On 21 January 1968, an aircraft accident, sometimes known as the Thule affair or Thule accident (; da, Thuleulykken), involving a
United States Air Force
The United States Air Force (USAF) is the Aerial warfare, air military branch, service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part ...
(USAF)
B-52 bomber
The Boeing B-52 Stratofortress is an American long-range, subsonic, jet-powered strategic bomber. The B-52 was designed and built by Boeing, which has continued to provide support and upgrades. It has been operated by the United States Air ...
occurred near
Thule Air Base
Thule Air Base (pronounced or , kl, Qaanaaq Mitarfik, da, Thule Lufthavn), or Thule Air Base/Pituffik Airport , is the United States Space Force's northernmost base, and the northernmost installation of the U.S. Armed Forces, located north ...
in the Danish territory of
Greenland
Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland i ...
. The aircraft was carrying four
B28FI thermonuclear bombs on a
Cold War "
Chrome Dome" alert mission over
Baffin Bay when a cabin fire forced the crew to abandon the aircraft before they could carry out an
emergency landing
An emergency landing is a premature landing made by an aircraft in response to an emergency involving an imminent or ongoing threat to the safety and operation of the aircraft, or involving a sudden need for a passenger or crew on board to term ...
at
Thule Air Base
Thule Air Base (pronounced or , kl, Qaanaaq Mitarfik, da, Thule Lufthavn), or Thule Air Base/Pituffik Airport , is the United States Space Force's northernmost base, and the northernmost installation of the U.S. Armed Forces, located north ...
. Six crew members ejected safely, but one who did not have an
ejection seat
In aircraft, an ejection seat or ejector seat is a system designed to rescue the pilot or other crew of an aircraft (usually military) in an emergency. In most designs, the seat is propelled out of the aircraft by an explosive charge or rock ...
was killed while trying to bail out. The bomber crashed onto
sea ice in
North Star Bay
North Star Bay ( da, North Star Bugt), also known as Thule Harbor and Wolstenholme Bay, is a bay off the mouth of Wolstenholme Fjord, Greenland.
The bay is named after HMS ''North Star''. Thule Air Base is located at the edge of the bay. There ...
, Greenland, causing the conventional explosives aboard to detonate and the nuclear payload to rupture and disperse, resulting in
radioactive contamination
Radioactive contamination, also called radiological pollution, is the deposition of, or presence of radioactive substances on surfaces or within solids, liquids, or gases (including the human body), where their presence is unintended or undesirab ...
of the area.
The United States and Denmark launched an intensive clean-up and recovery operation, but the
secondary stage of one of the nuclear weapons could not be accounted for after the operation was completed. USAF
Strategic Air Command "Chrome Dome" operations were discontinued immediately after the accident, which highlighted the safety and political risks of the missions. Safety procedures were reviewed, and more stable explosives were developed for use in nuclear weapons.
In 1995, a political scandal arose in Denmark after a report revealed the government had given tacit permission for nuclear weapons to be located in Greenland, in contravention of Denmark's 1957
nuclear-free zone
A nuclear-free zone is an area in which nuclear weapons (see nuclear-weapon-free zone) and nuclear power plants are banned. The specific ramifications of these depend on the locale in question.
Nuclear-free zones usually neither address nor pro ...
policy. Workers involved in the clean-up program campaigned for compensation for radiation-related illnesses they experienced in the years after the accident.
__TOC__
Thule Monitor Mission
In 1960, the
USAF
The United States Air Force (USAF) is the Aerial warfare, air military branch, service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part ...
Strategic Air Command (SAC) began
Operation Chrome Dome
Operation Chrome Dome was a United States Air Force Cold War-era mission from 1960 to 1968 in which B-52 strategic bomber aircraft armed with thermonuclear weapons remained on continuous airborne alert and flew routes to points on the Soviet ...
, a
Cold War airborne alert program devised by General
Thomas S. Power
General Thomas Sarsfield Power (June 18, 1905 – December 6, 1970) was a United States Air Force officer who served as commander in chief of the Strategic Air Command. He was an active military flier for more than 30 years.
