Arctic Circle oil spill: Russian prosecutors order checks at permafrost sites
Russian prosecutors have ordered checks at "particularly dangerous installations" built on permafrost after a huge oil spill in the Arctic.
An emergency was declared after 20,000 tonnes of diesel leaked into a river when a tank at a power plant near the city of Norilsk collapsed last Friday.
Initial Russian inquiries suggest ground subsidence as the cause.
The plant is owned by a subsidiary of Norilsk Nickel, which is the world's leading nickel and palladium producer.
Delays over reporting the collapse prompted criticism from President Vladimir Putin and the power plant's director, Vyacheslav Starostin, has been taken into custody.
The Russian Investigative Committee has launched a criminal case over pollution and alleged negligence.
Arctic permafrost has been melting in exceptionally warm weather for this time of year.
What checks have been ordered exactly?
Russia's chief prosecutor, Igor Krasnov, gave orders for regional and environmental prosecutors to conduct a "thorough check" of "particularly dangerous installations" located on "territories exposed to permafrost melting".
The aim is to prevent a repeat of the incident at the plant near Norilsk.
A spokesman for Mr. Krasnov's department told Russian media prosecutors would assess companies' adherence to safety laws, environmental monitoring, and measures to prevent emergencies.
The effectiveness of state monitoring would also be assessed, he said.
What can be done to clear up the damage?
The incident has prompted stark warnings from environmental groups, who say the scale of the spill and geography of the river mean it will be difficult to clean up.
Greenpeace has compared it to the 1989 Exxon Valdez disaster in Alaska.
Oleg Mitvol, former deputy head of Russia's environmental watchdog Rosprirodnadzor, said there had "never been such an accident in the Arctic zone".
He said the clean-up could cost 100bn roubles (£1.2bn; $1.5bn) and take between five and 10 years.
Minister of Natural Resources Dmitry Kobylkin warned against trying to burn off such a vast quantity of fuel oil and has proposed trying to dilute the oil with reagents.