Journal of Health and Safety at Work

---

Introduction: Needlestick (NSI) is a known serious treat and occupational exposure among health care workers especially nurses. Since nurses are the biggest part of healthcare workers, and considerable percent of NSI are preventable, we decided to determine frequency of NSI and some related occupational factors among a group of them.

.

Methods and Materials: This cross-sectional project was conducted among all the nurses (340 nurses with at least one year work experience) in Babol and Amirkola educational and private hospitals (in north of Iran). The data were gathered by means of a tailor-made data collection sheet including personal information and some occupational effective factors, during autumn and winter. The data were analyzed with descriptive statistical indexes and Chi-square test.

.

Results: Our result showed that the relative frequency of NSI among the nurses group (the mean age of nurses was 33.8±7.7 years old and the mean work experience was 10.3±8 years) was 59.7 percent. Chi-square test result indicated that there were significant differences between NSI in different groups of some personal and occupational factors including age, years of experience, training condition, and needle recapping(p<0.05).

.

Conclusion: According to positive effects of training and negative effects of incorrect working habits, repetition and completion of occupational education is necessary.

---

Introduction: Application of agricultural machineries such as tractor has been yielded a considerable development in different agricultural activities and productions. However, noticeable health problems such as noise pollution impact the users of these off-road vehicles. The purpose of this study was to determine the noise level induced by agricultural tractors and to evaluate the driver’s noise exposure level.

.

Material and Method: The sound pressure levels of three brands of tractor include John Deere, Ferguson and Romani were measured by sound level meter model Tes-1358. The characteristics of place for measuring tractors noise pollution were determined based on the ISO standard No 7216, 5131. The acquired data was analyzed using spss16 software.

.

Result: The results showed that the highest and the lowest noise level around the tractors were 83.8 dB (A) and 73.9 dB (A) for the John Deere and Romani, respectively. The effect of different transmission gears on the noise level of tractors was not statistically significant Pvalue>0.05. While, the effect of the tractor engine speeds on the noise level was statistically significant Pvalue<0.01. The exposure time of the most of drivers was frequently about 8 hour or more In this regards, the exposure levels of the tractor’s drivers to noise measured between 85-90 dB (A) were higher than the Iranian occupational exposure limit (85 dB (A)).Moreover, mean noise reduction rate of exsisting room which was used upon the typical tractor’s body was 9.5 dB in one octave band.

.

Conclusion: Application of standard cockpit and expansion mufflers can effectively reduce noise pollution emission and driver’s occupational exposure. Moreover, regular preventive maintenance and effective hearing conservation program including annual audiometry, hearing protection device, occupational health training for drivers must be implemented.

---

Introduction: According to the literature, a large number of people working in industries and service providing personnel, such as firefighters, physicians, and nurses, are shift workers. The spread of shift working in industrial societies and the incidence of the problems resulting from shift working have caused the researchers to conduct studies on this issue. The present study also aimed to investigate melatonin and cortisol circadian rhythms in the security guards of Shiraz University of Medical Sciences, Shiraz, Iran.

.

Material and Method: The present study was conducted among 20 security guards of Shiraz University of Medical Sciences. In order to collect the required data, blood samples were taken from the participants in different times of the day (1, 4, 7, 10, 13, 16, 19, and 22) and cortisol and melatonin levels were determined using radioimmunoassay and enzyme immunoassay techniques, respectively. Then, the data were entered into the SPSS statistical software (v. 16.0) and analyzed using One-Way ANOVA.

.

Result: The results showed that as the intensity of light increased during night time, the level of plasma cortisol increased, as well. Besides, no statistically significant difference was found between the plasma cortisol levels in natural light and 4500-lux light. On the other hand, a significant difference was observed between the level of plasma cortisol in natural light and 9000-lux light as well as 4500- and 9000-lux lights. The study findings also showed that as the intensity of light increased at night, the level of plasma melatonin decreased. In addition, a statistically significant difference was found between the plasma melatonin levels in natural light and 4500-lux light. Nevertheless, no significant difference was observed between the plasma melatonin levels in natural light and 9000-lux light as well as 4500- and 9000-lux lights.

.

Conclusion: The present study aimed to investigate the subsequences of shift working in the security guards of Shiraz University of Medical Sciences and showed that occupational exposure to bright light could affect some biological markers, such as melatonin and cortisol secretion.

