Journal of Health and Safety at Work

Cause-Consequence Modeling of Occupational Accidents in Construction Sites: A Retrospective Study in Iran

Iraj Mohammadfam

Introduction: Nearly half of occupational accidents in Iran occur in construction sites. Therefore, modeling of occupational accidents in these sites is one of the solutions to design safety strategies to reduce occupational accidents in the field of construction. This study was designed and conducted with the aim of modeling the cause-consequence of accidents in construction sites.
Material and Methods: This study was conducted based on a retrospective analysis of 10-year accident data (2010-2019) in Iranian construction sites in 2020. The main variable included the types of occupational accidents in construction sites. The study tool included accidents checklist as well as a detailed report of the studiedaccidents. The required data were collected based on a conceptual model designed to model the cause-consequence of accidents in the construction sites. Cause-consequence modeling of the studied accidents has been done based on the structural equation modeling and using IBM SPSS AMOS v. 22.0.
Results: The frequency of the studied accidents was 3854 accidents. The annual averages of AFR and ASR indices were 17.27 ± 8.54 and 322.42 ± 44.23 days, respectively. The results of cause-consequence modeling of these construction accidents showed that individual and occupational, safety training and risk assessment factors as well as variables related to these factors have a negative and significant relationship with the indicators of the construction accidents, and the factors of environmental conditions and unsafe acts and variables belonged to these factors have a positive and significant relationship with these indicators (p < 0.05).
Conclusion: The findings of the study revealed that the highest impact factors on accident indicators were related to safety training, risk assessment and unsafe acts and their variables. Therefore, the results of this modeling can help to design safety strategies in construction sites.

Different Colors of Noise and Their Application in Psychoacoustics: A Review Study

Soheila Khodakarim Ardakani

Introduction: The study of noise has always been of interest to occupational health professionals as a harmful physical factor in the workplace. However, the psychological and psychoacoustic aspects of noise in the workplace have been less studied. This study has dealt with different colors of noise and their applications in psychoacoustics.
Material and Methods: This review study was conducted by searching the databases of Google Scholar, ProQuest, Science Direct, PubMed, and Scopus to extract the articles related to the research subject within a 50-year interval from 1970 to 2020.
Results: Based on the results of the present study, colored noises and white noise seem to have the potential to be used as acoustic stimuli to improve the sleep of employees, especially shift workers, to improve memory and attention, especially in jobs that require high care and attention. Colored noise and white noise have potential applications to improve cognitive function in different occupations to reduce the activity of the sympathetic nervous system and anxiety and stress, especially in jobs with high job stress. Also, these noises are helpful for people’s privacy, especially in the open workplace, for noise masking and noise control purposes, as well as for medicine and treatment of disorders such as tinnitus, ADHD, and hyperacusis.
Conclusion: Paying attention to the colors of noise and their psychoacoustic impacts shows us that the noise impacts are not limited to their undesirable and damaging effects. Instead, their positive and applied aspects should also note. Familiarity with such aspects and their introduction can identify the existing information gaps in this field and pave the way to fill them.

Effect of Anti-Fatigue Mat on Leg Muscle Discomfort and Muscle Activity Due to Prolonged Work in Upright Position among Production Workers

Karmegam Karuppiah

Introduction: The manufacturing, service professions, and other occupations commonly require their employees to spend more than 2 hours of their workday in an upright position which can potentially cause temporary or permanent health effects. The objective of this study is to determine the effect of anti-fatigue mats on leg muscle discomfort and muscle activity due to prolonged standing.
Material and Methods: A total of 100 workers were involved in the study. The control and experimental group stood for 2 hours in a controlled room with or without the anti-fatigue mat while sorting an assortment of mixed items. Borg’s scale questionnaire and EMG signals were used to monitor the muscle discomfort and activity of the respondents.
Results: The discomfort ratings and muscle activity in the experimental group were always at lower levels compared to the control group, which meant there was a reduction in mean perceived exertion rating for the knees, calves, and feet, i.e., 1.8, 2.5 and 2.6, respectively. The results showed that there was a statistically significant (P < 0.001) difference in the Borg’s scale of discomfort ratings and leg muscle activity between both groups.
Conclusion: The anti-fatigue mat can have a positive effect in preventing muscle discomfort and reduce muscle activity among the respondents during prolonged standing.

