Workers' Exposure to Indium Compounds at the Electronics Industry in Republic of Korea

Objectives@#The aim of this study was to provide baseline data for the assessment of exposure to indium and to prevent adverse health effects among workers engaged in the electronics and related industries in Republic of Korea. @*Methods@#Total (n = 369) and respirable (n = 384) indium concentrations were monitored using personal air sampling in workers at the following 19 workplaces: six sputtering target manufacturing companies, four manufacturing companies of panel displays, two companies engaged in cleaning of sputtering components, two companies dedicated to the cleaning of sputtering target, and five indium recycling companies. @*Results@#The level of exposure to total indium ranged from 0.9 to 609.3 μg/m3 for the sputtering target companies; from 0.2 to 2,782.0 μg/m3 for the panel display companies and from 0.5 to 2,089.9 μg/m3 for the indium recycling companies. The level of exposure to respirable indium was in the range of 0.02 to 448.6 μg/m3 for the sputtering target companies; 0.01 to 419.5 μg/m3 for the panel display companies; and 0.5 to 436.3 μg/m3 for the indium recycling companies. The indium recycling companies had the most samples exceeding the exposure standard for indium, followed by sputtering target companies and panel display companies. @*Conclusions@#The main finding from this exposure assessment is that many workers who handle indium compounds in the electronics industry are exposed to indium levels that exceed the exposure standards for indium. Hence, it is necessary to continuously monitor the indium exposure of this workforce and take measures to reduce its exposure levels.

Workers' Exposure to Indium Compounds at the Electronics Industry in Republic of Korea

Objectives@#The aim of this study was to provide baseline data for the assessment of exposure to indium and to prevent adverse health effects among workers engaged in the electronics and related industries in Republic of Korea. @*Methods@#Total (n = 369) and respirable (n = 384) indium concentrations were monitored using personal air sampling in workers at the following 19 workplaces: six sputtering target manufacturing companies, four manufacturing companies of panel displays, two companies engaged in cleaning of sputtering components, two companies dedicated to the cleaning of sputtering target, and five indium recycling companies. @*Results@#The level of exposure to total indium ranged from 0.9 to 609.3 μg/m3 for the sputtering target companies; from 0.2 to 2,782.0 μg/m3 for the panel display companies and from 0.5 to 2,089.9 μg/m3 for the indium recycling companies. The level of exposure to respirable indium was in the range of 0.02 to 448.6 μg/m3 for the sputtering target companies; 0.01 to 419.5 μg/m3 for the panel display companies; and 0.5 to 436.3 μg/m3 for the indium recycling companies. The indium recycling companies had the most samples exceeding the exposure standard for indium, followed by sputtering target companies and panel display companies. @*Conclusions@#The main finding from this exposure assessment is that many workers who handle indium compounds in the electronics industry are exposed to indium levels that exceed the exposure standards for indium. Hence, it is necessary to continuously monitor the indium exposure of this workforce and take measures to reduce its exposure levels.

Comparison of Real Time Nanoparticle Monitoring Instruments in the Workplaces

BACKGROUND: Relationships among portable scanning mobility particle sizer (P-SMPS), condensation particle counter (CPC), and surface area monitor (SAM), which are different metric measurement devices, were investigated, and two widely used research grade (RG)-SMPSs were compared to harmonize the measurement protocols. METHODS: Pearson correlation analysis was performed to compare the relation between P-SMPS, CPC, and SAM and two common RG-SMPS. RESULTS: For laboratory and engineered nanoparticle (ENP) workplaces, correlation among devices showed good relationships. Correlation among devices was fair in unintended nanoparticle (UNP)-emitting workplaces. This is partly explained by the fact that shape of particles was not spherical, although calibration of sampling instruments was performed using spherical particles and the concentration was very high at the UNP workplaces to allow them to aggregate more easily. Chain-like particles were found by scanning electron microscope in UNP workplaces. The CPC or SAM could be used as an alternative instrument instead of SMPS at the ENP-handling workplaces. At the UNP workplaces, where concentration is high, real-time instruments should be used with caution. There are significant differences between the two SMPSs tested. TSI SMPS showed about 20% higher concentration than the Grimm SMPS in all workplaces. CONCLUSIONS: For nanoparticle measurement, CPC and SAM might be useful to find source of emission at laboratory and ENP workplaces instead of P-SMPS in the first stage. An SMPS is required to measure with high accuracy. Caution is necessary when comparing data from different nanoparticle measurement devices and RG-SMPSs.

