While process hazard analyses have been voluntarily used in the chemical processing industries for over 30 years and required by U.S. regulation for certain processes involving highly hazardous chemicals since the early 1990's, continued misapplication of these techniques allow process hazards to remain either undetected or unappreciated. Using past CSB investigations as examples, this paper discusses some problems observed in process hazard analyses that diminished their overall effectiveness and prevented them from fully identifying and/or evaluating process hazards. Some practical solutions are presented for making process hazard analyses more effective.