On a chilly spring morning in March, British coast guards spotted something unusual around 100 kilometers off the Scottish shoreline: a dark stain, stretching 23 kilometers into the North Atlantic Ocean.

According to an internal analysis prepared by the coast guard’s satellite services and seen by POLITICO, the likely source of that stain was Innova, a tanker roughly the size of the Eiffel Tower that at the time was hauling 1 million barrels of sanctioned oil from Russia on its way to a refinery in India.

Yet the coast guard did little to investigate further, and the tanker — free from any repercussion — continues to trade oil today, helping fill the Kremlin’s war chest more than two years into its full-scale invasion of Ukraine.

The Innova is just one of hundreds in the world’s so-called shadow fleet, a collection of often aging, poorly maintained ships sailing in defiance of Western sanctions — and spreading environmental harm without consequences. 

A joint investigation by POLITICO and the not-for-profit journalism group SourceMaterial found at least nine instances of covert shadow fleet vessels leaving spills in the world’s waters since 2021, using satellite images from the SkyTruth NGO paired with shipping data from market analysis firm Lloyd’s List and commodity platform Kpler.

Swedish Foreign Minister Maria Malmer Stenergard told POLITICO the ships posed a “significant danger” to the marine environment. “The incidents [here] illustrate this.”

It’s a problem that’s only grown worse following Russian President Vladimir Putin’s full-scale invasion of Ukraine. With Moscow under Western sanctions, an increasing number of tankers are ferrying illicit goods — and potential environmental devastation — across the globe. Not only are these vessels creaky and largely unregulated, they’re often uninsured, meaning that in case of a leak, or more serious spill, a government would struggle to hold them accountable. 

POLITICO and SourceMaterial identified discharges everywhere from Thailand to Vietnam to Italy and Mexico, all linked to the shadow fleet. The tankers also passed through busy shipping corridors like the Red Sea and the Panama Canal, meaning any serious accident could rupture international trade routes. 

Experts believe it’s only a matter of time before one of these ships suffers a catastrophe with major environmental — and economic — devastation.

“The oil spills and risk of slicks are horrendous,” said Isaac Levi, Europe-Russia lead and a shadow fleet expert at the Centre for Research on Energy and Clean Air (CREA), a think tank. “Beyond the environmental damage, some of which will be irreversible, it’s a huge impact to coastal states that have to bear the cost of cleaning this up.”

In short: “It’s a ticking time bomb,” Levi said.

Rising dangers

The situation poses a global dilemma: How can democratic countries squeeze Moscow’s revenues while avoiding disastrous ramifications?

When the West first imposed sanctions on Russian oil in 2022, it aimed to throttle a critical lifeline for the Kremlin, which relies on oil and gas exports for almost half its budget.

But almost two years later, the measures — which include a blanket import ban to the European Union and an oil price cap that G7 allies imposed with other partners — have largely come up short.

Instead, Moscow has found creative work-arounds. It relabeled its crude oil to mask its origins and it organized an ever-growing fleet of over 600, with ownership often obscured by shell companies, and used it to dodge the $60-per-barrel price cap set by the G7 — tactics that Iran and Venezuela also use for similar purposes.

So far, the price cap “has proved to be a very leaky instrument,” said Michelle Wiese Bockmann, a shipping analyst and shadow fleet expert at Lloyd’s List. 

According to CREA, around 80 percent of Moscow’s seaborne crude was transported on vessels outside Western control. Meanwhile, the overall number of shadow fleet vessels has more than tripled since 2022.

And the cash has kept flowing into Russia’s war coffers. According to data analyzed by CREA, the think tank, Moscow’s shadow fleet had transported €80 billion worth of crude by September since the G7 imposed the price cap two years ago. 

At the same time, the fleet is “presenting a lot of safety and environmental concerns,” Bockmann said. 

These tankers, which Lloyd’s List defines as having no known insurance, obscure ownership and having been built 15 years ago or more, are classified as “high-risk” by engineers. That leaves them more vulnerable to technical problems that could affect their steering, structural integrity and seaworthiness.

With four-fifths of these vessels lacking credible insurance, according to data from Lloyd’s List, they often escape international oversight and regulation. That risk only increases when tankers turn off their transponders or transmit false locations, using so-called spoofing methods.

Where spills happen, cleanups can cost coastal countries and their taxpayers millions, Bockmann said, since the vessels’ owners cannot be tracked. Ships could also block trade choke-points like the Suez Canal if captains lose control of their vessel, she added.

The spills also pose “a very serious problem” for local wildlife, said Stepan Boitsov, a researcher specializing in marine pollution at the Norwegian Institute of Marine Research. They can harm marine life, render consumer products like shellfish toxic and prevent fish reproduction. Cleaning up presents its own problems: The chemicals involved can spread further contamination, he added.

Then there’s the collision risk. In July, a Russian shadow fleet vessel hit another tanker in Malaysian waters, causing both to catch fire. 

The risk caused by the shadow fleet is global: An analysis of shadow fleet routes shows the vessels traveled down the west coast of the United States, repeatedly passed through the Mediterranean, split the English Channel and hugged China’s shoreline. And that’s just when their transponders are operating. 

The problem is particularly acute in Europe, where “the dark fleet is an accident waiting to happen,” Bockmann said, given that many unregulated ships pass through EU waters after leaving Russia’s Baltic and Siberian ports.

Leaving their mark  

Satellite images show small-scale accidents are already occurring around the world, largely unnoticed by authorities.

The Innova is a case in point. On March 12, six days after departing from the port of Murmansk in northwest Russia, satellites captured images of a long black slick on the sea’s surface. Transponder signals from the ship put it at the scene when the blight appeared. 

