Russian authorities sought to limit the damage on Monday from oil spilled into the Kerch Strait by two ageing tankers that were damaged during a heavy weekend storm, highlighting the environmental and insurance risks of Russia's 'shadow fleet'.

One crew member was killed after the Volgoneft 212 split in half, with 12 rescued, while authorities said all 14 crew aboard the Volgoneft 239, which ran aground 80 metres from the shore near the port of Taman, were also rescued.

The more than 50-year-old ships were carrying some 9,200 metric tons (62,000 barrels) of oil products in total, Russian news agency TASS said, but how much leaked is being determined.

A view from the Volgoneft 239 oil tanker shows the sinking part of the vessel, whose damage caused an oil spill, in the Kerch Strait, Crimea, December 15, 2024, in this screen grab obtained from social media video. Social Media/via REUTERS

Volgoneft 212 dates back to 1969 and Volgoneft 239 was built in 1973, certificates seen by Reuters showed.

The spill could become one of the largest environmental disasters to affect the region in recent years, although the scale of possible insurance claims was not immediately clear.

The shipping industry has raised concern in recent months over the risks and potential for collisions posed by hundreds of "shadow" tankers in open sea lanes, with little incentive for these vessels to follow cleaner shipping standards.

Russia has increasingly used a shadow fleet, which deploys various techniques to bypass international sanctions.

The Kerch Strait, which separates mainland Russia from the Moscow-annexed Crimea region, is a key route for exports of its grain and fuel products.

The Finland-registered Centre for Research on Energy and Clean Air (CREA) think-tank said 369 vessels exported Russian crude oil and oil products last month, of which 206 were shadow tankers, and 28% of these were at least 20 years old.

Before the weekend incidents, CREA said the cost of clean up and compensation resulting from an oil spill from tankers with unknown insurance or no insurance provision could amount to more than $1 billion for the coastal country's taxpayers.

Russia rejects Western pressure to limit its oil exports and in the past year the number of tankers transporting cargoes that are not regulated or insured by Western providers has grown.

The documents showed the Volgoneft 212 was covered by insurance from Russia's VSK, while the vessel's operator, Kama-Shipping, said it was carrying 4,200 tons of fuel oil.

Russia's OOO Absolyut Strakhovaniye covered the insurance for the Volgoneft 239, documents seen by Reuters showed.

Neither immediately replied to requests for comment.

President Vladimir Putin on Sunday ordered the government to set up a working group to deal with the rescue operation and mitigate the impact of the spill, Russian news agencies cited Kremlin spokesman Dmitry Peskov as saying.