A Case of Tracheal Adenoid Cystic Carcinoma in a Worker Exposed to Rubber Fumes

BACKGROUND: Primary tracheal tumors occur infrequently, accounting for less than 0.1% of all tumors. Adenoid cystic carcinoma (ACC) is the second most common type of malignancy of the trachea after squamous cell carcinoma (SCC). Little has been reported on the risk factors for tracheal ACC. The purpose of this study is to describe a case of tracheal ACC in a patient who had been exposed to rubber fumes, and to review the relationship between tracheal ACC and rubber fumes. CASE REPORT: A 48-year-old man who had been experiencing aggravation of dyspnea for several months was diagnosed as having ACC of the trachea on the basis of a pathologic examination of a biopsy specimen obtained via laser microscopy-guided resection. The patient had been exposed to rubber fumes for 10 years at a tire manufacturing factory where he worked until ACC was diagnosed. His job involved preheating and changing rubber molds during the curing process. CONCLUSION: ACC of both the trachea and the salivary glands show very similar patterns with regard to histopathology and epidemiology and are therefore assumed to have a common etiology. Rubber manufacturing is an occupational risk factor for the development of salivary gland tumors. Further, rubber fumes have been reported to be mutagenic. The exposure level to rubber fumes during the curing process at the patient's workplace was estimated to be close to or higher than British Occupational Exposure Limits. Therefore, tracheal ACC in this case might have been influenced by occupational exposure to rubber fumes.

Work Environments and Exposure to Hazardous Substances in Korean Tire Manufacturing

OBJECTIVES: The purpose of this study is to evaluate the tire manufacturing work environments extensively and to identify workers' exposure to hazardous substances in various work processes. METHODS: Personal air sampling was conducted to measure polycyclic aromatic hydrocarbons, carbon disulfide, 1,3-butadiene, styrene, methyl isobutyl ketone, methylcyclohexane, formaldehyde, sulfur dioxide, and rubber fume in tire manufacturing plants using the National Institute for Occupational Safety Health Manual of Analytical Methods. Noise, carbon monoxide, and heat stress exposure were evaluated using direct reading instruments. Past concentrations of rubber fume were assessed using regression analysis of total particulate data from 2003 to 2007, after identifying the correlation between the concentration of total particulate and rubber fume. RESULTS: Workers were exposed to rubber fume that exceeded 0.6 mg/m3, the maximum exposure limit of the UK, in curing and production management processes. Forty-seven percent of workers were exposed to noise levels exceeding 85 dBA. Workers in the production management process were exposed to 28.1degrees C (wet bulb globe temperature value, WBGT value) even when the outdoor atmosphere was 2.7degrees C (WBGT value). Exposures to other substances were below the limit of detection or under a tenth of the threshold limit values given by the American Conference of Governmental Industrial Hygienists. CONCLUSION: To better classify exposure groups and to improve work environments, examining closely at rubber fume components and temperature as risk indicators in tire manufacturing is recommended.

Outbreak of Sudden Cardiac Deaths in a Tire Manufacturing Facility: Can It Be Caused by Nanoparticles?

