What is pre-war steel, and why are people stealing it?

Over the next 35 years, the United States, Soviet Union, Great Britain, France, and China conducted more than 1,000 atmospheric nuclear tests. This resulted in the spread of huge quantities of isotopes across the entire planet — and its atmosphere.

The Bessemer Process, used to make steel, involves blowing atmospheric air through molten iron. Consequently, the isotopes not only ended up in the air, but also in nearly every piece of steel produced post-1945. This may not seem important, but the contamination is actually enough to disrupt some scientific apparatus made from this steel.

Since working ships from the pre-1945 era are very rare (other than as museum exhibits), the only significant source today of this pre-1945 steel is old shipwrecks.

Thankfully, since the end of atmospheric nuclear testing in the 1960s, radiation levels have decreased to near natural levels. In most cases, modern steel is sufficiently "uncontaminated" for use in most radiation-sensitive applications. This is because steelmaking has also largely turned away from the Bessemer Process in favor of the Basic Oxygen Process, which uses uncontaminated pure oxygen instead of atmospheric air.

Advances in electronics have also allowed scientific apparatus to compensate for stray radioactive emissions, meaning that low-background steel is no longer necessary for all but the most sensitive instruments like neutrino detectors.

However, some highly sensitive applications, like particle accelerators, Geiger counters (for obvious reasons), and sensing equipment aboard spacecraft, still require very low-to-zero contamination. Even low-background steel can be too radioactive for the most demanding applications, and high-purity copper may be used instead.

5 uses for pre-war steel

As previously mentioned, pre-war steel is precious for applications requiring little contamination from radionuclides. This includes scientific equipment, medical equipment, and some aerospace applications. But what are some specific examples?

1. Neutrino detectors

A neutrino is a subatomic particle similar to an electron but has no electrical charge and a very small mass, which might even be zero. Neutrinos are one of the most abundant particles in the universe. Because they have very little interaction with matter and are incredibly difficult to detect, physicists need to build detectors deep underground to shield them from cosmic rays. The material that makes up the detector also needs to be as "clean" as possible to ensure that no false signals are detected.

2. Dark matter experiments

Like neutrino detectors, experiments trying to detect dark matter particles directly require the utmost sensitivity. Low-background steel is essential for the shielding and sometimes the structure of these detectors.

3. Gamma-ray spectroscopy

Gamma-ray spectroscopy measures the distribution and intensity of gamma rays to produce a tell-tale spectrum for scientific and technical analysis. This could include the composition of a material or hunting for water on distant planets.

Any background radiation from the instrument's materials can skew the results. Low-background steel creates a "clean" environment for these measurements, making them as accurate and reliable as reasonably practicable.

4. Geiger counters

A Geiger counter is an electronic device for detecting and measuring ionizing radiation. It is commonly employed in radiation dosimetry, radiological protection, experimental physics, and the nuclear industry. One prime example are the Whole-Body Counting Rooms used in hospitals and nuclear power plants to measure radioactive absorption. These rooms require thick metal shielding to prevent background radiation interference, but only steel produced before 1945 is safe to use, due to contamination.

While most Geiger counters are fine with modern steel for extremely precise measurements or when measuring very low radiation levels, a low-background version might be necessary to avoid interference from the counter itself.

5. Space missions

Space missions that involve sensitive instruments or environments with low natural radioactivity may require low-background steel to ensure optimal instrument performance. Some prime examples include the sensors onboard the Voyager 1 and 2 spacecraft and the Explorer 1 spacecraft, but more on that later.

Why is pre-war steel so valuable?

In short, because it is so rare. Most steel created before nuclear testing began is long gone, having been recycled, scrapped, or repurposed. However, when ships go down, they effectively "lock up" that steel for a long time. And it is not just the ship's hulls that are valuable.

Many elements of old ships would also contain the highly sought-after steel, including armaments (guns and shells), derricks, equipment, and other items still onboard when the ship sunk. But that is only part of the story. Many of these wrecks are hundreds to thousands of feet underwater, especially those in the Pacific.

This makes them incredibly difficult to reach for most salvage companies. Anyone hoping to plunder an old warship will need costly specialist equipment to get to the wreck. Dissecting and recovering the steel to the sea's surface is another major challenge.

