On Wednesday, Russian President Vladimir Putin declared a state of emergency to deal with the environmental catastrophe, which has been described as the worst in the Arctic.
A diesel tank collapsed in a power station outside the northern city of Norilsk in Siberia on May 29, which resulted in the leakage of 15 thousand tons of it into a river, and another six thousand tons in the soil, including a total of 21 thousand tons.
In his announcement, Putin criticized - as Maria Antonova wrote to Agence France-Presse and reported to him, Science Alert - that Norilsk Nickel, the owner of the collapsed tank, had not acted swiftly to deal with the leak.
The Greenpeace in Russia said the accident was "the first of its kind in the Arctic region" and could be compared to the Exxon Valdez disaster off the coast of Alaska in 1989.
The Russian investigation committee said that the supervisor of the power station has been arrested, and he will be charged soon after investigations into environmental pollution and safety violations, and no information was provided on possible charges against him.
The scale of the disaster
Andrei Malov, a spokesman for the Russian Naval Rescue Service, which is clearing the marine spills, was called up at the weekend. The reinforcements arrived at the far site on Thursday.
"There have been no such spills in the Arctic before," he told AFP. "It must be collected very quickly because the fuel dissolves in water," he added.
The Amparnaya River, which was affected by the spillage, flows into Lake Piaceno, a major source of water and the source of the Piacena River, which is of vital importance to the Timmer Peninsula, which lies on the entire Arctic Ocean.
A spokesman for Russia's Fisheries Agency, Dmitry Klokov, said it would take "decades" to restore the natural ecosystem of polluted water.
"The scale of this disaster is not insignificant," he told Tass news agency, adding that most of the fuel had sunk to the bottom of the river and had already reached the lake.
Maloff said that the Maritime Rescue Service has put up six barriers to contain oil in the Amparnaya River to stop the transmission of diesel from the river to the lake, and is also using special devices to remove fuel.
But he stressed that the cleaning mission was hampered by the lack of roads in the area and the inclement weather that had already caused the ice blocks to break down the barriers, release more fuel towards the lake and force the rescue service to put it back.
"It is a moorland, and everything there can only be delivered to vehicles that operate in all terrain," Maloff explained, and predicted that the collected fuel should remain on site until winter in special tanks.
Melting permafrost
Prosecutors said in the Krasnoyarsk region - in a statement - that the leak polluted 180,000 square meters of land before hitting the river.
Norilsk Nickel said the accident may have occurred as the ground fell beneath the fuel tank due to the permafrost melting due to climate change.
Alexei Kneznikov, a WWF expert in Russia, explained that while climate change affected frosty soils, the accident would not have occurred if the company followed the rules.
He said that under Russian law, there must be a containment structure around any fuel tank in order for most spills to remain on site. He added, "Much of the blame rests with the company."
The difficult terrain in the area prompted some officials to propose burning the fuel collected at the scene, but the head of the Russian Environmental Protection Agency Svetlana Radionova ruled out on Thursday.
"There will be no burning of petroleum products," Interfax news agency quoted her as saying, also promising in consultation with the scientific community about the best course of action to address the effects of the environmental disaster.