Synthesis, Characterization, and Efficiency Testing of Ag3PO4/TiO2 Heterogeneous Nano-Photocatalyst in Removing Gaseous Formaldehyde as an Occupational Carcinogen

Yahya Rasoulzadeh

Introduction: Rapid population growth and industrialization have increased chemical pollutants. Some studies show that employee exposure to formaldehyde in industrial places, hospitals, and laboratory settings is more than the allowed limits. Therefore, it is necessary to implement a proper control system to reduce this exposure. This study aimed to synthesize Ag3PO4/TiO2 nanocomposite, determine its morphological and structural characteristics, and test the degradation efficiency of this photocatalyst on formaldehyde.
Material and Methods: Ag3PO4/TiO2 composites were synthesized via an in-situ precipitation method. The physicochemical, morphological, and optical properties of the synthesized sample were investigated by employing the BET method, X-ray diffraction (XRD), UV–visible absorption spectroscopy, and scanning electron microscopy (SEM). The photocatalyst degradation efficiency test was performed on gaseous formaldehyde in a 3.2-liter photoreactor under visible light radiation.
Results: The UV–Vis absorption spectrum of the Ag3PO4/TiO2 sample noticeably shifted to the visible light region compared to that of the TiO2. The bandgap energy of the nanocomposite was 2.3 eV. The SEM image demonstrated that the average particle size of the nanocomposite was about 102 nm. The result of the degradation efficiency tests revealed that 63% of the formaldehyde was removed under visible light irradiation after 90 minutes by the Ag3PO4/TiO2 photocatalyst.
Conclusion: The adopted synthesis method adopted was highly efficient and appropriate for the synthesis of Ag3PO4/TiO2 nanocomposite according to the analyses. The Ag3PO4/TiO2 photocatalyst performed well under visible light radiation and could be used in pollution control systems.

The Assessment of Oxidative Stress Parameters of Workers Co-exposed to Noise and Whole-body Vibration: A Case Study in a Foundry Industry

Farideh Golbabaei

Introduction: Studies show that in many cases, environmental hazardous agents such as heat, noise, as well as chemical pollutants cause adverse health effects through the mechanism of oxidative stress. This study has examined the effect of exposure to noise and whole-body vibration (WBV) on some parameters of oxidative stress (enzyme superoxide dismutase (SOD), total antioxidant capacity (TAC), and malondialdehyde (MDA)) of workers in a foundry industry.
Material and Methods: The workers were selected based on the calculations related to the sample size and taking into account the inclusion criteria as well as completing the informed consent form. The level of exposure to noise and WBV was measured according to ISO 9612 and ISO 2631, respectively. For each worker, the time-weighted average was calculated. The level of exposure of workers to the studied stressors was divided into three categories: low, medium, and high. The blood samples were taken from all participants between 7-9 am. Then, via ELISA method according to the protocol of the kit manufacturer, the samples were prepared and analyzed. Univariate analysis of variance was performed to determine the “effect size” of each physical stressors on the studied parameters.
Results: The mean levels of MDA, SOD, and TAC among participants were 22.48 (11.19) nmol / ml, 61.28 (10.97) U / ml, and 1.64 (0.90) mM, respectively. Among the exposure variables, noise had the largest effect on MDA level (B = 0.090), which was not statistically significant (P = 0.865). WBV had the largest effect on SOD level (B = -1.469) which was statistically significant (P = 0.016). None of the studied variables had a significant effect on the TAC level; however, among the exposure variables, the greatest effect was related to WBV (B = -0.077; P = 0.133).
Conclusion: The effect of noise on oxidative stress parameters was not statistically significant. The effect of whole-body vibration on oxidative stress parameters except SOD was not statistically significant. Noise and WBV had increasing effect on MDA and decreasing one on SOD and TAC levels.