---

Introduction: Existing literatures indicate that occupational exposure to formaldehyde may decrease blood platelets. In this study, the influences of occupational exposure to formaldehyde on the number of blood plateletsand clinical symptoms were studied while determining the occupational exposure of employees of a wood industry to formaldehyde.

.

Material and Method: In a case study, the occupational exposure to formaldehyde was determined among 30 workers from production line and 30 administrative staffs of a wood company using US-NIOSH method No 2541. The number of blood platelets was determined using the normal blood count method and related indices. Demographic data as well as the clinical symptoms of exposure to formaldehyde were collected using a standard questionnaire. The smokers and those using drugs interacting with similar symptoms and blood characteristics were excluded from the study. Ethical principles for medical research involving human subjects announced in Helsinki declaration were considered. The research proposal had been approved by the university committee of ethics prior to its execution. Details of tests were explained for all subjects and a written consent was signed by each subject.

.

Result: Occupational exposure of workers in various parts of particle board production line ranged from 0.5 ppm to 1.52 ppm which was higher than the ceiling level (0.3 ppm) recommended by US-ACGIH. The prevalence of all studied symptoms from formaldehyde exposure in workers was significantly higher than the administrative staffs. In case group, tearing rate was the highest average 8.98 while the chest pain with an average rate of 3.20 was the lowest. In control group, the prevalence of coughing with an average rate of 6.62 was the highest and the chest pain with an average rate of 5.53 was the lowest. The average number and standard deviation of blood platelets of workers in production line and staffs were statistically different with the range 207.33±41.79 and 254.60±71.05, respectively. The statistical tests showed no relationship between the level of occupational exposure to formaldehyde and the number of blood platelets (p>0.05). This means that, increasing the exposure level would not lead to a further reduction in the number of platelets.

.

Conclusion: Occupational exposure to formaldehyde significantly changed the number of blood platelets.

---

Introduction: Lead exposure is considered as a global health problem. The irreparable harmful effects of this heavy metal on human have been proven in various studies. Comparing to general population, workers in related industries are more exposed to lead. Several studies have investigated lead occupational exposure and its biological evaluation in Iran; however there is no overall estimate. Thus, the present study was conducted to determine the occupational exposure to lead and its biological evaluation in Iranian workers, using systematic review and meta-analysis.

Material and Method: This study was carried out based on information obtained from databases including Magiran, Iranmedex, SID, Medlib, Trials Register, Scopus, Pubmed, Science Direct, Cochran, Embase, Medline, Web of Science, Springer, Online Library Wiley, and Google Scholar from 1991 to 2016, using standard key words. All of the reviewed papers which met the inclusion criteria have been evaluated. Data combination was performed according to Random Effects Model using Stata software version 11.1.

Result: In the 34 qualified studies, the mean blood lead level (BLL) concentration in Iranian workers was estimated 42.8µg/dl (95% CI: 35.15-50.49). The minimum and maximum BLL were belonged to west (28.348µg/dl) and center (45.928µg/dl) regions of Iran, respectively. Considering different occupations, the lowest mean value was reported in textile industry workers (12.3 µg/dl), while the highest value was for zinc-lead mine workers (72.6 µg/dl). Mean breathing air lead level of Iranian workers reported in 4 studies was estimated 0.23 mg/m3 (95% CI: 0.14-0.33).

Conclusion: According to the high concentration of BLL and breathing air, it is recommended to increase protective measures and frequent screening. Scheduled clinical and paraclinical examination should also be performed for workers.

---

Introduction: Limited studies have been done to evaluate the whole-body vibration (WBV) exposure experienced by Taxi drivers. Therefore, the aim of this study was to evaluate the exposure to whole body vibration and repeated shocks in urban taxi drivers and also to compare different methods of evaluation in this job environment.

Material and Method: Measurement and evaluation process were conducted in accordance with procedure of the ISO 2631-1 and ISO 2631-5 standards. The measurements were done by SVAN 958 Sound and Vibration Analyzer and using tri-axial accelerometer centered on the contact surface between the seat and the driver in 9 taxis.  

Result: The measurements done according to ISO 2631-1 method showed greater risk compared to Daily Equivalent Static Compression Dose, Sed, presented in ISO 2631-5. Calculated daily exposure durations for exposure action level in root-mean square, vibration dose value, and daily equivalent static compressive stress methods were 4.55, 3.54 and 31.70 hours, respectively.

