Pentagon Lifts Shelter-in-Place Order After Air Quality Alert Proved False

The Pentagon briefly placed parts of the building under a shelter-in-place order Thursday morning after internal systems detected a potential air quality issue. An alert sent to employees in multiple corridors carried a severe rating and directed staff to remain in place while other personnel were told to avoid the area.

m. Eastern Time.

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.

The Pentagon has spent years developing systems designed to detect and contain airborne threats inside the building. Following the Sept. 11 attacks, officials launched the Pentagon Shield program, which uses sensors, computer modeling and building ventilation controls to help identify chemical, biological and radiological hazards.

Building systems can adjust airflow and isolate affected areas while emergency responders assess a potential threat. 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.

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