In this May 22, 2013, file photo crews works to contain odors from a slow-burning underground fire smoldering near a cache of nuclear waste at the Bridgeton Landfill in Bridgeton, Mo. Authorities have quietly adopted an emergency plan in case the smoldering embers ever reach the waste, a potentially "catastrophic event" that could release radioactive fallout in a plume of smoke over a densely populated area of suburban St. Louis.

(Roland Klose, St. Louis Post-Dispatch)