Nov. 21 (UPI) -- Russian authorities said an "extremely high" level of radioactive pollution was detected in the Ural mountains weeks ago -- but denied the contamination came from a nuclear accident.
The French Institute of Radioactive Protection reported this month a cloud of radioactive pollution had been detected in Germany, Austria, Italy and Switzerland in late September -- and that it likely originated from a nuclear facility in Russia or Kazakhstan.
The pollution from ruthenium-106 occurs when atoms are split in a reactor, and is also used in certain medical treatments.
Russia's meteorological agency, Rosgidromet, said pollution was of Ru-106 nearly 1,000 times normal levels at the Argayash weather station in late September and early October. At the Novogorny station, levels were 440 times higher than in the previous month.
The stations are located in the Chelyabinsk region in the southern Ural mountains. The Argayash post is 20 miles from the Mayak nuclear facility, which reprocesses fuel and produces radioactive material for industrial and research purposes.
Data from Rosgidromet show the radiation cloud was weaker nearer Mayak than Argayash.
The Mayak plant, part of Russian nuclear energy company Rosatom, said Tuesday, "the atmospheric pollution by the isotope Ruthenium-106, indicated in the report of Roshydromet, is not related to the activities of the FSUE Mayak Production Association."
Yevgeny Savchenko, the Chelyabinsk region public safety minister, said Monday "fluctuations in background radiation" had not reached dangerous levels and "there was no basis for protective measures."
"Roshydromet's data on isotope contamination with ruthenium-106 allow us to conclude that the dose that could have been received by a person is 20 thousand times less than the maximum permissible annual dose and does not pose any danger to human health and life," Rosatom added.
The energy agency said last month allegations that the contamination came from a nuclear accident are "baseless."
Greenpeace Russia said Tuesday it will ask prosecutors to look to see if there's any evidence of a cover-up.
An accident at the Mayak plant has happened before. An explosion there in 1957 exposed at least 272,000 people to dangerous levels of radiation.