Early career
Thomas ...
to fly nuclear-armed
Boeing B-52 Stratofortress bombers to the borders of the Soviet Union. The flights were scheduled to ensure that twelve bombers were aloft at all times. These bombers gave SAC offensive capability in the event of a Soviet
first strike, Beginning in 1961, B-52 bombers also secretly flew as part of the "Hard Head" mission (or "Thule Monitor Missions") over Thule Air Base. The objective of "Hard Head" was to maintain constant visual surveillance of the base's strategically important
Ballistic Missile Early Warning System
The RCA 474L Ballistic Missile Early Warning System (BMEWS, "474L System", Project 474L) was a United States Air Force Cold War early warning radar, computer, and communications system, for ballistic missile detection. The network of twelve ra ...
(BMEWS), which provided early warning of Soviet missile launches. This ensured that, if the communication link between
North American Aerospace Defense Command
North American Aerospace Defense Command (NORAD ), known until March 1981 as the North American Air Defense Command, is a combined organization of the United States and Canada that provides aerospace warning, air sovereignty, and protection ...
and the base was severed, then the aircraft crew could determine if the interruption resulted from an actual attack or a mere technical failure. The monitoring mission started when the designated aircraft reached a
waypoint A waypoint is an intermediate point or place on a route or line of travel, a stopping point or point at which course is changed, the first use of the term tracing to 1880. In modern terms, it most often refers to coordinates which specify one's posi ...
at in Baffin Bay and entered a figure-eight
holding pattern
In aviation, holding (or flying a hold) is a maneuver designed to delay an aircraft already in flight while keeping it within a specified airspace.
Implementation
A holding pattern for instrument flight rules (IFR) aircraft is usually a racet ...
above the air base at an altitude of .
In 1966, United States Secretary of Defense
Robert McNamara
Robert Strange McNamara (; June 9, 1916 – July 6, 2009) was an American business executive and the eighth United States Secretary of Defense, serving from 1961 to 1968 under Presidents John F. Kennedy and Lyndon B. Johnson. He remains the ...
proposed cutting "Chrome Dome" flights because the BMEWS system was fully operational, the bombers had been made redundant by missiles, and $123 million ($ as of ) could be saved annually. SAC and the
Joint Chiefs of Staff
The Joint Chiefs of Staff (JCS) is the body of the most senior uniformed leaders within the United States Department of Defense, that advises the president of the United States, the secretary of defense, the Homeland Security Council and the ...
opposed the plan, so a compromise was reached whereby a smaller force of four bombers would be on alert each day. Despite the reduced program and the risks highlighted by the
1966 Palomares B-52 crash
The 1966 Palomares B-52 crash, also called the Palomares incident, occurred on 17 January 1966, when a B-52G bomber of the United States Air Force's Strategic Air Command collided with a KC-135 tanker during mid-air refueling at over the Med ...
, SAC continued to dedicate one of the aircraft to monitoring Thule Air Base. This assignment was without the knowledge of civilian authorities in the United States, who SAC determined did not have the "
need to know
The term "need to know", when used by government and other organizations (particularly those related to the military or espionage), describes the restriction of data which is considered very sensitive. Under need-to-know restrictions, even if one ...
" about specific operational points.
Broken Arrow
On 21 January 1968, a B-52G Stratofortress, serial number 58-0188, with the callsign "HOBO 28" from the
380th Strategic Bomb Wing at
Plattsburgh Air Force Base, New York was assigned the "Hard Head" mission over Thule and nearby
Baffin Bay. The bomber crew consisted of five regular crew members, including Captain John Haug, the aircraft commander. Also aboard were a substitute navigator (Captain Curtis R. Criss) and a mandatory third pilot (Major Alfred D'Mario).
Before take-off, D'Mario placed three cloth-covered foam cushions on top of a heating vent under the instructor navigator's seat in the aft section of the lower deck. Shortly after take-off, another cushion was placed under the seat. The flight was uneventful until the scheduled mid-air refueling from a
KC-135 Stratotanker
The Boeing KC-135 Stratotanker is an American military aerial refueling aircraft that was developed from the Boeing 367-80 prototype, alongside the Boeing 707 airliner. It is the predominant variant of the C-135 Stratolifter family of trans ...
