Work-related Low Back Pain(LBP) is one of tile most important Issues in the field of industrial safety and health. Particularly, manual lifting is known as a major cause of work-related LBP and impairment. Total number of 163 manual lifting tasks in motor assembly processes were investigated. The 1981 and the 1994 equations developed by National Institute for Occupational Safety and Health(NIOSH) were applied to evaluate potential hazards of lifting-related LBP. Comparisons between the 19R I and 1994 NIOSH criteria were made. The relationships between the NIOSH criteria and lifting-related LBP were also analyzed. The results of this study are as follows: 1. The values of Action Limit(AL) by the NIOSH 1981 lifting equation. Recommended Weight Limit(RWL) by the 1994 equation and the weight of the load handled at each manual lifting task were shown log-normal distributions. 2. LI'(the weight of tile load/AL) and LI(the weight of the load/RWL) were calculated estimate the physical stress imposed by each individual lifting task. As a result. 76.7% of the total LI' value exceeded 1 and 12.9% exceeded 3, and 84.7% of the total LI values exceeded 1 and 20.9% exceeded 3. 3. Bus 2 Department showed the highest rate of LI'>1 and LI>1 and Bus 1 Department showed the highest rate of LI'>3 and LI>3 4. In general, the RWLs by the 1994 equation were found lower than the ALs by the 1981 equation. It is assumed to he resulted from the fact that the 1994 equation includes methods evaluating asymmetrical lifting tasks and lifts of objects with less then optimal hand-container couplings, and also covers a larger range of work durations and lifting frequencies than the 1981 equation. 5. Significant correlations were found between LI' and incidence of LBP (R=0.734, p<0.05). LI and incidence of LBP(R=0.671. p<0.10) and load-weights and incidence of LBP(R=0.797, p<0.05). 6. Control measures are required to achieve the value of LI less than 1 for some tasks having high LI values. Engineering control is highly recommended for some tasks having the value of LI above 3.

Cumulative trauma disorders(CTDs) have been a growing problems for US and European industries with higher incidence rate every year. The increase and their associated costs has led companies to form committes and implement programs to address this problem. In our country, we have just started to recognize and to work on the problems in industry. This study conducted an ergonomic analysis for typical jobs of ship building industry which was not usually surveyed for CTD problem. A baseline CTD checklist which was supposed to do a risk assessment was developed and applied in this study. Initially, we considered five major parts in the checklist which consisted of personal, frequency, posture, force, and miscellaneous information. Most jobs in ship building industry were much different from typical assembly work and VDT work that have been major part of the previous CTD studies. Specifically, job characteristics in terms of frequency and posture were quite different. There were relatively long cycle time, awkward postures for whole body (not just for upper extremities). Also, CTD risk scores based on checklist were a lot higher than the scores for VDT jobs which was a case of preceding application of the checklist. Specifically, grinding jobs turned out to be the most risky one in terms of CTDs. In conclusion, usual CTD prevention guidelines are not likely to he effective in this type of industry. An individual job based interventions are strongly suggested to have a good control of CTD problems in ship building industry.

The purpose of this study is to investigate the relationship between the work postures and upper extremity cumulative trauma disorders(CTDs) in female medical insurance bill reviewers(n=448). This study included diagnosis for CTDs, anthropometry and job analysis (workstations and posture). The characteristics of subject were 33.6 years of average age and 8.7 years of average work duration. The results were as fallows. Ergonomic conditions of workstation were unsuitable compared with anthropometry result. The height of work surface(79.5 cm) and chair(43.0 cm)were high. work space was small, and legs space under the table was limited. Work postures were awkward compared with recommended neutral postures. Neck flexion($21.0-36.0^{\circ}$), elbow elevation, shoulder abduction ($46.0-47.0^{\circ}$). wrist radial and ulnar deviation, forearm supination and pronation, and wrist repeated motion(12.7-21.5 freq./min) were analyzed as hazardous risk factors by job analysis. The prevalence of CTDs was 32.8 % by medical diagnosis. The prevalence rate of CTDs in hazardous work posture group was significantly greater than safe work posture group both neck-shoulder (relative prevalence = 5.2, p<0.001) and wrist-hand (relative prevalence = 2.5, p<0.05).