The Mediating Role of Safety Climate in the Relationship between Organizational Resilience and Safety Performance

Gholamreza Moradi

Introduction: Safety climate potentially affects safety performance in high-hazard industries. Resilience is a developing concept and is defined as the ability that can affect the continuous improvement of safety performance. The present study assesses the influence of organizational resilience on workers’ safety performance in a steel-manufacturing industry. In this regard, the safety climate mediates the effect of organizational resilience on safety performance.
Material and Methods: A cross-sectional study was accomplished in the steel manufacturing industry in 2021. The survey included three parts: (1) organizational resilience, (2) safety performance, and (3) safety climate. Besides, the organizational resilience was measured by a scale with six dimensions and 19 items. Also, safety performance was assessed by six items regarding two performance dimensions (i.e., safety compliance and safety participation). In addition, safety climate was measured by 19 items, comprising four dimensions (i.e., safety communication, supervisor safety perception, coworker safety perception, and work pressure).
Results: The structural equation modeling results showed that the organizational resilience and safety climate had significant impacts on safety climate (β = 0.23, P ≤ 0.05) and safety performance (β = 0.43, P ≤ 0.05), respectively. Also, the indirect results indicated that safety climate mediated the relationship between organizational resilience and workers’ safety performance.
Conclusion: The increment of organizational resilience and safety climate improves workers’ safety performance. Besides, organizational resilience and related dimensions (e.g., reporting culture, learning, and awareness) improve the safety performance dimensions (i.e., safety compliance and safety participation).

Validity and Reliability of the Persian Version of Usefulness, Satisfaction, and Ease of use (USE) Questionnaire for Evaluation of Smartphones for Elderly Users

Zahra Vahedi

Introduction: Usability has been defined as the extent to which specific users can efficiently use a product to achieve specific goals. Along with the increased number of the elderly population, there is a need for user-centered products for this group of people. Smartphones are widely used products in modern society. USE (Usefulness, Satisfaction, and Ease of use) questionnaire is an easy-to-use, quick, and accurate instrument to assess product/service usability. Thus, this study was done to determine the validity and reliability of the Farsi version of the USE questionnaire to evaluate the usability of smartphones for elderly users.
Material and Methods: The USE questionnaire was developed by Lund (2001) to assess usability, considering four separate dimensions: usefulness, satisfaction, ease of use, and ease of learning. This is a 30-item questionnaire that evaluates usability on a 7-point Likert scale. In order to assess the face and content validity of the questionnaire, a panel of nine experts was asked to rate the relevancy, clarity, simplicity, and necessity of each question using the Likert scale. Subsequently, the Content Validity Ratio (CVR) and Content Validity Index (CVI) were computed. In order to confirm the reliability of the questionnaire, two methods of internal reliability and test-retest reliability were used. In this sense, Cronbach’s alpha was calculated as the measure of internal reliability. Cronbach’s alpha equal to and above 0.7 was considered the minimum acceptable value. To measure the test-retest, 50 old adults (aged 60 years old and above) were asked to answer the questionnaire twice at a two-week interval. Then, the Pearson correlation coefficient was calculated between the two sets of scores. Also, the receiver operating characteristic (ROC) curve was utilized for specifying its sensitivity, specificity, and cut -off point
Results: Based on the comments of the expert panel, CVI scores of all questionnaire items were above 0.78, whereas four items rated less than 0.78 in terms of CVR scores; and, consequently, were removed from the questionnaire. Moreover, according to the reliability assessment results, both internal correlation and test-retest scores obtained acceptable values. Specifically, Cronbach’s alpha coefficient for usefulness, satisfaction, ease of use, and ease of learning were 0.771, 0.862, 0.756, and 0.798, respectively. In the ROC curve, the cut-off point was reported as 4.88 with the sensitivity and specificity of 97.8% and 75%, respectively, and area under the ROC curve at this cut-off point was obtained 81%.
Conclusion: Comparing a product’s characteristics with standards is a prerequisite to determining the level of usability of that product. The Farsi version of the USE questionnaire is a reliable tool for measuring usability with satisfactory validity and reliability. This questionnaire can be used in future studies in smartphone usability.