, which had to be conducted manually because of an error with the B-52G's autopilot. About one hour after refueling, while the aircraft was circling above its designated area, Captain Haug directed co-pilot Svitenko to take his rest period. His seat was taken by the spare pilot, D'Mario. The crew was uncomfortable because of the cold, although the heater's
rheostat
A potentiometer is a three-terminal resistor with a sliding or rotating contact that forms an adjustable voltage divider. If only two terminals are used, one end and the wiper, it acts as a variable resistor or rheostat.
The measuring instrume ...
was turned up, so D'Mario opened an
engine bleed valve to draw additional hot air into the heater from the engine manifold. Because of a heater malfunction, the air barely cooled as it traveled from the engine manifold to the cabin's heating ducts. During the next half-hour, the cabin's temperature became uncomfortably hot, and the stowed cushions ignited. After one crew member reported smelling burning rubber, they looked for a fire. The navigator searched the lower compartment twice before discovering the fire behind a metal box. He attempted to fight it with two fire extinguishers, but could not put it out.
At 15:22 EST, about six hours into the flight and south of Thule Air Base, Haug declared an emergency. He told Thule
air traffic control
Air traffic control (ATC) is a service provided by ground-based air traffic controllers who direct aircraft on the ground and through a given section of controlled airspace, and can provide advisory services to aircraft in non-controlled airs ...
that he had a fire on board and requested permission to perform an emergency landing at the air base. Within five minutes, the aircraft's fire extinguishers were depleted, electrical power was lost and smoke filled the cockpit to the point that the pilots could not read their instruments.
[AEC Observers' Interim Report of Thule Accident, 1968] As the situation worsened, the captain realized he would not be able to land the aircraft and told the crew to prepare to abandon it. They awaited word from D'Mario that they were over land, and when he confirmed that the aircraft was directly over the lights of Thule Air Base, the four crewmen ejected, followed shortly thereafter by Haug and D'Mario. The co-pilot, Leonard Svitenko, who had given up his ejection seat when the spare pilot took over from him, sustained fatal head injuries when he attempted to bail out through one of the lower hatches.
The pilotless aircraft initially continued north, then turned left through 180° and crashed onto sea ice in North Star Bay at a relatively shallow angle of 20 degrees—about west of Thule Air Base—at 15:39 EST. The conventional
high explosive
An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An ...
(HE) components of four 1.1
megaton
Megaton may refer to:
* A million tons
* Megaton TNT equivalent, explosive energy equal to 4.184 petajoules
* megatonne, a million tonnes, SI unit of mass
Other uses
* Olivier Megaton (born 1965), French film director, writer and editor
* ''Me ...
B28FI thermonuclear bombs detonated on impact, spreading
radioactive material
A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is a nuclide that has excess nuclear energy, making it unstable. This excess energy can be used in one of three ways: emitted from the nucleus as gamma radiation; transfe ...
over a large area in a manner similar to a
dirty bomb
A dirty bomb or radiological dispersal device is a radiological weapon that combines radioactive material with conventional explosives. The purpose of the weapon is to contaminate the area around the dispersal agent/conventional explosion with ...
.
"Weak links" in the weapon design ensured that a
nuclear explosion
A nuclear explosion is an explosion that occurs as a result of the rapid release of energy from a high-speed nuclear reaction. The driving reaction may be nuclear fission or nuclear fusion or a multi-stage cascading combination of the two, tho ...
was not triggered. The extreme heat generated by the burning of of jet fuel during the five to six hours after the crash melted the ice sheet, causing wreckage and munitions to sink to the
ocean floor
The seabed (also known as the seafloor, sea floor, ocean floor, and ocean bottom) is the bottom of the ocean. All floors of the ocean are known as 'seabeds'.
The structure of the seabed of the global ocean is governed by plate tectonics. Most of ...
.