Satellite imagery cannot determine whether the slick was definitely oil. But according to Alexandros Glykas, a marine engineer and CEO of the DYNAMARINe shipping services firm, such slicks often result from the discharge of slops, an oily-water mixture produced as the vessel operates. The fact that the substance can be seen from space also strongly indicates the presence of oil.

Intentional overboard discharge of waste oil slops is illegal under MARPOL, an international treaty that aims to curb shipping pollution, according to Sean Pribyl, a maritime lawyer at Holland & Knight. Signatories of the treaty include many European countries, as well as Russia and Vietnam, the country where the Innova was registered at the time and whose laws it was accountable to — its so-called flag state.

Yet the United Kingdom did not send a vessel to investigate the Innova slick further. A Maritime and Coastguard Agency spokesperson told POLITICO it did not find “sufficient evidence of a violation” — even though there is a requirement to investigate visible slicks when reasonably possible, even with a physical inspection if the ship docks at a port.

“Action will always be considered where there is evidence of the potential for environmental or social harm, which was not the case here,” the spokesperson said.

Evidence of a possible violation usually requires the vessel’s flag state to investigate potential MARPOL violations and sanction any breaches, which could result in certain certificates being revoked.

The foreign ministries of Vietnam and Sierra Leone, Innova’s flag states at the time of the spill and after it occurred, did not reply to detailed questions from POLITICO. Innova’s owner at the time, Sao Viet Petrol Transportation, also did not respond to several requests for comment.

Innova’s trip eventually ended at the Vadinar refinery in India, which last year alone received 82 million barrels of oil from Russia worth an estimated €5 billion. Then in July, Innova changed its name, managers and owner.

The Innova is far from the only ship to have literally left a trail of pollution in its wake. 

On Feb. 18, satellites spotted another 47 kilometer-long slick off the Italian coast matching the coordinates of another shadow fleet tanker, the Aruna Gulcay. 

That tanker, flagged in the Marshall Islands, was carrying ballast — seawater that keeps the ship afloat — from the port of Ravenna in Italy to the southern Russian port of Novorossiysk. But it’s unlikely the discharge was ballast, said Glykas, the engineer, since seawater would not be visible from space, implying another MARPOL violation.

Similarly, the Italian coast guard did not carry out an inspection of the ship. Instead, an Italian maritime agency spokesperson said it had contacted nearby ships for information on the spill. The Marshall Islands government did not respond to a request for comment, and the ship soon changed its name and manager.

Analysts at SkyTruth said the nine slicks they could clearly link to shadow fleet vessels were likely an extremely small subset of the real problem. That’s primarily because the analysis relied on the vessels having their transponders on at the time of the slick, a requirement that ships in the business of evading sanctions don’t always observe. 

“I’m absolutely convinced that what you have noticed is the tip of the iceberg,” said Bockmann, the shipping analyst. “These ships are designed to [transport] sanctioned oil … as cheaply as possible, and there is absolutely no regard for conventional marine standards.”

Clamping down

The evidence of spills is leading to fresh calls for government action. But options for stopping the shadow fleet are limited.

The findings are “obviously outrageous,” said one EU diplomat, granted anonymity to speak candidly. Coastal European countries like Italy and the U.K. “have the responsibility to take extra efforts to investigate ships when they are linked to Russia,” the diplomat added.

The Innova and Aruna Gulcay in particular, the EU diplomat said, should now be “strong candidates” for Brussels’ next sanctions package against Russia given they may have breached the international maritime convention. In all, diplomats from four EU countries said the two ships should face sanctions if they breached MARPOL as the findings suggest. 

“If the vessels referred to are involved in irregular or high-risk shipping practices or contributing to Russia’s war efforts, they run a high risk of being added to the [EU’s] sanctions regime,” Swedish Foreign Minister Stenergard told POLITICO.

The EU has sought to tighten the screws on Moscow’s shadow fleet by more closely monitoring the sale of old tankers to foreign countries before they get into Russian hands. The bloc also banned 27 suspect tankers from accessing the bloc’s ports or services — a tactic the U.S. also uses.

The U.K., too, has slapped restrictions on individual tankers. Last month, it added 10 more shadow fleet vessels to its sanctions list on top of the 15 already penalized. A U.K. foreign ministry spokesperson did not respond to questions about the Innova but said Britain was “going after vessels” enabling sanctions circumvention. 

Italy’s foreign ministry told POLITICO it “stands ready” to sanction vessels according to EU rules, but added it had “not received any information in this regard” for the Aruna Gulcay.

A spokesperson for the European Commission said the EU’s executive arm was “constantly” exploring “possible future listings of vessels, including from the dark fleet.” All 27 EU countries must agree to adopt new sanctions.

Sanctioning individual tankers has proven to be a “pretty effective” move, said Levi, the CREA think tanker. Those blacklisted by the U.S., for example, saw their ability to trade oil drop 90 percent three months after being penalized.

“We very much encourage” the West to significantly expand the number of vessels on those sanctions lists, he said, which scare service providers like engineers and traders from cooperating with the tankers.

The EU and U.K. should also consider banning tanker sales to countries facilitating trade with Russia, Levi said, and automatically sanction vessels sailing through EU waters without known insurance.

The EU’s more hawkish countries on Russia also agree the bloc must step up its efforts, given the stakes involved.

“We are happy that we created this sanction and we listed these ships,” Estonia’s Foreign Minister Margus Tsahkna told POLITICO, “but also we are clear that we need to continue.” 

If the next oil spill is larger, he warned, “it will be a catastrophe for us.”

Stuart Lau contributed reporting.