Objectives: The purpose of this study is to evaluate exposure characteristics of lead using data from the domestic occupational exposure literature. Methods: Occupational airborne exposure data on lead reported in the domestic literature from 1981 to 2018 were collected and re-analyzed. The exposure levels in the data were expressed as an estimated arithmetic mean and a weighted arithmetic mean (WAM) of the number of samples. Lead exposure characteristics were analyzed by industry, process, and year. Results: From a total of 14 documents, 8,305 airborne lead measurements for 17 industries were identified, and the WAM concentration in eight industries exceeded the occupational exposure limit of 50 ㎍/m³. Three industries (battery manufacturing, lead smelting, and litharge manufacturing) accounted for 95% of the total data, and exposure trends could be confirmed over 10 years. Exposure levels continue to decrease in all three industries. Conclusions: Considering the distribution outlook of lead and lead compounds, the main management targets are lead storage battery manufacturing and secondary smelting for lead regeneration.

Objectives: The aim of this study is to evaluate exposure levels of the extremely low frequency magnetic fields(ELF-MF) radiated from various electric facilities in Liquid Crystal Display(LCD) manufacturing processes. Methods: This study measured the exposure levels of personal and local ELF-MF for the electronic facilities installed in two LCD manufacturing companies. Samplers were installed around workers' waist during working hours to identify personal exposure levels, and direct reading equipment were located at 3 cm, 10 cm, and 30 cm away from the surface of the electronic facilities to measure local exposure levels. Average and maximum(ceiling) values were calculated for personal and local exposure levels. Results: Average and maximum of personal exposure levels for each worker were 0.56(mean) ± 0.02(SE) µT and 6.31 ± 0.75 µT, respectively. Statistical analyses of the study found that maximum of the personal exposure levels for engineers was significantly higher than that for operators since engineers spend more time near the electronic facilities for repairing. The range of maximum personal exposure levels was 0.50 ~ 43.50 µT and its highest level was equivalent to 4.35 % of ACGIH(American Conference of Governmental Industrial Hygienists) exposure limit value(1 mT). Maximum of local exposure levels was 8.18 ± 0.52 µT and the electronic facilities with higher exposure levels were roof rail and electric panel, which were not related to direct manufacturing. The range of maximum local exposure levels was 0.60 ~ 287.20 µT and its highest level was equivalent to 28.7 % of the ACGIH exposure limit value. Lastly, the local exposure levels significantly decreased as the measurement distance from the electronic facilities increased. Conclusions: Maximum of personal and local exposure levels did not exceed the exposure limit value of ACGIH. However, it is recommended to keep the workers as far as possible from the sources of ELF-MF.

Objectives: The purpose of this study is to suggest an optimal method by comparing the analysis methods of work environment measurement datasets including left-censored data where one or more measurements are below the limit of detection (LOD). Methods: A computer program was used to generate left-censored datasets for various combinations of censoring rate (1% to 90%) and sample size (30 to 300). For the analysis of the censored data, the simple substitution method (LOD/2), β-substitution method, maximum likelihood estimation (MLE) method, Bayesian method, and regression on order statistics (ROS)were all compared. Each method was used to estimate four parameters of the log-normal distribution: (1) geometric mean (GM), (2) geometric standard deviation (GSD), (3) 95th percentile (X95), and (4) arithmetic mean (AM) for the censored dataset. The performance of each method was evaluated using relative bias and relative root mean squared error (rMSE). Results: In the case of the largest sample size (n=300), when the censoring rate was less than 40%, the relative bias and rMSE were small for all five methods. When the censoring rate was large (70%, 90%), the simple substitution method was inappropriate because the relative bias was the largest, regardless of the sample size. When the sample size was small and the censoring rate was large, the Bayesian method, the β-substitution method, and the MLE method showed the smallest relative bias. Conclusions: The accuracy and precision of all methods tended to increase as the sample size was larger and the censoring rate was smaller. The simple substitution method was inappropriate when the censoring rate was high, and the β-substitution method, MLE method, and Bayesian method can be widely applied.

Objectives: The purpose of this study is to understand the impact on accident reduction by analyzing the policy effectiveness of an industrial accident prevention clean workplace support project targeting the construction industry. Methods: In this study, DID and PSM models were used to analyze workplaces receiving and not receiving financial support based on the status of industrial accidents in recent years and the status of the workplaces by year. Results: The research results show that meaningful effects continued to occur in terms of reducing accidents and increasing employment. Conclusions: In this study, we show the effectiveness of the clean workplace support project, one of the South Korean government's financial support projects in the field of occupational safety and health focusing on the construction industry. Financial support projects such as clean projects should be further expanded based on the results of this study.

