Human error is known to be the primary and principal causes of accidents in high risk industries such as oil and gas industries. This study has been mainly conducted because of the importance and sensitive nature of these industries in identifying and assessing human error in CNG stations. This descriptive-sectional study was performed using SHERPA technique in order to govern and assess human errors in CNG stations of Khoy County - Iran. Initially, desirable information was collected using task observation and interviews with safety responsibilities, authorities of units and operators. Subsequently, through HTA (Hierarchical Task Analysis) the critical tasks were defined. Finally, human errors in each critical tasks were recognized and assessed using SHERPA technique (systematically human error reduction and prediction method). Analysis of SHERPA questionnaires exhibited that, the total number of identified human errors in CNG job positions were equivalent to 113 errors, thereby highest and lowest percentages of errors were action error (51.33%) and communication error (3.54%), respectively. Based on the results, (63.7 %) of the identified errors risks were reported intolerable. In order to prevent and decrease the identified errors, and their consequences, reducing the rate of these errors is essential. In addition, appropriate control measures in the form of hardware changes in equipment design, periodic training courses and updating work instructions, and stress management as well as avoiding fatigue are to be prioritized towards corrective actions. Moreover, according to the results, the action errors with highest rate of errors should be considered for priority control measures.

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