• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.9 no.2
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• pp.158-166
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• 1999

The purpose of this study was to investigate the correlation between airborne total dust and man-made mineral fibers (MMMF), and to estimate total dust concentration to maintain below the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV$^{(R)}$) for the MMMF. The regression coefficients between airborne total dust concentrations and fiber concentrations determined in the industries producing glass fibers, rock wool. refractory ceramic and continuous filament glass fibers products were 0.41, 0.42, 0.20 and 0.19, respectively. The size characteristics of fibers as well as the amounts of contaminated non-fibrous dusts could affect the correlation intensities. When total dust and fiber exposure data were compared with the occupational exposure limits, there was a large gap between two evaluation results. The regression coefficient between total dust and fiber data was increased ($r^2=0.88$) in the process of insulation installation generating in the higher levels of glass or rock wool fibers. In this case, an estimated total dust concentration of glass wool or rock wool fibers complying with the ACGIH TLV (1 f/cc) was $1.7mg/m^3$. In conclusion, the total dust and fibers concentrations was highly correlated at the higher exposure levels so that total dust-monitoring data could be used to control simply and economically and to estimate worker's exposure to fibers.

• Safety and Health at Work
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• v.6 no.4
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• pp.268-278
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• 2015

Background: This study aimed to assess the whole-body vibration (WBV) exposure among large blast hole drill machine operators with regard to the International Organization for Standardization (ISO) recommended threshold values and its association with machine- and rock-related factors and workers' individual characteristics. Methods: The study population included 28 drill machine operators who had worked in four opencast iron ore mines in eastern India. The study protocol comprised the following: measurements of WBV exposure [frequency weighted root mean square (RMS) acceleration ($m/s^2$)], machine-related data (manufacturer of machine, age of machine, seat height, thickness, and rest height) collected from mine management offices, measurements of rock hardness, uniaxial compressive strength and density, and workers' characteristics via face-to-face interviews. Results: More than 90% of the operators were exposed to a higher level WBV than the ISO upper limit and only 3.6% between the lower and upper limits, mainly in the vertical axis. Bivariate correlations revealed that potential predictors of total WBV exposure were: machine manufacturer (r = 0.453, p = 0.015), age of drill (r = 0.533, p = 0.003), and hardness of rock (r = 0.561, p = 0.002). The stepwise multiple regression model revealed that the potential predictors are age of operator (regression coefficient ${\beta}=-0.052$, standard error SE = 0.023), manufacturer (${\beta}=1.093$, SE = 0.227), rock hardness (${\beta}=0.045$, SE = 0.018), uniaxial compressive strength (${\beta}=0.027$, SE = 0.009), and density (${\beta}=-1.135$, SE = 0.235). Conclusion: Prevention should include using appropriate machines to handle rock hardness, rock uniaxial compressive strength and density, and seat improvement using ergonomic approaches such as including a suspension system.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.19 no.3
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• pp.195-201
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• 2009

To identify relationship between the airborne concentrations of formaldehyde and the causal factors in the endoscope unit of hospitals, a total of 48 workers selected from 4 hospitals (3 university hospitals and 1 national hospital) were investigated. Airborne formaldehyde samples were collected using passive samplers and subsequently analyzed by HPLC according to the OSHA method 1007. The geometric mean(GM) of airborne formaldehyde concentrations was 0.056 ppm (range: 0.003~0.923 ppm). The rates of exceeding exposure limits of OSHA PEL-TWA and NIOSH REL-TWA were 4.2 % and 83.3%, respectively. The STEL GM concentration was 1.428 ppm(range: 0.103~14.773 ppm). Ventilation condition (p=0.001) and temperature (p=0.017) were statistically significant causal factors for the airborne exposure concentration of formaldehyde in the endoscope unit of hospitals. In conclusion, the workers in the endoscope unit of hospitals were highly exposed to formaldehyde, and adequate controls such as appropriate management of ventilation and temperature are recommended to reduce over exposure to formaldehyde.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.4 no.1
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• pp.33-42
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• 1994