Analysis of Oxygen Release Scenario in Central Oxygen Unit of the Hospital through Fault Tree Analysis Method and Fuzzy Bayesian Network

Omid Kalatpour

Introduction: Oxygen-generating central plays a vital role in the continuous performance of hospitals. Any leakage or failure in this section can not only endanger the health and safety of patients but also cause fire and explosion. Probabilistic risk assessment is a useful tool for identifying the main root causes of leakage in oxygen-generating central. This study aimed at risk assessment of an oxygen-generating central in a hospital in Hamadan using fuzzy sets theory and Bayesian networks.
Material and Methods: First, all root causes supposed to contribute to oxygen leakage from any part of the oxygen-generating central were identified, and based on them a fault tree analysis (FTA) was constructed. Then, the FTA was mapped in a BN. The failure probability of root causes was calculated using fuzzy sets theory and experts’ opinions. Belief updating based on BN was utilized for subsequent analyses.
Results: According to this study, ignorance of labels on the oxygen generation and distribution system is the most important root cause leading to oxygen leakage. Moreover, removing masks from patient’s faces is the main cause of oxygen leakage in patient rooms. Once leakage occurred, the presence of an ignition source can lead to fire or explosion.
Conclusion: oxygen leakage can create considerable risks in hospitals. All staff should be provided with sufficient training regarding hazards of oxygen-generating and distributing systems and oxygen leakage. Particular attention should be paid to such leakages and their adverse consequence in emergency planning and hospital crisis management.

Evaluation of Ergonomics Culture at the North Tehran Health Center by Delphi Method and Using an Expert Questionnaire

Mina Torabifard

Introduction: Ergonomics culture emphasizes ergonomics policies, goals, and programs that create behavioral, environmental, and structural reforms in the governing environment of the organization. The present study assesses the ergonomics culture dimensions in the North Tehran Health Center office building through the Delphi method and an expert questionnaire.
Material and Methods: The Delphi method was used to develop an expert questionnaire. The evaluation criteria were determined based on the engineering dimensions of human factors and the organizational culture factor model. Besides, the sub-criteria were specified based on the macro-ergonomics approach. In this case, the most critical sub-criteria were chosen using 15 experts and the Delphi method. Thus, a questionnaire was developed with 15 questions. The ergonomics culture criteria were classified considering the frequency of negative responses. The highest frequency of negative response demonstrated poor ergonomic status and vice versa.
Results: The results revealed that the maximum average negative score among the six principal evaluation criteria was related to the information and communication index at an average score of 66. The other criteria were ranked as follows: the management, staff, equipment design, environment layout, and job characteristics with average scores of 58, 56, 54.67, 49.5, and 36.8, respectively.
Conclusion: The ergonomics culture questionnaire was prepared and analyzed by an expert team using the Delphi method. According to the indices, the ergonomics culture level was unacceptable at the North Tehran Health Center. Thus, it is recommended to provide ergonomics courses and seminars, video clips, pamphlets, posters, and related courses. Also, training and development of ergonomics instructions can help establish an ergonomics culture in the organization to a significant extent.