Conclusion: The large differences in estimated exposure durations of action limits and permissible limits resulted by different methods reflect the inconsistency of the selected evaluation methods. Therefore, future research is necessary to amend the limits presented in the standard.

---

Introduction: Occupational exposure to crystalline silica increases the risk of lung cancer and restrictive lung disease with extensive fibrosis. Silica dust is a major health hazard in foundry factories. The aim of this study was to determine core making workers’ exposure to respirable crystalline silica dust in a foundry factory.

Material and Method: This cross-sectional study was conducted in core-making unit of a foundry factory in 2015. Occupational exposure of 55 workers to respirable crystalline silica aerosols was evaluated by using the improved NIOSH7602 method in core-making unit. Risk assessments for silicosis and excess lifetime risk of mortality from lung cancer were done according to Manettej and Rice models, respectively. Data was analyzed with Spss19 software.

Result: The mean of respirable crystalline silica dust was 0.246 ± 0.351 (mg/m3). All  workers’ exposure to respirable crystalline silica was higher than recommended occupational exposure limits. Silicosis mortality risk and excess lifetime risk of mortality from lung cancer were estimated in the range of 6-63 and 65 per thousand people, respectively.

Conclusion: The mean of workers’ exposure to respirable crystalline silica was higher than recommended occupational exposure standards in core making unit. The risk assessment of silicosis mortality and excess lifetime risk of mortality from lung cancer were higher than acceptable levels of risk.

---

Introduction: Exposure to crystalline silica dust can seriously threaten health of workers engaged in processes such as casting, stone crushing, grinding, construction activities, insulator manufacturing, and glassblowing and sandblasting. The aim of this study was to assess occupational exposure to crystalline silica and to determine the risk of mortality from silicosis and lung cancer in an insulator manufacturer.

Material and Method: Air personal sampling was performed using 10 mm nylon cyclone and mixed cellulose ester (MCE) membrane filters (5 mm diameter, 0.8 μm pore size) for 60 male workers. Samples were prepared and analyzed according to the National Institute for Occupational Safety and Health (NIOSH) 7601 standard method. The risk assessment of mortality due to silicosis resulting from crystalline silica exposure was done by using model of Mannetje et al. for the period of 10 years. The mortality rate of lung cancer was determined using a linear regression model derived from the study Rice et al.  

Result: The highest and lowest exposure levels to silica were belonged to the packing unit (0.54±0.28 mg/m3) and the furnace (0.02±0.01 mg/m3), respectively. Crystalline silica concentrations for all samples were higher than Threshold Limit Values (0.025 mg/m3) recommended by the American Conference of Governmental Industrial Hygienists (ACGIH). According to Mannetje et al. model, the cumulative exposure of 25% workers was in the range 0 to 0.99 that it represents 1 death per 1,000 people. The risk of mortality due to lung cancer was obtained in the range of 7-94 persons per 1000 workers exposed to silica.

Conclusion: In general, the geometric and arithmetic mean of crystalline silica exposure was higher than threshold limit value for most of the subjects. For all workers of the insulator manufacturer, the risk of silicosis related mortality was higher than 1/1,000 (unacceptable level of risk). Predicting the lung cancer mortality from silica exposure indicated a high level of mortality risk among understudied workers.

---

Introduction: Nowadays, millions of people are exposed to the dusts in their workplaces. Occupational exposure to dusts is considered as one of the most common and serious occupational hazards to workers’ health. The purpose of this literature review was to review the literature related to the occupational exposure to dusts in Iran published over the past 14 years.  
Material and Methods: In this review, published articles were obtained from Web of Science, PubMed, Google Scholar, Scopus, ScienceDirect, Islamic World Sciences Citation (ISC), Magiran, SID، Iran Medex, and Civilica search engine. The main keywords for search were Occupational Exposure, Lung, Dust, Total Dust, and Respirable Dust. The relevant articles published in Iran over the past 14 years were searched and extracted after checking their relevancy. All articles were classified based on the titles, years of publication, places of publication, type of industries, geographic distributions, sampling and analysis methods, fields of study, and the amounts of exposure.
Results: Findings showed that in spite of increases in the rate of published literature in recent years and by considering geographical variation and the large number of dust generating firms and industries, a relatively small number of studies was conducted and published in this field. Majority of the studies in this field considered the levels of dust exposure and respiratory effects of dust exposures.  In most studies the levels of occupational exposure to dusts (and crystalline silica dusts) were higher than the recommended limit values.
Conclusion: Although an increasing number of studies can be seen in recent years on occupational exposure to dusts and their effect, by considering the presence of large and small size industries with dust generating pollution  in Iran, the large number of exposed people, adverse-health  effects,  and  the need for control measures, few studies have been published in this field and further works need to be done in this area.

