A radioactive wasp nest was found next to a site in South Carolina that once made key parts for nuclear bombs.

The hazardous insect abode was located near a set of tanks filled with liquid nuclear waste, although the team didn’t detect any leaks. Instead, experts believe the nest set off Geiger counters through what’s known as “onsite legacy radioactive contamination.

A radioactive wasp nest was found at the Savannah River Site in South Carolina, a facility where the US once produced nuclear weapons.