Emergency crews responded to a facility fire at the Savannah River Site near Aiken late Wednesday that officials said has since been extinguished.
The federal complex closed entry points to incoming traffic and restricted rail, river and air traffic and required a shelter in place to some affected workers as a precaution.
Barricades were lifted around 9:18 p.m. and the Department of Energy site said there are no longer operational emergencies or scheduled delays at the Savannah River Site.
"Incoming and outgoing traffic has resumed at all barricades and oncoming shift workers should report to work as usual," a notice at the top of the Savannah River Site's website read.
The first alert came just before 6:40 p.m. Wednesday.
It said an event at the Department of Energy's Savannah River Site prompted an emergency response, and that there was no indication as to impacts beyond the site's boundaries.
The second alert came an hour later, saying officials declared a site area emergency after 5 p.m. after a fire was reported at the Savannah River National Laboratory, a research and development facility on the complex.
There was no contamination outside of the affected facility, and radiological surveys indicated no detectable levels of contamination, a notice said.
The emergency was terminated at 9:45 p.m. Wednesday.
A notice said Highway 125 remained open, and oncoming shift workers should report to work as usual.
The Savannah River Site did not say what led to the fire.
Spanning 310 square miles in Aiken, the Savannah River Site was built in the 1950s to primarily produce plutonium and tritium to use in the creation of nuclear weapons until the end of the Cold War. The site now focuses on management of nuclear materials, cleanup and research and development.
In addition to Aiken County, the Savannah River Site also covers parts of Allendale and Barnwell counties.
This story may be updated.