Haug and D'Mario parachuted onto the grounds of the air base and made contact with the base commander within ten minutes of each other. They informed him that at least six crew ejected successfully and the aircraft was carrying four nuclear weapons. Off-duty staff were mustered to conduct search and rescue operations for the remaining crew members. Owing to the extreme weather conditions, Arctic darkness, and unnavigable ice, the base relied largely on the Thule representative of the Royal Greenland Trade Department, Ministry of Greenland, Jens Zinglersen, to raise and mount the search using native dog sled teams. Three of the survivors landed within of the base and were rescued within two hours. For his initial actions and later services, Zinglersen received the Air Force Exceptional Civilian Service Medal on 26 February 1968 at the hands of the U.S. Ambassador, K. E. White. Captain Criss, who was first to eject, landed from the base—he remained lost on an ice floe for 21 hours and suffered
hypothermia
Hypothermia is defined as a body core temperature below in humans. Symptoms depend on the temperature. In mild hypothermia, there is shivering and mental confusion. In moderate hypothermia, shivering stops and confusion increases. In severe ...
in the temperatures, but he survived by wrapping himself in his parachute.
An aerial survey of the crash site immediately afterwards showed only six engines, a tire and small items of debris on the blackened surface of the ice. The accident was designated a
Broken Arrow, or an accident involving a nuclear weapon but which does not present a risk of war.
Project Crested Ice
The resulting explosion and fire destroyed many of the components that had scattered widely in a by area. Parts of the
bomb bay
The bomb bay or weapons bay on some military aircraft is a compartment to carry bombs, usually in the aircraft's fuselage, with "bomb bay doors" which open at the bottom. The bomb bay doors are opened and the bombs are dropped when over t ...
were found north of the impact area, indicating the aircraft started to break-up before impact. The ice was disrupted at the point of impact, temporarily exposing an area of seawater approximately in diameter; ice floes in the area were scattered, upturned and displaced. South of the impact area, a by blackened patch was visible where fuel from the aircraft had burned—this area was highly contaminated with
JP-4 aviation fuel and radioactive elements that included
plutonium
Plutonium is a radioactive chemical element with the symbol Pu and atomic number 94. It is an actinide metal of silvery-gray appearance that tarnishes when exposed to air, and forms a dull coating when oxidized. The element normally exhibi ...
,
uranium
Uranium is a chemical element with the symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weak ...
,
americium and
tritium
Tritium ( or , ) or hydrogen-3 (symbol T or H) is a rare and radioactive isotope of hydrogen with half-life about 12 years. The nucleus of tritium (t, sometimes called a ''triton'') contains one proton and two neutrons, whereas the nucleus of ...
. Plutonium levels as high as 380 mg/m
2 were registered in the area.
American and Danish officials immediately launched "Project Crested Ice" (informally known as "Dr. Freezelove"), a clean-up operation to remove the debris and contain environmental damage. Despite the cold, dark Arctic winter, there was considerable pressure to complete the clean-up operation before the sea ice melted in the spring and deposited further contaminants into the sea.
Weather conditions at the site were extreme; the average temperature was , at times dropping to . These temperatures were accompanied by winds of up to . Equipment suffered high failure-rates and batteries worked for shorter periods in the cold; operators modified their scientific instruments to allow the battery packs to be carried under their coats to extend the batteries' lifespan. The operation was conducted in
arctic darkness until 14 February, when sunlight gradually began appearing.
A base camp (named "Camp Hunziker" after
Richard Overton Hunziker
Richard Overton Hunziker (6 July 1916 – 29 May 1971) was a decorated World War II fighter pilot and later United States Air Force major general. He played a significant role in the Cold War and commanded operations at Project Crested Ice.
Ea ...
, the USAF general in charge of the operation), was created at the crash site; it included a heliport, igloos, generators and communications facilities. A "zero line" delineating the by area in which
alpha particle
Alpha particles, also called alpha rays or alpha radiation, consist of two protons and two neutrons bound together into a particle identical to a helium-4 nucleus. They are generally produced in the process of alpha decay, but may also be pr ...
contamination could be measured was established by 25 January, four days after the crash. The line was subsequently used to control
decontamination
Decontamination (sometimes abbreviated as decon, dcon, or decontam) is the process of removing contaminants on an object or area, including chemicals, micro-organisms or radioactive substances. This may be achieved by chemical reaction, disinfecti ...
of personnel and vehicles. An
ice road
An ice road or ice bridge is a human-made structure that runs on a frozen water surface (a river, a lake or a sea water expanse).Masterson, D. and Løset, S., 2011, ISO 19906: Bearing capacity of ice and ice roads, Proceedings of the 21st Inte ...
was constructed to Thule from the site. This was followed by a second, more-direct road so that the ice on the first road was not fatigued by overuse. The camp later included a large prefabricated building, two ski-mounted buildings, several huts, a decontamination trailer and a latrine. These facilities allowed for 24-hour operations at the crash site.
