Transcript

Broken Arrow Over Greenland: Thule, 1968

From The History Guy: History Deserves to Be Remembered · Episode page · Watch on YouTube

· 17 min · 2,686 words · 21 timestamped sections

This is the full, timestamped transcript of "Broken Arrow Over Greenland: Thule, 1968", an episode of The History Guy: History Deserves to Be Remembered published January 21, 2026 (17 min, about 2,686 words). It mentions 16 people, works and ideas, including Operation Chrome Dome, John Hog, Alfred Deario, Frank Hopkins, Tuli Air Force Base.

What this episode is about

is the heightened awareness of the risks associated with storing and transporting nuclear arms. The 1968 incident involving a mattress fire at Thule Air Base in Greenland, which led to the accidental release of four thermonuclear bombs, underscores the potential dangers of such military protocols and the consequences of accidents involving nuclear weaponry during the Cold War.

Key takeaways

  • More than 20,000 mattress fires annually prove that even restful nights can ignite chaos.
  • A single mattress fire once triggered a nuclear incident—proof that hazards turn history into a ticking time bomb.
  • Operation Chrome Dome kept bombers airborne at all times, but risk management fell asleep at the wheel.
  • From Greenland to the USSR: a mattress mishap became the spark for Cold War nuclear strategy.
  • Sometimes, the biggest dangers are hidden—like nuclear weapons flying in figure eights over Greenland.

Who speaks in this episode?

What is discussed, and when

  1. – 3:00: Operation Chrome Dome
  2. – 6:00: Michael Quigley, Operation Blue J, Operation Hardhead
  3. – 9:00: Alfred Deario, Frank Hopkins, John Hog, Tuli Air Force Base
  4. – 12:00: Project Crested Ice
  5. – 15:00: Project Crested Ice, Atomic Energy Commission, Los Alamos Scientific Laboratory
  6. – 16:35: Operation Chrome Dome

Notable quotes from "Broken Arrow Over Greenland: Thule, 1968"

  • The operation after 1961 under the overall title Operation Chrome Dome officially flew three routes. A western route over Alaska, a northern route over Greenland, and a southern route over.
    about Operation Chrome Dome · at
  • Remote location under the code name Operation Blue J involved some 12,000 men and was so difficult that Quigley notes that the effort was compared to that of building the…
    about Michael Quigley · at
  • Orbit continuously near the Tuli Greenland site of the ballistic missile early warning system. The aircraft would be in a position to determine quickly the nature of any…
    about Tuli Air Force Base · at
  • Alfred Deario was the third pilot. The navigator was Major Frank Hopkins with substitute navigator Captain Curtis R.
    about Curtis R. Chris · at
  • The cabin was quickly filling with smoke. Hog immediately contacted Tulie, requesting permission for an emergency landing and began his descent. The crew was trying to control the problem. Markx opened a window to exhaust the smoke.
    about John Hog · at
  • The co-pilot, did not have an ejection system as Deario, the third pilot, was occupying his seat. Cventco was forced to jump out through a lower hatch and tragically sustained…
    about Leonard Seinkco · at
  • Of 14,720 cubic feet, was completed by February 20th. While Grant notes that US and Danish officials both concluded that the radioactivity spread was not a hazard to people or biological species, the US nonetheless agreed to remove all the.
    about Rebecca Grant · at

Who and what is mentioned in this episode?