This study was carried out to assess worker exposure to vinyl chloride monomer (VCM) and to present control measures in the factories processing and producing polyvinyl chloride (PVC) resin. The conclusion remarks are as follows. Only two personal samples in the factory ("E") processing polyvinyl chloride resin were analysed to be 27.6 ppm and 12.6 ppm, respectively. But, these concentration exceed 1 ppm, Permissible Exposure Limits (PEL) of OSHA. So, worker's exposure to VCM at "E" factory should be reevaluated. In "A", "B" and "C" factory producing polyvinyl chloride resin, the average worker's exposures to VCM were 0.12 ppm, 0.86 ppm and 1.23 ppm, respectivery. Worker exposure to VCM at distillation and dry process was higer than other processes at "A" factory. The average exposure concentration of worker at polymerization process of "B" and "C" factory was 1.23 ppm, and 1.46 ppm respcetively. These concentration exceed 1 ppm, Permissible Exposure Limits of OSHA. Control room of "B" and "C" factory had 0.91 ppm and 0.65 ppm of worker's exposure concentration respectively. "A" factory was evaluated to be "acceptable", but "B" and "C" factories were evaluated to be "not acceptable", by the workplace exposure assessment program of AIHA. Process other than bagging and control room of "A" factory was evaluated to "not acceptable". Immediate correction measures for preventing workers from exposure to VCM should be performed in the factories or process that were evaluated to be "not acceptable". After these control measures are taken, worker exposure to VCM must be reevaluated through personal air monitoring. Control measures presented by this study are complete sealing of connecting pipe lines, flanging, packing, bolting and nutting. Periodic leak test for leak parts is also required. And positive pressure facility should be constructed at control room of "B" and "C" factory. Fresh air through cleaner such as HEPA filter should be supplied to control room. In addition to these control measures, periodic personal monitoring for evaluating worker exposure to VCM should be performed.

• Safety and Health at Work
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• v.11 no.4
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• pp.500-508
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• 2020

Background: Research on the status of many chemicals used in the semiconductor industry is needed. The purpose of this study was to describe the overall status of chemical use in the semiconductor industry in Korea and to examine it from a health perspective. Methods: Data on the status of chemical use and safety data sheets at 11 of 12 major semiconductor workplaces in Korea were collected. The number of chemical products and chemical constituents, quantities of chemicals, and trade secret ingredients used, as well as the health hazards were examined. Results: On average, 210 chemical products and 135 chemical constituents were used at the surveyed workplaces. Among all chemical products, 33% (range: 16-56%) contained at least one trade secret ingredient. Most of the trade secret ingredients were used in the photolithography process. Several carcinogens, including sulfuric acid, chromic acid, ethylene oxide, crystalline silica, potassium dichromate, and formaldehyde were also used. Only 29% (39 of 135) of the chemical constituents had occupational exposure limits, and more than 60% had no National Fire Protection Association health, safety, and reactivity ratings. Based on the aforementioned results, this study revealed the following. First, many chemical products and constituents are being used in the semiconductor industry and many products contained trade secret ingredients. Second, many products contained significant amounts of carcinogenic, mutagenic, and reproductive toxicant materials. Conclusion: We conclude that protecting workers in the semiconductor industry against harm from chemical substances will be difficult, due to widespread use of trade secret ingredients and a lack of hazard information. The findings of the status of chemical use and the health and safety risks in semiconductor industry will contribute to epidemiological studies, safe workplace, and worker health protection.

• Journal of Radiation Protection and Research
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• v.30 no.4
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• pp.175-183
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• 2005

Dose distribution of Korean radiation workers classified by occupational categories was analyzed. Statistics of the occupational radiation exposure(ORE) in 2002 of the radiation workers in diagnostic and dental radiology were obtained from the Korea Food and Drug Agency(KFDA) who maintains the database for individual radiation dose records. Corresponding statistics for the rest of radiation workers were obtained by processing the individual annual doses provided by the Korea Radioisotope Association(KRIA) after deletion of individual information. The ORE distribution was classified in term of 28 occupational categories, annual individual dose levels, age groups and gender of 52733 radiation workers as of the year of 2002. The total collective dose was 66.4 man-Sv and resulting average individual ORE was 1.26 mSv. Around 80% of the workers were exposed to minimal doses less than 1.2 mSv. However, it appeared that the recorded doses exceeded 20 mSv for 43 workers in the industrial radiography and for 147 workers in the field of radiology. Particularly, recorded doses of 23 workers in radiology exceeded the annual dose limits of 50 mSv, which is extraordinary when the working environment is considered. It is uncertain whether those doses are real or caused by careless placing of dosimeters in the imaging rooms while the X-ray units are in operation. No one in the workforce of 16 operating nuclear power plant units was exposed over 20 mSv in 2002. Number of workers was the largest in their 30's of age and the mean individual dose was the highest in their 20's. Women were around 20% of the radiation workers and their average dose was around one half of that of man workers.

• Journal of Radiation Protection and Research
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• v.23 no.3
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• pp.149-157
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• 1998

An analysis has been performed to estimate the additional number of workers and the additional collective dose in man-cSv which would be required, nuclear industry-wide as a result of reducing individual dose limit. This analysis can be extended to the reduction in the dose limits recommended by ICRP Publ.60 and BEIR V report as well as the proposed dose limits by regulatory authorities. An industry-wide database was employed in the analysis based on a summary of industry-wide occupational radiation exposure compiled by the Korea Radioisotope Association. Correlation model was employed to compute the affects of setting specific annual individual dose limits. In this study, we have addressed worker non-productivity while in the radiation environment on a parametric or 'sensitivity analysis' basis. This alleviates the need for developing such data underlying a summation of many individual tasks at many nuclear facilities. It has the advantage that very low non-productivity assumptions can readily be defended as conservative, in that it is difficult to approach such low worker non-productivity factors even in the best of environments in any industry. On a per facility basis, for calendar year 1997, the number of workers required would be increased from 231 workers to 269 workers and collective man-cSv dose would be also increased by approximately fourteen percent if the individual dose limit was reduced to 2 cSv/y and an individual worker non-productivity fraction of 0.1 is assumed.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.30 no.2
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• pp.153-162
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• 2020

