At least 8,500 potentially polluting shipwrecks are rusting on the ocean floor with fuel still inside; leaks in Micronesia show the risk that one storm or earthquake could unleash

It might sound like the setup to a disaster film, not a real news story: sunken warships, still packed with fuel, sitting one storm away from rupturing. But in September 2025, that scenario played out for real when divers spotted oil bleeding from a WWII wreck into waters that local families depend on for food. It wasn't the first time. It probably won't be the last.

In September 2025, divers in Chuuk Lagoon, Micronesia, found oil leaking from a sunken World War II ship. Within days, the slick had reached nearby village shorelines. Local officials declared a state of emergency, and Micronesia's president later appealed for international help at the United Nations.

According to reporting by the Pacific Island Times, the leak traced back to a Japanese transport ship sunk during a US attack on the lagoon in 1944. This was not a new problem. A similar spill forced an entire lagoon to shut down fishing back in 2001, and thousands of other wrecks are still sitting quietly on ocean floors worldwide, slowly falling apart.


A graveyard of warships is turning into a global pollution risk
The scale of the problem stretches well beyond the Pacific. Scattered from the Baltic Sea to the South Asia-Pacific, some wrecks are already leaking, threatening marine ecosystems, fisheries, and nearby communities, with an estimated 8,500 potentially polluting wrecks lying beneath the waves, most dating back to World War I and II.

Within that global total research published in Ocean & Coastal Management titled ‘Sunken WWII shipwrecks of the Pacific and East Asia: The need for regional collaboration to address the potential marine pollution threat’ found that more than 3,800 ships from World War I and World War II are still resting on seafloors across the Pacific and East Asian sea area, together holding as much as 1.5 billion gallons of oil at the time of their sinking. That works out to roughly 2,270 Olympic swimming pools' worth of fuel.

Most of these are steel-hulled ships that have been underwater for 80 years or more. Saltwater slowly eats through steel, and it never really stops. Every year the hulls get a little thinner. Many of these wrecks also contain old ammunition and heavy metals, not just fuel.

For decades, these wrecks sat quietly out of sight, mostly forgotten, while their walls kept thinning in the dark.

When an American tanker leaked, an entire lagoon lost its fishing grounds
One of the clearest warnings came from Ulithi Lagoon, a remote atoll in the Federated States of Micronesia. In August 2001, a short time after a storm passed through the area, oil began leaking from the USS Mississinewa, a US Navy fuel tanker sunk during the war. According to the official spill response report, between 18,000 and 24,000 gallons of oil spread across the lagoon over about two months, threatening coral reefs and sea turtle nesting grounds. Local authorities responded with a complete ban on fishing in the lagoon.

The cleanup was not quick. The Pulitzer Center reported that the full remediation and salvage operation took almost three years and cost around $6 million.

That was not an isolated case. Chuuk Lagoon, once a major Japanese naval base, is now home to more than 60 sunken WWII ships. It is now a popular scuba diving destination, and the same report says Micronesian leader Manny Mori warned decades ago that the wrecks were a ticking time bomb.

Climate change is speeding up the clock
Rising ocean temperatures and stronger storms are affecting more than just distant glaciers. According to a 2021 study, ‘Ticking ecological time bombs: Risk characterization and management of oil polluting World War II shipwrecks in the Pacific Ocean,’ published in Marine Pollution Bulletin, more than 3,800 WWII wrecks sit in the Pacific and East Asian sea area alone, and warmer, more acidic seas combined with more frequent storms are speeding up how fast their hulls corrode.

The study's lead researcher, Matt Carter, has warned that the bigger danger is sudden failure, not slow leaking. According to the Pulitzer Center, Carter has pointed to earthquakes and storm surges as events that could crack open an already-weakened hull in an instant, releasing decades of trapped oil all at once.

Officials in Chuuk believe something similar may now be underway. Corrosion in the lagoon is accelerating as the seas warm and storms intensify, pushing several wrecks closer to failure.

Why this should matter to American readers too
Many of these wrecks are not foreign ships lost in someone else's war. The USS Mississinewa was a US Navy vessel, and many American ships and aircraft were lost across the Pacific during World War II. It was also the US Navy that sank most of the ships now sitting in Chuuk Lagoon, during Operation Hailstone, a February 1944 assault on the Japanese base there. Guam, a US territory in the western Pacific, sits in the same broader region as many of these wreck sites.

What can actually be done about it
Fixing this problem is expensive. The Conversation notes that addressing polluting wrecks worldwide at scale could cost as much as $340 billion in total. Scientists are increasingly using underwater drones, called Autonomous Underwater Vehicles, to scan wrecks for leaks without sending divers into old, unstable hulls, the same report notes.

A global partnership known as Project Tangaroa is also pushing governments to share data, fund cleanups, and set clear rules for handling these wrecks before disaster strikes, rather than after, according to The Conversation.

For now, most of these ships remain exactly where they have been for more than 80 years, sitting on the seafloor, slowly rusting away.