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World Trade Center Building Performance Study: Data Collection, Preliminary Observations, and Recommendations (FEMA 403)

On the morning of September 11, 2001, two commercial airliners that had departed from Boston’s Logan Airport were hijacked and flown into the two 110-story towers in New York’s World Trade Center (WTC) complex. The resulting structural damage, combined with the ensuing fires, resulted in the total collapse of both towers. As the towers collapsed, debris consisting of crushed and broken building components fell on and blew into surrounding buildings, causing extensive collateral damage and, in some cases, igniting fires and causing additional collapses. A total of 2,830 people lost their lives that day at the WTC site—2,270 building occupants, 157 airplane crew and passengers, and 403 firefighters, police personnel, and other emergency responders.

Detailed information about the Team's findings and recommendations, including numerous photographs and illustrations, is presented in FEMA 403, World Trade Center Building Performance Study: Data Collection, Preliminary Observations, and Recommendations.

In addition to FEMA, the Department of Commerce's National Institute of Standards and Technology (NIST) has played a leading role in investigating the WTC disaster. Under the National Construction Safety Team (NCST) Act, signed into law in October 2002, NIST is authorized to investigate major building failures in the United States. The NIST investigators will establish the likely technical causes of the building failure and evaluate the technical aspects of emergency response and evacuation procedures in the wake of such failures. The goal is to recommend improvements to the way in which buildings are designed, constructed, maintained, and used.

The new law specifically applies to the NIST WTC building and fire safety investigation that was formally initiated on August 21, 2002 ( The study of WTC Buildings 1 and 2 and WTC 7 is focusing on the building construction, the materials used, and all of the technical conditions that contributed to the outcome of the WTC disaster.

You may obtain a printed copy of this publication by contacting FEMA's Distribution Center at 1-800-480-2520, and requesting publication number FEMA 403.

Last Modified: Wednesday, 11-Aug-2010 13:00:57 EDT