The same storm in the Black Sea and Azov Sea also sank four freighters, three carrying sulphur and one with a cargo of scrap metal. The heavy seas also cracked the hull of another oil tanker, but the ship was afloat and not leaking.
The sunken tanker, Volganeft-139, had travelled from the Russian port of Azov and was anchored outside Kerch in Ukraine's eastern Crimea to ride out the weather, when high waves broke its back at around 0715 hrs today, media reported.
The 1978-built tanker, designed primarily for inland and coastal service, was carrying 4,000 tonnes of fuel oil in total when it was hit by the storm, which has knocked out electricity supplies to much of Crimea.
''This problem may take a few years to solve. Fuel oil is a heavy substance and it is now sinking to the seabed,'' Oleg Mitvol, deputy head of Russia's environment agency Rosprirodnadzor told state-run Vesti-24 television channel.
''This is a very serious environmental disaster.'' Environment agency Rosprirodnadzor said some 2,000 tonnes of fuel oil had spilt, but Emergencies Ministry spokesman Viktor Beltsov told Reuters not more than 1,200 tonnes had leaked.
The tanker's 13 crew members drifted for hours in waves up to 6 metres high aboard the ship's stern before beaching safely a few miles from the bow section, the emergencies ministry said.
The crew were safe, it added.
The likely effects of the spill were not immediately clear.
A spill over 700 tonnes is considered large, but the biggest ones run into the tens or even hundreds of thousands.
The polluted area is at the heart of the migration route from central Siberia into the Black Sea of red-throated and black-throated Siberian divers.
''The peak of the migration season is right now,'' Kees Camphuysen, a marine ornithologist at the Royal Netherlands Institute for Sea Research, told Reuters by telephone.
''The quantity (of oil spilt) doesn't matter. One tonne in the wrong place will do a lot of damage while a 100,000 tonnes will do no damage in the centre of the ocean,'' he said.
The area is also home to porpoises.
STORM TOLL Almost at the same time as the Volganeft-139 broke up, a freighter carrying 2,000 tonnes of sulphur sank off the port of Kavkaz in the Kerch Strait. Its crew of nine was rescued.
''We hope that in the water sulphur will not form any substances dangerous to humans,'' Mitvol said.
Several hours later, another freighter carrying sulphur sank off Kavkaz, Interfax news agency quoted the port adminstration as saying, adding three of its crew had been rescued by a Ukrainian ship. The fate of the other eight sailors was unclear.
The same storm, which is expected to rage for up to 3 days, also sank a freighter with scrap metal off Sevastopol in southern Crimea. Two of its crew were rescued, but the fate of the other 15 was unknown, Ukraine's emergencies ministry said.
The hull of the oil tanker, Volganeft-123, cracked after being hit by high waves, but Maxim Stepanenko, Novorossiisk transport prosecutor, told Russian television this tanker was afloat and its oil products were not leaking.
REUTERS SBC HT2220