Investigating the relationship between physical, cognitive, and environmental factors of ergonomics with the prevalence of musculoskeletal disorders: A case study in a car-parts manufacturing industry.

BACKGROUND: Work-related musculoskeletal disorders (WRMSDs) is a multi-factorial disorder in most occupational setting and it has increased significantly in recent years. OBJECTIVE: This study aimed to investigate the relationship between physical, cognitive, and environmental factors of ergonomics with the prevalence of WRMSDs in a car-parts manufacturing industry. METHODS: This cross-sectional study was performed among 220 workers in a milling unit of a car parts manufacturing company in 2021-2022. The prevalence of WRMSDs was assessed using the Extended Version of the Nordic Musculoskeletal Questionnaire. Noise exposure was evaluated using dosimetry method. Mental and physical workload were evaluated by the NASA-TLX and key index methods (KIM-MHO and KIM-LHC), respectively. Data analysis was performed using SPSS version 25.0. RESULTS: The subjects' mean age and work experience were 36.3±6.5 and 8.35±6.41 years, respectively. Eighty-five percent of the subjects reported WRMSDs in at least one area of the body. The results of mental workload assessment revealed a high workload mean range (73.23±14.89) in all of the subjects. Mean score of KIM-LHC and KIM-MHO were 738.18±336.42 and 201.86±36.41, respectively with odds ratio of 1.32 for KIM-LHC in creating the WRMSDs. There was a significant relationship between the noise exposure, mental and physical workload and the prevalence of WRMSDs (p-value <  0.05). CONCLUSION: The results of the present study revealed that environmental, physical and cognitive factors can simultaneously be effective in the prevalence of WRMSDs. Therefore, performing effective control measures requires comprehensive attention to physical, environmental, and cognitive ergonomics in the algorithm of ergonomics management in the workplace.

Evaluation of human vulnerability and toxic effects of chronic and acute occupational exposure to ammonia: A case study in an ice factory.

BACKGROUND: The hazardous material release has frequently occurred worldwide. As a respiratory stimulant and a toxic substance, ammonia has numerous adverse effects on human health. OBJECTIVE: The purpose of this study was to evaluate the human vulnerability and toxic effects of both chronic and acute respiratory exposure to ammonia. METHODS: This study was conducted in an ice factory. Ammonia reservoirs were selected as the danger center. The scenarios were evaluated from the perspective of the worst-case. The Emergency Response Planning Guidelines 1-3 was used to predict the dangerous concentrations in acute exposure. The probability of human vulnerability was estimated using the Probit model. PHAST 7.2 software was used to model consequences. As a measure of chronic exposure to ammonia, NMAM 6016 was used. A respiratory symptom questionnaire developed by the American Thoracic Society was used for collecting respiratory symptom histories. RESULTS: The ERPG3 level or concentration of 750 ppm was found at a distance of 617.71 and 411.01 meters from tanks, respectively, as a result of a rupture in reservoir 1 over a period of two halves of the year. It was found that the highest probit values for tank 2 at distances of zero, 25, 50, 75, 100, 125, and 150 meters were 9.55, 5.92, 5.47, 4.82, 4.23, 3.56 and 2.96, respectively. The prevalence of pulmonary symptoms, which include coughing, dyspnea, phlegm, and wheezing, was 28%, 19%, 15%, and 26% in the chronic exposure group. CONCLUSION: In the event that an ammonia reservoir ruptures catastrophically, it may cause human injury at ERPG-2 or ERPG-3 levels. Results revealed that exposure to this substance can impose many pulmonary symptoms on the respiratory system of workers in industries. In order to reduce the vulnerability of humans to potential release scenarios, control measures must be implemented. Also, preventive and mitigation measures can be designed to enhance safety and resilience against the release of hazardous materials.

Does exposure to ammonia concentrations lower than the threshold limit value cause acute pulmonary effects?

