determining human error global causes in a petrochemical control room with a cognitive analytical approach-cream

control room is the heart of each system in which even a minor error can result in irrecoverable consequences. the purpose of this study was to determine the probable control modes (pcms) and cognitive failure probability (cfp), and also build a cognitive demands profile (cdp) in a petrochemical control room, using cognitive reliability and error analysis technique (cream). first, tasks of boardman (b.m), shift control (s.c), and head control (h.c) in control room were analyzed, applying hierarchical task analysis. following, pcm, cfp and cdp were determined for the analyzed tasks. according the results, control modes for the tasks of b.m and s.c were determined as opportunistic; while for h.c tasks it was obtained as tactical. of the all error types, execution failure (48.57%), interpretation failure (18.57%), planning failure (15.71%), and observation failure (17.15%) were identified. the most important cdps were communicate, monitor, execute, plan, diagnose, evaluate, co-ordinate, verity, record, and scan.   based on the findings, number of simultaneous goals, time of day and adequacy of training and experience in the study field were the common performance conditions that led to reduction of performance reliability. these factors contributed to the opportunistic control mode. in order to prevent or reduce cognitive errors in the control room, we need to know the exact type of cognitive activities, and develop a comprehensive program to increase the knowledge and skills for performing the cognitive activities.