(Newser) – The telling sign is a crane barge floating above. Once its divers inspect the shipwreck below, they lower explosives that rip it to shreds of steel, copper, and brass. This is how as many as 40 British, American, Australian, Dutch, and Japanese warships from World War II—which also serve as the graves of up to 4,500 crew members—have been desecrated in waters off Singapore, Indonesia, and Malaysia, at an increasing rate and to an increasing extent. Using impressive maps and graphics, the Guardian describes the efforts of salvage divers posing as researchers or fishermen in the Java Sea. Australia-based maritime archaeologist James Hunter says he "couldn't believe" the shift from plucking off pieces of a ship to taking it in its entirety until he saw it with his own eyes. "I was completely horrified," he says.

Though some experts believe a single ship can yield $1 million worth of steel, even if it's in poor shape, Hunter scratched his head at how the value of the corroded metal can offset the cost of the operation. The age of the steel is potentially why, and Outside explained the science earlier this year: During the steel-making process, oxygen is blown into the mix, "along with ambient atmospheric particulates." Once we began detonating nukes in the 1940s, steel started to contain radiation. Radiation-free steel from these pre-nuclear-era ships commands very high prices. And Hunter fears the deepest wrecks won't long be protected from divers. Technology "is enabling people to find and potentially salvage wrecks in extremely deep water," he says. "This threat is getting bigger." (More on the salvaging here.)