One of the major toxic effects of exposure to ammonia is the resulting pulmonary acute and chronic effects. This study investigated the acute pulmonary effects of exposure to ammonia lower than the recommended threshold limit value (TLV). This cross-sectional study was conducted in 2021 in four chemical fertilizer production industries using ammonia as the main raw material. A total of 116 workers who were exposed to ammonia were investigated. The level of exposure to ammonia was measured by NMAM 6016, and the evaluation of pulmonary symptoms and function parameters was done using the American Thoracic Society and European Respiratory Society protocols in four sessions. The paired-sample t-test, repeated measures test, Chi-square, and Fisher's exact test were run to analyze the collected data. The prevalence rates of pulmonary symptoms, including cough, dyspnea, phlegm, and wheezing, were 24.14, 17.24, 14.66, and 16.38%, respectively, after one exposure shift. It was observed that all pulmonary function parameters were reduced after one exposure shift to ammonia. The results revealed that the parameters of vital capacity, forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), the FEV1/FVC ratio, and peak expiratory flow significantly decreased (p < 0.05) across four exposure shifts. The findings indicated that exposure to ammonia at concentrations lower than one-fifth of TLV could bring about acute pulmonary effects and reduce pulmonary function parameters, similar to the pattern observed in obstructive pulmonary diseases.

Occupational safety risk analysis in construction sites based on fuzzy analytic hierarchy process: A case study in a large construction project.

BACKGROUND: Construction projects are one of the most critical occupational sectors that experienced many challenges in occupational accidents and safety performance. OBJECTIVE: This study was designed to assess safety risk in construction projects based on fuzzy analytic hierarchy process. METHODS: This study was conducted with 12 construction and occupational safety experts in one of the largest construction projects in Tehran-Iran in 2020. The process of this study included (1) risk identification, (2) measurement of risk parameters and sub-parameters, and (3) risk assessment based on a fuzzy analytic hierarchy process. Risk-forming parameters in this study included the probability and severity of the event. The probability of occurrence was estimated based on four sub-parameters of technical inspection, accident experience, detection probability, and human reliability. Sub-parameters of severity included human injury, cost imposition, tarnishing the organization's esteem, and impact on project timing and work stoppage. RESULTS: Twenty-eight identified hazards were examined in the studied construction project, including falling from a height (9-hazard), falling objects (2-hazard), electric shock (6-hazard), falling crane or load (6-hazard), elevator crashes (2-hazard), and soil fall (3-hazard). Safety risk assessment revealed that 27 risk sources were at the tolerable level and one risk source was unacceptable. CONCLUSION: This study demonstrated that the risk levels in the studied construction project were tolerable and unacceptable. The obtained model in this study demonstrated that using parameters that determine the probability and severity of risk according to the nature of the working environments can be a practical step in risk evaluating and implementing control measures.

Consequence modeling and root cause analysis (RCA) of the real explosion of a methane pressure vessel in a gas refinery.

Background: The present study aimed to consequence modeling and root cause analysis of the real explosion of a methane pressure vessel in separation unit of a gas refinery in Iran. Method: ology: This study was performed in a gas refinery in the south of Iran. The studied scenario was the actual scenario that occurred in the studied pressure vessel. Modeling of possible consequences was performed using PHAST 7.2 software. Also, the root causes analysis of the accident was performed using experts' brainstorming. Results: At radii of 15 and 45 m, the radiation level reaches 12.5 and 4 kW/m2, respectively. In the late explosion worst-case, the vapor cloud explodes after reaching a distance of 20 m from the pressure vessel. At radii of 20 m, 25 m, and 150 m from the center of the explosion, the pressure reaches 0.2068, 0.1379, and 0.02068 bar, respectively. In the Early Explosion Overpressure, the acceptable pressure is obtained at a distance of 193 m. Moreover, in the Early Explosion Overpressure radiation, at radii of 28 m, 38 m, and 193 m, the pressure reaches 0.2068, 0.1379, and 0.02068 bar, respectively. Conclusion: The findings revealed that creating an appropriate risk management algorithm with a focus on consequence modeling can be an effective step towards reducing losses in the process industry. This results can create a novel insight in comparing the two reactive and proactive approaches and also reveal the effectiveness of consequence modeling in reducing the severity of risks.

