Key facts
- The Pentagon was temporarily locked down due to an air quality issue.
- A security response and investigation were initiated.
- Subsequent testing confirmed no hazard.
- Normal operations have resumed at the Pentagon.
The Pentagon, the headquarters of the United States Department of Defense, was temporarily locked down due to an unspecified air quality issue. The security measure prompted an investigation into the cause of the problem. Subsequent testing confirmed no hazard, and normal operations have since resumed.