Oil Tankers Rocked by Mystery Blasts After Trips to Russia

By Alex Longley (Bloomberg) —

At least four oil tankers have been hit with explosions so far this year — all of them having visited Russia’s territorial waters in the weeks prior to the blasts happening.

Nobody has claimed responsibility for the incidents, three of which have happened in the Mediterranean and one in the Baltic, and shipping industry officials say it would be premature to blame Ukraine. Kyiv hasn’t claimed responsibility and Greek and Italian authorities have launched investigations. There have also been other incidents involving Russian ships so far this year. 

“All the indications are that these have been deliberately orchestrated, but it’s with a significant degree of sophistication,” said Munro Anderson, head of operations at Vessel Protect, a major war-risk insurer of ships. “So, the big question that leads to is: ‘by who?’”

The blasts nevertheless point to heightened risk for tankers moving Russian petroleum. They come at a time when Ukraine has claimed responsibility for attacking a pipeline that allows Kazakh oil to flow, disrupting supply. But the tanker explosions and other incidents involving ships calling at Russia don’t all share the same characteristics, making it hard to be certain about the motives, Anderson said. 

“Until further details become available, any further assessment would be supposition at best.”

Over the weekend, the 800-foot Seajewel suffered an apparent blast while at the Italian port of Savona, prompting the country’s prosecutors to open an anti-terror probe. The ship’s Athens-based operator Thenamaris described what happened as a suspected “security incident”.

A month earlier, another of Thenamaris’s tankers, the Seacharm, also suffered an incident while sailing toward Ceyhan in Turkey, the company said. Shipping industry publication Lloyds List said that vessel also had an explosion.

While both the firm’s tankers went to Russia prior to getting attacked, neither appeared to actually transport Russian oil, meaning they would have been acting in adherence to western sanctions. Both collected a cargo of Kazakh crude from near the Russian port of Novorossiysk, shipping data compiled by Bloomberg show. In both instances the voyage wasn’t the ship’s most recent one.

The two other vessels — the Koala and the Grace Ferrum — had visted Ust-Luga, in the Baltic Sea. The Koala suffered a blast when it was at the Russian oil port. The Grace Ferrum incident happened when the tanker arrived in Libyan waters weeks later, LloydsList said.

Local authorities described the Koala blast as a “man-made incident.” The ship suffered several explosions, security company Ambrey Analytics said at the time. 

The Grace Ferrum has now been off Libya’s coast for weeks and was last signaling that it wasn’t under command. 

It’s not just oil tankers that have been targeted.

The biggest cargo ship in the Russian military’s logistics fleet also sank in the Mediterranean late last year after an explosion in its engine room. Moscow described what happened as a terrorist attack.

Bimco, the world’s largest shipping trade group, said it is too early to conclude anything about the incidents collectively. 

“We are aware of the incidents where some ships trading to and from Russian ports have experienced explosions resulting in hull damages,” said Jakob P. Larsen, chief safety and security Officer at Bimco. “We are in close dialogue with authorities to learn more about the incidents and improve our understanding of the potential implications to the supply chains.”

© 2025 Bloomberg L.P.

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