Ergonomic assessment of musculoskeletal disorders risk level among workers of a petrochemical company

Musculoskeletal disorders (MSDs) are one of the most common causes of occupational injuries that appear in back، neck and upper limb mainly. This study was conducted with the objectives of determination of prevalence rate of MSDs and ergonomics assessment of the risk of MSDs in workers of a petrochemical company. In this study، 327 randomly selected workers in a petrochemical compan y with at least one year work experience in office and operational units participated. O ffice and operational staff were studied separately d ue to different nature of their works. In office jobs، data were gathered using demographic questionnaire، Nordic musculoskeletal disorders questionnaire (NMQ) and ergonomics checklist for assessment of working conditions. In operation jobs، demographic questionnaire، NMQ and QEC method were applied to collect the required data. Data were analyzed using statistical tests including t-test، Chi-square and test of proportion by SPSS software (Version 16. 0). Means of age and job tenure of study subjects were found to be 32. 2±6. 63 and 5. 53±4. 01 years، respectively. Prevalence rates of MSDs in office and operation staff were 68. 1 % and 46. 6%، respectively. The r esults showed that the prevalence of musculoskeletal disorders in neck، back، low back and knees in the office staff were significantly higher than those of operational workers. Working condition assessment by the checklist in office staff revealed that the lowest index wa s related to posture and workstation. This means that in the corrective program improving working posture should be considered as a priority. The results of assessment of physical exposure to musculoskeletal risks by QEC technique among operational workers showed that in 38. 4% of workers studied، the level of exposure to musculoskeletal risks was in Action L evel (AC) 1، 19. 2 % in AC 2، 31. 5 % in AC 3 and 11% in AC 4. Totally، in 42. 5% of workers studied، the level of exposure to musculoskeletal risks was high or very high. This indicated that the jobs and working conditions in the operational units were conducive for developing MSDs and needed corrections. Based on the results، some interventional measures were implemented. The prevalence of musculoskeletal in the office staff wa s significantly higher than that of operational subjects. In working conditions improvement، taking risk factors of lower back، neck، upper back، knee، shoulder and wrist into consideration seemed essential.