This study was conducted to estimate crystalline silica contents in airborne respirable dust from various manufacturing industries and to compare analytical performance of two methods of quantifying crystalline silica, X-ray diffraction(XRD) and Fourie transform infrared spectroscopy (FTIR). For this study, various manufacturing industries with a history of having pneumoconiosis cases and also known to generate dusts containing crystalline silica were investigated. These industries include: foundry, brick, potteries, concrete, and abrasive material, etc. Both personal and area respirable dust samples were collected using 10 mm, Dorr-Oliver nylon cyclone equipped with 37mm, $5{\mu}m$ pore size, polyvinylchloride (PVC) filters as collection media. In addition, total dust samples were collected side-by-side to the respirable samples. All samples were weighed before and after sampling and were pretreated according to the NIOSH sampling and analytical methods 0500, 7500, and 7602 for dust collection and quartz analysis. In addition, bulk samples were collected and analyzed by X-ray fluorescence (XRF) for minerals. In this article, only the results obtained from foundry are reported. The results from various other industries will be published in future articles. The respirable dust concentrations from personal samples by cyclone were $0.46-1.06mg/m^3$ and those from area samples were $0.34-0.73mg/m^3$. Dust concentrations of personal samples were significantly higher than those of area samples. The highest dust concentration was obtained from the personal samples of the finishing operation. Total dust concentration ranged $1.24-3.40mg/m^3$. The mean quartz contents estimated by FTIR and XRD in the personal respirable dust samples were 5.12% and 4.41%, respectively, without significant difference between them. For quartz analyses, the two techniques were highly correlated with $r^2$ ranged 0.803-0.920. But the results by FTIR were mostly higher than those by XRD. In addition, cristobalite was not detected by FTIR. Significant correlations between contents of crystalline silica and such minerals as $Al_2O_3$, CaO, $TiO_2$, and $K_2O$ suggest possible interferences from these minerals.

The objectives of this study were both to evaluate the level and correlations of hazardous agents and to suggest measures to control industrial hygiene problems caused by using water-soluble metalworking f1uids(MWF). Geometric mean of formaldehyde(0.039 ppm) was higher than criteria of NIOSH(0.016ppm). Formaldehyde, originally existed in the biocide, is released and used to kill microbes in soluble MWF. Microbe concentrations were above $10^4No./mL$ in 14 MWF tanks among 20 tanks surveyed. Nitrosamines that is formed by reaction of nitrosating group and amines was detected to $18.4-47.1{\mu}g/m^3$. Formaldehyde concentration was low when microbes were abundant(r=-0.67, p=0.011), and high when open tank area was wide(r=0.75. p=0.012). The significant relationship between pH and microbes(r=-0.76. p=0.003) was also observed. The predominant bacteria species in MWF were Pseudomonas spp., Bacillus spp., Comamonas testosteroni, Acinetobacter haemolyticus, Bordertella bronchiseptica in order. Therefore, hazardous agents emitted by using water-soluble MWF seems to be correlated microbial growth. In order to minimize worker's exposure to several hazardous agents by an water-soluble MWF and to increase productivity, microbial growth must be controlled to the lowest level as possible. Administrative control as well as engineering control must comprehensively be applied to control microbe's growth in water-soluble MWF.

The concentration of welding fume was measured by 221 welders themselves in chassis frame workplace of the manufactory from February, 1, 1996 to May, 31, 1997. Welding parameters were the welding current and the distance between helmet and arc. Those two optimum conditions were proposed by excess probability analysis using logistic regression, so the best position in the workplace was proposed considering two factors to control the welding fume. The results are as followings; 1) The excess proability of welding fume TLV was over 99% in above 260 Amperes of welding current and also in below 30cm of distanced between helmet and arc. 2) The equation from logistic regression analysis using SPSS/PC+5.02 had the welding current as a independent variable and the excess of welding fume TLV as a dependent variable (p<0.05). Logit(welding fume TLV) = 0.1296 ${\times}$ wlding currnet - 28.8750 3) The equation from logistic regression analysis using SPSS/PC+5.02 had the distance between helmet and arc as a independent variable and the excess of welding fume threshold limit value a, a dependent variable (p<0.05). Logit (welding fume TLV) = -0.6809 ${\times}$ distance between helmet and arc +25.1665 4) Considering both cases or 2) and 3). the result equation is following. (p<0.05). Logit (welding fume TLV) = 0.1346 ${\times}$ welding current -0.3859 ${\times}$ distance between helmet and arc -15.7382 5) The excess probability of welding fume threshold limit value was 100% in above 240 Ampere of welding current. Thus, below 220 Ampere can be suggested to reduce the 40% number of welders who have a excess welding fume threshold limit value. 6) The excess probability of welding fume TLV was 100% in below 34cm of distance between helmet and arc. Thus, over 38cm can be suggested to reduce the 33% number of welders who have a excess welding fume TLV. 7) Considering both 5) and 6) cases, first of all, the best welding current can be 200 Ampere to have a below 15% of welding fume excess probability for the welders who works in distance of 34-37cm. Secondly, to have a below 30% excess probability of welding fume TLV, the working distance must be over 38cm in 220 Ampere and 32cm in 200 Ampere. 8) To reduce the average exposure concentration of welding fume ($8.21{\pm}5.83mg/m^3$), the movable local exhaust system equipped with flexible hoods can be used.

