News Release

Ecowar looming with sunken wartime wrecks

Reports and Proceedings

New Scientist

As dawn was breaking on 20 November 1944, a one-man Japanese suicide submarine packed with explosives made its way towards an American fuel tanker anchored in a lagoon off the island of Yap near the Philippines. As it drew alongside, the submarine blew itself up, killing 63 of those on board the tanker, sending it and its cargo to the bottom of the lagoon. For years, the USS Mississinewa was just another wreck at the bottom of the Pacific Ocean.

v But that all changed nearly 60 years later, in July 2001, when a typhoon shifted the Mississinewa, rupturing its fragile, corroded hull. Suddenly, oil gushed to the surface. Over the next few months, the tanker spewed 91,000 litres of oil, fouling beaches around Yap and polluting its vital fishing waters. The Governor of Yap declared a state of emergency and the US Navy stepped in to temporarily plug the leak.

Now the Navy is taking more drastic action. Over the next few weeks, between 9 and 10 million litres of oil will be pumped out of the Mississinewa's tanks, around 99.5 per cent of what is thought to still be on board. The oil will be pumped into a tanker on the surface, evaluated for its commercial value and then either sold or recycled.

While the Mississinewa will then be left to corrode in peace, its rupture has sounded alarm bells across the Pacific. According to scientists with the South Pacific Regional Environment Programme (SPREP), there are around 1080 wrecks from the Second World War littering the floor of the Pacific Ocean, many of which must be as corroded as the Mississinewa. Last July, a forum of environment ministers from the Pacific region passed a motion urging a systematic review of the wrecks and the pollution danger they might pose.

More leaks are inevitable. "It's not a question of 'if', but 'when'," says Trevor Gilbert, a former advisor to SPREP, whose members include Pacific Ocean and Pacific Rim nations. "Military vessels that have been sunk during wartime are expected to have suffered extensive structural damage prior to sinking," he says. "With every year that passes, these vessels deteriorate more, and the risk of significant oil release becomes more likely."

When the tanker Prestige sank some 200 kilometres off the north-west coast of Spain on 19 November 2002, many thought that the cold waters and depth of 3.5 kilometres would solidify the oil, hindering its release. This was not the case. "The Prestige spill proves that even in these [cold] conditions, oil will still leak," says Sefanaia Nawadra, a marine pollution advisor at SPREP. Because most Second World War wrecks lie in warm, tropical waters, the oil on board will be even runnier, making it even more of a threat. "In tropical conditions oil remains fluid even at depth," she says. "For example, the oil on the Mississinewa is as fluid as the day it came out of the refinery."

Gilbert and Nawadra compiled and presented a map of these wrecks at Spillcon 2002, an international oil spill conference held in Sydney last September. Addressing an audience of marine pollution experts, they urged an investigation into the state of the wrecks. Without a proper study, they will have no idea how much oil is still contained in the wrecks, which range from 60-tonne diesel vessels to 40,000-tonne battleships. "This is one of the main gaps in our knowledge," says Gilbert.

The problem is that no one is very interested in funding such an investigation. Pacific Island nations, which stand to lose the most from any oil spills, do not have enough money. The two main adversaries from the battles in the Pacific, Japan and the US, show varying degrees of disinterest. Japan maintains it has no obligation to clean up ships that were sunk in wartime, although 70 per cent of the wrecks in question are Japanese. Unlike commercial vessels that can be plundered by salvage companies, warships remain the property of the nations that originally owned them.

The US Navy agrees that assessing the chances of further leaks requires a lengthy study. "The corrosion rates of other Second World War sunken vessels in the Pacific and the likelihood of an oil release from any of these vessels cannot be established without doing detailed on-site investigations, sampling, engineering analyses and studies," a US Navy spokesperson told New Scientist. But the Navy has no plans to launch such an investigation.

Costly clean-up

An ocean-wide programme to clean up the wrecks would clearly not come cheap- the Mississinewa operation alone is expected to cost around $6 million. Added to this is the fact that many wrecks are designated war graves, and some survivors are opposed to having them disturbed, even to remove potentially damaging oil cargoes. The lack of concerted action means little is known about the threat the wrecks pose. SPREP is carrying out its own study: finding out which ships were sunk during the Second World War, where and when they sank and what fuel load they were carrying. This will allow an initial categorisation of the wrecks into high, medium and low-pollution risk.

Working out which wrecks are the biggest threats is key. In deep enough waters, the lack of oxygen means corrosion all but grinds to a halt and small oil leaks could be broken down naturally. "There isn't a huge amount of oil in a warship," says Simon Boxall, a marine pollution expert at the Oceanography Centre at the University of Southampton. "Any leaks can usually be handled naturally, by bacterial action at the surface," he says. "The big problem is tankers, especially those in shallower water." Of the 1080 war wrecks in the Pacific, 50 are tankers according to SPREP, and many were sunk close to land as they attempted to resupply bases or fleets. The remaining wrecks include at least 23 large aircraft carriers, 213 destroyers and 22 battleships.

While SPREP does not yet know which wrecks are the most dangerous, tankers like the USS Neosho are bound to be near the top of the list. The Neosho was sunk in May 1942 after refuelling two American warships and lies just a few hundred miles east of the Lihou reefs and cays near Australia's Great Barrier Reef. Despite having off-loaded some of her oil and burning more before she sank, Gilbert estimates that the Neosho could still have up to 19 million litres of fuel on board. Together with the Mississinewa, these two tankers alone contain nearly as much oil as the Exxon Valdez that spilled 42 million litres off the coast of Alaska in March 1989.

Gilbert says only computer models of oil leak rates, ocean currents and local weather will tell whether any oil leaking from the Neosho will wash up on the shorelines or spoil the reefs. Even if a slick does not reach shore, it could still threaten marine species including dolphins, sea turtles and pelagic fish, says Gilbert. Disturbingly, the National Park authority responsible for the Great Barrier Reef admits it has no knowledge of the tanker or the nature of the threat it might pose.

Gilbert plans to raise the issue of the Pacific's wrecks at an international oil spill conference in Canada in April. He is optimistic action will be taken eventually. "Understanding the breadth of the problem will take the skills of marine scientists, spill response professionals and salvage organisations," he says. "But above all, it will take international cooperation."

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New Scientist issue: 22 February 2003

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