Objectives: 3D printing technologies have become widely developed and are increasingly being used for a variety of purposes. Recently, the evaluation of 3D printing operations has been conducted through chamber test studies, and actual workplace studies have yet to be completed. Therefore, the objective of this study was to determine the emission of volatile organic compounds(VOCs), metals, and particles from printing operations at a workplace. This included monitoring conducted at a commercial 3D printing service workplace where the processes involved material extrusion, material jetting, binder jetting, vat photo polymerization, and powder bed fusion. Methods: Area samples were collected with using a Tenax TA tube for VOC emission and MCE filter for metals in the workplace. For particle monitoring, Mini Particle Samplers(MPS) were also placed in the printer, indoor work area, and outdoor area. The objective was to analyze and identify particles' size, morphology, and chemical composition using transmission electron microscopy with energy dispersive spectroscopy(TEM-EDS) in the workplace. Results: The monitoring revealed that the concentration of VOCs and metals generated during the 3D printing process was low. However, it also revealed that within the 3D printing area, the highest concentration of total volatile organic compounds(TVOC) was 4,164 ppb at the vat photopolymerization 3D printing workplace, and the lowest was 148 ppb at the material extrusion 3D printing workplace. For the metals monitoring, chromium, which, is carcinogenic for humans, was detected in the workplace. As a characteristic of the particles, nano-sized particles were also found during the monitoring, but most of them were agglomerated with large and small particles. Conclusions: Based on the monitoring conducted at the commercial 3D printing operation, the results revealed that the concentration of VOCs and metals in the workplace were within Korea's occupational exposure limits. However, due to the emission of nano-sized particles during 3D printing operations, it was recommended that the exposure to VOCs and metals in the workplace should be minimized out of concern for workers' health. It was also shown that the characteristics of particles emitted from 3D printing operations may spread widely within an indoor workplace.

• 월간산업보건
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• s.5
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• pp.4-15
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• 1988

In order to proffer the fundamental data for the better working environment and the effective establishment of hearing conservation program on workers exposed to industrial noise, author assessed noise levels on the 42 noisy processes among 84 manufactures of 9 industries and measured noise gearing loss by the type of industries on 3,104 workers at these noisy processes from March, 1986 to Februry, 1987. The results were summarized as follows: 1. The averge of A-weight sound level of 23 processes(54.8%) and the avergae of sound level at each octave band of 14 processes(33.3%) exceeded the permissible exposure limits in 8 hours per day. 2. The noise level was the highest in process of cocking of ship building(109.1dBA), and followed by plating of steel rolling(104.3dBA), rivet of manufacture of motor vehicles(102.5dBA), shot of ship building(98.5dBA), aciding(95.7BA) and steel tubing(95.0dBA) of steel rolling, weaving of textiles(95.0dBA). 3. The permissible exposure time for the average of sound level at each octave band was only 30 minutes in the process of cocking of ship building, plating of steel rolling and rivet of manufacture of motor vehicles. 4. As a result of audiometric examination in 3,104 workers, the rate of hearing loss over 50dB at 4,000Hz was 7.3%(227 workers) and the rate of hearing loss over 41dB at 60average method was 2.9%(89 workers). 5. The prevalence of occupational hearing loss in ship building and manufacture of motor vehicle was 5.2% and it was the highest among prevalence of these 9 industries. 6. As a result of this suvery, the noise control and gearing conservation program were required especially in the industry of ship building and manufacture of motor vehicle.

• Korean Journal of Occupational Health Nursing
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• v.24 no.3
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• pp.183-193
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• 2015

Purpose: The purpose of this study was to describe cleaning workers' working experiences in Korea. Methods: The data were collected in two focus-group interviews with 9 cleaning workers. The phenomenological analytic method suggested by Colaizzi was used to analyze the data. Results: Five theme clusters and thirteen themes emerged from the analysis. The first theme clusters, 'Dead-end choice' included Limits of elderly women workers, Financial difficulties, Lowered self-esteem. The second theme clusters, 'Facing with discriminatory working environments' included Fear and unfair working conditions. The third theme clusters, 'Potential health problems' included Physical overload, Repeated exposure to hazardous substances and Emotional labor. The fourth theme clusters, 'Excluded from protection of the law' included Gloomy reality and Sexual harassment. The fifth theme clusters, 'Desire to get out of social isolation' included Efforts to maintain the status, Desire to live confidently and Desire to change social recognition. Conclusion: The findings of the study provide understanding on cleaning workers' working experiences to explain by their vision and language and should ensure proper working conditions and environment to live a better life.