In mid-March 1966, Alvin located the missing nuclear weapon on a steep slope about 2,550 feet below the Mediterranean off Palomares. During the first recovery attempt, a lifting line failed. The weapon slid downslope into disturbed sediment and vanished from view. The Navy had spent weeks finding it; now the same slope had to be searched again.

The collision happened over farmland

On the morning of January 17, 1966, a U.S. Air Force B-52 carrying four nuclear weapons met a KC-135 tanker above southeastern Spain for an airborne refueling.

Shortly after ten in the morning, the aircraft collided over the area around the farming village of Palomares. Seven airmen died. Four members of the B-52 crew survived. Three weapons came down on or near Spanish soil; the fourth fell into the Mediterranean.

Calling the weapons “unarmed,” as contemporary and later U.S. records often do, can be misleading if it is read as “inert.”

There was no nuclear detonation. The safety systems prevented that.

But the conventional high explosives associated with two of the weapons that hit land did detonate at low order, breaking apart their nuclear-material packages and dispersing plutonium across agricultural ground around Palomares.

So the accident immediately became two different emergencies.

One was visible on land.

The other had gone underwater.

Three bombs were easier than four

The Air Force accounted for the three land weapons quickly.

The fourth was another problem entirely.

Navy salvage specialists arrived with an unusually mixed collection of machines: surface ships, submarine-rescue vessels, small submersibles, deep-diving vehicles, remotely controlled equipment and more than 150 divers. The divers could search shallow areas and support the operation, but the suspected depth of the weapon was far beyond anything a human diver could simply descend to and retrieve.

What helped narrow the sea was a fisherman.

Francisco Simó Orts had seen something descending under a parachute toward the water on the day of the collision. He led the American search team toward the area where he believed it had entered the Mediterranean.

That observation did not hand the Navy a coordinate.

A parachute entering deep water does not necessarily deposit its load directly beneath the place where someone watched it disappear from the surface. The seabed off Palomares dropped into steep underwater terrain, and the weapon could move along it.

The search still required machines that could go down and look.

The Navy had only recently built those machines

One of them was Alvin.

The little three-person submersible had entered service only in June 1964. It belonged to a generation of vehicles intended to replace or supplement much larger bathyscaphes and give scientists and the Navy a more maneuverable way to work in the deep ocean.

Another was the PERRY “Cubmarine,” a tiny vehicle that worked shallower portions of the Palomares search area.

Then there was CURV.

CURV did not look like a submarine. It was a tethered box of equipment lowered from a ship and steered remotely through the water. The original system had been developed to recover torpedoes after test firings and was rated to about 2,000 feet.

Nobody had built CURV so that it could recover a hydrogen bomb from a Mediterranean canyon.

That assignment arrived later.

The first discovery has two dates

Even Navy records disagree slightly about exactly when Alvin first located the weapon.

The U.S. Naval Undersea Museum gives March 17, at 2,550 feet. The official history of USS Albany, flagship of the task force, gives March 15.

I do not see a good reason to choose one merely because a story reads more smoothly with an exact date.

Mid-March is enough.

What both records agree on matters more.

Alvin found the bomb.

And the first attempt to bring it back failed.

During lifting operations, a line broke. The weapon slid farther downslope, disappeared into stirred-up sediment and was lost from view.

The Navy now knew approximately where the missing nuclear weapon had been.

That is not the same thing as knowing where it was.

The second search was smaller and probably worse

Once an object has been seen, it is psychologically difficult to accept that it is missing again.

The search resumed.

The Albany history says the weapon was located again after nine more days. The Undersea Museum chronology places the second discovery on April 2 and gives the new depth as roughly 2,900 feet. Those accounts do not align perfectly on the calendar, so the exact rediscovery date is better left qualified than forced into agreement.

The useful fact is where the bomb had gone.

Deeper.

That pushed the operation past CURV’s normal design depth.

Navy engineers modified CURV I so it could operate there anyway. The Undersea Museum gives the eventual recovery depth as about 2,850 feet.

It is a small but revealing detail about how new the technology was.

Today, remotely operated vehicles working thousands of feet down are ordinary tools of offshore engineering, oceanography, archaeology, cable repair and subsea inspection.

