On October 4, 1960, Eastman Chemical Company suffered the worst accident in its 83-year history, when an aniline manufacturing facility exploded. Sixteen people were killed, and more than 300 injured, as a result of the blast. This paper analyzes the incident and its aftermath using both historical records and modem analytical techniques. The results provide useful insight into both the technical and cultural safety issues raised, as well as valuable information that can be applied to current processes. Careful analysis, even years after the fact, can reveal new information, as well as reinforce that which is already known. For example, the used of residue curve mapping techniques, combined with the ternary liquid-liquid phase diagram revealed a combination of circumstances that was not anticipated in 1960. As a result of this accident, Eastman instituted a Process Safety Review Committee structure that has continued to this day. One of the results of this structured approach has been an order-of-magnitude reduction in serious incidents, sustained over a four-decade period. (C) 2004 American Institute of Chemical Engineers.