Search

Background: Musculoskeletal disorders (MSDs) are the most common problems in the work settings. This study aimed to assess the potential causes of the musculoskeletal disorders in the upper extremity among the workers of an electronic company to determine the risk level. Materials and Methods: In this cross-sectional study, 50 workers were randomly selected from assembly line workers. Data were collected using the RULA and Strain index (SI) methods and Nordic questionnaire. The safe and unsafe jobs were determined and the risk factors for MSDs were evaluated. Results: According to the RULA method, 52% of the cases for the right hand and 54% for the left hand were at grade 3, 2% for both hands were at grade 4 and in the automatic PC board tester job, 25% of the cases in both hands were at grade 4. According to the SI scoring, 64% of the cases in the right hand and 42% of them in the left hand were unsafe. Moreover, the most prevalent disorders were seen in waist and shoulder (48%), wrist (32%), neck (28%) and back (24%). There was a correlation between work experience and shoulder pain (P=0.016) and leg pain (P=0.032) and between the results of the SI method in the left hand and shoulder pain (P =0.002). Kappa coefficient showed the agreement between the results of both RULA and SI methods. Conclusion: The frequency of the MSDs, especially in waist, shoulder, neck and back, the unsafe cases in the SI method and also the high risk levels in RULA method are considerable. [ABSTRACT FROM AUTHOR]

In the present study, a novel fixed-bed continuous reactor with a preheating chamber was designed to be utilized for the practical application of removal studies of dangerous pollutants, especially NO X removal by NO X Storage Reduction (NSR) catalysts on a laboratory scale. The reactor's design and operational parameters, including outer wall temperature (50-600 °C), volumetric flow rate (0.3-3 L/min), wall temperature time (0.16-10 min), and granule surface area inside the preheating chamber (0-270 cm 2 ), were statistically modeled and optimized using Response Surface Methodology (RSM). For more logical and effective parameter optimization, the ratio of gas and catalyst temperatures and pressure drop to the reactor outer wall temperature (GT/ROWT, CT/ROWT, and PD/ROWT) were also included in the optimization process. Experimental results showed that gas temperature, catalyst temperature, and pressure drop ranged from 31 to 177 °C, 51-585 °C, and 7-153 Pa, respectively. Optimal conditions were determined to be an outer wall temperature of 230 °C, a volumetric flow rate of 3 L/min, a wall temperature time of 0.16 min, and a granule surface area of 67.3 cm 2 . The results demonstrated that outer wall temperature, flow rate, time, and surface area of granules have significant and interaction effects on the responses and should be considered when researchers assess the removal efficiency of thermal catalysts., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

Objectives Human error has been recognized as one of the top causes of most accidents in mines. This study aimed to identify and assess cognitive errors among copper miners using the cognitive reliability and error analysis method (CREAM). Methods. This cross-sectional study was carried out in one of the copper mines in Iran. First, all tasks were analyzed by hierarchical task analysis (HTA). Then cognitive errors were assessed using the CREAM. Results. With respect to the basic CREAM results in the operational units, including extraction, crushing and processing, human error probability (HEP) was obtained as 0.056, 0.0315 and 0.0177, respectively. Based on the results of the extended CREAM, the types of errors identified for all tasks in the three operational units were mainly associated with execution (53.4%), observation (40%), interpretation (5%) and planning (1.6%). Also, the cognitive errors were related to execution, monitoring, observation, communication, diagnosis, recording and planning, respectively. Conclusion . The results showed that human error is very high in the operational units of the mine. Therefore, immediate actions are needed to improve safety performance in the mine units, which determine the role of various factors in human errors and can provide the possibility of implementing more effective interventions.

Identifying the individual factors is a major issue in determining the likelihood of human error and ultimately human reliability. In current human reliability assessment methods, this is determined based on a list of performance shaping factors and experts' judgment. This was a qualitative content analysis study, in which the participants were selected using purposive sampling from combined cycle power plant control rooms. Semi-structured interviews were performed and collected data were analyzed. A total of 32 operators (20 module controllers, eight head operators and four managers) were interviewed. Five categories were extracted, namely 'mental condition', 'consciousness at work', 'professional competence', 'communication skills' and 'quick reactions and decision-making capabilities'. Accordingly, it is suggested to taken into account such factors as professional competence and speed of reactions and to pay more attention to their important factors in the reliability of operators in combined cycle power plant control rooms.

Background: The outbreak of COVID-19 has adversely affected both global economy and public health around the world. These effects have also been observed in many workplaces, including mines., Objective: This study aimed to examine the human error of copper miners during the pandemic., Method: This descriptive-analytical, cross-sectional study was performed on 192 workers of a copper mine in Iran. For this, occupation tasks were firstly analyzed using the Hierarchical Task Analysis (HTA), and then the human error in different subunits was assessed using the basic Cognitive Reliability and Error Analysis Method (CREAM). The prevalence of COVID-19 among miners was determined by assessing positive PCR test records., Results: The probability of human error in the operational subunits including mining, crushing, processing, and support subunits was estimated to be 0.0056, 0.056, 0.0315, and 0.0177, respectively. All three operational units were found to be in the scrambling control mode. The support unit was determined to be in the tactical control mode. Approximately 50% of all workers had been infected with COVID-19, with the highest prevalence in support units., Conclusion: The results suggest that during the COVID-19 pandemic, copper miners are at higher risk of human error induced by poor working conditions. Therefore, it is recommended to employ some management strategies such as promotion of safety, health monitoring, and adopting supportive measures to control occupational stresses and therefore the probability of human error in the mine's operational units.