Development of a novel Electrical Industry Safety Risk Index (EISRI) in the electricity power distribution industry based on fuzzy analytic hierarchy process (FAHP).

Many workers are exposed to electrical energy during the fulfillment of their tasks. It is necessary to identify the potential risk factors for electrical damages. The present study aimed to develop a novel Electrical Industry Safety Risk Index (EISRI) in the electricity power distribution industry based on fuzzy analytic hierarchy process (FAHP). In this study several different safety risk assessment methods were analyzed. Then, common activities in the electricity distribution industry were classified into ten occupational groups. To identify the general structure of risk assessment and determine three main components, including personal, environmental, and organizational a three-stage Delphi study was conducted with the participation of 30 experts. The fuzzy analytic hierarchy process approach was used to weight the components and parameters in each job group. Finally, the results of the EISRI were compared with the failure mode and effect analysis (FMEA) method. The most effective component in determining the risk level was the personal component (PC), with a 0.537 weighted average. Cronbach's alpha values for each of the personal, environmental, and organizational components and the entire model were 0.90, 0.85, 0.82, and 0.86, respectively, and model reliability was confirmed. The results obtained from the EISRI method were compared with the FMEA method, the results of both methods were very close to each other (p < 0.05). The results of this study revealed that the highest weighted average was related to the personal component due to the high impact of the human factors in carrying out activities in various occupations. The EISRI can be applied as a substitute for general risk assessment methods due to the suitability of this method with the nature of activities in this industry. The present technique can be a practical step toward developing suitable risk management algorithm.

Development of an ergonomics management model in the workplace: Introduction of the TUGA ergonomics management and analysis model (TEMA).

BACKGROUND: Conducting practical studies in ergonomics requires attention to all aspects of ergonomics with a comprehensive approach and focus on continuous improvement cycles. OBJECTIVE: This study aimed to develop and present an ergonomics management model in the workplace. METHODS: This study was performed using a three-stage Delphi study with 30 experts and a fuzzy analytical hierarchy process. According to the literature review and experts' opinions, the general cycle of the ergonomics management system with eight steps was developed. New methods were formed in two of these eight steps: the 3rd step (developing an ergonomic evaluation method) and the 5th step (creating a cost-benefit evaluation method). RESULTS: The eight implementation steps of the TEMA were determined as follows: 1) Performing task analysis (TTA), 2) Ergonomic hazard identification, 3) Estimating the ergonomic index, 4) Determining control measures, 5) Evaluating cost-benefit parameter, 6) Implementing control measures, 7) Continuous monitoring, and 8) Evaluating the effectiveness of control measures. The Delphi study revealed that the number of deleted parameters includes one item (burnout), and the remaining parameters were 16 items. The mean CVI and CVR values were 0.92 and 0.80, respectively. Cronbach's alpha values for each of the physical, environmental, and cognitive components and the entire model were 0.91, 0.87, 0.85, and 0.89, respectively. CONCLUSION: Using the mentioned management model can be a practical step towards properly evaluating the most critical dimensions of ergonomics in the workplace and optimal planning to implement control measures to establish a dynamic management system to reduce ergonomic risk factors in the workplace.

Development of a novel ergonomic index assessment in the workplace based on physical, cognitive, and environmental components.

