A reported hazardous materials incident at the Pentagon prompted emergency response measures Thursday, including evacuations, shelter-in-place orders and the deployment of hazardous materials crews.
Emergency units from the Arlington County Fire Department, including its hazardous materials team, responded to the Pentagon in support of the Pentagon Force Protection Agency’s hazmat team.
In a social media post, the fire department said its personnel were “operating at the Pentagon in support of PFPA’s Hazmat Team during a hazardous materials incident.”
ACFD units, including our Hazardous Materials Team, are currently operating at the Pentagon in support of PFPA’s Hazmat Team during a hazardous materials incident. pic.twitter.com/7qzOzbwh8W
— Arlington Fire & EMS (@ArlingtonVaFD) June 11, 2026
Pentagon spokesman Sean Parnell said that building systems detected an air-quality concern, triggering precautionary measures while officials worked to assess the situation.
“The Pentagon has sophisticated systems to ensure the safety of the building and its occupants,” Parnell said, according to CBS News. “Those systems have detected an air quality issue necessitating precautionary measures until we determine its significance.”
According to officials, a shelter-in-place order was issued for the affected areas of the building. An email sent shortly before 11 a.m. Eastern Time instructed personnel in designated corridors from the second through fifth floors to shelter in place and comply with the directive. Employees were also advised to move in-person meetings to virtual formats.
Parnell said the Defense Department was following established safety procedures.
“The Department is executing standard protection protocols, including a shelter-in-place order for the affected area,” he said, CNN reported. “Response teams are in place and ready to support building occupants.”
A message distributed by the Pentagon’s security team informed employees that an air quality issue had been detected and additional testing was underway.
“This additional testing could take one to two hours. Response teams are in place and ready to support building occupants if necessary. You may observe response personnel from multiple agencies and precautionary measures taking place in the center courtyard. Please do not interpret these activities,” the message stated, per CNN.
Sources familiar with the response said some areas of the Pentagon were evacuated while others remained under shelter-in-place orders. Corridors four through seven on floors two through five were reportedly locked down during the incident. One source said police inside the building were wearing gas masks and full chemical protective gear.
Later on Thursday, two sources familiar with the matter told CNN that the lockdown and evacuations were the result of a false alarm, but official sources have not confirmed that information.
No injuries have been reported. This is a developing story, and The Dallas Express will update its readers as more information becomes available.
