The Russian Meteorological Service said in a statement Tuesday that it recorded the release of Ruthenium-106 in the southern Urals in late September and classified it as “extremely high contamination.”

France’s nuclear safety agency earlier this month said that it recorded radioactivity in the area between the Volga River and the Ural Mountains from a suspected accident involving nuclear fuel or the production of radioactive material. It said the release of the isotope Ruthenium-106 posed no health or environmental risks to European countries.