Abstract
The paper analyzes through conversation analysis how the 9-1-1 emergency system understood the attack to the World Trade Center on September 11, 2001; the data set consists of 356 phone calls to the 9-1-1 emergency number, registered during the 102 minutes encompassed between the first attack to the WTC and the second collapse of the Towers. Our analysis displays that existing theoretical models based on cumulated cue discrepancies fail to capture some fundamental dynamics that characterize the detection of novel emergencies. We show that: i) emergency units become progressively aware that they are experiencing a novel situation, ii) rapidly evolving situations and a distributed structure of information processing make it harder to distinguish relevant novel information from background noise, and this difficulty affects the possibility to detect new types of disasters. The paper suggests what emergency organizations can do to prepare themselves to cope with the unthinkable.