BACKGROUND: Currently, proper assessment of the existing ergonomic hazards, focusing on improving the health of individuals, is of great importance. OBJECTIVE: This study aims to develop a new model for ergonomic index assessment in the workplace, focusing on physical, cognitive, and environmental components. METHODS: To determine the parameters to be measured for each group of occupations, the most critical indicators in each ergonomic dimension were identified using a review of scientific texts and obtaining expert opinions. The opinions of 30 experts were studied in three stages Delphi study. Cronbach's alpha was used to calculate model reliability in SPSS version 25. An analytical hierarchy process was used to determine the weight values of each component and parameter. The weights were calculated in Expert Choice version 11. RESULTS: The mean CVI and CVR values were 0.92 and 0.80, respectively. Cronbach's alpha values for each of the physical, environmental, and cognitive components and the entire model were 0.91, 0.87, 0.85, and 0.89, respectively. Physical components and parameters of physical condition during work, mental workload, lighting, and thermal stress in the workplace were among the most important parameters in the three groups of office, operational, and services jobs. CONCLUSION: The model can be a practical step toward properly evaluating the ergonomic components and planning to implement control measures to reduce physical, cognitive, and environmental risk factors. Considering the study of different variables in occupational ergonomic risk assessment, this model can be a helpful tool in ergonomic management systems used in different occupational environments.

Construction accident data mining: A retrospective study using structural equation modeling based on 10-year data.

BACKGROUND: The data mining of construction accidents based on a robust modeling process can be used as a practical technique for reducing the frequency of construction accidents. OBJECTIVE: This study was designed to data-mine construction accidents. METHODS: This study was conducted in 2020 on construction accidents in Iran for ten years (2009-2018). The instruments to collect the required data were the checklists and descriptive reports of the accidents. The dependent variables of the study included reactive safety indicators related to construction accidents (lost working days (LWD) and total accident costs (TAC)). The independent variables consisted of four latent factors: personal variables, organizational variables, unsafe working conditions, and unsafe acts. The data were collected based on the conceptual model designed for data mining. The data mining process was carried out based on the structural equation modeling by IBM AMOS V. 23.0. RESULTS: A total of 5742 construction accidents occurring in 10 years were analyzed. The means of TAC and LWD indicators were estimated to be 248.20±52.60 days and 1893.10±152.22 $. These two indicators directly correlated with the two latent factors of unsafe conditions and unsafe acts and their related variables and were indirectly influenced by latent personal and organizational factors. The relationship between unsafe conditions and unsafe acts was significantly positive. The relationship between latent personal and organizational factors and the two construction accident indicators was significantly negative (p <0.05). CONCLUSION: The model results showed that personal and organizational variables could, directly and indirectly, affect reactive safety indicators in construction projects. Thus, these findings can be used to design and improve safety strategies to prevent and decrease construction accidents and incidents.

A fuzzy Bayesian network DEMATEL model for predicting safety behavior.

Objectives. Safety behavior significantly affects safety performance in the workplace. This study aimed to develop a Bayesian network (BN) model for managing and improving safety behavior. Methods. This study was carried out in the chemical industries in Iran. The data were gathered by a questionnaire consisting of 13 variables including organization safety priority, systems design, safety communication, safety education, work strategy, human-system interaction, mental workload, environmental distractions, work pressure, fatigue, sleepiness, safety knowledge and locus of control. The BN structure was created using the fuzzy decision-making trial, evaluation laboratory method and expert opinions. Belief updating was used to determine variables with the strongest effect on safety behavior. Results. Locus of control, organization safety priority and safety knowledge were the best predictors of safety behavior. Moreover, it was found that improving organization safety priority and safety knowledge is the best intervention strategy to improve safety behavior significantly. Conclusions. BN is a powerful tool that can model causal relationships among variables. Improving organization safety priority and safety knowledge can lead to the maximum possible level of safety behavior.

Evaluating the potential severity of biogas toxic release, fire and explosion: consequence modeling of biogas dispersion in a large urban treatment plant.

Objectives. Biogas production in treatment plants for energy generation has increased in recent years. This study aimed to model the consequence of biogas release in a large urban treatment plant. Methods. The study modeled biogas storage tank consequences in a large urban treatment plant in Iran. Due to potential for biogas harmfulness, three consequences of toxic release, fire and explosion were evaluated. Scenarios were evaluated in the worst-case situation. All modeling steps were performed using PHAST version 7.2. Results. In the case of catastrophic reservoir rupture in summer, distances of 3788.94, 128.86 and 91.72 m from the reservoir in the wind direction will be in the range of 100, 500 and 1000 ppm biogas, respectively. Study of pressure values due to explosion in the catastrophic rupture scenario revealed that distances of 57.19, 14.70 and 115.84 m from the biogas reservoir were in the range of 0.02, 0.13 and 0.2 bar pressure increase, respectively. Conclusion. Due to the treatment plant's location in a dense urban area, biogas dispersion could lead to exposure of many people to high-risk areas. Therefore, taking control measures comparable with the consequence modeling output can be a practical step toward reducing vulnerability against such incidents.