Background . Understanding the causes of accidents plays a major role in learning from accidents and developing accident prevention and control strategies. Objective . This study aimed at application and modification of the Tripod Beta method for analyzing accident causes in the oil and gas industries. Materials and methods . A total of 68 accidents occurring in the oil and gas industries during 2005-2016 were analyzed. For this purpose, we used the Tripod Beta method and modified it using Reason's Swiss cheese model and analysis accident results. Results . The main causes that have been ignored in the Tripod Beta method were supervision factors involved in 66% of the accidents (underlying causes) and unsafe conditions that contributed to 55% of accidents (immediate causes). The former was incorporated as a sublayer of the underlying cause and the latter as a sublayer of immediate cause to the modified Tripod Beta method. Conclusions . The results of the present study added to the knowledge on the causes of accidents. These results can help increase the capabilities of the Tripod Beta method for analyzing accident causes, such as supervision factors and unsafe conditions, which have been ignored in analyses performed using the Tripod Beta method.

Introduction . There is a close relationship between safety culture and safety climate and safety performance. However, the details of this relationship are somewhat unclear, due to different attitudes toward safety culture and safety climate, and the use of various tools for their evaluation, and various measures of safety performance. Methods . In this study, articles published in English from 2005 to 2017 were selected from various databases. Then, certain journals in the field of safety were specifically searched using the keywords 'safety and safety performance', 'safety climate and safety performance', 'safety culture and safety performance', 'safety climate and safety outcome', 'safety culture and safety outcome', 'safety culture and injury and fatalities' and 'safety climate and injuries and fatalities'. Results . In the current article, the role of safety culture and safety climate in improving safety performance was evaluated in 31 selected studies. It seems that reactive criteria and safety compliance is more consistent with safety climate and safety culture. Conclusions . The findings emphasized that increasing the level of safety climate and safety culture could be effective in reducing incidents and improving safety performance indicators.

Introduction . Neal and Griffin's safety performance scale is an appropriate tool to evaluate safety performance. This article was validated and relied on the Persian version of Neal and Griffin's scale as the widely used tool to assess safety performance. Methods . Neal and Griffin's scale has eight questions and two dimensions - safety compliance and safety participation. A back-forward method was used to translate the original English version into Persian. A total of 161 employees of a petrochemical complex were selected for data collection. Content validity, Cronbach's α and split-half methods, concurrent validity and confirmatory factor analysis were used for psychometric evaluation. Results . The content validity index and content validity ratio were 0.82 and 0.84, respectively. Cronbach's α for total items was 0.9, indicating a high consistency. Additionally, Cronbach's α values for safety compliance and safety participation were 0.87 and 0.83, respectively. Spearman's correlation coefficients indicated a positive correlation between safety performance and safety culture items ( r  = 0.182-0.852, p  < 0.01). Goodness-of-fit indexes in the default model had poor values. Thus, these values were improved in the modified model. Conclusion . The results demonstrated that Neal and Griffin's scale could be a reliable tool to evaluate preventive measures of safety performance among Iranian workers.

Background: Construction workers are at a high risk of exposure to various types of hazardous substances such as crystalline silica. Though multiple studies indicate the evidence regarding the effectiveness of different silica exposure reduction interventions in the construction sector, the decisions for selecting a specific silica exposure reduction intervention are best informed by an economic evaluation. Economic evaluation of interventions is subjected to uncertainties in practice, mostly due to the lack of precise data on important variables. In this study, we aim to identify the most cost-beneficial silica exposure reduction intervention for the construction sector under uncertain situations., Methods: We apply a probabilistic modeling approach that covers a large number of variables relevant to the cost of lung cancer, as well as the costs of silica exposure reduction interventions. To estimate the societal lifetime cost of lung cancer, we use an incidence cost approach. To estimate the net benefit of each intervention, we compare the expected cost of lung cancer cases averted, with expected cost of implementation of the intervention in one calendar year. Sensitivity analysis is used to quantify how different variables affect interventions net benefit., Results: A positive net benefit is expected for all considered interventions. The highest number of lung cancer cases are averted by combined use of wet method, local exhaust ventilation and personal protective equipment, about 107 cases, with expected net benefit of $45.9 million. Results also suggest that the level of exposure is an important determinant for the selection of the most cost-beneficial intervention., Conclusions: This study provides important insights for decision makers about silica exposure reduction interventions in the construction sector. It also provides an overview of the potential advantages of using probabilistic modeling approach to undertake economic evaluations, particularly when researchers are confronted with a large number of uncertain variables.

Background: Exploring experiences of individuals for barriers they confront relating to safety could help to design safety interventions with an emphasis on the most safety influencing factors., Objective: This study strived to present an empirical exploration of individuals' experiences across the petroleum industry at different levels of the organizational structure for factors that influence occupational accidents., Method: Based on accidents history, face-to-face semi-structured interviews were conducted with individuals who engaged in fatal activities, as well as authorities responsible for managing safety. The qualitative content analysis of 46 interview transcripts was conducted using MAXQDA software., Results: A three-layer model comprising organizational, supervisory and operator level influencing factors with 16 categories were found influence factors of occupational safety. The results highlighted the role of organizational factors, including inappropriate contract management, inadequate procedures, and issues relating to competency management and the organizational climate. Moreover, defects relating to the monitoring and supervision system were identified as important causes of accidents., Conclusions: The findings demonstrated that the qualitative approach could reveal additional latent aspects of safety influencing factors, which require consideration for the appropriate management of occupational safety. This study can guide the planning of preventive strategies for occupational accidents in the petroleum industry.

