Russian scientists have criticized efforts to clean up oil washed ashore from two oil tankers in the Black Sea, citing a lack of sufficient equipment.

On December 15, two Russian oil tankers, the Volgoneft-212 and the Volgoneft-239, were hit by a storm in the Kerch Strait, causing one to sink and the other to run aground.

The strait separates southern Russia from Ukraine’s Crimean peninsula, which it annexed in 2014.

According to Russian authorities, the ships were carrying 9,200 tons of fuel oil, about 40% of which may have spilled into the sea.

President Vladimir Putin called it an “ecological catastrophe” last week.

Thousands of volunteers were mobilized to remove oil-soaked sand from surrounding beaches. But scientists say the volunteers don’t have the necessary equipment.

“There are no bulldozers there, no trucks. Practically no heavy machinery,” Viktor Danilov-Danilyan said at a press conference.

Danilov-Danilyan is scientific director of the Institute of Water Problems at the Russian Academy of Sciences and was Russia’s environment minister in the 1990s.

The volunteers only have “shovels and useless plastic bags that tear,” he said.

“While the bags are waiting to finally be picked up, storms arise and they end up back in the sea. It’s unthinkable!”

Public criticism of the authorities is rare in Russia.

Up to 200,000 tons of sand could be contaminated with oil, Russia’s natural resources minister said on Monday.

Almost 30,000 tons have already been collected, Krasnodar Region Governor Veniamin Kondratyev said on Wednesday.

Sergei Ostah, a professor at the Russian Academy of Natural Sciences, said the oil could soon reach Crimea’s shores.

“Nobody should have any illusions that it will stay clean,” he said, calling for quick action.

The oil spill may have killed 21 dolphins, the Delfa Dolphin Rescue Center said, although additional testing was needed to confirm the cause of death.