Linking mental health to safety behavior in construction workers: The mediating effect of work ability and sleep quality.

BACKGROUND: The severity of occupational accidents and injuries in the construction industry is the greatest across all industries. Few studies have examined the causal relationships among physical and psychological variables affecting the safety behavior of construction workers. OBJECTIVE: This study aimed to investigate the relationships among three factors (metal health, work ability and sleep quality) influencing the safety behavior of construction workers. METHODS: This cross-sectional study was conducted on 204 workers in civil construction projects in Iran. The data were gathered via self-reporting questionnaires. The acquired data were analyzed by the Smart PLS3 software using structural equation modeling with the partial least squares (PLS) regression approach. RESULTS: The R square revealed an acceptable fineness of the structural model. Similarly, as Q square values were higher than 0.15 for all factors, the predictability of the model was approved. The direct effect of mental health on safety behavior was not significant, but work ability and sleep quality had significant direct effects on safety behavior. Moreover, a decrease in mental health significantly reduced construction workers' sleep quality and work ability. CONCLUSION: The results of this study prove that sleep quality and work ability mediate the relationship between mental health and safety behavior. The deterioration of construction workers' mental health can increase the risk of unsafe behavior and occupational injuries. Therefore, appropriate measures need to be taken to maintain and improve the mental health of construction workers.

Developing a risk assessment method for infectious diseases focusing on COVID-19 based on the Delphi method and fuzzy analytical hierarchy process.

BACKGROUND: Given the coronavirus 2019 (COVID-19) risk, it is essential to develop a comprehensive risk assessment method to manage the risk of the infectious diseases. OBJECTIVE: This study aimed to develop a risk assessment method for infectious diseases focusing on COVID-19. METHOD: This study was based on the fuzzy Delphi method (FDM) and fuzzy analytical hierarchical process (FAHP) in three steps: (a) designing the preliminary risk assessment algorithm by reviewing the literature, (b) corroborating the designed structure based on the majority opinions of the expert panel and assigning scores to different factors according to the Delphi method, and (c) determining the weight of components and their factors based on the FAHP. RESULTS: The COVID-19 risk index (CVRI) was found to be affected by four components and 19 factors. The four components consisted of the probability of getting sick (5 factors), disease severity (4 factors), health beliefs level (3 factors), and exposure rate (6 factors). The identified components and their relevant factors had different weights and effects on the CVIR. The weights of probability, severity, health beliefs level, and exposure rate components were 0.27, 0.20, 0.14, and 0.38, respectively. The CVRI was found to range from 0.54 to 0.82, defined in three levels. CONCLUSION: Given the significant effects of identified components, factors, and parameters on the incidence of COVID-19 on the one hand and using the FDM and FAHP on the other, the proposed method can be considered as an appropriate method for managing the risk of COVID-19 and other infectious diseases.

Carcinogenic and health risk assessment of respiratory exposure to acrylonitrile, 1,3-butadiene and styrene in the petrochemical industry using the US Environmental Protection Agency method.

