Firefighters ‌were investigating a ​hazardous ⁠materials incident ‌at the ‌Pentagon ‌on Thursday (June 11, 2026), ⁠Arlington ⁠County fire and ​rescue ‌officials said in a post ‌on ​X.

The building was ⁠under lockdown ‌with people evacuated from several ‌floors, CNN ​reported, citing ⁠unidentified sources. It said emergency responders were wearing full gas ​masks and chemical ‌protection suits.

“The Pentagon has sophisticated systems to ensure the safety of the building and ‌its occupants. Those systems have ​detected an air quality issue necessitating precautionary measures ⁠until we determine its significance,” Pentagon spokesperson Sean Parnell said in an ‌email.

“The Department is executing standard protection protocols, including a shelter-in-place order for the affected area. Response teams are in place and ready to ‌support building occupants.”

Floors two through five ​were locked down, as well as some corridors, CNN ⁠reported.

The five-sided Pentagon building is ‌one of the world’s largest office buildings.