A mysterious radiation cloud spread over Europe in September. Russia finally acknowledged it.

After weeks of denying its existence, the Russian government this week acknowledged the strange surge of radiation that billowed over Europe in September.

The French nuclear safety regulator IRSN first detected the radioactive element ruthenium 106 in the air in late September, tracing its origins to the Ural Mountains in the border region between Russia and Kazakhstan. Other European cities like Stockholm, Milan, and Budapest also began picking up radiation traces.

Toxic Liquid Nuclear Waste Headed for US Roadways

The Department of Energy, to the consternation of environmental groups, is preparing to transport 6,000 gallons of highly toxic liquid nuclear waste over American roadways.

The spent nuclear fuel is "target residue material" containing highly enriched uranyl nitrate—which after processing can be used as fuel. The DOE has spent years planning for the transfer of the waste from Canada's Chalk River Laboratories in Ontario to the Savannah River Site, a reprocessing facility in South Carolina. It will be transported in at least 100 to 150 separate truck shipments over a period of about three years, encased in cannisters normally used to transport solids that have been retrofitted to handle liquids. For security reasons, DOE won't reveal the exact timing or routes of the shipments. But elected officials in states it is likely to pass through are concerned about safety.