Objectives. This study aimed to assess carcinogenic and health risks of respiratory exposure to acrylonitrile, 1,3-butadiene and styrene (ABS) in the petrochemical industry. Methods. This cross-sectional study was conducted in a petrochemical plant producing ABS copolymers. Respiratory exposure to each of acrylonitrile, 1,3-butadiene and styrene was measured using methods No. 1604, No. 1024 and No. 1501 of the National Institute of Occupational Safety and Health (NIOSH), respectively. The US Environmental Protection Agency (USEPA) method was used to assess carcinogenic and health risks. Results. The average occupational exposure to ABS was 560.82 µg m-3 for 1,3-butadiene, 122.8 µg m-3 for acrylonitrile and 1.92 µg m-3 for styrene. The average lifetime cancer risk in the present study was 2.71 × 10-3 for 1,3-butadiene, 2.1 × 10-3 for acrylonitrile and 6.6 × 10-3 for styrene. Also, the mean non-cancer risk (hazard quotient) among all participants for each of 1,3-butadiene, acrylonitrile and styrene was 4.04 ± 6.93, 10.82 ± 14.76 and 0.19 ± 0.11, respectively. Conclusion. The values of carcinogenic and health risks in the majority of the subjects were within the unacceptable risk levels due to exposure to ABS vapors. Hence, corrective actions are required to protect the workers from non-cancer and cancer risks.

The Prediction of Chronicity in Patients With Acute and Subacute Nonspecific Low Back Pain and Associated Risk Factors: A Case-Control Study.

BACKGROUND: Chronic low back pain is one of the most common musculoskeletal disorders in different countries. AIMS: This study aimed to predict the chronicity of nonspecific acute and nonspecific low back pain (LBP) and related risk factors among cases referred to physiotherapy clinics. DESIGN: A case-control and cross-sectional study. SETTINGS: Two physiotherapy centers in Tehran, Iran. PARTICIPANTS: This study included 502 patients with acute, subacute and chronic LBP. METHOD: This study included 502 patients with acute, subacute and chronic LBP. Data were obtained using the Fear-Avoidance Beliefs Questionnaire, Patient Health Questionnaire, Pain Catastrophic Scale, Tampa Scale for Kinesiophobia, Pittsburgh Sleep Quality Index, Walker's Health-Promoting Lifestyle Questionnaire, Roland Morris Disability Questionnaire, and Numerical Pain Rating Scale. Data analysis was performed by applying independent sample t test, χ2, and multiple logistic regression in SPSS software version 25. IBM Amos version 22 was used for path analysis. RESULTS: It was found that some demographic parameters (i.e., weight, BMI, job, type of occupational task performance, history of low back pain, work shift, underlying diseases and income), some cognitive parameters (i.e., fear-avoidance beliefs, kinesiophobia, catastrophic pain, and depression), some lifestyle parameters (i.e., health responsibility, physical activity, and interpersonal relationships), sleep quality and pain related disability were among the most critical risk factors in the chronicity of acute and subacute LBP (p < .05). CONCLUSIONS: Personal, psychological, and psychosocial parameters can be among the most critical predictors in the chronicity of acute and subacute nonspecific LBP. Hence, paying attention to all the mentioned factors at the beginning of patients' treatment to create a targeted treatment algorithm and prevent the conversion of acute and subacute into chronic LBP has particular importance.

A field study of mental workload: conventional bus drivers versus bus rapid transit drivers.

Road traffic accidents are increasing worldwide and cause a high number of fatalities and injuries. Mental Work Load (MWL) is a contributing factor in road safety. The primary aim of this work was to study important MWL factors and then compare conventional and BRT (Bus Rapid Transit) drivers' MWL. This study evaluated bus drivers' MWL using the Driving Activity Load Index (DALI) questionnaire conducted with 123 bus drivers in Tehran. The results revealed significant differences between conventional and BRT drivers' mental workload. Moreover, data modelling showed that some organisational and environmental factors such as bus type, working hours per day, road maze, and route traffic volume contribute to drivers' mental workload. These findings suggest some essential customised factors that may help measure and offer practical solutions for decreasing the level of bus drivers' MWL in real-world road driving. Practitioner summaryMental workload is affected by several contributing factors. Depending on the working context, some of these contributing factors have a more significant influence on the level of the experienced MWL. Therefore, the main factors influencing the MWL of BRT and conventional bus drivers were assessed in their real-life environment.Abbreviations: MWL: mental work load; BRT: bus rapid transit; CB: conventional bus; DALI: driving activity load index; NASA-TLX: NASA task load index; SWAT: subjective workload assessment technique; EEG: electroencephalography electrocardiogram; fNIRS: functional magnetic resonance imaging; ITS: intelligent transportation systems; AVL: automated vehicle location.

