Comparative Assessment of Carcinogenic Risk of Styrene Vapors Using Two Semi-Quantitative Methods in a Petrochemical Industry

Background: Styrene is one of the chemicals used in industries, especially the petrochemical industry, which affects health. Singaporean methods and the WHO use different parameters to assess the carcinogenic risk of the substance. Therefore, this study aimed to compare the level of carcinogenic risk due to exposure to styrene using the Singapore Department of Occupational Health with the risk levels provided using the WHO to achieve high-reliability results. Methods: In this study, 150 air samples were collected from the respiratory area of 50 employees by NIOSH1501 method, after identification of styrene emission units and preparation of identical exposure groups. The samples were analyzed by Varian-cp3800 gas chromatograph. Finally, the risk of styrene's health effects on petrochemical staff was calculated using the method of the Singapore Department of Occupational Health, and the results were compared with the risk levels of styrene presented by WHO. Results: The carcinogenicity of styrene was higher in polybutadiene latex (PBL) (2.3 ) and the fire department (1.3 ) in comparison with the other units. The World Health Organization-defined risk levels predicted 22% of staff to be a "definitive" carcinogenic risk. While the Singapore Department of Occupational Health approached a "low" risk rating. Conclusion: A "low" risk rating was obtained through the Singapore Department of Occupational Health. But the WHO method for 30 years of exposure to styrene predicted "probable risk" and "definitive risk." This showed a high difference in the results of the two semi-quantitative methods used.