People

  • John Hog — Person · Referenced participant (aircrew commander) · 1 mention · first at
    Identified as the B-52G aircraft commander (Hobo 28) who requested emergency landing and ordered bailout during the Thule crash sequence.
  • Alfred Deario — Person · Referenced participant (third pilot) · 1 mention · first at
    Described as the third pilot whose placement of seat cushions near a heat source contributed to the onboard fire; also occupied a seat affecting ejection availability.
    Flight hours, the aircraft's cabin temperature became uncomfortably cool, Deario increase the cabin heat by switching to the emergency right-hand inboard position, the cabin's…
  • Frank Hopkins — Person · Referenced participant (navigator) · 1 mention · first at
    Named as the navigator who attempted to fight the fire and later survived a prolonged exposure after ejecting and landing far from base.
    Was trying to control the problem. Markx opened a window to exhaust the smoke from the cabin while Hopkins tried to smother the fire with an aviator flight kit or A3 bag.…
  • Michael Quigley — Person · Referenced expert (museum representative) · 1 mention · first at
    Provides historical context on US military presence in Greenland and the establishment/strategic role of the Thule base and BMEWS.
  • Leonard Seinkco — Person · Referenced participant (co-pilot; fatality) · 1 mention · first at
    Identified as the co-pilot who could not use an ejection seat due to seat occupancy and died after exiting via a lower hatch.
  • Rebecca Grant — Person · Referenced journalist/author · 1 mention · first at
    Quoted as an Air Force Magazine writer summarizing the cause and consequences of the Thule B-52 fire/crash and nuclear weapon breakup.
  • Curtis R. Chris — Person · Referenced participant (substitute navigator) · 1 mention · first at
    Listed as the qualified substitute navigator carried due to mission length/crew requirements on the Thule monitoring flight.
  • Jeffrey Carwell — Person · Referenced eyewitness · 1 mention · first at
    Quoted as an eyewitness at Thule (in the NCO club) describing the crash impact; cited via military.com.
    Were found 5 mi north of the impact point, which was some 7 and 12 miles from Tuli base. Jeffrey Carwell, a shipping clerk for a Danish contractor, was in the NCO's club at…
  • Calvin Snap — Person · Referenced participant (aerial gunner) · 1 mention · first at
    Named as the staff sergeant serving as aerial gunner aboard Hobo 28 during the incident.
    Chris. The crew also included an electronic warfare officer, Captain Richard Marx, and an aerial gunner, Staff Sergeant Calvin Snap. Rebecca Grant wrote in a 2011 edition of…

Companies & orgs

  • Los Alamos Scientific Laboratory — Company · 1 mention · first at
    The US scientific group eventually included 23 scientists from facilities like the Los Alamos Scientific Laboratory and the Atomic Energy Commission. American and Danish.
  • Atomic Energy Commission — Company · 1 mention · first at
    The US scientific group eventually included 23 scientists from facilities like the Los Alamos Scientific Laboratory and the Atomic Energy Commission. American and Danish.

Places & events

  • Operation Chrome Dome — Event · 2 mentions · first at
  • Tuli Air Force Base — Place · 1 mention · first at
  • Project Crested Ice — Event · 2 mentions · first at
    Immediately began a program to collect the crash debris and radioactive material. Officially called Project Crested Ice, the men involved in formerly called the project Dr.…
  • Operation Blue J — Event · 1 mention · first at
    The base was part of a NATO defense program and Denmark being among the first nations to join NATO. The construction of the base in such a remote location under the code name…
  • Operation Hardhead — Event · 1 mention · first at
    The nature of any communications failure between the site and warning centers in the United States. These flights operated under the code name Operation Hardhead. The flights…

Full transcript with timestamps

Mattress fires are a relatively common hazard in the United States. According to the US Fire Administration, there are more than 20,000 mattress fires every year, causing hundreds of injuries and even several fatalities. You should always be careful with open flame around bedding or placing a space heater too close by because mattress fires can cause significant damage. For example, on January 21st, 1968, when a mattress fire caused the United States Air Force to drop four thermonuclear bombs on Greenland, it's history that deserves to be remembered.

Noting the risk that a surprise nuclear first strike by the Soviet Union could the US ability to retaliate, United States Air Force General Thomas S. power in charge of the strategic air command proposed a radical solution. Keep a significant portion of the US nuclear armed B-52 strategic bombers airborne at all times allowing the planes to carry out a retaliatory strike against the Soviet Union at any moment. The first pilot program began in 1958 and at its height, the US had a dozen nuclear bombers in the air at any given time, flying routes that positioned the aircraft carrying as many as four thermonuclear bombs to quickly attack the Soviet Union. A mission could typically take 24 hours, requiring two refueling stops. The brisk pace in a single month, November 1961, more than 2,000 sorties were flown, totaling more than 47,000 flight hours, stressed both crews and airframes. Accidents were

inevitable. Between 1961 and 1966, the program had resulted in four accidents involving the loss of nuclear weapons. Those accidents are the subjects of other episodes of the history guide, but one, a January 1966 accident over Spain, resulted in a significant international incident. A collision during refueling resulted in the crash of both a B-52G and a KC135 tanker aircraft and resulted in the loss of four nuclear weapons causing radiological contamination across approximately two square kilometers. One result of the accident was that the Spain banned US aircraft carrying nuclear weapons from flying over Spain.