The mediating effect of workers' situation awareness on the relationship between work-related factors and human error: a path analysis approach.

Situation awareness is the main reason behind different patterns of unsafe behavior among workers and can play a mediating role in the relationship between predictive situational variables and human error. This questionnaire-based study carried out with Iranian workers investigated the direct and indirect effects of work pressure, mental workload, human-systems interaction and environmental distractions on three types of human error (i.e., slips, lapses and mistakes). The results of path analysis showed that, based on model fit indexes, the model is appropriately fit (χ2 / df = 3, comparative fit index = 099, Tucker-Lewis index = 0.99, root mean square error of approximation = 026). It was also observed that the effects of four independent variables on all three types of human error are indirect and mediated by situation awareness. Consequently, it is confirmed that situation awareness plays a key role in the occurrence of human error and is a sharp-end causal factor for human error in industrial workplaces.

Psychological and Psychosocial Impact and Related Factors during the COVID-19 Pandemic among Iranian Oil Refineries Personnel: A longitudinal study.

BACKGROUND: The COVID-19 outbreak is currently a critical challenge, and proper perception of the mental health situation of individuals in the working environments has become a crucial issue. This study aimed to investigate the psychological and psychosocial impact during the COVID-19 pandemic among Iranian oil refineries personnel. METHODS: This longitudinal study was conducted in two phases from November 2019 to July 2020 among the 850 employees of three refineries in Iran. To study the mental workload, job burnout, lifestyle, occupational stress, general health, and memory quotient of personnel, the NASA-TLX questionnaire, Maslach Burnout Inventory (MBI) questionnaire, Walker's health-promoting lifestyle questionnaire, health and safety executive (HSE) job stress questionnaire, general health questionnaire, and Wechsler memory scale were used, respectively. Data were analyzed using paired sample t test, independent sample t test, and one-way ANOVA in SPSS version 25. RESULTS: The study results revealed that the mean age of studied personnel was 34.62±13.48 years. There was a meaningful correlation between the values of mental workload, job burnout, occupational stress, general health, healthy lifestyle, and memory quotient of personnel before and during the COVID-19 pandemic (P value<0.05). CONCLUSION: The COVID-19 pandemic can significantly affect the psychological and psychosocial parameters of employees in working environments. Therefore, implementing psychological interventions is absolutely necessary to promote personnel's mental health during the COVID-19 pandemic.

Evaluation of the toxic effects of ammonia dispersion: consequence analysis of ammonia leakage in an industrial slaughterhouse.

Ammonia is a toxic compound and has many toxic effects on humans and the environment. This study was designed to model the consequences of ammonia leakage in an industrial slaughterhouse. Given the potential hazard of ammonia, only the toxic dimension of this gas was evaluated. The scenarios were evaluated in the worst possible condition and in the case of the complete rupture. Findings showed that in case of a catastrophic rupture scenario in reservoir 1 in the first and second 6 months of the year, the distances of 920.37 and 569.38 m from the reservoir in the wind direction were at Emergency Response Planning Guidelines, level 3 (ERPG3), respectively. In reservoir 2, in the first and second 6 months of the year, the distances of 699.58 and 384.86 m from the reservoir were at the ERPG3 level, respectively. In reservoir 3, in the first and second 6 months of the year, the distances of 203.48 and 748.28 m from the reservoir were at the ERPG3 level, respectively. Examination of the probit values showed that in reservoirs 1 and 2, the probit values were more than 4.28 up to 100 m from the reservoirs, and in the reservoir 3, the mortality rates were lower. The findings revealed that the catastrophic rupture of ammonia reservoirs in the studied slaughterhouse and the release of ammonia could lead to the fatality of large numbers of people in ERPG2 and ERPG3 areas. Therefore, it is necessary to take control measures to reduce the vulnerability against such accidents.