[BBC] Des spécialistes chimistes Russes ont été envoyés en Sibérie, près de la ville de Omsk.
Oily yellow and orange snowflakes fell over an area of more than 1,500sq km (570sq miles) in the Omsk region on Wednesday, Russian officials said.
« We are waiting for the results of a thorough test on samples. »
But Vladimir Gurzhey, an official with the civil defence ministry in Omsk, told the Russia TV channel that the snow had four times the normal levels of iron in it.