Normal operations resumed at the Pentagon after the building went into a lockdown Thursday over an “air quality issue.”
Hazmat teams responded after the defense facility’s systems detected an “air quality issue necessitating precautionary measures until we determine its significance,” Pentagon spokesperson Sean Parnell told The Independent on Thursday morning. Parts of the building were then placed on lockdown.
Normal operations resumed around 1:30 p.m. local time, after “subsequent testing confirmed no hazard exists,” Parnell wrote on social media.
Sources told CNN the response was triggered by a malfunctioning sensor system that detected possible anthrax in the air. The Independent has reached out to the Pentagon for comment.
In addition to the lockdown, some people were evacuated from the facility, CNN reports.
The Pentagon Force Protection Agency’s hazmat team responded, assisted by units from the Arlington County Fire Department.
The Pentagon, located near the Potomac River in the Washington, D.C., area, serves as the Defense Department’s headquarters. About 24,000 military personnel and civilians work in the building, along with 3,000 non-defense support workers.
Pentagon 'air quality issue' sparks hazmat response
16:47 , Katie HawkinsonThe Pentagon detected an air quality issue this morning that prompted a lockdown and response from hazmat teams.
"The Pentagon has sophisticated systems to ensure the safety of the building and its occupants. Those systems have detected an air quality issue necessitating precautionary measures until we determine its significance. The Department is executing standard protection protocols, including a shelter-in-place order for the affected area. Response teams are in place and ready to support building occupants," Pentagon spokesperson Sean Parnell told The Independent.
The Arlington County Fire Department confirmed its units, including a “hazardous materials team,” are responding to the incident.
Those units are providing support to the Pentagon Force Protection Agency’s hazmat team, which has taken the lead on the response, according to the department.
Pentagon officials doing 'additional testing'
16:51 , Katie HawkinsonSecurity officials at the Pentagon detailed the ongoing response to the “air quality issue” that prompted a lockdown at the facility, according to a message obtained by CNN.
“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 reads.
What is the Pentagon?
17:05 , Katie HawkinsonThe Pentagon, located near the Potomac River in the Washington, D.C., area, serves as the Defense Department’s headquarters.
Its employees include 24,000 military personnel and civilians, along with 3,000 non-defense support workers.
The building first opened in 1943, after about two years of construction.
Arlington Fire & EMS assisting Pentagon Force Protection Agency in response
17:09 , Isabel KeaneArlington Fire & EMS was at the Pentagon in support of the Pentagon Force Protection Agency’s Hazmat Team “during a hazardous materials incident,” the EMS service wrote on X.
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
Which levels of the Pentagon are on lockdown?
17:20 , Katie HawkinsonThe Pentagon issued a shelter-in-place order for certain areas of the facility after an “air quality issue” prompted a hazmat response.
According to CNN, certain corridors on floors two through five of the building were placed on lockdown in response to the incident.
First responders spotted in protective gear
17:36 , Katie HawkinsonPolice who responded to the Pentagon today over the “air quality issue” were wearing protective gear and gas masks, a source told CNN.
The Pentagon Force Protection Agency’s hazmat team is leading the response with assistance from the Arlington County Fire Department.
Hazmat situation may have been false alarm: report
17:53 , Katie HawkinsonToday’s hazmat situation at the Pentagon may have been triggered by a false alarm, sources told CNN.
Hazmat teams responded to the Pentagon after its systems detected an “air quality issue necessitating precautionary measures until we determine its significance.”
Pentagon shelter-in-place order remains in effect
18:00 , Katie HawkinsonThe Pentagon’s shelter-in-place order was still in effect as of 12:24 p.m. local time, according to the Pentagon Force Protection Agency.
The Pentagon issued the order for certain impacted areas after its systems detected an “air quality issue.”
🚨 Shelter in place continues in affected areas in the Pentagon until all clear is given. https://t.co/NSADvTjxZN
— Pentagon Force Protection Agency (@PFPAOfficial) June 11, 2026
What is the Pentagon Force Protection Agency?
18:34 , Katie HawkinsonThe Pentagon Force Protection Agency is leading the response to today’s hazmat situation.
The agency is in charge of protecting the Defense Department’s personnel and infrastructure within the Washington, D.C., area and provides 24/7 protection against threats, according to its website.
Agency personnel include law enforcement officers, counterintelligence agents and technical specialists.
False alarm may have been tied to false anthrax detection: report
18:54 , Katie HawkinsonToday’s hazmat situation at the Pentagon may have been triggered by a false alarm after a malfunctioning sensor detected possible anthrax, CNN reports.
Anthrax can be released into the air, causing a serious and sometimes fatal infection to those who breathe it in, according to the CDC.
Ex-Pentagon official says there's 'history' of anthrax false alarms
19:30 , Katie HawkinsonHayley Severance, an ex-adviser to the Defense Department, told CNN that “there is a history of … some false alarms” with anthrax detection.
“It’s really good that they’re taking these seriously, because … it deserves this type of rapid precautionary response,” she added.
Normal operations resume at Pentagon
20:03 , Katie HawkinsonNormal operations have resumed at the Pentagon, spokesperson Sean Parnell said.
“Earlier this morning, Pentagon occupants were notified of a potential air quality issue, prompting immediate precautionary safety measures and evaluation. Subsequent testing confirmed no hazard exists, and normal operations have resumed,” he wrote on X.
STATEMENT:
— Sean Parnell (@SeanParnellASW) June 11, 2026
Earlier this morning, Pentagon occupants were notified of a potential air quality issue, prompting immediate precautionary safety measures and evaluation. Subsequent testing confirmed no hazard exists, and normal operations have resumed.
We express our sincere… https://t.co/QReD77PR4V
