An explosion on an oil tanker at a port in northwest Russia forced the crew to evacuate on Sunday and is now under investigation, according to the country’s federal shipping agency.

The Rosmorrechflot maritime and river transport agency reported on Telegram that the blast occurred in the engine room of the tanker Koala at Ust-Luga port, west of Saint Petersburg, on Sunday morning.

The crew safely evacuated, and officials confirmed that the explosion did not result in any cargo spills or oil leaks, nor did it pose a risk of the vessel sinking. Authorities are now assessing the ship’s condition and investigating the incident.

Ship-tracking data from Vesselfinder shows that the Koala, built in 2023 and registered under the Antigua and Barbuda flag, arrived at Ust-Luga on Thursday.

Russia’s Baza Telegram channel reported that the tanker is carrying 130,000 tonnes of heavy fuel oil. This incident follows two tanker wrecks in the Black Sea in December, which caused a major fuel spill still affecting the coastline.

In January, the U.S. designated more than 180 Russian vessels as part of a “shadow fleet” allegedly used to export crude oil despite Western sanctions. However, the Koala is not on this list.

Meanwhile, Ukraine’s security services previously claimed responsibility for a drone strike on a fuel terminal at Ust-Luga, stating that the port is a key hub for Russia’s oil and gas exports through the shadow fleet.