A fire at a portable building in the Hanford 300 Area just north of Richland was quickly extinguished late Wednesday morning, according to Mission Support Alliance.
Two workers at a mobile office trailer noticed smoke, according to the Department of Energy.
The Hanford and Richland fire departments responded and found an overhead fire in the trailer.
The workers got out safely and no hazardous materials were involved, according to DOE. The trailer was not destroyed.
The trailer was used by Hanford nuclear reservation contractor Johnson Controls, which provides HVAC services. It was near the 331 Building used by Pacific Northwest National Laboratory.
The cause of the fire is under investigation by the Hanford fire marshal.