ARLINGTON, Va. — The Pentagon in Arlington, Virginia, was locked down on Thursday due to a potential hazmat issue.

Update 12:34 p.m. ET, June 11: The Pentagon Force Protection Agency posted to X that the shelter in place continued until the all clear was given. The post was published after CNN reported that the lockdown was over.

Update 12:05 p.m. ET, June 11: Two sources told CNN that the lockdown was over and was a false alarm. But that has not been confirmed by the Department of Defense or local agencies on the ground.

Original report: Arlington Fire & EMS posted to X.com that the fire department teams, including a Hazardous Materials Team, are on site and are working in support of the Pentagon Force Protection Agency’s Hazmat Team.

CNN reported that several floors and corridors were locked down while others were being evacuated.

Pentagon spokesperson Sean Parnell said on Facebook that systems within the building “have detected an air quality issue necessitating precautionary measures until we determine its significance.”

Officials have not given specifics about the incident, and there has been no initial mention of an investigation, WUSA reported.

The Pentagon, the “nerve center” of the nation’s military, is composed of five concentric rings and 10 intersecting corridors. Rings A and E allow people to walk around the entire building, while others may not, and some rings are only accessible from the basement.

The Pentagon’s Historical Office said, “The Pentagon is three in one: It is a building, an institution, and a symbol.”

It has 6,500,000 square feet of office space and 17 1/2 miles of corridors, according to the Department of Defense, and has about 27,000 military and civilian employees as of 2025.

Check back for more on this developing story.

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