Background and Objective:The most important goal of modeling is to acquire knowledge about the actual behavior of the system. Toxic leakage is a likely issue in process and chemical industries and one of the threatening factors for the personnel and residents involving in the mentioned industries. In this regard, the present study aimed to model the effect of ammonia leakage from the ammonia reservoirs. Materials and Methods: In the present study, the ammonia liquid release from the reservoir was modeled using ALOHA software version 5.4.7 in one of the southern refineries. This study was modeled based on the three scenarios, including the formation of the toxic vapor clouds, flammable environment, and toxic explosive atmosphere. Results: Based on the results of the present modeling, the concentration of ammonia was 1,100 ppm, 5 km around the reservoir (red range). In addition, from this area to about 160 miles (about 10 km) around the reservoir (orange range) the concentration of ammonia was 160 ppm. In the event of full leakage of ammonia from the reservoir up to 500 m, the ammonia concentration was reported to be about 90,000 ppm, which was approximately 60% of the minimum flammable concentration of ammonia gas. Furthermore, the ammonia concentration up to about 1.7 km of the tank was 15000 ppm, which was about 10% of the minimum of the flammable ammonia concentration. It should be considered that in the event of vapor cloud explosion, the explosive wave pressure is approximately 700 m from the reservoir equivalent to Psi 8 that can cause serious damage to the buildings. Conclusion: According to the results of modeling, ammonia intoxication is the most important threat to personnel. Therefore, the inspections in accordance with the manufacturer company's proposal on ammonia repositories and emergency response plans will have an effective role in the limitation of the harmful effects of toxic and dangerous emissions.

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Background: Risk perception and employees' attitudes towards safety is one of the requirements for establishing safety culture and having a safer working environment. If the attitude of employees to safety can be improved and accomplished, their safety performance will also be improved. So, to achieve an appropriate working environment, it is necessary to measure a person's perception of safety. The current study aims to explore the relationship between attitudes and safety performance among employees of the cement factory in Fars Province in Iran. Methods: The present study is sectional analytical research, which was conducted among employees of the cement factory in the south of Iran in 2018. The required information was collected through the attitude questionnaire and safety performance. Finally, 130 questionnaires were completed. The data analysis was carried out through the SPSS software version 24 by using Kruskal–Wallis tests and man Whitney tests. Results: The mean safety attitude was determined by 3.85(0.28). According to the results, there is no significant relationship between the level of safety attitude with age (P=0.32), the degree of education (P=0.36), work experience (P=0.52), accident numbers (P=0.47) and also the education (P=0.320). On the other hand, the safety attitude showed a significant relationship with safety performance (P=0.001).  Conclusion: According to the results of the study and the significant relation between the safety attitude and performance, functional improvements in employee's safety attitudes could be achieved by planning and taking occupational health preventive measures.

Introduction: The working conditions, type of activity, and production or consumption of different materials expose the employees to harmful biological factors, which leads to infectious diseases. The purpose of this study was to investigate the harmful biological agents of the work environment among administrative personnel of a power plant in south of Iran. Methods: This descriptive and cross-sectional study was conducted among 200 administrative workers of different sections of power plant in 2016. The participants used personal protective equipment and samples were collected from five parts of the participants' body including auricle, inside the ear, the area between the toes, palm of foot, toe nails. Finally, 1000 samples were collected. Results: The mean age of the workers was  years and all participants were male. Of the 1000 samples cultivated in the laboratory, 192 (96%) people had negative and 8 (4%) had positive culture results. The results showed that auricle had the highest rate of opportunistic pathogenic fungi (87.5%). The most positive cases of opportunistic pathogens were associated with workshops, warehouses, and operational buildings. Conclusion: Regarding the results of the study, we need to implement more health care in the mentioned places, observe personal hygiene in keeping the feet dry, not using protective handsets (air plug and earmuff) of other people, disinfecting the personal protective equipment, and daily washing to prevent the spread of the disease to other people.