The USAF worked with Danish nuclear scientists to consider the clean-up options. The spilled fuel in the blackened area was heavily contaminated, raising concerns that when the ice melted in the summer, the radioactive fuel would float on the sea and subsequently contaminate the shore. The Danes thus insisted on the removal of the blackened area to avoid this possibility. The Danes also requested that the nuclear material not be left in Greenland after the cleanup operation was complete, therefore requiring General Hunziker to remove the contaminated ice and wreckage to the United States for disposal. USAF personnel used
grader
A grader, also commonly referred to as a road grader, motor grader, or simply a blade, is a form of heavy equipment with a long blade used to create a flat surface during grading. Although the earliest models were towed behind horses, and lat ...
s to collect the contaminated snow and ice, which was loaded into wooden boxes at the crash site. The boxes were moved to a holding area near Thule Air Base known as the "Tank Farm". There, contaminated material was loaded into steel tanks prior to being loaded onto ships. Debris from the weapons was sent to the
Pantex plant in
Texas
Texas (, ; Spanish: ''Texas'', ''Tejas'') is a state in the South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2020, it is the second-largest U.S. state by ...
for evaluation,
and the tanks were shipped to
Savannah River in
South Carolina
)'' Animis opibusque parati'' ( for, , Latin, Prepared in mind and resources, links=no)
, anthem = " Carolina";" South Carolina On My Mind"
, Former = Province of South Carolina
, seat = Columbia
, LargestCity = Charleston
, LargestMetro = ...
. According to General Hunziker, 93 percent of the contaminated material was removed from the accident site.
In 1987–88 and again in 2000, reports surfaced in the Danish press that one of the bombs had not been recovered. SAC stated at the time of the accident that all four bombs were destroyed. In 2008, the
BBC #REDIRECT BBC #REDIRECT BBC
Here i going to introduce about the best teacher of my life b BALAJI sir. He is the precious gift that I got befor 2yrs . How has helped and thought all the concept and made my success in the 10th board exam. ...
...
published an article that was based on its examination of partly declassified documents obtained some years earlier, via the United States
. The documents appeared to confirm that within weeks of the accident, investigators realized only three of the weapons could be accounted for. One of the declassified documents—dated to January 1968—details a blackened section of ice which had refrozen with
from a weapon parachute: "Speculate something melted through the ice such as burning
or secondary." A July 1968 report states, "An analysis by the AEC of the recovered secondary components indicates recovery of 85 percent of the uranium and 94 percent, by weight, of three secondaries. No parts of the fourth secondary have been identified."
The BBC tracked down several officials involved in the accident's aftermath. One was William H. Chambers, a former nuclear-weapons designer at the
. Chambers headed a team dealing with nuclear accidents, including the Thule crash. He explained the logic behind the decision to abandon the search: "There was disappointment in what you might call a failure to return all of the components ... it would be very difficult for anyone else to recover classified pieces if we couldn't find them."
In August 1968, the United States military sent a Star III mini-submarine to the base to look for weapon debris, especially the uranium-235 fissile core of a secondary. A much bigger operation at
off the coast of Spain two years earlier led to the recovery of a lost nuclear weapon from the
bomb was lost for 80 days after a mid-air collision between a B-52 on a "Chrome Dome" mission and its
refueling aircraft. Christensen asserts that the purpose of the underwater search at Thule was obvious to the Danish authorities, contrary to other reports that suggested its true purpose had been hidden from them. At lower levels, however, the dives were surrounded by some confidentiality. One document from July 1968 reads, "Fact that this operation includes search for object or missing weapon part is to be treated as
", meaning it was not to be disclosed to non-US nationals. It continues, "For discussion with Danes, this operation should be referred to as a survey, repeat survey of bottom under impact point." Further indications of the search are apparent in a September 1968 interim report by the