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From car keys to glasses to rifles, everyone misplaces something important from time to time. But when you’re the U.S. government, sometimes that important thing is a superweapon that is designed to destroy cities and kill millions of people.

Over the decades, the U.S. military has had 32 nuclear accidents, also called “Broken Arrow” incidents. These incidents include accidental launches, radioactive contamination, loss of a nuclear weapon or other unexpected events involving nuclear weapons. Luckily, of those 32 accidents, there were only six U.S. nuclear weapons that could not be located or recovered, and of those six weapons, only one was capable of a nuclear detonation when it was lost.

While even one missing nuclear weapon sounds scary, it’s worth noting that the Soviet Union lost far more during the Cold War, often due to submarines sinking with a dozen or more nuclear missiles on board.

“Compared to the Soviet Union, the U.S. record is pretty impressive, given how many nuclear weapons it has operated and transported everywhere over the years,” Hans Kristensen, director of the Nuclear Information Project for the Federation of American Scientists, told Task & Purpose.

palomares
Barrels of contaminated soil collected at Palomares, Spain for removal to the United States, 1966. (U.S. Air Force)

In fact, U.S. government agencies often go to great lengths to secure lost weapons. One such incident occurred on Jan. 17, 1966, when a B-52 and a KC-135 refueling tanker collided over southern Spain and scattered four B-28 thermonuclear bombs around the fishing village of Palomares. The conventional explosives for two of the bombs exploded, but the nuclear components did not detonate because they were not armed. The U.S. military sent troops to pick up the undetonated one that fell on land, clean up the radioactive pieces scattered by the two which detonated, and find the fourth which landed in the sea. The U.S. government even dispatched a submarine to find the one in the Mediterranean Sea. Called ‘Alvin,’ the small deep-ocean sub was high-tech for its time, but the crew nearly died when the sub was almost entangled in the parachute that was still attached to the bomb on the ocean floor. Meanwhile, the service members who helped find the landward bombs and clean up the wreckage also developed cancers which they say are linked to that mission 56 years ago.

Considering the extent to which the U.S. looks for lost nukes like it did in Palomares, the stories behind the five instances where recovery crews could not locate or recover weapons are extraordinary. Below is a list of those five accidents, one of which resulted in two missing nuclear weapons. Keep in mind that in all but one, the lost nuclear weapons did not include the pit or capsule that contains the components for triggering a nuclear detonation. That means we can all sleep a little easier knowing those weapons cannot blow up a city. However, the U.S. government still classifies those pit-less devices as nuclear weapons: sophisticated, expensive machines that at the time were closely-guarded tools of mass destruction. And there are many more out there from other governments like the Soviet Union which may never be found.

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July 28, 1957 – Atlantic Ocean: An Air Force C-124 cargo aircraft that had taken off from Dover Air Force Base, Delaware lost power from two of its engines while flying over the Atlantic Ocean. Though the aircraft had two other engines, it could not maintain level flight, according to one report released in 2006 by the Department of Energy. The C-124 was carrying three nuclear weapons and one nuclear capsule at the time. Luckily, none of the weapons had the capsule installed, so none of the weapons could cause a nuclear detonation. With that in mind, the C-124 crew decided to jettison two of the weapons, perhaps to save weight and extend the aircraft’s range en route to an emergency landing near Atlantic City, New Jersey.

The US military is still missing 6 nuclear weapons that were lost decades ago
A U.S. Air Force Douglas C-124C Globemaster II (s/n 52-1035) in flight. Golden Gate Bridge and Marin County, California in the background. (U.S. Air Force)

The crew jettisoned the first weapon at an altitude at 4,500 feet, and the second at 2,500 feet. The report said that both the weapons were presumed to have been damaged by the impact from such a great height and then submerged “almost instantly.” Meanwhile the aircraft landed safely with the remaining nuclear weapon and capsule aboard.

“A search for the weapons or debris had negative results,” reads the report, which noted that the ocean varies in depth in the area of the jettisons. One of the reasons this incident stands out from the rest on this list is that the aircraft involved was a transport plane, not a bomber or attack plane like the ones involved in many of the other events. Kristensen noted that today transport aircraft like the Air Force’s C-17 are the only jets allowed to fly America’s nuclear weapons when they need to be transported for inspection, replacement or redeployment. Flying may be the only option when transporting nuclear weapons to and from bases in Europe, but within the U.S., the government prefers to use trucks and trains since they are less risky than flight, Kristensen said.

The Department of Energy even has heavily modified tractor trailers complete with booby traps, immobilizing foam and tear gas designed to stop would-be thieves while transporting nuclear weapons by road. But don’t relax just yet, there is always a chance for something to go wrong. Kristensen noted that the U.S. still has thousands of nuclear weapons in about a dozen states, a handful of European countries, and aboard 14 Ohio-class ballistic missile submarines, so there are still plenty of possibilities for individual incidents.

“We don’t constantly fly them on B-52 [bombers] anymore, but there are still plenty of movements of nuclear weapons occurring,” said Kristensen, who pointed out that there are sometimes inconsistencies in public records on how many incidents count as a ‘broken arrow.’

