Russian authorities have arrested three managers at a thermal power plant that leaked tons of fuel into the fragile Arctic environment.
The disaster occurred on May 29, when a holding tank at the facility near the industrial city of Norilsk spilled at least 20,000 tons of diesel fuel into the soil, two rivers, and a downstream lake.
Russia’s Investigative Committee said on June 10 that the head of the power station, Pavel Smirnov, and two top engineers were arrested on suspicion of violating environmental protection rules.
The committee said it had established that the fuel-storage tank needed repairs in 2018 but continued to function in violation of safety regulations.
"As a result the accident occurred," the investigators' statement said.
Another manager at the plant was arrested and charged earlier this month.
The power plant is owned by a subsidiary of Norilsk Nickel, the world's leading nickel and palladium producer, which said the leak was caused when pillars supporting a storage tank sank due to thawing permafrost soil.
The Prosecutor-General's Office has also issued preliminary findings revealing that sagging ground helped trigger the disaster.
Russian President Vladimir Putin ordered a state of emergency after the extent of the spill became known and Norilsk Nickel has since promised to pay for the costs of the cleanup, estimated at 10 billion rubles ($145 million).
Norilsk Nickel is own by Russia’s richest man, Vladimir Potanin. The company denies allegations that management hushed up and downplayed the scale of the disaster for at least two days after the accident.
On June 9, the company said that the fuel-storage tank was repaired in 2017 and 2018 after which it went through a safety audit.
Those detained "are cooperating with law enforcement authorities and now they would be much more useful at the scene of the cleanup operation," the press service said in a statement to RIA Novosti news agency, citing Vice President Nikolai Utkin.
Regional officials say oil booms and other cleanup operations have failed to prevent all the spilled fuel and chemicals from flowing from the Daldykan and Ambarnaya rivers into Lake Pyasino.
Separately, the Emergency Situations Ministry said on June 10 that 14 countries, including the United States, have provided satellite data on the spill to aid in the response.
The ecological disaster came as temperatures in Siberia were up to 10 degrees Celsius above average in May and were also higher than normal earlier in the year, leading to thawing permafrost.
Sixty five percent of Russia is covered by permafrost. Norilsk, an isolated Arctic city, is constructed on permafrost and its infrastructure is threatened by climate change.