Background: The oil and gas industry is one of the riskiest industries for confined space injuries. This study aimed to understand an overall picture of the causal factors of confined space accidents through analyzing accident reports and the use of a qualitative approach., Methods: Twenty-one fatal occupational accidents were analyzed according to the Human Factors Analysis and Classification System approach. Furthermore, thirty-three semistructured interviews were conducted with employees in different roles to capture their experiences regarding the contributory factors. The content analyses of the interview transcripts were conducted using MAXQDA software., Results: Based on accident reports, the largest proportions of causal factors (77%) were attributed to the organizational and supervisory levels, with the predominant influence of the organizational process. We identified 25 contributory factors in confined space accidents that were causal factors outside of the original Human Factors Analysis and Classification System framework. Therefore, modifications were made to deal with factors outside the organization and newly explored causal factors at the organizational level. External Influences as the fifth level considered contributory factors beyond the organization including Laws, Regulations and Standards, Government Policies, Political Influences, and Economic Status categories. Moreover, Contracting/Contract Management and Emergency Management were two extra categories identified at the organizational level., Conclusions: Preventing confined space accidents requires addressing issues from the organizational to operator level and external influences beyond the organization. The recommended modifications provide a basis for accident investigation and risk analysis, which may be applicable across a broad range of industries and accident types.

Background . Accident analysis is the main aspect of accident investigation. It includes the method of connecting different causes in a procedural way. Therefore, it is important to use valid and reliable methods for the investigation of different causal factors of accidents, especially the noteworthy ones. Objective . This study aimed to prominently assess the accuracy (sensitivity index [ SI ]) and consistency of the six most commonly used accident analysis methods in the petroleum industry. Methods . In order to evaluate the methods of accident analysis, two real case studies (process safety and personal accident) from the petroleum industry were analyzed by 10 assessors. The accuracy and consistency of these methods were then evaluated. The assessors were trained in the workshop of accident analysis methods. Results . The systematic cause analysis technique and bowtie methods gained the greatest SI scores for both personal and process safety accidents, respectively. The best average results of the consistency in a single method (based on 10 independent assessors) were in the region of 70%. Conclusion . This study confirmed that the application of methods with pre-defined causes and a logic tree could enhance the sensitivity and consistency of accident analysis.

Objective: We estimate the potential cost-benefit of a caregiver-friendly workplace policies (CFWPs) educational intervention to facilitate uptake of supports for carer-employees (CEs) at a post-secondary institution., Methods: We identified CEs through a voluntary survey and estimated the economic burden of caregiving activities from the CEs' and employer's perspective. The latter is used as the baseline of comparison for evaluating the cost-benefit of the intervention., Results: The economic cost of caregiving-related activities for the "no intervention" scenario was estimated at $33,841,789 ($32,922 per-case) and $8,916,342 ($8,674 per-case) from the CEs' and employer's perspectives, respectively. We find the educational intervention is a cost-beneficial program with the net benefit ranging from $48,010 to $676,657, based on six scenarios of effectiveness., Conclusion: This study provides practical information for human resources and operations management decision-making in terms of a CFWPs educational intervention.

Cigarette smoking is a possible risk factor for hearing loss. However, the impact of simultaneous exposure to noise and smoke on hearing has remained controversial. This study investigated the combined effect of exposure to cigarette smoking and noise on hearing loss. Three groups of male Wistar rats (275 ± 25 g) were subjected to white noise (102 ± 0.5 dB), cigarette smoking (20 cigarettes), and both cigarette smoking and noise for 8 h and 10 days inside the exposure chamber. The control group was exposed to neither noise nor smoke. Distortion product otoacoustic emissions (DPOAE) were measured before any intervention, and it was repeated 1, 7, and 21 days after the last exposure. One-day postexposure to noise, cigarette smoking, and both cigarette smoking and noise, the mean of DPOAE amplitudes decreased significantly ( p < 0.05) between, respectively, 5.7-30.7, 1.5-7.5, and 5.2-32.6 dB within the frequency range of 4620-9960. Temporal DPOAE change in rats exposed to noise or both cigarette smoking and noise was not significantly different ( p > 0.05). DPOAE amplitudes returned to the baseline values in the group subjected to smoking 21 days postexposure. The most permanent change was observed in rats exposed to both cigarette smoking and noise. Accordingly, simultaneous subacute exposure to noise and cigarette smoking increases the effect of noise on permanent hearing loss. Therefore, smoking workers exposed to noise might be at a greater risk of developing hearing loss, and it is recommended that authorities in charge take note of this evidence.

Background: Noise exposure causes loss of cochlea hair cells, leading to permanent sensorineural hearing loss, and initiates pathological changes to the bipolar primary auditory neurons (ANs). This study focuses on the effects of N-acetyl-l-cysteine (NAC) in protecting the density of spiral ganglion cells and in histological changes induced by continuous noise exposure in rats., Methods: Twenty-four male Wistar rats were randomly allocated into four experimental groups to receive NAC, saline, noise, or both noise and NAC. Noise exposure continued for ten days. Saline and NAC were injected daily during the noise exposure, and 2 days before and after the noise exposure. Evaluation of cochlear histopathology and the density of spiral ganglion cells was performed 21 days after exposure., Results: In the animals exposed to noise, a reduction in the density of spiral ganglion cells was evident in both the basal and middle turns of the cochlea. This improved on receiving NAC treatment ( P = 0.046). In the histopathology evaluation, some histological changes, such as disorganised architecture of the outer hair and supporting cells and a slightly thickened basilar membrane, were found in the basal turns in the noise group., Conclusion: NAC offered partial protection against noise exposure by improving the density of spiral ganglion cells and reducing morphological changes., Competing Interests: Conflicts of Interest None

