In recent years there has been increased emphasis on process safety as a result of major chemical incidents involving gas releases, major explosions, and environmental incidents. Spending some time to fix our eyes on the historical catastrophes of industrial processes is necessary for process safety improvement. While each case history presents an important foundation for understanding, identifying, and eliminating root causes, to prevent recurrence of these incidents there is a need to identify the common lessons learned. Root causes are usually deficiencies in safety management systems, but can be any factor that would have prevented the incident if that factor had not occurred. In this article, multiple case histories were analyzed to understand the common similarities between process incidents. The objective of this article is to focus on learning some common lessons from the historical incidents in order to prevent recurrences of similar incidents. Ten important lessons were identified and are described in this article. (C) 2011 American Institute of Chemical Engineers Process Saf Prog 30: 143-147, 2011