Radioactive contamination mysteriously spread beyond a restricted laboratory at one of America’s largest nuclear complexes, triggering alarms as three workers attempted to leave.
Tests detected radioactive material on the soles of their shoes emitting between 80,000 and 300,000 disintegrations per minute, levels that exceeded federal contamination limits.
The alarming incident unfolded at the US Department of Energy’s Savannah River Site (SRS) in South Carolina, which processes tritium and manages plutonium infrastructure vital to America’s nuclear stockpile.
It was quietly disclosed in a federal safety report covering the week ending June 26 but was not publicly announced by site officials at the time.
Investigators later discovered contamination outside areas intended to contain it, but were unable to determine precisely where the material came from or how it spread.
The three workers were decontaminated, and officials found no evidence that they inhaled or absorbed radioactive material.
The incident was one of two safety lapses revealed at the sprawling nuclear complex that week.
At another facility at SRS, an operator began transferring radioactive liquid without first adding a chemical required to protect nuclear-waste tanks from corrosion.
The alarming incident unfolded at the US Department of Energy’s Savannah River Site (SRS) in South Carolina, which processes tritium and manages plutonium infrastructure vital to America’s nuclear stockpile
SRS, a 310-square-mile site in Aiken, focused on the production of plutonium and tritium for use in the manufacture of nuclear weapons from its inception in the early 1950s until the end of the Cold War.
In 1992, the focus at SRS turned to environmental cleanup, nuclear materials management and research and development activities.
The site generated more than 165 million gallons of liquid nuclear waste, which has, through evaporation, been reduced to about 34 million gallons, according to Savannah River Mission Completion.
There are still 43 of the underground tanks in use, while eight have been closed.
The three laboratory workers were inside a radiological buffer area, a controlled zone designed to prevent radioactive material from spreading into clean areas, when the personnel contamination monitor started blaring as they exited.
Follow-up radiation monitoring checks identified beta and gamma contamination on the soles of their shoes, according to the report.
Beta and gamma contamination occur when unwanted radioactive material, specifically atoms that emit beta particles or gamma rays, settles on surfaces, skin or inside the body.
The follow-up investigation later found contamination beyond the laboratory’s restricted areas.
Tests detected radioactive material on the soles of their shoes emitting between 80,000 and 300,000 disintegrations per minute, levels that exceeded federal contamination limits (stock)
Investigators learned that workers sometimes carried test wipes from radioactive fume hoods to the edge of those areas to scan them, a practice officials said should be avoided.
They also discovered problems with cleanliness and organization inside the laboratory.
Although officials could not determine exactly how the contamination escaped, managers pledged to tighten housekeeping rules, increase supervision and retrain radiation-safety staff on proper testing procedures.
At another facility on the site, an operator mistakenly began transferring radioactive liquid between two waste tanks without first adding sodium nitrite, a chemical needed to prevent corrosion.
A control-room manager caught the error 30 minutes into the transfer. Officials decided it could continue because they could adjust the amount of liquid being moved and add the chemical afterward.
Investigators found that the transfer procedure had recently changed and the operator misunderstood when the chemical was supposed to be added.
Staff acknowledged that the instructions were unusually structured and discussed improving briefings following procedural changes.
A federal inspector also recommended reviewing other procedures to determine whether they contained similarly confusing instructions.
The safety lapses emerged nearly a year after a radioactive wasp nest was discovered near tanks holding liquid nuclear waste at the same sprawling complex.
Workers conducting routine inspections on July 3, 2025, found the contaminated nest attached to a post in the Savannah River Site’s F-Area Tank Farm.
Tests revealed radiation levels 10 times higher than federal limits, although officials said there was no evidence that any of the underground waste tanks had leaked.
The nest was sprayed, removed and disposed of as radioactive waste. No wasps were found, and surveys detected no contamination on the surrounding ground.
Officials blamed the bizarre discovery on ‘onsite legacy contamination,’ radioactive residue left behind by decades of nuclear-weapons production during the Cold War.
However, the Savannah River Site Watch watchdog group criticized the government’s account for failing to identify the precise source of the radiation or explain whether other contaminated nests could remain undiscovered.
‘I’m as mad as a hornet that SRS didn’t explain where the radioactive waste came from or if there is some kind of leak from the waste tanks that the public should be aware of,’ executive director Tom Clements said at the time.
Site officials maintained there was no threat beyond the facility.
The tank farm sits deep within the complex, while wasps generally travel only a few hundred yards from their nests.
The Daily Mail has contacted the Department of Energy for comment.
