A hazardous materials incident was reported at the Pentagon on Thursday, leading to a lockdown and the evacuation of several floors. Pentagon spokesperson Sean Parnell said building monitoring systems detected an air quality issue necessitating precautionary measures until its significance could be determined. Sources told CNN the Pentagon lockdown and evacuation were triggered by a false alarm. One claim reports an actual hazardous materials incident; the other claims the incident was a false alarm — mutually incompatible as to whether a real hazardous material event occurred. The Pentagon Department executed standard protection protocols, including a shelter-in-place order for the affected area, according to economictimes.indiatimes.com. Subsequent testing confirmed no hazard existed at the Pentagon, according to abcnews.com. Normal operations at the Pentagon have resumed, according to abcnews.com.