In 1966, the machine going after the bomb had to be pushed roughly 850 feet beyond the depth it had been designed to handle.

Somebody else nearly died before they found it

The Palomares recovery is also part of Carl Brashear’s story, though not in quite the way later retellings can make it sound.

Brashear was serving aboard the salvage ship USS Hoist. On March 23, while the Navy was still searching and preparing for eventual recovery, he was directing the transfer of a crate intended to hold the weapon once it came aboard.

A supply boat broke its mooring.

A steel pipe came loose across the deck.

Brashear moved sailors out of its path and was struck in the left leg. The injuries were catastrophic. The leg was eventually amputated below the knee.

The bomb had not injured him.

The machinery surrounding the effort to recover it had.

That distinction is worth keeping because large technical operations contain ordinary industrial dangers long before their exotic centerpiece does anything.

Brashear refused efforts to retire him from active diving service. After rehabilitation and retraining, he returned to diving and in 1970 became the Navy’s first African American master diver.

Palomares took part of his leg.

It did not get his career.

Three lines

When the Navy found the bomb again, Alvin was no longer going to be asked to finish the recovery alone.

CURV went down.

Operators maneuvering it from USS Petrel attached three lifting lines to the weapon. Somewhere in that work, the bomb’s parachute tangled itself around the remotely operated vehicle.

This created a choice that sounds like something invented after the fact.

It was not.

They could try to disentangle the vehicle thousands of feet underwater and risk losing the bomb again.

Or they could pull up the entire mess.

Rear Admiral William Guest chose the second option.

Bomb. Parachute. CURV. All together.

The system came upward.

April 7

On the morning of April 7, 1966, the weapon reached the surface beside USS Petrel.

The official ship history confirms the date and says the weapon was brought aboard Petrel before being transferred to USS Cascade.

A second Navy photograph shows the bomb afterward with the sort of damage that makes the clean word recovered feel slightly dishonest.

The weapon had spent nearly three months in the Mediterranean.

The Navy had found it twice.

A football helmet

The U.S. Naval Undersea Museum owns one of the stranger artifacts from the operation.

It is a football helmet.

USS Petrel carried a submarine rescue chamber intended to reach stranded submariners at depths down to about 850 feet. Someone had brought the helmet aboard to protect his head from the steel interior of the chamber.

During the Palomares search, the divers began joking that the helmet might also protect whoever wore it if the hydrogen bomb detonated. They signed it.

It is not hard to make too much of a detail like that.

Nobody aboard Petrel seriously believed football equipment was nuclear protection.

That is why the joke works.

These were sailors spending weeks hovering over a weapon none of them could reach directly, waiting for experimental machinery to bring it close enough to touch.

The helmet gave them something ordinary to laugh at.

The story did not end on the deck of Petrel

This is where the underwater story can distort Palomares.

The sea bomb is the part with Alvin, robots, search ships and an ending precise enough to photograph.

The contamination on land was less cooperative.

U.S. records say roughly 1,400 tons of contaminated soil and vegetation were removed from the Palomares area and transported to the United States. The Department of Energy says Spain’s CIEMAT subsequently maintained a long-running medical and radiological surveillance program for residents who had lived in the affected area.

And that work is not merely historical.

CIEMAT’s current program still describes environmental radiological surveillance around Palomares and monitoring of the effect of residual contamination on the population. Its research program continues to characterize land affected by plutonium and americium from the accident.

So it would be wrong to end the accident when the bomb reached the ship.

One weapon had been recovered from the sea.

The land still had a history.

The official story was uncomfortable from the beginning

Contemporary diplomatic records make another part of Palomares unusually visible.

Spanish officials were deeply worried about publicity surrounding the accident and radiation. On January 19, the U.S. Embassy reported that Spanish authorities strongly preferred that no further public statement be made unless circumstances forced one. The embassy also softened language concerning radiation after Spanish objections.

Three days later, the embassy reported increasing concern that the missing fourth bomb would eventually have to be acknowledged publicly if the search continued without success. Its telegram called locating the weapon a matter of “utmost urgency.”

That does not make every later claim about a grand Palomares cover-up automatically true.

It does show that information management was part of the accident from almost the first day.

The diplomatic documents preserve that without much need for embellishment.