Solar ultraviolet (UV) radiation is the second most prevalent carcinogenic exposure in Canada and is similarly important in other countries with large Caucasian populations. The objective of this article was to estimate the economic burden associated with newly diagnosed non-melanoma skin cancers (NMSCs) attributable to occupational solar radiation exposure. Key cost categories considered were direct costs (healthcare costs, out-of-pocket costs (OOPCs), and informal caregiver costs); indirect costs (productivity/output costs and home production costs); and intangible costs (monetary value of the loss of health-related quality of life (HRQoL)). To generate the burden estimates, we used secondary data from multiple sources applied to computational methods developed from an extensive review of the literature. An estimated 2,846 (5.3%) of the 53,696 newly diagnosed cases of basal cell carcinoma (BCC) and 1,710 (9.2%) of the 18,549 newly diagnosed cases of squamous cell carcinoma (SCC) in 2011 in Canada were attributable to occupational solar radiation exposure. The combined total for direct and indirect costs of occupational NMSC cases is $28.9 million ($15.9 million for BCC and $13.0 million for SCC), and for intangible costs is $5.7 million ($0.6 million for BCC and $5.1 million for SCC). On a per-case basis, the total costs are $5,670 for BCC and $10,555 for SCC. The higher per-case cost for SCC is largely a result of a lower survival rate, and hence higher indirect and intangible costs. Our estimates can be used to raise awareness of occupational solar UV exposure as an important causal factor in NMSCs and can highlight the importance of occupational BCC and SCC among other occupational cancers.

Objectives: The present study was designed to investigate the simultaneous effects of physical, psychosocial and other work-related risk factors on the work ability index (WAI) score among industrial workers., Methods: This study used a cross-sectional design with a questionnaire survey. A total of 280 workers were included in the study. Data were collected using three questionnaires including the Persian version of the WAI, the Persian version of the job content questionnaire and an author-developed measure (to assess work-related factors, health-related factors and socio-demographic characteristics)., Results: The majority of the participants were young, but they had poor WAI scores (mean 37.3 ± 6.4) and 44.3% of them had poor or moderate work ability. Occupational accidents and injuries were found to be the strongest predictors of WAI scores. Additionally, there was a strong association between WAI scores and supervisor support, skill discretion, occupational training, sleep quality, work nature and educational level., Conclusions: Intervention programs should focus on improving supervisor support, sleep quality, job skills and knowledge and on decreasing physical and mental work demands. Additionally, implementing a comprehensive occupational health and ergonomics program for controlling and reducing hazardous working environments and occupational injury rates should be considered.

Background: Widespread use of X-band frequency (a part of the super high frequency microwave) in the various workplaces would contribute to occupational exposure with potential of adverse health effects.  According to limited study on microwave shielding for the workplace, this study tried to prepare a new microwave shielding for this purpose., Methods: We used EI-403 epoxy thermosetting resin as a matrix and nickel oxide nanoparticle with the diameter of 15-35 nm as filler. The Epoxy/ Nickel oxide composites with 5, 7, 9 and 11 wt% were made in three different thicknesses (2, 4 and 6 mm). According to transmission / reflection method, shielding effectiveness (SE) in the X-band frequency range (8-12.5 GHz) was measured by scattering parameters directly given by the 2-port Vector Network Analyzer. The fabricated composites characterized by X-ray Diffraction and Field Emission Scanning Electron Microscope., Results: The best average of shielding effectiveness in each thickness of fabricated composites obtained by 11%-2 mm, 7%-4 mm and 7%-6 mm composites with SE values of 46.80%, 66.72% and 64.52%, respectively. In addition, the 11%-6 mm, 5%-6 mm and 11%-4 mm-fabricated composites were able to attenuate extremely the incident microwave energy at 8.01, 8.51 and 8.53 GHz by SE of 84.14%, 83.57 and 81.30%, respectively., Conclusions: The 7%-4mm composite could be introduced as a suitable alternative microwave shield in radiation protection topics in order to its proper SE and other preferable properties such as low cost and weight, resistance to corrosion etc. It is necessary to develop and investigate the efficacy of the fabricated composites in the fields by future studies.

Knowing about organisational safety culture in public transportation system can provide an appropriate guide to establish effective safety measures and interventions to improve safety at work. The aim of this study was investigation of association between safety culture dimensions (leadership styles and company values, usage of crashes information and prevention programmes, management commitment and safety policy, participation and control) with involved self-reported crashes. The associations were considered through Spearman correlation, Pearson chi-square test and logistic regression. The results showed an association among self-reported crashes (occurrence or non-occurrence) and factors including leadership styles and company values; management commitment and safety policy; and control. Moreover, it was found a negative correlation and an odds ratio less than one between control and self-reported crashes.

Background: This study assessed the effect of supplementation of omega-3 fatty acids and ascorbic acid alone and in combination on the level of lipid peroxidation (malondialdehyde, MDA concentration), total antioxidant capacity (TAC) and depression scores in depressed rotational shift workers in the Tehran Shahid Tondgoyan Oil refinery., Material and Methods: In this randomized, double-blind, placebo-controlled trial, 136 men who met the inclusion and exclusion criteria and had a Beck Depression Inventory (BDI) score ≥ 10 were selected. Among the participants, 33 received omega-3 fatty acid soft gel (1000 mg twice daily) with vitamin C (250 mg twice daily) (group 1), 31 took omega-3 fatty acid supplements and vitamin C placebo (group 2), 30 took omega-3 fatty acid supplement placebo and vitamin C (group 3), and 32 received omega-3 fatty acid supplement placebo and vitamin C placebo (group 4) for 2 months. Measured were serum MDA, TAC concentrations, and BDI scores at baseline and after 2 months., Results: This study showed that the BDI score was reduced significantly in all 4 groups, however, the level of decrease was more in the omega-3 fatty acid (alone) supplementation group (mean 6.29 score decrease) (p < 0.001). MDA level decreased significantly in groups with omega-3 fatty acids (mean 0.78 μmol/L ± 1.64 μmol/L decrease) (p = 0.014) or vitamin C supplementation alone (mean 0.74 μmol/L ± 1.55 μmol/L decrease) (p = 0.014), but not in combination., Conclusions: Supplementation of omega-3 fatty acids alone and not in combination with vitamin C had a better impact on depression and MDA level pronounced in depressed male shift workers.