Korea has been rapidly industrialized during the past 35 years. During this period, Korea has emphasized only production and workers health has been ignored. Workers are most frequently exposed to organic vapors, such as thinners. This study was performed to evaluate worker exposures to organic solvents by size and type of industry. Results are summarized below. Workers were exposed to mixtures of toluene, xylenes, trichloroethylene, n-hexane, acetone, methanol, n-butanol, n-butyl acetate, and MIBK. Considering additive effects of the compounds, exposure indices (EIs) were calculated. It was found that worker exposures to organic solvents were highest in small industries and lowest in large industries. During a day shift, the highest exposure was indicated 3 - 5 p.m. in the afternoon. Workers in small industries had potential exposures exceeding permissible exposure limits for organic solvents. Local exhuast systems were inappropriate and respiratory protective devices were not supplied to the workers in small industries. Neither program for safe use and storage of toxic materials nor program for respirators was found in any of the plants investigated. Based on the results of the study, workers of small scale industries should be considered first in industrial health.

This Study was conducted at nine Histological Laboratories in the hospitals located in Seoul from August 20 to October 10, 1996. The main purpose of this study was to assess the TWA & STEL exposure to formaldehyde and to evaluate factors affecting formaldehyde concentration in Histological Laboratory. With evaluated factors, proper improvement strategy to minimize exposure was suggested. The results are summarized as follows ; 1. The TWA concentrations of the personal samples ranged from 0.02 to 3.86 ppm and that of one laboratory out of nine was exceeding 0.75 ppm, USA OSHA standard. The TWA concentrations of the area samples ranged from 0.08 ppm to 1.49 ppm and those of three laboratories out of nine were exceeding OSHA standard. 2. When measurement was conducted on the working tables. around Formaldehyde vessel, fixation container and storage cabinet, the geometric means of TWA concentrations were 0.62 ppm, 0.64 ppm. 0.58 ppm and 0.37 ppm respectively. 3. When overnight fixed specimens were examined, the STEL concentrations of personal samples ranged from 0.59 ppm to 5.01 ppm, those of three laboratories out of nine were exceeding 2 ppm, OSHA standard and the STEL concentrations of area samples ranged from 0.31 ppm to 3.08 ppm, those of four laboratories from nine were exceeding OSHA standard. 4. Factors affecting Formaldehyde exposure level were sanitation state of laboratory, volume of the room and opening state of fixation container & formaldehyde vessel(p<0.05).

In this study, 108 thinners were analyzed to identify their composition. The purposes of this study were to provide the data for MSDS and worker exposure levels. Thinners were collected from manufacturing industries, distributors and users. Wide ranges of thinner components were found ; Toluene, xylene, and ethyl benzene were most often found. Next, MIBK, cellosolve acetate, butyl cellosolve, and butyl acetate were found in 20-40 thinners. Others, such as acetone, n-hexane, cyclohexane, heptane, methylcyciohexane, octane and nonane were also found. There were about 5-6 components in each thinner. In the view point of Industrial Hygiene, Benzene was the most important component of thinners, which procures leukemia. Benzene was found from 8 kinds of thinners out of the total 108 surveyed. Thus, Content of benzene in thinners must be evaluated when industrial hygiene surveys are performed. Aromatic hydrocarbons were identified from 71 kinds of thinners out of total 108 and their contents were 10-87%. Alkanes were not contained in automobile painting, spraying, degreasing, urethane and epoxy thinners but lacquer, enamel and coating thinners.

Vinyl chloride monomer exists as gas phase at normal temperature and reacts with oxygen and strong oxidant in the air to form oxidized materials. Because of being easily synthesized, it is used as a main source at the synthetic reaction process of PVC synthesis factories. Ministry of Labor regulates its usage as a carcinogen and its exposure level as 1 ppm. But the amount of VCM production in PVC and VCM production process hasn't been exactly estimated. In addition, facilities of this factory are located in outdoor. Therefore, this study was designed to investigate effects of temperature on breakthrough of charcoal tube at a fixed concentration and temperature during VCM sampling based on NIOSH and OSHA methods which were used as methods of occupational environment measuring and analysis. During the sampling of VCM, methods of OSHA and NIOSH require flow rate of 0.05 lpm and sampling volume of $3{\ell}$, $5{\ell}$ respectively, at this time carbon molecular sieve tube and coconut shell charcoal tube are used to observe the breakthrough along with concentration and temperature. As a result, significant difference between average adsorbed amounts of OSHA methods but that of NIOSH methods cannot be found. NIOSH method is likely to be effected by high temperature and normal temperature in high concentration. Breakthrough is not found in the method of OSHA at different conditions of temperature and concentration. As the result of this study we could verify that breakthrough occurred in the process of sampling VCM with NIOSH methods. Therefor in summer time, breakthrough should be considered and research on the breakthrough volume should be done. It is considered the research about the specificity of the coconut shell charcoal and carbon molecular sieve sorbent should be done when sampling VCM in comming days.