Applying the HEART Technique to Identify and Assess the Human Error in the Central Railway Traffic Control Room

Ali Salehi Sahlabadi

Introduction: Human error can occur in many work environments, especially in control rooms. Due to the vital role of the central railway traffic control room in guiding and controlling all types of trains along the railway network, any error in this control room can lead to a catastrophic accident. This study aims to identify and assess human error in the central control room of railway traffic using the HEART technique.
Material and Methods: This descriptive cross-sectional study was performed in 2021. In this research, tasks and sub-tasks were identified using the hierarchical task analysis (HTA) method. Then, the probability of human error was assessed using the HEART technique.
Results: Based on the results of the HTA method, 67 main tasks, and 149 sub-tasks were identified. The study results on the probability of human error using the HEART technique showed that the three main tasks of the traffic expert (distribution of types of diesel, establishing the freight priority, and planning the movement of trains) had the highest probability of error. In addition, the most critical factors influencing human error were “evidence of illness among employees”, “sleep disorder”, “inexperience”, “unfamiliarity”, and “stress”.
Conclusion: The results of this study indicated that the central railway traffic control room employees are prone to errors, and if these staff make errors, irreparable accidents will occur. To reduce the probability of error of these employees, measures should be considered, such as using regular and appropriate shifts, the use of skilled and competent people, and so on.

Determine the Relationship between System Engineering Initiatives for Patient Safety Models Elements with Occupational Fatigue among Nurses

Seyed Mohammad Seyedmehdi

Introduction: Occupational fatigue is one of the harmful factors in many work environments, including health centers, which can have adverse effects on the health and safety of staff. This study was designed and conducted to determine the relationship between occupational fatigue and elements of the systems engineering model for patient safety in nurses.
Material and Methods: This descriptive correlational study was conducted with the participation of 457 nurses of Shahid Beheshti University of Medical Sciences in 2018. Dimensions of fatigue were assessed by a Multidimensional Fatigue Inventory (MFI) and Systems Engineering Initiative for Patient Safety (SEIPS) model’s elements using the SEIPS model’s questionnaire. Validity was examined using the Lawshe method; calculating Content Validity Ratio (CVR) and Content Validity Index (CVI) was approved through the confirmation of experts. Reliability was assessed using the intraclass correlation coefficient (ICC) and Cronbach’s alpha. Data analysis was performed using SPSS version 21
Results: The findings of this study indicated that the highest score of fatigue was related to the general fatigue dimension with an average of 12.86 and SD of 3.23, and the lowest score was related to the reduction of the motivation dimension with an average of 9.11 and SD of 3.66. In this study, no significant relationship was observed between demographic characteristics and fatigue dimensions, but a significant relationship was observed between the dimensions of fatigue with the element of organization, task, technology/tools, and physical environment.
Conclusion: The results of this study showed that fatigue in nurses was moderate, and the factors of the work system play a greater role in the occurrence of fatigue than demographic factors. Therefore, planning to improve the work system can help reduce fatigue in nurses.

Identifying, Assessing and Prioritizing Pressure Reduction Station Risks Using FMEA Based on SWARA-VIKOR Multi-criteria Decision-making Methods

Ali Karimi

Introduction: Failure modes and effects analysis (FMEA) method is used in industries to identify, assess and prioritize risks. Multi-criteria decision-making methods (MCDM) select the best option from different criteria. Therefore, this study aims to identify, assess and prioritize risks using FMEA based on SWARA-VIKOR multi-criteria decision-making methods in a gas pressure reduction station.
Material and Methods: In this descriptive and analytical study, stepwise weight assessment ratio analysis (SWARA) and decision-making optimization and compromise solution (VIKOR) methods were used to rank the risks of failure modes identified in FMEA. SWARA method was employed to determine the severity, probability and discovery weights, and VIKOR technique was applied to rank the failure modes of the system equipment. Finally, an operational example of the pressure reduction station was presented to show the application and feasibility of the proposed model. A comparative study was conducted to confirm the practicality and effectiveness of the proposed model.
Results: In total, 35 main failure modes were identified in the pressure reduction station. Failure of regulator sleeve and safety valve and regulator diaphragm rupture were assigned the first, second and third ranks of risk priority, respectively. The sensitivity analysis results showed the proposed approach had desirable stability and only the failure mode of increasing the heater flame temperature was very sensitive to changes in the weight of the criteria. Results of ranking the failure modes of the station indicated there were many changes in the ranking of failure modes based on the proposed approach.
Conclusion: The proposed approach could provide more reasonable and accurate results for ranking risks because the criteria were weighed step by step based on the experts’ opinion.

