WASHINGTON, June 11 - Firefighters were on scene at the Pentagon on Thursday conducting an investigation into a hazardous materials incident, Arlington County fire and rescue officials said in a post on X.
The five-sided building was placed under partial lockdown and people were evacuated from multiple floors, with media reports citing unidentified sources indicating that emergency personnel were operating in full gas masks and chemical protection suits.
In an emailed statement, Pentagon spokesman Sean Parnell said the building is equipped with sophisticated systems designed to protect occupants. "Those systems have detected an air quality issue necessitating precautionary measures until we determine its significance," he wrote. Parnell added that the Department is following standard protection protocols, which include a shelter-in-place order for the area affected, and that response teams are positioned to support building occupants.
Media reports have said that floors two through five were locked down and that some corridors were also closed as responders worked to assess the situation.
The Pentagon, one of the world’s largest office buildings, retains a prominent place in national defense infrastructure. Officials have not provided further details about the incident beyond the steps taken to restrict movement within parts of the facility and to deploy specialized response units.
Emergency response teams remained on site while authorities evaluated the air quality readings. The precise nature and severity of the material detected have not been disclosed, and officials emphasized that precautionary measures were being carried out while the investigation continued.
This event prompted immediate protective actions from building management and emergency services, including targeted evacuations, lockdowns of specified floors and corridors, and the use of protective equipment by responders. Authorities have indicated they will determine the significance of the detected air quality issue through ongoing assessment.
Note: Information in this piece reflects statements and reports made by Arlington County fire and rescue officials, a Pentagon spokesman and media reports citing unidentified sources. Officials have not released additional details about the substance involved or the outcome of the investigation.