Pentagon Lifts Shelter-in-Place Order After Sensors Flagged Possible Air Quality Issue

The Pentagon placed parts of the building under a shelter-in-place order on Thursday morning after internal systems detected a potential air quality issue; the order was later lifted after testing found no hazard. An alert carrying a severe rating was sent to employees in multiple corridors directing staff to remain in place, while other personnel were told to avoid the affected area.

Subsequent testing confirmed no hazard exists, and normal operations resumed.

A hazardous materials team scrubbed several locations in the Pentagon's A ring, the center-most section of the building. Officials described the event as a hazardous materials incident that triggered the building's safety protocols. A device picked up a biohazard scent in part of the building.

The Arlington, Virginia, fire department sent its Hazardous Materials team to support the Pentagon Force Protection Agency’s Hazmat team. Offices of Defense Secretary Pete Hegseth and Chairman of the Joint Chiefs of Staff Gen. Dan Caine are not located in the corridors placed under lockdown.

The Pentagon Shield program, launched after the Sept. 11 attacks, uses sensors, computer modeling and building ventilation controls to identify chemical, biological and radiological hazards. The last notable Pentagon lockdown occurred in August 2021, when a Pentagon police officer was killed during a violent incident at the Pentagon Transit Center.

Approximately 23,000 to 27,000 people work in the Pentagon on any given day.