Background: Because of occupational accidents, permanent disabilities and deaths occur and economic and workday losses emerge., Objectives: The purpose of the present study was to investigate the factors responsible for occupational accidents occurred in Iran., Patients and Methods: The current study analyzed 1464 occupational accidents recorded by the Ministry of Labor and Social Affairs' offices in Iran during 2008 - 2012. At first, general understanding of accidents was obtained using descriptive statistics. Afterwards, the chi-square test and Cramer's V statistic (Vc) were used to determine the association between factors influencing the type of injury as occupational accident outcomes., Results: There was no significant association between marital status and time of day with the type of injury. However, activity sector, cause of accident, victim's education, age of victim and victim's experience were significantly associated with the type of injury., Conclusions: Successful accident prevention relies largely on knowledge about the causes of accidents. In any accident control activity, particularly in occupational accidents, correctly identifying high-risk groups and factors influencing accidents is the key to successful interventions. Results of this study can cause to increase accident awareness and enable workplace's management to select and prioritize problem areas and safety system weakness in workplaces.

Aim: Construction is a major source of employment in many countries. In construction, workers perform a great diversity of activities, each one with a specific associated risk. The aim of this paper is to identify workers who are at risk of accidents with severe consequences and classify these workers to determine appropriate control measures., Methods: We defined 48 groups of workers and used the Bayesian theorem to estimate posterior probabilities about the severity of accidents at the level of individuals in construction sector. First, the posterior probabilities of injuries based on four variables were provided. Then the probabilities of injury for 48 groups of workers were determined., Results: With regard to marginal frequency of injury, slight injury (0.856), fatal injury (0.086) and severe injury (0.058) had the highest probability of occurrence. It was observed that workers with <1 year's work experience (0.168) had the highest probability of injury occurrence. The first group of workers, who were extensively exposed to risk of severe and fatal accidents, involved workers ≥ 50 years old, married, with 1-5 years' work experience, who had no past accident experience., Conclusion: The findings provide a direction for more effective safety strategies and occupational accident prevention and emergency programmes.

Background: Falls from height are one of the main causes of fatal occupational injuries. The objective of this study was to present a model for estimating occurrence probability of falling from height., Methods: In order to make a list of factors affecting falls, we used four expert group's judgment, literature review and an available database. Then the validity and reliability of designed questionnaire were determined and Bayesian networks were built. The built network, nodes and curves were quantified. For network sensitivity analysis, four types of analysis carried out., Results: A Bayesian network for assessment of posterior probabilities of falling from height proposed. The presented Bayesian network model shows the interrelationships among 37 causes affecting the falling from height and can calculate its posterior probabilities. The most important factors affecting falling were Non-compliance with safety instructions for work at height (0.127), Lack of safety equipment for work at height (0.094) and Lack of safety instructions for work at height (0.071) respectively., Conclusion: The proposed Bayesian network used to determine how different causes could affect the falling from height at work. The findings of this study can be used to decide on the falling accident prevention programs.

Background: There can be little doubt that the construction is the most hazardous industry in the worldwide. This study was designed to modeling the factors affecting unsafe behavior from the perspective of safety supervisors., Methods: The qualitative research was conducted to extract a conceptual model. A structural model was then developed based on a questionnaire survey (n=266) by two stage Structural Equation Model (SEM) approach., Results: An excellent confirmed 12-factors structure explained about 62% of variances unsafe behavior in the construction industry. A good fit structural model indicated that safety climate factors were positively correlated with safety individual factors (P<0.001) and workplace safety condition (P<0.001). The workplace safety condition was found to play a strong mediating role in linking the safety climate and construction workers' engagement in safe or unsafe behavior., Conclusions: In order to improve construction safety performance, more focus on the workplace condition is required.

Objective: The aim of this study was to determine the oxidative stress; serum level of Total Antioxidant Capacity (TAC)and Malondialdehyde (MDA) level and the depression score among the depressed rotational shift workers in Shahid Tondgouyan Refinery in Tehran (Iran)., Methods: A cross-sectional study was conducted among all the 189 shift workers in Shahid Tondgouyan oil refinery who were eligible to participate in the study. They did not take any antidepressants for two months or any supplements for two weeks prior to the study entry. Written consent was obtained from the participants. 21- Item Beck Depression Inventory was used to measure the depression level. Furthermore, body weight, height and systolic and diastolic blood pressure were collected from all the participants. The levels of Total Antioxidant Capacity (TAC) and Malondialdehyde (MDA) were measured by 8 ml fasting blood sample. MDA was determined by thiobarbituric acid reaction. Serum total antioxidants were measured using the spectrophotometric ABTS. In the ABTS test, 2,2'-azinobis (3-ethylbenzthiazoline-6-acid) (ABTS) is converted into its radical cation (ABTS•+) by addition of sodium persulphate. This blue-green radical cation absorbs light at 734 nm. ABTS•+ is reactive towards most antioxidants. Descriptive statistics, ANOVA, ANCOVA and regression tests and correlation were used to analyze the data using SPSS software version 16., Results: The age of the participants ranged from 21 to 52 years. The mean age of the participants was 30.58 year (±6.97yr). Of all the participants, 28% (n= 53) had no depression symptoms (depression score between 0 and 9), 65.1% (n=123) were categorized as having mild depression (depression score between 10 and 18) and 6.9% (n=13) were categorized as having moderate depression (depression score between 19 and 29). The participants' BMI ranged from 15.9 to 34.3; the mean BMI of the participants was 24.82 kg/m(2) (+ 3.81 kg/m(2)). The mean of the serum TAC level was 2.51 (± 0.56) mg/dl, and the mean serum MDA level was 3.67(± 1.08) μmol/l. There was a significant difference in the mean TAC concentration between the non-depressed group and the group with mild depression (p=0.029)., Conclusion: Depression was associated with reduced mean TAC concentration and an increase in MDA level. There was a linear relationship between the depression score and shift work experience among the rotational shift workers, which showed a high level of stress and depression among the shift-workers.