Objectives: This study intends to review the impact on cleaning workers and suggest directions for improvement by reviewing the legal and institutional ways in which Article 86 Nos. 7 and 16 of the Enforcement Decree of the Occupational Safety and Health Act work on the maintenance and promotion of cleaning workers' health. Methods: The following laws and systems were reviewed and considered: First, the occupational safety and health legislation obligated or required to be applied to protect the health of cleaning workers; Second, the status of control of chemicals or mixtures used at cleaning sites through the Consumer Chemicals Product and Biocide Safety Control Act; Third, Control of consumer products according to foreign material safety data sheet related laws. Results: Legal and institutional measures necessary to protect the health of cleaning workers include the legal control of harmful substances to be controlled, work environment monitoring, and special health examinations. The application of the Consumer Chemicals Product and Biocide Safety Control Act does not satisfy the legal and practical level of health maintenance and promotion required by the Occupational Safety and Health Act, and the communication of chemical information is insufficient. Overseas, there are restrictions on the use of consumer products in the workplace without material safety data sheets. Conclusions: It is necessary to improve the system to ensure the health of workers handling consumer chemical products. The remaining laws and regulations exempted from the obligation to prepare material safety data sheets should be additionally reviewed.

Objectives: This study was designed to evaluate the filtration efficiency, inhalation resistance, and liquid resistance of commercial reusable masks in comparison to the performance of KF-AD masks (reference masks). Methods: Thirty-six masks were purchased from an online market. Filtration efficiency and inhalation resistance were determined in the same manner as in MFDS certification testing, respectively using TIL/IL & Filter Test 1300S (SFP Services, UK) and Breathing Resistance Analyzer DA2001 (Lambda Ray, South Korea). Results: Most of the filtration efficiencies found for the 19 masks were far lower than the test standard for KF-certified masks. Four masks met KF94 and three masks even met KF80. Most inhalation resistances were also much lower than the standard, with many almost one-half of the standard. In addition, all the masks except KF-AD masks did not pass the liquid resistance test. Conclusions: Although most of the filtration efficiency performance results found in this study for the reusable masks, which emerged as an alternative, were lower than the standard for health masks, multi-use masks can be used with a replacement filter inserted.

Objectives: The purpose of this study is to objectify the level of case management performance and the factors influencing performance, to improve the case management performance at the Korea Worker's Compensation & Welfare Service (KWCWS) on the basis of the recognition of the objective realities of case management by job coordinators at the KWCWS, to develop a model of case management fit for the KWCWS, and to provide a basis for establishing guidelines for standardized case management. Methods: A total of 156 questionnaires were distributed to job coordinators at the KWCWS's headquarters, six regional headquarters, and 55 branches. One hundred forty-one questionnaires were collected and 126 were analyzed statistically using SPSS 21.0. Factor analysis and reliability analysis were conducted to verify the validity and reliability of the main measurement items in the research model. Frequency analysis was conducted for general characteristics of survey subjects. Frequency analysis or descriptive statistics were conducted to identify the level of independent variables (case manager's individual variables, job variables, institutional and organizational variables). Dependent variables (case management performance) and the degree of correlation were analyzed through correlation analysis between research variables. Multiple regression analysis and hierarchical regression analysis were conducted to examine the effect of independent variables on case management performance. Results: The results of the study showed that the level of overall performance in the five stages of case management was ordinary, with an average level of 3.45 on a 5-point scale. Levels of performance by step were institutional approach and intake (3.69), assessment (3.63), goal setting and intervention planning (3.46), implementation of intervention plan (3.32), and evaluation and termination (3.20), in that order. The explanatory power of case management performance (overall) by case managers with the KWCWS was case manager's institutional and organizational variables, job variables, and individual variables, in that order. At each stage of case management, the explanatory power of a case manager's institutional and organizational variables was found to be the greatest. The model changes at each stage of case management assume similar aspects statistically. In hierarchical regression analysis, it was institutional support that had a significant effect on case management performance (overall), and institutional support had the greatest effect. The results of multiple regression analysis in which all variables are input simultaneously showed that institutional support and expertise as well as self-efficacy had a positive effect. However, case management work experience, expertise (technology), and autonomy were found to have a negative effect during the stage of case management performance. Conclusions: As a result of the study, it was confirmed that raising the case manager's expertise and support from the institution and organization are important factors to improve the level of case management performance. The research also derived practical ways of reinforcement of case manager capacity, institutional and organizational support, operation of rehabilitation-case management teams, and occupational health-related aspects.

Objectives: To develop the smart sensor to protect worker's health from chemical exposure by adopting ICT (Information and Communications Technology) technologies. Methods: To develope real-time chemical exposure monitoring system, IoT (Internet of Things) sensor technology and regulations were reviewed. We developed and produced smart sensor. A smart sensor is a system consisting of a sensor unit, a communication unit, and a platform. To verify the performance of smart sensors, each sensor has been certified by the Korea Laboratory Accreditation Scheme (KOLAS). Results: Chemicals (TVOC; Total Volatile Organic Compounds, Cl₂: Chlorine, HF: Hydrogen fluoride and HCN: Hydrogen cyanide) were selected according to a priority logic (KOSHA Alert, acute poisoning statistics, literature review). Notifications were set according to OEL (occupational exposure limit). Sensors were selected based on OEL and the capabilities of the sensors. Communication is designed to use LTE (Long Term Evolution) and Wi-Fi at the same time for convenience. Electronic platform were applied to build this monitoring system. Conclusions: Real-time monitoring system for OEL of hazardous chemicals in workplace was developed. Smart sensor can detect chemicals to complement monitoring of traditional workplace environmental monitoring such as short term and peak exposure. Further research is needed to expand the scope of application, improve reliability, and systematically application.