---

Introduction: Styrene (C₆H₅CH=CH₂) is known as one of the volatile organic substances produced or used in petrochemical industries. Exposure to this chemical compound can thus lead to respiratory diseases. Therefore, this study aimed to evaluate occupational exposure to styrene vapor and to determine the risks of its health consequences in petrochemical industry workers through a quantitative method.
Material and Methods: In this descriptive cross-sectional study, a total number of 150 samples from 50 employees were studied using the National Institute for Occupational Safety and Health (NIOSH) 1501 method. The samples were then analyzed by the Varian CP-3800 chromatograph. Upon determining exposure to styrene vapor, the risk assessment of the health consequences of styrene in the workers in the given industry was evaluated via the relationships established by the United States Environmental Protection Agency (US/EPA).
Results: According to the results, the polybutadiene latex unit (PBL) was observed with the highest average exposure (0.44 mg.(kg-day)-1). Therefore, the top predictors of carcinogenic and non-carcinogenic risks were valued 0.44 and 0.71, respectively, for the PBL unit. Given the lowest average exposure (0.0012 mg.(kg-day)-1) in the drying unit, the prediction revealed the most moderate carcinogenic (0.1 ×10-5) and non-carcinogenic risks (2×10-3) for the same employees.
Conclusion: Overall, the health risk was higher than the permissible limit in the petrochemical industry studied, especially in the PBL unit. Therefore, it is recommended to make use of artificial ventilation, notably the local type, in addition to the natural ones.

---

Introduction: Climate change and hot processes in the workplaces has led to an increase in the effects of heat stress on employed people, which has become a major concern, especially in tropical and subtropical countries. Early detection of biomarkers in induction of heat stress-related DNA damage can be used in the identification and evaluation of health and safety, including occupational health professionals, as well as to prevent serious diseases caused by heat stress in various occupations with the nature of hot processes or to help different warm seasons of the year. Therefore, this review study was conducted to identify diagnostic biomarkers heat stress induced- DNA damage in occupational exposure.
Material and Methods: Databases such as PubMed, Scopus, Google Scholar, and Web of Science were systematically searched to meet the study’s goals. Moreover, references to relevant publications were examined. Finally, suitable articles were selected and analyzed using the inclusion (studies on different occupations, different biomarkers in hot work environments, all articles published without time limit until the end of April 2022 , and English and Persian language)  and exclusion criteria.
Results: The results of search in databases showed that 9234 articles were found in the initial search. After removing duplicate and unrelated articles, 2209 eligible articles were selected. Based on abstract full-text screening, 7166 studies were excluded, and based on abstract full-text screening, 21 studies were not accessible. Finally, seven articles were selected to be reviewed. The evidence showed that diagnostic biomarkers included the measurement of 8-hydroxy-2-deoxyguanosine (8-OHdG), micronuclei semen quality, heat shock proteins (HSP70), and leukocytes were extracted to heat stress induced- DNA damage in occupational exposure.
Conclusion: Based on a review of studies,  biomarkers identified are suitable for heat stress induced- DNA damage as a result of occupational exposure to extremely high heat climate conditions. Understanding and identifying appropriate biomarkers in inducing DNA damage can help health and safety professionals determine the amount and magnitude of heat stress responses in occupational exposure to different temperatures and take appropriate measures and interventions to control and reduce the hazard effects of thermal stress. This study can also be considered as a preliminary study for research in the future.