Background: In hot weather, overweight and obesity are considered as significant risk factors for the incidence of cardiac strain in workers. This study was aimed to compare cardiac strain among overweight and normal-weight workers in hot, humid conditions in the south of Iran., Methods: This cross-sectional study was conducted on 71 workers in the south of Iran in summer 2010. The heart rate was measured at rest and at actual work. Cardiac strain based on working heart rate (WHR), the relative cardiac cost (RCC), the net cardiac cost (NCC), load relative cardiovascular (CVL), and heart rate reduction was analyzed in 35 normal-weight people (body mass index (BMI) <25 kg/m(2)) and 36 overweight people (BMI >25 kg/m(2)) using descriptive statistics., Results: In 42% of the total workers, BMI was >25 kg/m(2). The average of Wet Bulb Globe Temperature Index (WBGT Index) in the two groups was not significantly different. The mean WHR in the two groups was 101 ± 20.3 and 112 ± 18.9, respectively (P = 0.026). Percentages exceeded the acceptable limits in the parameters NCC, RCC, WHR, CVL, and Brouha index, which were significantly higher in overweight people than in those with normal weight., Conclusions: Based on the study results, it is concluded that the severity of cardiac strain was higher in overweight workers compared with that in normal weight workers. Hence, in order to decrease the cardiac strain, selecting overweight individuals for these jobs should be avoided and also some vital intervention for losing weight should be implemented such as nutrition education and encouraging them regarding physical activity.

Background: In the hot weather, overweight and obesity are considered as significant risk factors for the incidence of cardiac strain in workers. This study is aimed at comparing the cardiac strain among overweight and normal-weighted workers, in the hot, humid conditions of the south of Iran., Materials and Methods: This cross-sectional study was conducted on 71 workers in the south of Iran, in the summer of 2010. The heart rate was measured at rest and at actual work. Cardiac strain based on the working heart rate (WHR), the relative cardiac cost (RCC), the net cardiac cost (NCC), the load relative cardiovascular (CVL), and heart rate reduction were analyzed in 35 normal weight people (BMI <25) and 36 people who were overweight (BMI >25), using descriptive statistics and t- tests., Results: In 42% of the total workers, the body mass index was more than 25. The average temperature of the two groups was not significantly different. The mean WHR in these two groups was 101 ± 20.3 and 112 ± 18.9, respectively (P = 0.026). Percentages that exceeded the acceptable limits in parameters of NCC, RCC, WHR, CVL, and the Brouha index, were significantly higher in overweight people than those in people with normal weight., Conclusions: Based on the study results, the severity of cardiac strain was higher in overweight workers when compared with normal weight workers. Hence, in order to decrease the cardiac strain, selecting overweight individuals for these jobs should be avoided, as also some vital intervention for losing weight, such as, nutrition education and encouraging them to increase their physical activity, should be implemented.

Unlabelled: The present study aimed to assess the effect of supplementation of omega-3 and/or vitamin C on serum interleukin-6 and high sensitivity C-reactive protein concentration and depression scores among shift workers in Shahid Tondgoyan oil refinery. The study design was randomized, double-blind, placebo-controlled, parallel trial. Totally 136 shift workers with a depression score ≥10 in 21-item Beck Depression Rating Scale were randomly assigned to receive omega-3 (180 mg eicosapentaenoate acid and 120 mg docosahexaenoic acid) or/and vitamin C 250 mg or placebo twice daily (with the same taste and shape as omega-3 and vitamin C) for 60 days in four groups. Depression score, interleukin-6 and high sensitivity C-reactive protein were measured at baseline and after 60 days. This study showed that supplementation of omega-3 plus vitamin C is associated with a decrease in depression score (p<0.05). Supplementation of omega-3 without vitamin C, is associated with a reduction in depression score (p<0.0001) and high sensitivity C-reactive protein concentration (p<0.01). Therefore omega-3 supplementation showed a better effect on reducing depression score and high sensitivity C-reactive protein, but supplementation of vitamin C along with omega-3 did not have significant effect on change in C-reactive protein level compared to omega-3 alone. (, Registration Number: IRCT201202189056N1).

Background: There is tremendous concern regarding the possible adverse effects of cell phone microwaves. Contradictory results, however, have been reported for the effects of these waves on the body. In the present study, the effect of cell phone microwaves on sperm parameters and total antioxidant capacity was investigated with regard to the duration of exposure and the frequency of these waves., Materials and Methods: This experimental study was performed on 28 adult male Wistar rats (200-250 g). The animals were randomly assigned to four groups (n=7): i. control; ii. two-week exposure to cell phone-simulated waves; iii. three-week exposure to cell phonesimulated waves; and iv. two-week exposure to cell phone antenna waves. In all groups, sperm analysis was performed based on standard methods and we determined the mean sperm total antioxidant capacity according to the ferric reducing ability of plasma (FRAP) method. Data were analyzed by one-way ANOVA followed by Tukey's test using SPSS version 16 software., Results: The results indicated that sperm viability, motility, and total antioxidant capacity in all exposure groups decreased significantly compared to the control group (p<0.05). Increasing the duration of exposure from 2 to 3 weeks caused a statistically significant decrease in sperm viability and motility (p<0.05)., Conclusion: Exposure to cell phone waves can decrease sperm viability and motility in rats. These waves can also decrease sperm total antioxidant capacity in rats and result in oxidative stress.

