Authorities in Kazakhstan have scrambled to reassure the public after an opposition politician in Russian warned of high radiation levels in a region near the border caused by a suspected leak of ruthenium-106 from a nuclear fuel processing plant.

Ksenia Sobchak, the socialite-turned-politician now running for the presidency in Russia, claimed in remarks to Rossiya-1 TV station that the city of Chelyanbinsk, which is 150 kilometers from the Kazakh border, has succumbed to a “ruthenium catastrophe.” She described the situation as comparable to Chernobyl.

Nobody in Russia appears to be taking such talk seriously and experts are sanguine about the threat posed by ruthenium-106, but Kazakhstan’s Energy Minister Kanat Bozumbayev has been moved all the same to tamp down concern. The minister said on November 27 that the Kazgidromet meteorological service had detected no traces of radiation on Kazakhstan’s territory.

Bozumbayev did say that the National Nuclear Center had detected traces of the ruthenium-106 isotope in the atmosphere around the Baikal atomic reactor in the West Kazakhstan region between September 13 and October 6. But he said that the levels detected were vastly below anything considered dangerous to health.

“Levels of ruthenium-106 are 30 times higher in Romania than here. In Italy, it is 80 times higher. In Ukraine, 100 times. Slovenia, 100 times, and Poland, 400 hundred times,” Bozumbayev said.

Ruthenium-106 is an artificially manufactured isotope produced as a byproduct at atomic energy plants and is used for medicinal purposes in chemotherapy treatment.

Radiation safety officials in Germany and France last month reported detecting a cloud of radiation making its way west from a location in the southern Ural mountains. That led them to speculation that some kind of leakage had occurred in a facility in either Russia or Kazakhstan. The source has now seemingly been narrowed down to Russia, although authorities there are tight-lipped about what precisely has occurred.

Greenpeace has suggested that a discharge of the isotope might be linked with a process called nuclear waste vitrification, whereby hazardous material that is to be disposed of is transformed into an easily storable glasslike solid. The environmental group said another possibility was that ruthenium-106 was placed in a furnace for remelting metals. Both processes are carried out at a Rosatom facility called Mayak, which is in the location identified by radiation specialists, Greenpeace said.