The Korean-made passive samplers were evaluated at the working environment for field testing. Tested materials were n-hexane, toluene and trichloroethylene. The performance of passive samplers depended on types and concentrations of organic vapors. Sampling rates were not steady until certain concentrations. The optimum concentration for determination of airborne toluene by passive samplers was equal to or over 10 ppm which is 1/10 of the Korean occupational exposure limit. Optimum concentration of n-hexane was equal to and over 1 ppm which is 1/50 of Korean occupational exposure limit. But for trichloroehtylene, coefficient of variation was 53.5 %. Passive samplers may be used for determination of n-hexane. For other materials, further study on the performance of Korean-made passive samplers is required.

The purposes of this study were to assess current status of respirator usage among workers in the small-scale industries and to identify those factors causing respirator wearers not to continuously wear respirators during work. Total 168 workers participated voluntarily in the survey. In order to cover all possible reasons, though not exclusive, 33 diverse questions were developed based upon the results in the published literatures and from researchers' own experience. The most common type of respirator worn was the disposable single-use respirator(42%). However, masks made of gauze, which should not be considered as a respirator, were widely used (38%). Only 28% of respondents indicated they wear respirators continuously during work. The major reasons for removing respirators include, in descending order of frequency, difficulty in breathing (46%), sweating (39%), bothered by frequent removal (21%), inadequate mask size (19%) and hot air temperature inside the respirator (19%), etc. In addition, minor reasons including mask design, administrative, and personal reasons were also identified. These reasons should be considered in a well designed respirator program in order to improve workers' acceptance and usage of respirators.

This study was designed to investigate the workers' exposure level to electromagnetic field(EMF) in accordance with the VDT arrangement in the work place and distance from VDT. Author compared the exposure strength of EMF in line group(workers exposed to EMF from both front and back side) and in shielding group(workers exposed to EMF exclusively from front side). The levels of EMF at 30cm and 50cm from front side and at 30cm from back side of VDT were also measured. The result were as follows: 1. Mean distance between a monitor and a worker in shielding group ($47.7{\pm}8.7cm$) significantly longer than that in line group($44.3{\pm}7.2cm$). Strength of EMF in shielding group [$1.3{\pm}0.7V/m$ (electric field) and $18.2{\pm}11.5mA/m$ (magnetic field) were lower than in line group [$1.4{\pm}0.6V/m$ and $26.6{\pm}11.6mA/m$, respectively] at the workers' position. 2. The strength of EMF was decreased with the distance from VDT. The strength at 70cm from VDT was nearly the same as the background strength in the ordinary office rooms. 3. Working distance from 9 inch monitor was significantly shorter than that from 14 inch and wider sized monitors. 4. The strength of EMF in extremely low frequency spectrum of color monitors was higher then that of black and white monitor. 5. Metal coated filters significantly decreased the electric field strength of EMF when earth line was connected. Metallic shield was effectively decreased the EMF strength from VDT, but wooden shield was not. From the above results, line type arrangement of VDT in the work place using metallic shield at the back side of VDT, and metal coated filter to monitor with application of earth line were recommended. It is also recommended to maintain workers position to be 60cm or more distance from monitor and 140cm or more between VDTs for minimizing workers' exposure to EMF.

This study reviewed on the occupational health status of female workers in China, where the half of female population are workers in occupational settings and realizes the importance of occupational health among them, to establish the occupational health management system in Korea as Korean female workers have been increasing for the last few decades. Results of the study were as follows. 1. The proportion of female workers in total workers have increased from 7.5% in 1949 up to 37.6% in 1990. As for the distribution of female workers by industry, manufacturing part has the highest proportion of female workers in total and out of total female workers, the rank was health social welfare (53.2%), community personal service(45.4%) and agriculture forestry fishing(44.1%). 2. The system of occupational health management for female workers was related to superior organization well by administrative district & work place and professionals were distributed to one per ten thousand persons or more, depending on each region's conditions. 3. The regulations of occupational health management for female workers are defined in a variety of fields. Considering the physiological characteristics of female workers, government has tried to minimize the loss due to menstruation, pregnancy, delivery and lactation and has let them have vacations, guaranteeing the health facilities at the same time. Also government has defined the scope of prohibited work to protect legal right of them.