So, the combination of rarity and the difficulty of salvage means suppliers can charge "top dollar" for the stuff. But how much of a markup are we talking about here?

Exact figures per weight are not very easy to find, but to get an idea, it is known that pre-war lead did sell for $33/kg when salvaged from the Spanish galleon San Ignacio. This is compared to around $1.87/kg for the spot price of normal lead.

But what about steel?

At the time of writing, a ton of steel can be bought at a spot price on the New York Exchange (NYSE) for around $1,930 per ton. If pre-war steel is as valuable as pre-war lead, then this would mean it might fetch something like $34,000 per ton.

Steel raids on famous shipwrecks

So, given its value, you might be wondering which potential wrecks around the world are in the most danger of being plundered for their steel. Let's look at some of the most famous in the news.

1. HMS Prince of Wales

Depth: 223 feet (68 meters)

Location: South China Sea

Laid down in 1937 and commissioned in 1939, the HMS Prince of Wales was a King George V-class battleship of the British Royal Navy. Coming in at around 43,780 tons displacement, she was one of the most decorated ships in the war.

However, she met her end in December of 1941, when she was sunk by torpedoes fired from Japanese aircraft during the Battle of Malaya. After floundering, the ship's remains sank to a depth of around 223 feet (68 meters), taking about 840 of her crew with her—a tragic and inglorious end to a much-beloved warship.

However, in 2014, it was discovered that the wreck of the ship (a designated war grave) has suffered "extensive damage" from explosives used by scavengers to retrieve her precious pre-war metals from the seafloor.

Despite protests from the British government, it appears the ship is still being plundered. A Chinese ship, Chuan Hong 68, was found illegally scavenged the wreck for its low-background steel in May 2023.

2. HMS Repulse

Depth: 105 feet (32 meters to her keel)

Location: South China Sea

Laid down in 2015 and launched in 1916, HMS Repulse was a Renown-class battlecruiser of the British Royal Navy. She displaced around 27,200 tons and was built in just over 15 months. Upon launch, she and her sister, the Renown, were the fastest capital ships afloat.

She was a highly decorated ship and served in many important actions during and between WW1 and WW2. Notable among them being her part in the hunt for the German Bismark. The story of the demise of HMS Repulse is intimately linked with that of the HMS Prince of Wales, as they were involved in the same fatal action. The Repulse was lost to Japanese bombers on the same day.

She lies near her consort, the Prince of Wales, and has been subject to metal scavengers in recent years.

3. German high seas fleet

Depth: 100 feet (30 meters on average)

Location: Scapa Flow, Scotland

Following the Armistice in November 1918, which concluded hostilities in World War I, the German High Seas Fleet was instructed to be held at a neutral port while the Allies decided what to do with it. The British naval base, Scapa Flow, in the Orkney Islands north of mainland Scotland was selected as the location for internment.

In June 1919, 74 ships of the German High Seas Fleet were held at Scapa Flow while the Allies debated their fate at the Versailles Peace Conference.

Admiral Ludwig von Reuter, the German officer in command, decided to scuttle the ships to prevent the interned fleet from falling into Allied hands. On June 21, 1919, fearing that the peace negotiations had failed and war might resume, he gave the order to scuttle the ships.

In a matter of hours, 52 of the 74 interned ships were sank. The British, caught by surprise, managed to beach a few ships to prevent them from sinking and opened fire on some German vessels and crews. Nine German sailors were killed, the last casualties of World War I.

The wrecks would remain in place until hull plates from the SMS Kronprinz Wilhelm were repurposed in 1974 to construct a whole-body counter room at a Scottish hospital.

There are also rumors that steel from the SMS Markgraf was utilized in radiation detectors on America's first satellite, Explorer 1, and the Voyager 1 and Voyager 2 space probes, making it the only battleship to reach space. However, such claims haven't officially been recognized by NASA.

And that is your lot for today.

Pre-war steel is a very valuable resource for some incredibly specialist applications, but sourcing the stuff comes with a minefield of ethical and technical considerations when plundering sunken vessels.

With many wrecks lying at depths far from land, it is unlikely that the plundering of these wrecks can ever be eliminated altogether. But efforts are underway to protect these wrecks as best we can.