---

Introduction: The use of antineoplastic drugs in cancer treatment, while essential, poses risks due to their non-selective action on both cancerous and healthy cells. Assessing and controlling environmental contamination with these drugs in workplaces is crucial. This study aimed to evaluate the efficacy of various commercial wipes in sampling the antineoplastic drug 5-fluorouracil from surfaces to develop standardized sampling methods.
Material and Methods: This study assessed the efficiency of commonly used commercial wipes (Whatman cellulose filter, cotton swab, Millipore™ filter, sterile gauze pad, and alcohol pad) for sampling 5-fluorouracil from different surfaces (stainless steel, vinyl, and ceramic). The sampling area was defined using disposable cardboard frames, and 1000 microliters of a 1 µg/mL 5-fluorouracil solution were applied to each surface. Sampling and extraction were conducted following NIOSH guidelines. The frame dimensions were 10 × 10 cm, limiting the sampling area to 100 square centimeters. Analysis was performed using high-performance liquid chromatography (HPLC), and results were analyzed using Prism GraphPad software, version 8.
Results: The sampling efficiency varied across wipes and surfaces, ranging from 11.2% to 86.2%. Alcohol pads showed the highest efficiency on stainless steel surfaces, while the Millipore™ filter had the lowest efficiency across all surfaces. Extraction efficiency ranged from 43.8% to 98.8%, with alcohol pads providing the highest recovery. Sample stability was maintained over 15 days.
Conclusion: Alcohol pads were most effective in collecting and extracting 5-fluorouracil, particularly from hard, smooth surfaces such as stainless steel and ceramic. These findings may improve sampling methods, thereby reducing occupational exposure to antineoplastic drugs. Further research on different wipes and extraction parameters could refine drug analysis techniques. 

---

Introduction: Fumigant gases in maritime and container chains, along with occupational noise in marine and manufacturing industries, are among the most significant chronic risk factors. They are usually assessed separately, despite their simultaneous impact on workers’ health. The importance of this study lies in presenting an integrated approach for real-time monitoring of combined risk and aligning it with occupational exposure limits (OELs). The aim is to develop and validate an interpretable, regulation-oriented framework for predicting combined risk.
Material and Methods: This research integrated and normalized data from the Global Burden of Disease (GBD) 2021 study including age-standardized disability rates (ASDR) and average annual percentage change (AAPC) for 204 countries with occupational exposure limit tables for fumigants. A Sugeno-type fuzzy inference system with three inputs and four rules was designed. Weights and membership function boundaries were optimized using the Prairie Dog Optimization algorithm, and a threshold-based scenario generation module was applied to produce high-risk synthetic data. Model performance was evaluated through an OEL compliance test.
Results: Findings revealed that the proposed optimization reduced the loss function by 42% compared to random search. The mean absolute error (0.028 ± 0.006) and root mean square error (0.041) were obtained. Threshold-based scenario generation improved data coverage in high-risk regions from 0.62 to 0.90 and increased the accuracy of critical condition detection from 0.71 to 0.89. The OEL compliance index reached 0.93, confirming input weighting as the most influential factor.
Conclusion: The proposed framework simultaneously ensures numerical accuracy, interpretability, and regulatory compliance with occupational exposure limits. It can be deployed within real-time monitoring dashboards for ports and factories. Future research should integrate IoT sensors and multi-objective optimization to enable dynamic updates in response to evolving regulations and operational conditions.

---

Introduction: Occupational noise is considered as an emerging risk factor for type 2 diabetes. Although previous studies have mainly examined the auditory outcomes of noise exposure and estimated the relative risk of diabetes, there is insufficient evidence to estimate the prevalence of type 2 diabetes in Workers exposed to occupational noise. The present study aimed to conduct a systematic review and meta-analysis of the pooled prevalence of type 2 diabetes in workers exposed to occupational noise.
Material and Methods: In this systematic review and meta-analysis, the Web of Science, Scopus, Medline (PubMed) databases and Google Scholar engine were searched up to May 2025. The quality of studies was assessed using the Newcastle-Ottawa scale. The pooled prevalence was estimated using the DerSimonian and Laird random effects model, and heterogeneity was assessed using the I² index. The pooled prevalence was reported in subgroups based on the method of diabetes diagnosis and type of study.
Results: Out of 1,193 initially identified studies, 14 studies with a total of 94,975 participants were included in the systematic review and meta-analysis. The pooled prevalence of type 2 diabetes among individuals exposed to occupational noise was estimated at 5.91% (95% CI: 4.85%–6.98%). Significant statistical heterogeneity was observed among studies (I² = 98%, p < 0.001). The subgroup analysis indicated that the prevalence of diabetes in studies based on clinical or paraclinical diagnostics was higher than in studies based on self-report (7.31% and 3.73%, respectively). Moreover, the prevalence of diabetes in cross-sectional studies was higher than in cohort studies (6.45% and 5.67%, respectively).
Conclusion: The findings indicated a moderate prevalence of diabetes among people exposed to occupational noise. This prevalence was based on preliminary studies with an acceptable level of quality. The findings highlight the importance of recognizing metabolic consequences of occupational noise exposure alongside its well-known auditory effects.