OBJECTIVES: The purpose of this study was to review clinical characteristics and working environments of sudden cardiac death (SCD) cases associated with a tire manufacturer in Korea, and review possible occupational risk factors for cardiovascular disease including nanoparticles (ultrafine particles, UFPs). METHODS: We reviewed (i) the clinical course of SCD cases and (ii) occupational and non-occupational risk factors including chemicals, the physical work environment, and job characteristics. RESULTS: Possible occupational factors were chemicals, UFPs of rubber fume, a hot environment, shift work, overworking, and noise exposure. The mean diameter of rubber fume (63-73 nm) was (larger than diesel exhaust [12 nm] and outdoor dust [50 nm]). The concentration of carbon disulfide, carbon monoxide and styrene were lower than the limit of detection. Five SCD cases were exposed to shift work and overworking. Most of the cases had several non-occupational factors such as hypertension, overweight and smoking. CONCLUSION: The diameter of rubber fume was larger than outdoor and the diesel exhaust, the most well known particulate having a causal relationship with cardiovascular disease. The possibility of a causal relation between UFPs of rubber fume and SCD was not supported in this study. However, it is necessary to continue studying the relationship between large sized UFPs and SCD.

Characteristics of Occupational Exposure to Benzene during Turnaround in the Petrochemical Industries

OBJECTIVES: The level of benzene exposure in the petrochemical industry during regular operation has been well established, but not in turnaround (TA), where high exposure may occur. In this study, the characteristics of occupational exposure to benzene during TA in the petrochemical companies were investigated in order to determine the best management strategies and improve the working environment. This was accomplished by evaluating the exposure level for the workers working in environments where benzene was being produced or used as an ingredient during the unit process. METHODS: From 2003 to 2008, a total of 705 workers in three petrochemical companies in Korea were studied. Long- and short-term (< 1 hr) samples were taken during TAs. TA was classified into three stages: shut-down, maintenance and start-up. All works were classified into 12 occupation categories. RESULTS: The long-term geometric mean (GM) benzene exposure level was 0.025 (5.82) ppm (0.005-42.120 ppm) and the short-term exposure concentration during TA was 0.020 (17.42) ppm (0.005-61.855 ppm). The proportions of TA samples exceeding the time-weighted average, occupational exposure level (TWA-OEL in Korea, 1 ppm) and the short-term exposure limit (STEL-OEL, 5 ppm) were 4.1% (20 samples of 488) and 6.0% (13 samples of 217), respectively. The results for the benzene exposure levels and the rates of exceeding the OEL were both statistically significant (p < 0.05). Among the 12 job categories of petrochemical workers, mechanical engineers, plumbers, welders, fieldman and scaffolding workers exhibited long-term samples that exceeded the OEL of benzene, and the rate of exceeding the OEL was statistically significant for the first two occupations (p < 0.05). CONCLUSION: These findings suggest that the periodic work environment must be assessed during non-routine works such as TA.

Characteristics of Occupational Exposure to Benzene during Turnaround in the Petrochemical Industries

OBJECTIVES: The level of benzene exposure in the petrochemical industry during regular operation has been well established, but not in turnaround (TA), where high exposure may occur. In this study, the characteristics of occupational exposure to benzene during TA in the petrochemical companies were investigated in order to determine the best management strategies and improve the working environment. This was accomplished by evaluating the exposure level for the workers working in environments where benzene was being produced or used as an ingredient during the unit process. METHODS: From 2003 to 2008, a total of 705 workers in three petrochemical companies in Korea were studied. Long- and short-term (< 1 hr) samples were taken during TAs. TA was classified into three stages: shut-down, maintenance and start-up. All works were classified into 12 occupation categories. RESULTS: The long-term geometric mean (GM) benzene exposure level was 0.025 (5.82) ppm (0.005-42.120 ppm) and the short-term exposure concentration during TA was 0.020 (17.42) ppm (0.005-61.855 ppm). The proportions of TA samples exceeding the time-weighted average, occupational exposure level (TWA-OEL in Korea, 1 ppm) and the short-term exposure limit (STEL-OEL, 5 ppm) were 4.1% (20 samples of 488) and 6.0% (13 samples of 217), respectively. The results for the benzene exposure levels and the rates of exceeding the OEL were both statistically significant (p < 0.05). Among the 12 job categories of petrochemical workers, mechanical engineers, plumbers, welders, fieldman and scaffolding workers exhibited long-term samples that exceeded the OEL of benzene, and the rate of exceeding the OEL was statistically significant for the first two occupations (p < 0.05). CONCLUSION: These findings suggest that the periodic work environment must be assessed during non-routine works such as TA.