Shift work is associated with sleep deprivation, occupational stress, and increased risk of depression. Depressed patients show increased oxidative stress. During excessive oxidative stress, Malondialdehyde (MDA) increases and total antioxidant capacity (TAC) decreases in body. This cross-sectional study was conducted to determine the serum level of TAC and MDA among depressed rotational shift workers in Shahid Tondooyan Tehran Oil Refinery. 21-item Beck Depression Inventory was used to measure depression level. The level of TAC and MDA was measured by 8 mL fasting blood sample. MDA was determined by thiobarbituric acid reaction. Serum total antioxidants were measured using the ABTS. Results of this study showed that TAC mean and standard deviation concentration was 2.451 (±0.536) mg/dL and MDA was 3.725 (±1.098) mic·mol/L, and mean and standard deviation of depression score and BMI were 14.07 (±3.84) and 24.92 (±3.65) kg/m(2), respectively. Depression score had a positive correlation with rotational shift work experience and work experience (r = 0.218 and r = 0.212), respectively, (P < 0.05).

Background: Heat exposure among construction workers in the Persian Gulf region is a serious hazard for health. The aim of this study was to evaluate the performance of wet bulb globe temperature (WBGT) Index for estimation of heat strain in hot/humid conditions by the use of Physiological Strain Index (PSI) as the gold standard., Material and Methods: This cross-sectional study was carried out on 71 workers of two Petrochemical Companies in South of Iran in 2010 summer. The WBGT index, heart rate, and aural temperature were measured by Heat Stress Monitor (Casella Microtherm WBGT), Heart Rate Monitor (Polar RS100), and Personal Heat Strain Monitor (Questemp II), respectively. The obtained data were analyzed with descriptive statistics and Pearson correlation analysis., Results: The mean (SD) of WBGT values was 33.1 (2.7). The WBGT values exceed from American Conference of Governmental Industrial Hygienists (ACGIH) standard (30°C) in 96% work stations, whereas the PSI values were more than 5.0 (moderate strain) in 11% of workstations. The correlation between WBGT and PSI values was 0.61 (P = 0.001). When WBGT values were less and more than 34°C, the mean of PSI was 2.6 (low strain) and 5.2 (moderate strain), respectively., Conclusion: In the Persian Gulf weather, especially hot and humid in the summer months, due to the WBGT values exceeding 30°C (in 96% of cases) and weak correlation between WBGT and PSI, the work/rest cycles of WBGT Index is not suitable for heat stress management. Therefore, in Persian Gulf weather, heat stress evaluation based on physiologic variables may have higher validity than WBGT index.

Noise induced hearin gloss (NIHL) is one of the most important occupational disease world wide. NIHL has been found potentiate by simultaneous carbon monoxide (CO) exposure. Free radicals have been implicated in cochlear damage resulted from the exposure to noise and due to the CO hypoxia. This study examined whether α-tocopherol administration , as a free radical scavenger, causes the attenuation of auditory brainstem response (ABR) threshold shifts resulting from noise exposure and noise plus CO exposure. Forty-two rabbits were divided in to seven groups including control, noise + saline, noise + CO + saline, noise + α-tocopherol, noise + CO + α-tocopherol , CO + α-tocopherol and α-tocopherol alone. ABR was assessed before exposure, 1 hand 14 days post exposure. The administration of 50 mg/Kg of α-tocopherol prior, following and post exposure to noise or noise plus CO recovered permanent ABR threshold shift at 1 and KHz almost to the baseline and provided significant attenuation in permanent ABR threshold shift at 4 and 8 KHz in subject swhich were exposed to noise but it did not block the potentiating of threshold elevation by CO exposure (extra threshold loss by combined exposure) at 4 and 8 KHz. α Tocopherol provides protective effect against the hearing loss resulting from noise exposure and simultaneous exposure to noise plus CO.

Synthesized magnesium/copper (Mg/Cu) bimetallic particles have shown good potential for use in the reduction of nitrate from aqueous solutions. This study was conducted to investigate the main factors affecting the kinetics of nitrate reduction by Mg/Cu particles (<100 microm) in uncontrolled reaction conditions. The Mg/Cu bimetallic particles removed the majority of the various nitrate concentrations tested (50, 100, 150, 200 and 300 mg L(-1)) within a short period. The time required for the removal of 90.6% of the NO3(-) from a 100 mg L(-1) solution was about 20 min using 2 gL(-1) bimetallic Mg/Cu at an initial solution pH of 6. The activation energy (Ea) for nitrate reduction by Mg/Cu over the temperature range of 5 to 60 degrees C was 14.21 kJ mol(-1). The experimental results of the kinetic analysis from batch studies indicated that a higher initial nitrate concentration yielded a greater reaction-rate constant and the denitrification rate increased with increase Mg/Cu dosage.

In 1988, the National Institute for Occupational Safety and Health (NIOSH) recommended that bitumen fumes should also be considered a potential occupational carcinogen and management practices such as engineering controls should be implemented. Changing the production process of bitumen, as a source control method, was investigated in our study. For the first time, a novel alternative process was used to produce paving grade bitumen with decreased PAH emissions as well as improved bitumen performance grade (PG). Post-consumer latex and natural bitumen (NB) were used as additives to obtain 60/70 modified bitumen directly from the vacuum bottom (VB) without any need for air-blowing. The emissions were produced by a laboratory fume generation rig and were sampled and analyzed by GC-Mass and GC-FID as described in NIOSH method 5515. The PG of the resulting modified 60/70 bitumen in this study covers a wider range of climatic conditions and has higher total resistance against deformation than conventional 60/70 bitumen. The total PAH emissions from modified 60/70 bitumen (100.2619 ng/g) were decreased approximately to 50% of PAHs emitted from conventional 60/70 bitumen (197.696 ng/g). Therefore, it is possible to obtain modified bitumen with lower PAH emissions and better quality than conventional bitumen via additives and without air-blowing., (Copyright © 2010 Elsevier B.V. All rights reserved.)

