without waiting for the normal handover procedures and safety
checks. When one silo and the first missile were ready on 26 October no
armed guards were available to cover transport from the normal separate
storage, so the launch- enabling equipment and codes were all placed in
the silo. It was thus physically possible for a single operator to
launch a fully armed missile at a SIOP target.
During the remaining period of the Crisis the several missiles at
Malmstrom were repeatedly put on and off alert as errors and defects
were found and corrected. Fortunately no combination of errors caused
or threatened an unauthorized launch, but in the extreme tension of the
period the danger can well be imagined.
October 1962: NATO Readiness.
It is recorded in British Prime Minister Harold Macmillan's diary for 22
October that in order to avoid provocation of U.S.S.R., he and the NATO
Supreme Commander, General Lauris Norstad, agreed not to put NATO on
alert. When the U.S. Joint Chiefs of Staff ordered DEFCON 3 Norstad was
authorized to use his discretion in complying. Norstad therefore did
not order a NATO alert. However, several NATO subordinate commanders
did order alerts to DEFCON 3 or equivalent levels of readiness at bases
in West Germany, Italy, Turkey, and Britain. This seems to have been
largely due to the action of General Truman Landon, CINC U.S. Air Forces
Europe, who had already started alert procedures on 17 October in
anticipation of a serious crisis over Cuba.
October 1962: British Alerts.
When U.S. SAC went to DEFCON 2, on 24 October, Bomber Command was
carrying out an unrelated readiness exercise. On 26 October Air
Marshall Cross, C-in-C Bomber Command, decided to prolong the exercise
because of the Cuba crisis, and later increased the alert status of
British Nuclear forces so that they could launch within 15 minutes.
It seems likely that Soviet intelligence would perceive these moves as
part of a coordinated plan in preparation for immediate war. They could
not be expected to know that neither the British Minister of Defence nor
Prime Minister Macmillan had authorized them.
It is disturbing to note how little was learned from these errors in
Europe. McGeorge Bundy wrote in Danger and Survival (New York: Random
House 1988) "the risk [of nuclear war] was small, given the prudence and
unchallenged final control of the two leaders."
1962, Oct.28: Moorestown false alarm.
Just before 9 a.m. on 28 October, the Moorestown, N.J., radar operators
informed national command post that a nuclear attack appeared to be
under way. A test tape simulating a missile launch from Cuba was being
run, and simultaneously a satellite came over the horizon. Operators
became confused and reported by voice line to NORAD HQ that impact was
expected 18 miles west of Tampa at 9.02 a.m. The whole of NORAD was
alerted, but before irrevocable action had been taken it was reported
that no detonation had taken place at the predicted time, and Moorestown
operators reported the reason for the false alarm.
During the incident overlapping radars that should have confirmed or
disagreed were not in operation. The radar post had not received
routine information of satellite passage because the facility carrying
out that task had been given other work for the duration of the Crisis.
False warning due to satellite sighting.
At 5.26 p.m. on 28 October, the Laredo radar warning site had just
become operational. Operators misidentified a satellite in orbit as two
possible missiles over Georgia, and reported by voice line to NORAD HQ.
NORAD was unable to identify that the warning came from the new station
at Laredo and believed it to be from Moorestown, and therefore more
reliable. Moorestown failed to intervene and contradict the false
warning. By the time C-in-C NORAD had been informed, no impact had been
reported and the warning was "given low credence".
END OF CUBA CRISIS EVENTS
1962 Nov.2: The Penkovsky False Warning.
In the Fall of 1962 Col. Oleg Penkovsky was working in Russia as a
double agent for the (U.S.) CIA. He had been given a code by which to
warn the CIA if he was convinced that a Soviet attack on the United
States was imminent. He was to call twice, one minute apart, and only
blow into the receiver. Further information was then to be left at a
"dead drop" in Moscow.
The prearranged code message was received by the CIA on 2 November,
It was not known at CIA that Penkovsky had been arrested on 22 October.
Penkovsky knew he was going to be executed. It is not known whether he
had told KGB the meaning of the code signal or only how it could be
given, nor is it known exactly why or with what authorization KGB staff
used it. When another CIA agent checked the dead drop he was arrested.
Power failure and faulty bomb alarms.