The program was not just a risk to its crews but to international relations. Still, the program continued even as better early warning systems and the development of intercontinental ballistic missiles reduced the strategic need. By 1968, the program had been significantly reduced. The operation after 1961 under the overall title Operation Chrome Dome officially flew three routes. A western route over Alaska, a northern route over Greenland, and a southern route over Europe. The northern route offered a particular risk. Greenland is a territory of Denmark which in 1957 banned nuclear weapons over its territory. While Prime Minister HC Hansen specifically or at least tacitly allowed the planes carrying nuclear weapons to overfly Greenland, an accident there involving nuclear weapons carried particular political risk. But the northern route was not in fact the only part of Operation Chromedome

operating over Greenland. Michael Quigley of the Perry McMillan Arctic Museum in Brunswick, Maine explains that the US military began operating in Greenland when the Kingdom of Denmark fell to the Nazis in 1940. An agreement was made at the time allowing the US military access to Greenland for the protection of the Danish colony in the North American continent. However, the strategic value of the island remained after the war. Quigley explains, "As World War II gave way to the Cold War, Greenland's geographic advantage to the United States shifted from its proximity to Europe to its proximity to the USSR.

Between 1951 and 1953, the United States established an air base in remote northwestern Greenland. what had originally been established as a weather station during the Second World War, built at the site of a former Inuit village called Tuli. The far northern location was directly across the North Pole from the Soviet Union and was considered the farthest northern location that could be reliably supplied by sea. Location was seen as a strategically valuable location from which planes could be launched to intercept Soviet bombers attacking across the pole. The agreement to build the base was part of a NATO defense program and Denmark being among the first nations to join NATO. The construction of the base in such a remote location under the code name Operation Blue J involved some 12,000 men and was so difficult that Quigley notes that the effort was compared to that of building the Panama Canal. A

feat made even more impressive as it was done in secret. In 1960, a new installation was added to the base, site J, where a massive phased radar array called ballistic missile early warning system or beuse was installed to provide the earliest possible warning of a Soviet ballistic missile strike. But there was a concern as the remote location meant that contact with the base could be lost due to weather. Thus, according to a now declassified 1969 Air Force report, in August 1961, the sink sack, General Thomas S. power gave the operation a new dimension when he ordered that the B-52 orbit continuously near the Tuli Greenland site of the ballistic missile early warning system. The aircraft would be in a position to determine quickly the nature of any communications failure between the site and warning centers in the United States. These flights operated under the code name Operation Hardhead. The flights operated from

Platsburg Air Force Base in northern New York. Instead of the normal routes flown by the operation chromedome planes, the 24-hour Tuli monitoring mission would fly to Tuli and operate in a figure 8 or bow tie pattern at 35,000 ft monitoring the base. On January 21st, 1968, a B-52G of the 380th Strategic Aerospace Wing using the call sign Hobo28 flew the Tuli monitoring mission cenamed Junkie 14. Crew E14, including according to the Air Force and owing to the mission length, one qualified substitute navigator and a required third pilot was operating the plane. The aircraft was commanded by Captain John Hog. Captain Leonard Seinkco was the co-pilot and Major Alfred Deario was the third pilot. The navigator was Major Frank Hopkins with substitute navigator Captain Curtis R.

Chris. The crew also included an electronic warfare officer, Captain Richard Marx, and an aerial gunner, Staff Sergeant Calvin Snap. Rebecca Grant wrote in a 2011 edition of Air Force magazine, "Hobo 28 was an experienced crew that made one small mistake. Extra seat cushions were brought aboard for the flight and placed too close to a heat source." The 1969 report explains that Deario, the third pilot, was assigned to occupy the instructor navigator's position. Before takeoff, he placed three clothcovered foam rubber cushions under the seat and on top of the hot air spray tube.

Shortly after takeoff, a fourth cushion was placed under the seat and a metal box was placed in front of and against the cushions. When after four or five flight hours, the aircraft's cabin temperature became uncomfortably cool, Deario increase the cabin heat by switching to the emergency right-hand inboard position, the cabin's heating and pressurization system. This drew hot air in directly from the engine manifold. The report explains the heat coming from the duct under the seat was hot enough to ignite the flammable cushions stuffed under the duct.

