The 20th Anniversary of September 11

II. USACE Headquarters Responds

  Four men in army uniforms in a meeting room

The Chief of Engineers, Lt. Gen. Robert Flowers, reads a note informing him of the second World Trade Center attack. Office of History. Photo by F.T. Eyre.

Tuesday, September 11, 2001, began as an ordinary late summer day at Army Corps of Engineers Headquarters in Washington, D.C. The Chief of Engineers, Lt. Gen. Robert Flowers, was addressing a group of retired USACE senior leaders when he received word that a plane had crashed into one of the World Trade Center towers. Soon after, he got word of a second strike, making it clear that an attack was underway. With that news the Chief of Engineers abandoned his briefing and activated the USACE Operations Center (UOC).

From his vantage point in the UOC, Flowers and his senior staff tried to make sense of a chaotic situation. Terrorists struck the Pentagon, and no one knew if other buildings in Washington and New York would also be targeted, by aircraft or other means. Accordingly, the USACE leadership turned its immediate attention to ensuring the safety of USACE employees at Headquarters, soon accounting for the staff and implementing additional building security measures. As it gradually became clear there would be no more attacks, the Corps Headquarters pivoted to its disaster response mission in the aftermath of an unprecedented event.

The Corps of Engineers’ role following disasters is established in the National Response Framework (known in 2001 as the Stafford Disaster Relief and Emergency Response Act), under which the Federal Emergency Management Agency (FEMA) is the lead agency. Under the plan, USACE is responsible for providing engineering and public works, which can include debris management services and technical assistance in structural engineering, as well as supplying temporary power, water, ice, and emergency housing. A year before the 9/11 attacks, the Corps overhauled its disaster response framework. Under the new system, USACE established Planning and Response Teams that included subject matter experts drawn from across the Corps who, with the proper training and equipment, could respond to disasters without delay. In addition, the Corps awarded a series of pre-negotiated contracts so that its support contractors, too, could respond almost immediately. Operating under the revised structure, the Corps was able to respond to the terrorist attacks within hours. Though it would be several days before FEMA gave the Corps its formal mission assignments, Headquarters was initiating preliminary planning and mobilization in anticipation of the request.

Army officers and civilians watch TV footage of burning buildings


Lt. Gen. Flowers (right) and the attendees of the USACE Leaders Emeritus meeting view news reports of the attack on the World Trade Center in New York. Office of History. Photo by F.T. Eyre.

Initially, the lack of reliable communications was a major obstacle for the affected Corps offices—New York District, New England District, and North Atlantic Division. The destruction of the Twin Towers severely disrupted the telephone infrastructure in the New York region and beyond. Despite those challenges, senior Corps leaders coordinated with FEMA officials in Washington and deployed USACE structural specialists and urban search and rescue teams from throughout the Corps of Engineers to New York. FEMA also requested the deployment of additional USACE teams to provide emergency power and to support initial attempts to clear debris. Headquarters also sent mobile command centers as part of its Deployable Tactical Operations System to help offset the lack of communications in New York City.

Within days of the attack, General Flowers traveled to New York to meet with FEMA and city and state officials. He assured them all that the Corps was ready to deploy its full arsenal of resources to support them in the response and recovery effort while also making it clear that USACE was in a supporting role. Flowers also met with Corps employees from the New York District and those who had deployed to the city from all over the country.

  Army officers and civilians at a meeting at a large table
The Corps of Engineers' senior military and civilian leadership meet at Headquarters on September 11, 2001, to discuss anticipated emergency response missions. Office of History. Photo by F. T. Eyre.

The USACE response at the Pentagon evolved very differently. As an active military facility, it fell outside the scope of the National Response Framework, so to provide assistance USACE turned to Brig. Gen. Carl Strock, the Director of Military Programs. While Headquarters staff assessed the situation, Strock went to the Pentagon to offer Corps support, which initially took the form of providing structural engineers to evaluate the stability of the building. Over the ensuing days and weeks, the Corps also procured supplies and provided logistical support for Army Engineer solders on site. As a result, USACE had a limited role in the response and recovery effort. However, later, Corps scientists and structural engineers initiated studies on the building’s ability to withstand future impacts and incorporated these findings into further design improvements for the building.

The Corps of Engineers Headquarters played a crucial role in the agency’s response to the September 11 attacks. Its Operations Center, working around the clock, managed information received from New York and the Pentagon and provided it to Corps leadership to allow them to make timely decisions and coordinate the USACE response. The Directorate of Civil Works established relationships with FEMA, the State and City of New York, and political leaders to ensure a smooth working relationship and an effective command structure. Headquarters also worked assiduously to put people and resources where needed. Finally, the Corps leadership was highly visible during the crisis, visiting New York and the Pentagon to support and encourage USACE personnel working there. By all accounts, the overall effort was successful.

September 2021. No. 145.

Office of History's series of articles remembering the responses to the attacks of September 11, 2001