Palomares also changed the emergency machinery

The institutional response extended beyond Spain.

The Department of Energy’s history of American nuclear-emergency response places Palomares directly in the development of a more formal national system. Only weeks after the sea recovery, the Atomic Energy Commission and Department of Defense established the Joint Nuclear Accident Coordinating Center, part of the lineage that eventually produced modern U.S. nuclear-accident response capabilities.

Again, I would not say one accident invented the entire system.

Nuclear weapons had existed for twenty years. Emergency planning existed too.

Palomares showed what happened when the emergency was neither a weapon being used nor a weapon sitting safely inside a controlled military installation.

It was an aircraft accident, a contaminated farming district, a deep-ocean salvage job, a diplomatic problem and a medical-monitoring problem.

The bureaucratic categories had to catch up.

CURV had an afterlife too

The underwater machine came out of Palomares with a different future.

CURV had been a torpedo-retrieval tool.

After its improvised deep-water performance off Spain, the Navy began developing deeper and more capable versions. The Naval Undersea Museum describes the Palomares recovery as a demonstration of the potential of the remotely operated system.

The lineage did not stop with nuclear weapons.

ROVs became ordinary equipment for recovering objects, examining shipwrecks and submarines, servicing underwater infrastructure and working where divers cannot.

Alvin had an even stranger career ahead of it. The same vehicle that helped find the Palomares bomb would later take scientists to hydrothermal vents and survey the wreck of Titanic.

That is one reason this story belongs in Final Vestige.

A Cold War accident did not merely leave a contaminated patch of Spain.

It briefly assembled part of the future of deep-ocean work.

Too deep for the divers

There is a natural connection here to Final Vestige’s Too Deep for the Rescue Bell, the USS Thresher story.

Thresher disappeared in 1963 at depths that rendered the Navy’s existing rescue systems essentially irrelevant. Deep-ocean search and recovery became a much more urgent technical problem afterward. Three years later, Palomares brought a different object into that same depth regime.

This time the object could be brought back.

The contrast is useful.

The machines being assembled around Palomares did not appear from nowhere. USS Hoist, for example, had worked with Trieste II at the Thresher site before being sent to Spain.

The Navy had already learned that the ocean floor was becoming operational territory.

Palomares gave it something on that floor everyone desperately wanted returned.

The second time

I keep coming back to the moment after the first lift failed.

The Navy had spent weeks looking for a hydrogen bomb. A new deep-diving submarine had found it. There was the proof, the location and the enormous relief of turning missing into found.

Then a line broke.

The weapon moved.

Silt filled the water.

And the search started again.

The bomb never detonated.

On land, people are still measuring plutonium.

Sources & Further Reading

The strongest record comes from contemporary U.S. diplomatic documents, official Navy histories and museum collections, Department of Energy records, and Spain’s continuing radiological-surveillance program.

• U.S. Department of State, Foreign Relations of the United States, Document 189. The January 18 White House memorandum recording the collision, deaths, four nuclear devices, low-order conventional detonations and possible radiation hazard.
• FRUS Document 190. Contemporary Embassy reporting on Spanish sensitivity to publicity and official language about radiation.
• FRUS Document 191. The January 22 telegram describing the missing fourth bomb as a matter of utmost urgency.
• U.S. Naval Undersea Museum, “USS Petrel Football Helmet.” Detailed Navy-museum narrative of Francisco Simó Orts, the search fleet, Alvin’s discoveries, CURV, the parachute entanglement, April 7 recovery and helmet artifact.
• Naval History and Heritage Command, USS Albany IV. Official task-force chronology preserving the alternate March 15 first-sighting date, failed lift and renewed search.
• Naval History and Heritage Command, “Alvin (DSV-2).” Official history of the then-new deep-ocean submersible and its later scientific career.
• Naval History and Heritage Command, Carl M. Brashear collection. Official record of Brashear’s injury, return to diving and qualification as the Navy’s first African American master diver.
• U.S. Department of Energy, Palomares Public Health Risk Assessment. Current federal summary of the land contamination, contaminated-soil removal and long-running U.S.-Spanish monitoring program.
• CIEMAT, Radiologically Contaminated Land research group. Current Spanish institutional evidence that residual Palomares contamination and its effects remain under environmental surveillance.