Russia declared a federal state of emergency on Thursday over an oil spill caused by two Russian tankers in the Black Sea, the Emergencies Ministry said.

On December 15, two Russian tankers, Volgoneft-212 and Volgoneft-239, ran aground during a storm in the Kerch Strait, which separates Russia from the Ukrainian peninsula of Crimea, which it annexed in 2014.

The first sunk, while the second was seriously damaged. One man died and 26 crew members were evacuated.

The tankers, both more than 50 years old, were carrying a total of about 9,200 metric tons (62,000 barrels) of fuel oil, and about 40 percent of that may have spilled into the sea, according to Russian authorities.