Career Adaptability and its Correlation with Quality of Work Life in Nurses Working in the Emergency Department

Faranak Jabbarzadeh Tabrizi

Introduction: Nurses of the emergency department experience stressful events that affect their mental health and reduce the quality of their work life. Career adaptability is considered a personal capability that enables employees to adapt to changes and avoid the negative consequences of job mismatch. This study was conducted to study career adaptability and its correlation with the quality of work life in the emergency department.
Material and Methods: This descriptive-correlational study was conducted on 104 nurses in the emergency department of teaching–therapeutic hospitals in Tabriz who were selected using random stratified sampling. Data was collected using a demographic checklist, the Career Adapt-Abilities Scale (CAAS) by Savickas, and the Quality of Nursing Work Life (QNWL) scale by Brooks & Anderson. Data were analyzed in SPSS using descriptive statistics (frequency, mean and standard deviation) and inferential statistics (independent t-test, one-way analysis of variance, Pearson’s correlation coefficient, and linear regression analysis).
Results: The total scores of career adaptability and the quality of nursing work life were 88.55±25.01 from the achievable range of 24-120 and 141.15±22.56 from the achievable range of 42-252, respectively, which were moderate. In this study, 85.6% of nurses enjoyed a moderate quality of work life. Furthermore, the results of Pearson’s correlation indicated a significant positive correlation between career adaptability and scopes with the quality of work life score (p=0.05). Regression analysis results indicated that career adaptability significantly predicts the quality of nursing work life (p=0.000).
Conclusion: In this study, nurses experienced moderate career adaptability and quality of work life. Given the above factors, and considering adaptability as a variable predicting quality of work life, it is suggested to take measures to increase career adaptability in nurses through training or consulting interventions to improve the quality of nursing work life.

The Relationship Between Anxiety, Stress and Protective Behavior in Nurses During COVID -19 Pandemic

Sima Rafiei

Introduction: Health workers, especially nurses, are facing a high risk of contracting the COVID-19 and consequent mental disorders such as stress, anxiety and depression. We aimed to study the relationship between anxiety, stress and the protective behavior of nurses during the Covid-19 pandemic.
Material and Methods: This cross-sectional study was conducted on nurses working in COVID -19 referral hospitals in Qazvin, Iran, in 2020. Out of 645 nurses working in two hospitals, 260 of them were selected randomly. Three questionnaires including demographic and contextual information, COVID-19 anxiety, stress and precautionary behaviors against COVID-19 were used. Descriptive statistical methods, Pearson correlation, t-test and one-way analysis of variance and binary logistic regression analysis were applied at 95% confidence interval.
Results: The prevalence of anxiety symptoms in nurses was 32.08%, the mean score of protective behavior was 18.45+5.66 and the maximum score was 22.06+4.7. The negative relationship between anxiety and nurses precautionary behavior) β=-0.36, P<0.05) and the significant effect of COVID-19 stress on nurses’ behavior) β=-0.22, P<0.05) were confirmed. Furthermore, adding stress as an interfering factor, affirmed the mediating role of stress in the relationship between anxiety and nurses’ precautionary behavior (β=-0.18, P<0.05). Nurses under 35 years of age were more likely (OR=1.62, P=0.004) to follow the protective rules; those with 6 to 10 years of hospital experience were respectively 32 times and 37 times more probable to use personnel protective equipment (PPE) (OR=1.32, P=0.002) .
Conclusion: The probability of effective use of PPE and observance of protective guidelines among nurses with severe and very severe anxiety levels was less than their counterparts. While in those with controlled level of stress level such obedience was much more probable. Therefore, all health service providers, need to develop supportive programs to emphasize on the promotion of employees’ mental health.