The objective of this study was to investigate the removal of an anionic surfactant from wastewater in ICEAS. The surfactant considered here was anionic SDS being widely used in the household and industrial detergents. Basic wastewater COD was 260 mg L(-1) and SDS surfactant added in range 20 to 400 mg L(-1). The effect of the inlet SDS concentration and reaction time on COD and SDS removal was investigated. The results from this study indicated that the aeration time of 2 h was sufficient for removal of SDS ranged 20 to 400 mg L(-1). Obtained data showed low effluent SDS concentrations of 0.3 to 5 mg L(-1) and removal of SDS was more than 98%. These results revealed that biological treatment using ICEAS process is capable to treating wastewaters containing high concentration of SDS surfactant.

Objectives: To investigate the interaction between welding fumes and noise in causation of hearing impairment., Methods: Groups of rabbits (n=6) were exposed to noise, welding fumes or combination of both prior to Distortion Product Otoacoustic-Emissions (DPOAEs) analysis. The function of outer hair cells (OHCs) was examined by DPOAE assessment over a broad range of frequencies. Variations in DPOAE amplitude were compared between control (n=6) and exposed (n=18) groups., Results: The DPOAEs levels measured at different frequencies (1379-6299 Hz) were found to decrease significantly (P<0.05) in rabbits exposed to 110 dB sound pressure level (SPL) broadband noise (8h/day, 12 days). In rabbits, exposed to carbon-steel welding fumes alone (157 mg/m(3)), the threshold shift was limited to the high frequencies (2759-6299 Hz), whereas, mixed exposure to noise and fumes resulted in reduction of DPOAEs at all the frequencies. Changes in DPOAEs were associated with increased susceptibility of erythrocytes to oxidation (P<0.05). Exposure to noise or fumes alone or simultaneously, suppressed total antioxidant ability of plasma as measured by ferric reducing ability of plasma (FRAP). Noise alone or in combination with fumes resulted in depletion of blood glutathione (GSH). Despite suppression of FRAP in the exposed groups, GSH was found to remain unchanged due to welding fumes suggesting that antioxidants other than GSH are affected by toxicants present in metal welding fumes., Conclusion: Exposure to very high levels of welding fumes can increase noise-related effects on OHC function by extending hearing threshold shift to wide band frequencies.

Previous work has demonstrated that the shield gas composition in gas metal arc welding can have a considerable effect on hexavalent chromium [Cr(VI)] concentration in the fume and on ozone concentrations near the arc. Normally a single shield gas is used. This paper describes a double shroud torch that allows used of concentric shield gases of different compositions. A solid stainless steel wire was used for welding. The double shroud torch used secondary shield gases containing small amounts of the reducing agents NO and C2H4. The Cr(VI) concentration in the fume and ozone concentration at a fixed point relative to the arc were measured and compared with results when using a single shield gas. Use of the reducing agents in secondary shielding using the double shroud torch was found to offer advantages for ozone concentration reduction compared with use in a conventional torch, but this was not found to be an advantage for reducing Cr(VI) concentrations.

Hexavalent chromium [Cr(VI)] and ozone are produced in many arc-welding processes. Cr(VI) is formed when welding with chromium-containing alloys and is a suspected carcinogen. Ozone is formed by the action of ultraviolet light from the arc on oxygen and can cause severe irritation to the eyes and mucous membranes. Previous work has demonstrated that reduction of sodium and potassium in manual metal arc-welding electrodes leads to substantial reductions in Cr(VI) concentrations in the fume as well as a reduction in the fume formation rate. In this paper replacement of potassium by lithium in a tubular wire welding electrode (self-shielding flux-cored) is shown to give reductions in Cr(VI) concentrations and fume formation rates. Previous work has also demonstrated that use of a tubular wire (metal cored) containing 1% zinc can, under certain conditions, result in a reduction in Cr(VI) formation rate and in ozone concentration near the arc but with a rise in the total fume formation rate. The effects of different shield gases and different levels of zinc are examined. An experimental chromium-containing tubular wire with 1% zinc was used with the following shield gases: argon, Argoshield 5, Argoshield 20, Helishield 101, Ar + 2% CO2, Ar + 5% CO2, Ar + 1% O2 and Ar + 2% O2. The wire gave > 98% reduction in Cr(VI) formation rate compared to the control wire provided the shield gas contained no oxygen. When the shield gas did contain oxygen, 1% zinc enhanced Cr(VI) formation rate, resulting in more than double the rates measured when welding with the control wire. Experiments with zinc concentrations, from 0.018 to 0.9% using Helishield 101, gave results indicating that there is an optimum zinc concentration from the point of view of Cr(VI) reduction. Implications of the use of lithium or zinc on the overall exposure risk are discussed.

This paper describes the relationships between ultra-violet emission, ozone generation and CrVI production in MIG welding which were measured as a function of shield gas flow rate, welding voltage, electrode stick-out and shield gas composition using an automatic welding rig that permitted MIG welding under reproducible conditions. The experimental results are interpreted in terms of the physico-chemical processes occurring in the micro- and macro-environments of the arc as part of research into process modification to reduce occupational exposure to ozone and CrVI production rates in MIG welding. We believe the techniques described here, and in particular the use of what we have termed u.v.-ozone measurements, will prove useful in further study of ozone generation and CrVI formation and may be applied in the investigation of engineering control of occupational exposure in MIG and other welding process such as Manual Metal Arc (MMA) and Tungsten Inert Gas (TIG).