Multiple floors of the Pentagon were evacuated Tuesday following the detection of a hazardous substance, according to CNN sources. The Pentagon’s monitoring systems flagged air quality concerns, prompting safety protocols including a shelter-in-place order for the affected areas. Spokesperson Sean Parnell confirmed the incident and stated the measures are precautionary until the nature and severity of the situation are determined. Emergency response teams and firefighters are currently on the scene. CNN reports that law enforcement personnel inside the building have been observed wearing gas masks and chemical protective gear. The cause of the hazardous substance and the extent of any potential danger remain unknown at this time. Investigations are ongoing to assess the situation and ensure the safety of personnel.