At 2022 hours, the electronic warfare officer reported that he smelled burning rubber. Fire is always a risk on a complex aircraft. The report says after a search, the smoldering cushions were discovered and fire extinguishers were brought into action. These firefighting actions were unsuccessful. Flames soon blossom from beneath the seat. The cabin was quickly filling with smoke. Hog immediately contacted Tulie, requesting permission for an emergency landing and began his descent. The crew was trying to control the problem. Markx opened a window to exhaust the smoke from the cabin while Hopkins tried to smother the fire with an aviator flight kit or A3 bag. Hopkins was not successful and according to the report, he reported the fire as uncontrollable.

Hog was trying to land the plane, but shortly after 2030 hours, the bomber's electrical power failed. When the aircraft commander estimated that he was close to Tuli Air Force Base, he ordered the crew to bail out. The time was 2037. The B-52 has a robust ejection system, but there was a problem in that Hobo 28 was carrying extra crew. The report states that six air crew members ejected safely at about 14,000 ft, although all received injuries. But Captain Cinko, the co-pilot, did not have an ejection system as Deario, the third pilot, was occupying his seat. Cventco was forced to jump out through a lower hatch and tragically sustained fatal injuries. The abandoned aircraft flew over the base, made a 180° turn, and started to break apart. Eventually, parts, including the Bombay doors, wing panels, and flaps, were found 5 mi north of the impact point, which was some 7 and 12 miles from Tuli base. Jeffrey Carwell, a

shipping clerk for a Danish contractor, was in the NCO's club at Tuli when the bomber crashed. It was quoted on the website military.com. The massive building shook as if an earthquake had hit. Tuli base at the time was operated by the 4683rd Air Defense Wing. The Air Force report writes that its reaction to this emergency was prompt and effective. The report reads, "The first priority was of course to rescue the crew. Speed was essential since the ground temperature was minus 24 degrees. Hog had waited until he was near the base to order the bailout and most of the crew landed near the base. In fact, two landed among base buildings. Five of the six survivors were rescued within 2 hours, although Hopkins, who had been the first to eject, had landed further away on an ice flow. He was subject to the weather for 21 hours before rescue and managed to stay alive by wrapping himself in his parachute.

Cventco's remains were also recovered. The report notes, helicopters of detachment 18, 54th Air Rescue and Recovery Squadron, flew nine sortizes in the next 19 hours. Eight other sorts were flown by other base aircraft. Base vehicles, including the taxi fleet, assisted in search operations. The plane had impacted on an Arctic ice shelf over Northstar Bay. The wreckage was still burning when the crash site was first observed by a base helicopter. The plane had been carrying four B28 thermonuclear bombs, the same type of bombs that had caused the radiological contamination in Spain in 1966.

The B28FI, meaning full fusing internal bombs, were 22 in in diameter, 145 in long, and weighed 2350 lb. Their yield was 1.1 megat tons, or the equivalent of 1,100,000 tons of TNT. Although there was no chance of a nuclear detonation, the bombs disintegrated on impact. Grant writes, "The B-52 and its four nuclear weapons dug a long charred scar in the ice. The four bombs held more than 13 pounds of plutonium, about half spilled onto the blacken streak, which also had tritium contamination and perhaps a half pound of the plutonium lodged in the ice. The remainder saturated the wreckage itself. The Tuli crash with bombs loose on Greenland territory was a diplomatic nightmare. Greenland belonged to Denmark and Denmark had a nuclear-free policy. Both the US and Danish governments falsely claimed that the accident had been a one-off as the plane needed to make an emergency landing, hiding that nuclear armed

planes were routinely operating over Greenland. US and Danish officials immediately began a program to collect the crash debris and radioactive material. Officially called Project Crested Ice, the men involved in formerly called the project Dr. Freeze Love. The project took place in two stages. In the first phase, all debris not embedded in the ice was collected and placed in temporary storage on Tuli base to be shipped in the summer, or as in the case of weapons components shipped by air to the United States. This phase, which collected a total of 163 drums, 14 engine containers, and 11 large fuel tanks of debris, a capacity of 14,720 cubic feet, was completed by February 20th. While Grant notes that US and Danish officials both concluded that the radioactivity spread was not a hazard to people or biological species, the US nonetheless agreed to remove all the radioactive ice. The report states phase

