Around 45 metric tons of aviation fuel have leaked from a depressurized pipeline operated by Russian mining giant Norilsk Nickel’s Norilsktransgaz, the latest leak to hit the fast-warming Arctic region since 21,000 tons of diesel leaked from a Nornickel plant in late May.

According to Norilsktransgaz, the July 12 leak near the village of Tukhard lasted 15 minutes. The village is located near the Bolshaya Kheta, a tributary to the Yenisei River which flows into the Arctic Ocean.

Nornickel said it has informed the emergency ministry and that it was conducting an internal investigation into the leak. Local officials declared a state of emergency and regional investigators opened a criminal case into environmental violations.

The accident happened weeks after another subsidiary of Nornickel, the Norilsk-Taymyr Energy Company, saw more than 20,000 metric tons of diesel oil leak into local soil and waters.

That spill happened after the ground beneath a major fuel reservoir sunk, damaging its foundation. Melting permafrost caused by climate change is believed to be the underlying reason for the catastrophe.

Russia’s federal nature protection agency Rosprirodnadzor in early July estimated the cost of the environmental damage at about 148 billion rubles ($2.1 billion).

Nornickel subsequently disputed the magnitude of the damage.

In addition to the two oil spills, Nornickel in late June also admitted that industrial waste waters had been dumped into local waterways.