Background and aims: Studies in the field of industrial accidents have shown that Human errors have the most important and significant role in accidents. According to studies conducted, 60 to 90 percent of accidents occur as a direct result of human errors.  The main objective of this study is to identify and assess human errors in Control Rooms of Arya Sasol Polymer Company by CREAM method.

Methods: This Descriptive, Cross_Sectional study was conducted in 2016, using the Hierarchical task analysis (HTA). 14 job tasks was analyzed in four control rooms of the Arya Sasol Polymer Company. Then, by using the basic and extended version of CREAM, common performance conditions and cognitive failure probability were determined and the results were analyzed.

Results: The results of this study show that 45%  of identified errors related to execution errors, 22% observation errors, 22% interpretation errors and 11% planning errors.

Conclusion: The results of this study show that it is required to Opportunistic Control Mode for initiating off-site section But for other tasks need to Tactical control mode. Using this technique is  appropriate to determine the type of errors and methods of control.