Employees who routinely check radiation levels at the Savannah River Site near Aiken found a wasp nest on July 3 on a post near tanks where liquid nuclear waste is stored.

The Department of Energy said radiation contamination levels on the wasps' nest were over ten times the regulated maximum.

Four radioactive wasp nests may indicate previously undetected environmental contamination at the decades-old Savannah River Site. Here’s what to know.