Feb. 5, 1958 – Tybee Island, Georgia: An Air Force B-47 bomber was flying a training mission from Homestead Air Force Base Florida when, at 3:30 a.m. while near Savannah, Georgia, the B-47 collided with an F-85 fighter jet. The B-47 pilot tried to land three times at nearby Hunter Air Force Base, Georgia, but the airplane was in rough shape, and it could not slow down enough to ensure a safe landing, the Department of Defense wrote in its list of nuclear weapons accidents. The pilot decided to ditch the Mark 15, Mod 0 nuclear weapon in Wassaw Sound, near Tybee Island, Georgia, rather than risk blowing up the base with the weapon’s 400 pounds of conventional explosives. Luckily, the nuke did not explode despite dropping from about 7,200 feet up. The B-47 landed safely, but the bomb was never found. Recovery crews searched a three-square-mile area using a ship, divers and an underwater demolition team wielding hand-held sonar devices. In 1998, a retired military officer and his partner also combed the sound with a Geiger counter but were also unsuccessful, the BBC reported earlier this month.

B-47
An air-to-air right side view of a restored B-47E-25-DT Stratojet aircraft in the markings of the 93d Bombardment Wing, June 17, 1986. The aircraft was one of the last flyable B-47s in the world. (Tech Sgt. Michael Haggerty/U.S. Air Force)

Today, the Department of Energy believes the 7,600 pound bomb is resting five to 15 feet under the seabed, according to a report shared by the BBC. The Department of Energy reported that there is no current or future possibility of a nuclear explosion, and the risk of a spread heavy metals is also low, but that could change if the bomb is disturbed. In other words, best to let sleeping nuclear dogs lie.

“[I]ntact explosive would pose a serious explosion hazard to personnel and the environment if disturbed by a recovery attempt,” the Air Force wrote in the report.

nuclear bomb
A Mark 15 Thermonuclear Bomb similar to the one lost near Tybee Island, Georgia, in 1958. (U.S. Atomic Energy Commission)

Sept 25, 1959 – Off the Washington/Oregon coast: A Navy P-5M, a flying boat designed for naval patrols and anti-submarine warfare, was carrying an unarmed nuclear anti-submarine weapon over the Pacific Ocean when it crashed in the sea about 100 miles west of the border between Washington and Oregon. Details about what led to the crash are scant, but the crew of 10 was rescued, according to the University of Southern California’s Broken Arrow Project. The nuclear weapons were not recovered, and while they did not contain any nuclear material, the weapons may still be somewhere on the ocean floor to this day.

Even if the nuclear weapons did not have nuclear material, could they be repurposed if found by bad actors? Kristensen reasoned that if the U.S. government with its abundant resources and intense focus when it comes to nuclear weapons cannot find the weapons off its own coast, then non-state actors or other countries such as Iran “have no chance to get them,” he said. “That’s just a fact.”

Indeed, the U.S. government is actually much more concerned with nuclear weapons being stolen from land-based sites rather than the few it has lost at sea. For example, in 2007 the Air Force was embroiled in controversy when a B-52 bomber crew took off from Minot Air Force Base, North Dakota and landed at Barksdale Air Force Base Louisana, not knowing they had six nuclear weapons mistakenly mounted to the aircraft’s wings. 

The US military is still missing 6 nuclear weapons that were lost decades ago
A U.S. Air Force B-52H Stratofortress assigned to the 5th Bomb Wing at Minot Air Force Base, North Dakota, flies alongside a KC-10 Extender assigned to the 305th Air Mobility Wing, Joint Base McGuire-Dix-Lakehurst, N.J., after receiving fuel, Jan. 6, 2021. (Staff Sgt. Stephanie Serrano/U.S. Air Force)

“For a day and a half the U.S. Air Force didn’t know where six of its nukes were,” Kristensen said. “That was a huge scandal.”

The incident led to significant changes in how the U.S. oversaw its nuclear command, controls and procedures, including the resignation of the Air Force secretary and chief of staff. Still, accidents happen, which is why the U.S. government pays more attention to the nukes in active circulation than the ones that were lost at sea.

Jan. 24, 1961 – Goldsboro, North Carolina:  An Air Force B-52 broke apart while on an airborne alert mission and dropped two nuclear bombs. One bomb’s parachute deployed and the weapon landed with little damage. However, the other bomb fell free and broke apart on impact, narrowly avoiding a detonation. After Robert McNamara took the post of Secretary of Defense later that year, he pointed to that incident and another nuke loss over Texas as evidence of how close the U.S. has come to accidental detonations, despite “spending millions of dollars to reduce this problem to a minimum.”

“By the slightest margin of chance, literally the failure of two wires to cross, a nuclear explosion was averted,” McNamara was quoted as saying in an article by The Guardian.

Part of that nuclear bomb containing uranium could not be recovered, even after excavating 50 feet down into waterlogged farmland, the Department of Energy wrote in a 2006 report. Kristensen explained that the nuclear core of a weapon like this one is so heavy with uranium, one of the most dense metals on Earth, that it has the capacity to sink deep into the mud, especially after falling from a great height. Since it could not find the bomb, the Air Force bought the land and anyone who wants to dig there must ask the Air Force’s permission first. There is no detectable radiation or hazard in the area, the Department of Energy wrote.

