Journal of School of Public Health and

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Background and Aim: Today in many work environments, such as nuclear, military and chemical industries, human errors may result in disasters. Accidents in different parts of the world bear evidence to this examples are the Chernobyl disaster (1986), the Three Mile Island accident (1974), and the Flixborough explosion (1974). Thus, identification of human error, especially in complex and intricate systems, and devising control measures are essential.

Materials and Methods: This project was a case study conducted in Zagross Methanol Company in Asalouye (South Pars), Iran. The walking-talking-through method was used to collect the required data and complete the Systematic Human Error Reductive and Predictive Approach (SHERPA) worksheets. The process experts and control room operators were interviewed and technical documents of the Company examined.

Results: Analysis of the SHERPA worksheets indicated that the majority (48.62%) of the 222 errors identified were action errors, followed by checking errors (31.97%), retrieval errors (6.75%), selection errors (0.9%), and communication errors (11.7%).

Conclusion: The results of this study show that the method can be used effectively in different industries, especially chemical industries, to identify human errors that may potentially lead to dangerous situations and accidents.

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  Background and Aim: After conducting a comprehensive study on shift work systems in petrochemical companies and recommending appropriate shift schedules, some companies changed shift patterns. After a year, the present study was carried out at a petrochemical company which changed its shift pattern from 4-4-4 to 3-3-3. The objective of the study was evaluation of effectiveness of shift schedule change on shift workers’ health problems.

  Materials and Methods: In this study, samples consisted of 195 shift workers of the present study and 44 shift workers from the previous study. Data were collected by an anonymous questionnaire, in which questions on demographic characteristics, health problems and workers’ opinions about shift pattern change were included. Data were statistically analyzed using SPSS 11.5.

  Results: The results showed that prevalence of gastrointestinal, cardiovascular, and musculoskeletal problems were not statistically different between the two groups (p>0.05), but prevalence of some psychological disorders were lower in the present study subjects as compared to the individuals of the previous study (p<0.01). The results revealed that from the viewpoint of shift workers new shift pattern improved quality and quantity of sleep. The findings showed that 76.8% of the subjects evaluated the new shift schedule to be better than the previous one.

Conclusion: Based on the findings, changing the shift pattern from 4-4-4 to 3-3-3 resulted in reduction of prevalence of psychological problems. Therefore, the change implemented in the shift pattern was useful.