After initiating the reaction on January 31, 2006, operators observed solvent vapor leaking from a hatchway on top of the reactor as the process overheated and pressure built up inside the reactor. Operators fled the production building and gathered just outside a doorway. A flammable vapor cloud formed inside the building, and a short time later it ignited and exploded, destroying the production facility and fatally burning a maintenance supervisor who had remained inside. Personnel who gathered just outside the building were among the injured.