A key mission of the US Chemical Safety and Hazard Investigation Board (CSB) is to determine the root causes of incidents, report the findings, and issue recommendations to prevent similar incidents from occurring. CSB investigators respond to a variety of events occurring in a wide range of workplaces, from chemical plants and refineries to food-flavoring factories and steel mills. The details of each investigation are unique and the root causes are pertinent to each specific case. However, a common thread that emerges in CSB investigations is the inadequacy of management systems that might have prevented the incident from occurring. Examples of the systemic issues identified in CSB reports are: Lack of hazard review to predict and prevent incidents Insufficient investigation and follow-up after previous incidents Inadequate training of staff Failure to implement effective mechanical integrity programs These issues are well recognized as elements of a process safety management (PSM) program, although many incidents investigated by the CSB occurred at,facilities that are not regulated by OSHA's process safety management rule.(1) Indeed, a number of these incidents occurred at facilities that are well outside society's definition of "chemical plants." Please note that the opinions and conclusions expressed in this paper are those of the author, and do not necessarily represent the opinions of the Chemical Safety and Hazard Investigation Board. (C) 2004 American Institute of Chemical Engineers Process.