The US military is still missing 6 nuclear weapons that were lost decades ago
Air Force personnel recovering parts of a MK-39 nuclear bomb that fell from a B-52 bomber that broke up over Goldsboro in 1961. (U.S. Air Force)

The U.S. Department of Defense declassified its list of nuclear weapons-related accidents in the 1980s. In one report, the government noted that many ‘Broken Arrow’ incidents stem from human errors or mechanical malfunctions aboard the aircraft transporting the nuclear weapons, or carrying them as part of Operation Chrome Dome. From 1960 to 1968 the U.S. Air Force flew B-52 bombers armed with thermonuclear weapons on continuous airborne alert 24/7, 365 days a year. The program ended in part because of the greater risk of disaster that came with keeping nuclear weapons airborne all year long.

Dec. 5, 1965 – The Philippine Sea: While the North Carolina bomb vanished deep beneath American soil, this missing weapon disappeared in watery depths on the other side of the world. A Navy pilot was rolling his A-4 Skyhawk attack plane onto the elevator of the aircraft carrier USS Ticonderoga. The aircraft carried a B-43 thermonuclear bomb for a training exercise. All was going well until the weapons loaders and other sailors noticed that the Skyhawk was about to go over the side of the ship.

“Suddenly, the plane directors—yellow shirts—began to blow their whistles frantically while crossing their fists, directing the pilot to set his brakes. But the Skyhawk kept rolling,” retired Chief Petty Officer Delbert Mitchell, who helped load the bomb onto the plane that day, recalled in an essay for Naval History Magazine. An investigation report later revealed that the pilot was oblivious to the whistles and looking down, Mitchell noted, but that didn’t stop the sailors from trying to stop the disaster.

“The directors ran to the plane, urgently signaling and blowing their whistles,” Mitchell wrote. “The Skyhawk did not stop. One blue shirt threw a chock around the starboard main mount tire, putting himself in harm’s way to stop the rolling aircraft.”

skyhawk
U.S. Navy Douglas A-4C Skyhawk of Attack Squadron 55 (VA-55) “Warhorses” landing on the aircraft carrier USS Ticonderoga (CVA-14), after a simulated strike on “enemy” forces during an operational readiness inspection, 18 January 1963. (U.S. Navy photo)

Another sailor tried to get his chock around the port tire, but he could not, and the airplane fell into the sea below. 

“We watched helplessly as the attack plane and pilot sank into the abyss, the ship continuing to move forward,” Mitchell wrote. “It was horrifying to watch a human being die before our very eyes, powerless to save him.”

All rescuers could find was the pilot’s helmet. The rest seemed to have gone to the bottom of the ocean, under 16,000 feet of water, the sailor said. This is the only weapon on our list that was capable of a nuclear detonation when it was lost, because it was not possible to remove the core from a B-43 thermonuclear weapon, Kristensen said. Though the incident took place just 70 miles from the Ryuku Islands, the U.S. government did not notify the Japanese government about the incident until 1989. 

Other incidents:

The nuclear weapon lost in 1965 is far from the only one on the bottom of the ocean. In May 1968, the U.S. submarine Scorpion sank to the bottom of the Atlantic for unclear reasons, carrying all hands and two Mark 45 ASTOR torpedoes with nuclear warheads down with it. The incident was not included on the list of missing nukes because the U.S. government found the wreck and knows exactly where it is, though it has not recovered the weapons there. The U.S. government and the Woods Hole Oceanographic Institution have not detected contamination in its periodic monitoring of the wreck site.

The US military is still missing 6 nuclear weapons that were lost decades ago
An August, 1986 view of the bow section of the nuclear-powered attack submarine USS Scorpion (SSN-589) where it rests on the ocean floor, 10,000 feet down and 400 miles southwest of the Azores. The bow carried nuclear weapons at the time the submarine was lost. (U.S. Navy)

As bad as accidents like the ones in the Philippine Sea and the Atlantic sound, they pale in comparison to some of the mistakes made by the Soviet Union. For example, about 600 miles northeast of Bermuda, under 18,000 feet of seawater, there lies a Soviet Yankee I class nuclear-powered missile submarine that suffered an explosion and fire in one of its missile tubes on October 3, 1986. The submarine sank three days later carrying 34 nuclear warheads. U.S. forces detected no radioactivity in the air or water around the submarine, but that incident alone accounts for more missing warheads than in this entire list of missing U.S. weapons.

Still, just because the U.S. has a pretty good record now does not mean an accident can’t happen tomorrow. For example, in February 2009, a British nuclear-powered missile submarines carrying nuclear warheads collided with a French submarine also carrying nuclear warheads in the eastern Atlantic Ocean. Though there were no casualties or contamination, it goes to show that the better part of nuclear warfare is just trying not to blow yourself up.

“It’s a reminder that these weapons are still out there and accidents can happen,” Kristensen said.

Update: This article has been updated to note that there are irregularities in public records of broken arrow incidents.

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