The explosion of the Koala oil tanker in the port of Ust-Luga, officially a human error, highlights the risks of a fleet made up of ships which, obsolete and without insurance, threaten the ecosystem of the reservoir

The Moscow’s shadow fleet consisting of old and insecure vessels is still threatening a already fragile ecosystem.

Early on February 9, the Antigua and Barbuda-flagged oil tanker Koala was rocked by three explosions in its engine room when it was berthed at the Russian port of Ust-Luga in the Leningrad region. The ship, which carried approximately 143,000 tons (130,000 metric tons) of heavy fuel, was severely damaged and began to take on water, causing it to ground at its stern. Fortunately, all 24 crew members survived.

Russian officials downplay the accident

Russian officials, from Leningrad Governor Alexander Drozdenko to the Federal Agency for Maritime and River Transport, downplayed the accident, calling it an instance of “human error” or a “technical failure during engine start-up.” They further said that the cargo tanks were intact and that oil had not leaked. This version was supported by the Finnish Border Guard, which dispatched an early warning plane immediately to the scene to check on developments.

But the incident has again pointed to Russia’s shadow fleet—a fleet of aging and often poorly maintained tankers with untrained crew who are not accustomed to the challenging navigation of the Baltic Sea. Russia utilizes them to export oil while avoiding Western sanctions imposed following its Ukraine invasion. The self-sufficient news agency Agentstvo noted that the Koala is listed on a list of Russian shadow fleet ships created by Greenpeace in October 2024.

Russia’s shadow fleet: a growing risk

70 to 80 oil tankers loaded with crude depart Russian ports such as Primorsk, Ust-Luga, Vysotsk, and St. Petersburg each week to head to international markets. Among them, some 30 to 40 are shadow fleet—numbers that surged since 2022 following sanctions. The report of the Kyiv School of Economics identified an estimated 430 of these ships on the high seas.

They frequently operate near, if not at, the law. Increasingly, they are switching off their Automatic Identification System (AIS) to conceal their activity and Russian port calls, and hence make them difficult to track and increase the risk of collision.

The issue is further compounded by the lack of sufficient Western insurance for such ships. In the event of an accident, cleanup and environmental damage would fall on the Danish taxpayers, for instance. As warns Yevgeniy Golovchenko, a professor at the University of Copenhagen, if one of these tankers makes an error off Denmark’s coast, “the most likely scenario is that Danish taxpayers will have to pay for the cleanup.”

The Koala, built in 2003, was carrying a very polluting load. A more devastating explosion or a sea accident could have triggered an oil spill of disastrous proportions. To give this some context, the Prestige disaster in 2002 off the Spanish coast involved the release of over 69,000 tons (63,000 metric tons) of oil, causing untold environmental and economic damage.

The Baltic Sea itself is extremely sensitive—a shallow, small body with ineffective currents and a slow rate of water change. A leak in it would be devastating in terms of long-range consequences.

Denmark tightens controls, but problems remain

In response to this mounting threat, Denmark has vowed to more stringently inspect tankers that pass through its straits. But as these are international waters, the possibilities for enforcement are finite. Any limiting measures would require a delicate balance of international law and political will among the coastal nations.

In addition, Russia’s shadow fleet also persists in navigating the Baltic Sea without due safety standards, posing a threat to the environment, the economy, and the regional geopolitical security.