Special bomb alarms were installed near military facilities and near
cities in U.S.A. so that the locations of nuclear bursts would be
transmitted before the expected communication failure. The alarm
circuits were set up to display a red signal at command posts the
instant that the flash of a nuclear detonation reached the sensor and
before the blast could put it out of action. Normally the display would
show a green signal, and yellow if the sensor was not operating or was
out of communication for any other reason.
During the commercial power failure in NE United States in November
1965, displays from all the bomb alarms for the area should have shown
yellow. In fact two of them from different cities showed red because of
circuit errors. The effect was consistent with the power failure being
due to nuclear weapon explosions, and the Command Center of the Office
of Emergency Planning went on full alert. Apparently the military did
1968, Jan.21: B-52 crash near Thule.
Communication between NORAD HQ and the BMEWS station at Thule had 3
1. Direct radio communication.
2. A "bomb alarm" as described above.
3. Radio communication relayed by a B-52 bomber on airborne alert.
On 21 January, 1968, fire broke out in the B-52 bomber on airborne alert
near Thule. The pilot prepared for an emergency landing at the base.
However the situation deteriorated rapidly, and the crew had to bale
out. There had been no time to communicate with SAC HQ, and the
pilotless plane flew over the Thule base before crashing on the ice 7
miles offshore. Its fuel and the high explosive component of its
nuclear weapons exploded, but there was no nuclear detonation.
At that time, the "one point safe" condition of the nuclear weapons
could not be guaranteed, and it is believed that a nuclear explosion
could have resulted from accidental detonation of the high explosive
trigger. Had there been a nuclear detonation even at 7 miles distant,
and certainly if much nearer the base, all three communication methods
would have given an indication consistent with a successful nuclear
attack on both the base and the B-52 bomber. The bomb alarm would have
shown red, and the two other communication paths would have gone dead.
It would hardly have been anticipated that the combination could have
been caused by accident, particularly as the map of the routes for B-52
airborne alert flights approved by the president showed no flight near
to Thule. The route had apparently been changed without informing the
Oct.73: False alarm during Middle East crisis.
On 24 October, 1973, when the UN-sponsored ceasefire intended to end the
Arab-Israeli war was in force, further fighting started between Egyptian
and Israeli troops in the Sinai desert. U.S. intelligence reports and
other sources suggested that U.S.S.R. was planning to intervene to
protect the Egyptians. President Nixon was in the throes of the
Watergate episode and not available for a conference, so Kissinger and
other U.S. officials ordered DEFCON 3. The consequent movements of
aircraft and troops were of course observed by Soviet intelligence. The
purpose of the alert was not to prepare for war, but to warn U.S.S.R.
not to intervene in Sinai. However, if the following accident had not
been promptly corrected then the Soviet command might have made a more
On 25 October, while DEFCON 3 was in force, mechanics were repairing one
of the Klaxons at Kinchloe Air Force Base, Michigan, and accidentally
activated the whole base alarm system. B-52 crews rushed to their
aircraft and started the engines. The duty officer recognized that the
alarm was false, and recalled the crews before any took off.
1979 Nov.9: Computer Exercise Tape.
At 8.50 a.m. on 9 November, 1979, duty officers at 4 command centres
(NORAD HQ, SAC Command Post, the Pentagon National Military Command
Center, and the Alternate National Military Command Center) all saw on
their displays a pattern showing a large number of Soviet missiles in a
full-scale attack on U.S.A. During the next 6 minutes emergency
preparations for retaliation were made. A number of Air Force planes
were launched, including the president's National Emergency Airborne
Command Post, though without the president! The president had not been
informed, perhaps because he could not be found.
No attempt was made to use the hot line either to ascertain the Soviet
intentions or to tell the Russians the reason for the U.S. actions.
This seems to me to have been culpable negligence. The whole purpose of
the "Hot Line" was to prevent exactly the type of disaster that was
threatening at that moment.
With commendable speed, NORAD was able to contact PAVE PAWS early
warning radar and learn that no missiles had been reported. Also, the
sensors on satellites were functioning that day and had detected no
missiles. In only 6 minutes the threat assessment conference was
The reason for the false alarm was an exercise tape running on the
computer system. U.S. Senator Charles Percy happened to be in NORAD HQ
at the time and is reported to have said there was absolute panic. A
question was asked in Congress. The General Accounting Office conducted
an investigation, and an off-site testing facility was constructed so
that test tapes did not in future have to be run on a system that could
possibly be in military operation.
Jun.80: Faulty Computer Chip.
