A fire occurred on the night of Feb. 20, 2003, in The Station nightclub at 211 Cowesett Avenue, West Warwick, Rhode Island. A band that was on the platform that night, during its performance, used pyrotechnics that ignited polyurethane foam insulation lining the walls and ceiling of the platform. The fire spread quickly along the walls and ceiling area over the dance floor. Smoke was visible in the exit doorways in a little more than one minute, and flames were observed breaking through a portion of the roof in less than five minutes. Egress from the nightclub, which was not equipped with sprinklers, was hampered by crowding at the main entrance to the building. One hundred people lost their lives in the fire. On Feb. 27, 2003, under the authority of the National Construction Safety Team (NCST) Act, the National Institute of Standards and Technology (NIST) established a National Construction Safety Team to determine the likely technical cause or causes of the building failure that led to the high number of casualties in that fire. This report documents the procedures, findings, and issues that were raised by the investigation. Volume I contains the main report and Volume II contains appendix material. The investigation concluded that strict adherence to 2003 model codes available at the time of the fire would go a long way to preventing similar tragedies in the future. Changes to the codes subsequent to the fire made them stronger. By making some additional changes – and state and local agencies adopting and enforcing them – we can strengthen occupant safety even further. Ten recommendations to improve model building and fire codes, standards and practices (as they existed in February 2003) resulted from the investigation, including (i) urging state and local jurisdictions to (a) adopt and update building and fire codes covering nightclubs based on one of the model codes and (b) enforce those codes aggressively; (ii) strengthening the requirements for the installation of automatic fire sprinklers; (iii) increasing the factor of safety on the time for occupants to egress; (iv) tightening the restriction on the use of flexible polyurethane foam -and other materials that ignite as easily and propagate flames as rapidly as non-fire retarded foam -as an interior finish product; (v) further limiting the use of pyrotechnics; and (vi) conducting research in specific areas to underpin the recommended changes.