Firefighters responded to a potential hazardous material incident at the Pentagon in Washington D.C. on Tuesday. Parts of the building were evacuated as a precautionary measure while emergency crews investigated the situation. The nature of the substance is currently unknown, and authorities are working to determine the cause of the incident. No injuries have been reported at this time. The Pentagon Protective Service and local hazmat teams are collaborating on the response. Normal operations were disrupted in the affected areas during the investigation and evacuation process. Further updates will be provided as more information becomes available.