A progress report on the National Institute of Standards and Technology (NIST) World Trade Center (WTC) building and fire safety investigation released in May did not offer any specific conclusions or recommendations, because the agency still considers the investigation to be in its early stages. NIST Director Arden Bement Jr., however, "reported solid progress by the investigation team at the one-third mark of the ongoing 24-month effort." The report focused on the floor system and its fireproofing. Dr. Shyam Sunder, lead investigator, however, says that the investigation to date has not determined that the floor trusses played a critical role in the collapse of the WTC towers. However, NIST has not been able to locate any information pertaining to fire endurance tests on the WTC floor system. The architect and the structural engineer of record stated in 1966 and 1975, respectively, that the fire rating of the floor system of the WTC towers could not be determined without testing.
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