two of the recovery plan ultimately consisted of removing the contaminated ice and snow, transporting it to Tuli Base, and packing it in containers to be transported back to the US for disposal. The project would include over 700 specialized workers representing 70 different agencies and about 1,200 Danish and local workers assisting. Working in temperatures grant rights of minus25° F and often windchill below -50°. The US scientific group eventually included 23 scientists from facilities like the Los Alamos Scientific Laboratory and the Atomic Energy Commission. American and Danish scientists, although relations were friendly, disagreed over the amount of material that had to be removed. A facility was established near the crash site and the cleanup would eventually take four months and collect 237,000 cubic feet of radioactive snow and ice, some of which was not removed from the base to the United States until the

following September. The project cost an estimated $9.4 million. At issue was the extent to which the nuclear material was recovered. Despite statements that all four bombs have been recovered and the Air Force report concluding in all ways crusted ice must be judged highly successful in a well-managed operation. Documents obtained by BBC in 2008 indicate that the US was aware that parts of the fourth bomb were never recovered despite even a search of the seafloor by a small submersible. Analysis of the documents have disagreed over the amount of material loss and the risk to the environment and native peoples.

The accidents at Tuli Greenland in Palomari Spain led to research and development of insensitive high explosives. These more stable, high explosives are less likely to accidentally detonate in extreme circumstances like impact or fire or electrical shock. And that makes both workplaces and nuclear weapons triggers much safer. Had they been available, they might have prevented the explosion of the conventional explosives in the warheads that caused the dispersal of the radioactive materials, Palomaris and Tuli. A 1997 investigation by Danish authorities determined that Prime Minister HC Hansen had deliberately allowed ambiguity in the 1957 base agreement tacitly allowing the US to operate nuclear armed aircraft and until 1965 even store nuclear weapons in Greenland despite the stated non-uclear policy dubbed Tuligate. The political scandal however directed more fault at Hansen than at the United States. Both

American and Danish workers have claimed that they have ill health effects from exposure to materials during the Tuli cleanup. Both have had trouble recovering damages and getting medical care from their respective governments who disagree with him over the amount of exposure despite extraordinarily high cancer rates among people who participated in the cleanup. Those lawsuits are still ongoing. The importance of the base for nuclear deterrence decreased with time and technological developments. In 2020, the base was officially turned over to the US Space Force, recognizing its now primary role of space and climate research. The base was renamed Beafik Space Base using a native name for the area. The Tuli accident was the last for Operation Chrome Dome. The already fading program could not withstand the fallout, both radiological and political. The program officially ended on January 22nd, 1968, the day after the

Tuli crash. I hope you enjoyed watching this episode of The History Guy. And if you did, please feel free to like and subscribe and share the history guy with your friends. And if you also believe that history deserves to be remembered, then you can support the history guy as a member on YouTube, a supporter on our community at locals, or as a patron on Patreon. You can also check out our great merchandise shop or book a special message from the history guy on Cameo.

Questions about this episode

Who speaks in "Broken Arrow Over Greenland: Thule, 1968"?

The History Guy (Host), Michael Quigley (Guest), Rebecca Grant (Guest), Captain John Hog (Guest), Captain Leonard Seinkco (Guest), Major Alfred Deario (Guest), Major Frank Hopkins (Guest), Captain Curtis R. Chris (Guest).

What is "Broken Arrow Over Greenland: Thule, 1968" about?

is the heightened awareness of the risks associated with storing and transporting nuclear arms. The 1968 incident involving a mattress fire at Thule Air Base in Greenland, which led to the accidental release of four thermonuclear bombs, underscores the potential dangers of such military protocols and the consequences of accidents involving nuclear weaponry during the Cold War.

What is mentioned in this The History Guy: History Deserves to Be Remembered episode?

16 people, works and ideas are mentioned, including Operation Chrome Dome, John Hog, Alfred Deario, Frank Hopkins, Tuli Air Force Base, Michael Quigley. Each one on this page links to its own page with every episode that mentions it.

How long is "Broken Arrow Over Greenland: Thule, 1968"?

The episode runs 17 min; the transcript is about 2,686 words in 21 timestamped sections.

More from The History Guy: History Deserves to Be Remembered

About this transcript: the episode's spoken words as captioned on YouTube, split into timestamped sections. Reclip.Me locates every person, work and idea in the text, keeps the time it is first named, and quotes the words around it verbatim. Last updated January 21, 2026.