The warning displays at the Command Centers mentioned in the last
episode included windows that normally showed
0000 ICBMs detected 0000 SLBMs detected
At 2.25 a.m. on 3 June, 1979, these displays started showing various
numbers of missiles detected, represented by 2's in place of one or more
0's. Preparations for retaliation were instituted, including nuclear
bomber crews starting their engines, launch of Pacific Command's
Airborne Command Post, and readying of Minuteman missiles for launch. It
was not difficult to assess that this was a false alarm because the
patterns of numbers displayed were not rational.
While the cause of that false alarm was still being investigated 3 days
later, the same thing happened and again preparations were made for
The cause was a single faulty chip that was failing in random fashion.
The basic design of the system was faulty, allowing this single failure
to cause a deceptive display at several command posts.
This selection represents only a fraction of the false alarms that
have been reported on the American side. Many probably remain
unreported, or are hidden in records that remain classified. There are
likely to have been as many on the Soviet side which are even more
difficult to access.
The extreme boredom and isolation of missile launch crews on duty
must contribute to occasional bizarre behaviour. An example is reported
by Lloyd J.Dumas in Bulletin of the Atomic Scientists vol.36, #9, p.15
(1980) quoting Air Force Magazine of 17 Nov.71. As a practical joke, a
silo crew recorded a launch message and played it when their relief came
on duty. The new crew heard with consternation what appeared to be a
valid launch message. They would not of course have been able to effect
an actual launch under normal conditions, without proper confirmation
from outside the silo.
COMMENT AND NOTE ON PROBABILITY
The probability of actual progression to nuclear war on any one of
the occasions listed may have been small, due to planned "failsafe"
features in the warning and launch systems, and to responsible action by
those in the chain of command when the failsafe features had failed.
However, the accumulation of small probabilities of disaster from a long
sequence of risks adds up to serious danger.
There is no way of telling what the actual level of risk was in
these mishaps but if the chance of disaster in every one of the 20
incidents had been only 1 in 100, it is a mathematical fact that the
chance of surviving all 20 would have been 82%, i.e. about the same as
the chance of surviving a single pull of the trigger at Russian roulette
played with a 6-shooter. With a similar series of mishaps on the Soviet
side: another pull of the trigger. If the risk in some of the events
had been as high as 1 in 10, then the chance of surviving just seven
such events would have been less than 50:50.
The following incident is added to illustrate that even now, when
the Cold War has been over for 8 years, errors can still cause concern.
Some have said this incident brought the world very close to an
accidental nuclear war. That is debatable, but there are still 30,000
nuclear weapons deployed, so grave danger would exist if two nuclear
weapons states should get into a hostile adversarial status again.
Jan.95: Norwegian Meteorological Missile.
On 25 January, 1995, the Russian early warning radars detected an
unexpected missile launch near Spitzbergen. The estimated flight time
to Moscow was 5 minutes. The Russian President, the Defence Minister
and the Chief of Staff were informed. The early warning and the control
and command systems switched to combat mode. Within 5 minutes, the
radars determined that the missile's impact point would be outside the
The missile was carrying instruments for scientific measurements. On 16
January Norway had notified 35 countries including Russia that the
launch was planned. Information had apparently reached the Russian
Defense Ministry, but failed to reach the on-duty personnel of the early
warning system. [Details in paper by von Hippel et.al., Scientific
Sagan, Scott D.: The Limits of Safety (Princeton, N.J.: Princeton
University Press, 1993).
Peace Research Reviews, vol.IX, 4, 5 (1984); vol.X, 3,4(1986) (Dundas,
ON.: Peace Research Institute, Dundas).
Calder, Nigel: Nuclear Nightmares (London: British Broadcasting
Britten, Stewart: The Invisible Event (London: Menard Press, 1983)
BMEWS Ballistic Missile Early Warning Site
CIA Central Intelligence Agency
CINC Commander in Chief
DEFCON Defense Readiness Condition
(DEFCON 5 is the peacetime state;
DEFCON 1 is maximum war readiness)
ICBM Intercontinental Ballistic Missile (land based)
KGB Komitet Gosudarstvennoi Bezopaznosti
(Soviet Secret Police and Intelligence)
NORAD North American Air Defense Command
PAVE PAWS Precision Acquisition of Vehicle Entry Phased-Array Warning
SAC Strategic Air Command
SIOP Single Integrated Operational Plan
SLBM Submarine Launched Ballistic Missile
Alan F. Phillips
11 January, 1997
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