Pentagon locked down and partially evacuated due to a false alarm by hazardous materials sensor, sources say
Pentagon Lockdown and Partial Evacuation Triggered by Sensor False Alarm, Sources Report
Pentagon locked down and partially evacuated - On Thursday, the Pentagon experienced a lockdown and partial evacuation after a hazardous materials sensor triggered a false alarm, according to two informed sources. The incident led to the sealing of multiple floors and corridors, with some areas being evacuated as a precautionary measure. A third source and the local fire department confirmed the event was classified as a “hazardous materials incident” initially.
Pentagon spokesperson Sean Parnell shared an update on X at 1:31 pm, stating that “normal operations have resumed” following the incident. He explained that occupants were alerted to a potential air quality issue, prompting immediate safety protocols. “Subsequent testing confirmed no hazard exists,” Parnell noted, emphasizing the thoroughness of the response.
Sensor Malfunction Causes Alarm
The evacuation was initiated when a sensor system at the Pentagon detected what appeared to be anthrax spores, as reported by first responder radio traffic and a source with knowledge of the event. However, one of the sources clarified that the sensor was malfunctioning, leading to the false alert. Internal security guidance indicated that an “air quality issue” had been identified, requiring further testing to confirm its nature.
“This additional testing could take one to two hours,” the message stated, adding that response teams were prepared to assist if needed. The center courtyard saw precautionary measures in place, with personnel from various agencies observed in action. “Please do not interpret these activities as an indication of an ongoing threat,” the note urged.
Expert Insight on Monitoring Systems
"Facilities like the Pentagon may use 'continuous air monitoring sampling,' where systems analyze large volumes of air for the presence of [anthrax] spores," explained Jake Jordan, who manages biosecurity programs for the Nuclear Threat Initiative. While hazmat teams can conduct quick on-site tests, pathogens such as anthrax necessitate specialized lab analysis for confirmation.
The Arlington County Fire Department deployed units to support the Pentagon Force Protection Agency’s hazardous materials team, as stated by Capt. Jamie Jill of the fire department. A social media post from Arlington Fire & EMS highlighted the team’s operations during the incident.
According to sources, floors two through five in corridors four through seven of the Pentagon complex were locked down. These floors are above-ground sections of the building, which has nine total corridors. Offices within the affected zones included the Navy’s main public affairs office and the Secretary of the Army’s workspace. One of the sources described how police personnel donned gas masks and full chemical protective gear during the alert.
History of False Alarms
Hayley Severance, a former senior advisor to the Defense Department on biological threat reduction, commented on the situation. “There is a history of some false alarms with anthrax detection,” she said. “But it’s really good that they’re taking these seriously, because it deserves this type of rapid precautionary response.”
This report has been updated with further details. Davis Winkie’s work at CNN is supported by a partnership between the Outrider Foundation and Journalism Funding Partners (JFP), while CNN maintains full editorial control over the content.