In the lobby of the north WTC tower, just after the South Tower is hit, Fire Commissioner Thomas Von Essen speaks briefly to Fire Chief Ray Downey. According to Von Essen, Downey—who is a highly respected expert on building collapses—says to him, “You know, these buildings can collapse.” Von Essen later recalls, “He just said it in passing, not that these buildings will collapse in 40 minutes and we have to get everybody out of here, or not that they’ll collapse by tomorrow, or not that they necessarily will collapse at all. Just that they can collapse.” [Fink and Mathias, 2002, pp. 229; 9/11 Commission, 5/18/2004] But other firefighters do not appear to have shared this concern. According to the National Institute of Standards and Technology (NIST), the Fire Department command officers who are planning for operations inside the Twin Towers expect that there will “be localized collapse conditions on the damaged fire floors,” but do “not expect that there [will] be any massive collapse conditions or complete building collapse.” At the end of its three-year investigation of the WTC collapses, NIST will report, “No one interviewed indicated that they thought that the buildings would completely collapse.” [National Institute of Standards and Technology, 9/2005, pp. 72 and 75-76] In fact, Deputy Fire Commissioner Lynn Tierney will meet up with Downey and others—including Von Essen—slightly later, on the south lawn of the WTC complex, where a new command center is set up. At that time, according to Tierney, Downey will only be concerned that the 360-foot antenna atop the North Tower will fall, and “No one ever thought the towers were going to come down.” [Pittsburgh Tribune-Review, 9/11/2006] However, shortly before the first tower comes down, EMT Richard Zarrillo will be asked to relay a message to some senior firefighters that the mayor’s Office of Emergency Management “says the buildings are going to collapse” (see (Before 9:59 a.m.) September 11, 2001). And later in the day, Mayor Giuliani will recount that around the same time, he had been told “that the World Trade Center was going to collapse” (see (Before 9:59 a.m.) September 11, 2001). The 9/11 Commission will state, “The best estimate of one senior [fire] chief, provided to the chief of the department sometime between 9:25 and 9:45, was that there might be a danger of collapse [of the South Tower] in a few hours, and therefore units probably should not ascend above floors in the sixties.” The Commission does not state, however, whether this fire chief was referring to a total building collapse or just a localized collapse. [9/11 Commission, 5/19/2004] Ray Downey is killed when the second tower collapses at 10:28 a.m. [New York Times, 9/9/2005]