A Russian watchdog warned mining giant Nornickel years ago about violating dozens of rules at a power station in the Arctic, where a massive oil spill occurred last week. The Russian media company RBC reports this on Friday.

According to Greenpeace, the disaster caused 15,000 tons of diesel to enter the Ambarnaja river and some 6,000 tons of diesel into the ground. The environmental organization speaks of one of the biggest oil spills ever.

According to Nornickel, melting permafrost, caused by climate change, has eroded the foundation of a fuel tank at a Norilsk power plant, relieving pressure and severely damaging the tank. As a result, tons of diesel fuel flowed out.

Environmental scientists have warned for years that climate change is causing the Arctic to warm up faster than other parts of the world. The melting permafrost, a substrate that normally never thaws completely, poses a direct threat to infrastructure built on permafrost.

Overdue maintenance on fuel tanks

Russian security watchdog Rostekhnadzor conducted three large random checks at a power plant belonging to a Nornickel subsidiary in 2017 and 2018 and uncovered several issues, including those related to fuel tanks.

In addition, the power station appeared to do too little to remove rust on the tanks, while the authorities had previously pointed this out.

According to Norickel, the world's largest producer of nickel and palladium, such overdue maintenance had not been identified at the tank where the leak occurred, but this warning related to the company's other fuel tanks.

Angry Putin declares a state of emergency

President Vladimir Putin has declared a state of emergency in the region around the remote city of Norilsk. He lashed out at the local authorities, who only took action two days after the disaster.

The exact damage is not yet known, but local fishing organizations say it may take decades for the area to recover. The Nornickel company has started to clean up the oil and has asked the Moscow government for help.

A floating dam has now been placed in the water to prevent further spreading of the oil. A Nornickel manager responsible for the oil tank was arrested by the police.