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.

Satisfaction Survey of Patients Toward Electroconvulsive Therapy / 신경정신의학

Objectives@#This study examined the satisfaction of patients who had undergone electroconvulsive therapy to provide important information for improving the social misunderstanding about electroconvulsive therapy, to increase the effectiveness of treatment, and make a decision of effective treatment. @*Methods@#A questionnaire survey was conducted to determine the satisfaction, adverse effects, attitudes, and experiences toward electroconvulsive therapy in patients at 2 to 4 weeks after finishing an acute course of electroconvulsive therapy in three psychiatric hospitals. @*Results@#There were 85 respondents (38 males), whose average age was 42.0±13.6 years and average illness duration was 12.8±8.9 years. Fifty-two patients (61.2%), 19 (22.4%), 8 (9.4%), and 6 (7.1%) were diagnosed with schizophrenia, major depressive disorder, bipolar disorder, and other mental disorders, respectively. The average session number for acute electroconvulsive therapy was 12.6±6.0 sessions, and 61 patients (71.8%) had received maintenance electroconvulsive therapy. Among the respondents, 60.0% reported that they were satisfied with the electroconvulsive therapy. Satisfaction was similar according to sex, age, diagnosis, electrode placement, and use of anesthetic agents. Forty-three (53.8%) patients experienced memory impairment during acute electroconvulsive therapy. @*Conclusion@#This study showed that patients who received electroconvulsive therapy were generally satisfied with the treatment and that memory impairment should be detected early and managed promptly. Follow-up studies with a large number of subjects and variables will be needed to determine the predictive factors affecting satisfaction toward electroconvulsive therapy.

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.

Satisfaction Survey of Patients Toward Electroconvulsive Therapy / 신경정신의학

Objectives@#This study examined the satisfaction of patients who had undergone electroconvulsive therapy to provide important information for improving the social misunderstanding about electroconvulsive therapy, to increase the effectiveness of treatment, and make a decision of effective treatment. @*Methods@#A questionnaire survey was conducted to determine the satisfaction, adverse effects, attitudes, and experiences toward electroconvulsive therapy in patients at 2 to 4 weeks after finishing an acute course of electroconvulsive therapy in three psychiatric hospitals. @*Results@#There were 85 respondents (38 males), whose average age was 42.0±13.6 years and average illness duration was 12.8±8.9 years. Fifty-two patients (61.2%), 19 (22.4%), 8 (9.4%), and 6 (7.1%) were diagnosed with schizophrenia, major depressive disorder, bipolar disorder, and other mental disorders, respectively. The average session number for acute electroconvulsive therapy was 12.6±6.0 sessions, and 61 patients (71.8%) had received maintenance electroconvulsive therapy. Among the respondents, 60.0% reported that they were satisfied with the electroconvulsive therapy. Satisfaction was similar according to sex, age, diagnosis, electrode placement, and use of anesthetic agents. Forty-three (53.8%) patients experienced memory impairment during acute electroconvulsive therapy. @*Conclusion@#This study showed that patients who received electroconvulsive therapy were generally satisfied with the treatment and that memory impairment should be detected early and managed promptly. Follow-up studies with a large number of subjects and variables will be needed to determine the predictive factors affecting satisfaction toward electroconvulsive therapy.

Electroconvulsive Therapy for Psychiatric Disorders in Elderly Adults

Electroconvulsive therapy (ECT) is indicated for various mental disorders (e.g., major depressive disorder, schizophrenia, and bipolar disorder) and the behavioral and psychological symptoms of dementia in elderly patients. Furthermore, ECT is a useful first-line treatment in emergency and crisis situations such as suicide risk, violent behavior, catatonia, and food refusal, which are more frequent in elderly patients. ECT is also effective in the treatment of the motor symptoms of neurological disorders, such as Parkinson’s disease and Huntington’s disease. Due to the high risk of various physical diseases, the comorbid physical conditions of elderly patients should be individually controlled to optimize ECT treatment. Compared to young adults, in elderly patients the seizure threshold is higher, the seizure duration is shorter, and the anesthetic dose is lower. On the contrary, the response rate in the elderly is both faster and higher. Considering potential cognitive decline and the prevention of further deterioration of cognitive function in elderly patients, in the absence of significant comorbidities, twice weekly sessions and right unilateral electrode placement with a lower seizure threshold and less cognitive effect are preferred to bilateral electrode placement, which has a high risk of adverse cognitive effects. After an acute course of ECT, continuation and maintenance of ECT, combined with prescription of therapeutic drugs, may prevent possible relapse or recurrence of mental disorders. In conclusion, ECT can be used to treat mental disorders in elderly adults, with safety and effectiveness comparable to that in young adults.

The Electroconvulsive Therapy in the Prevention of Suicide Risks and Attempts

Suicidality is the most serious complication of mood disorders and psychosis; effective treatment should reduce suicide rates. The Organization for Economic Cooperation and Development age-standardized suicide rate in Korea was 22.6 in 2018, much higher compared to other countries worldwide. As mental and psychiatric problems are the main reasons for suicide attempts, accounting for 31.6% in 2018, targeting such problems should be the focus of efforts to reduce suicide rates. However, the ability of current pharmacotherapeutic and psychotherapeutic interventions to reduce suicide rates is limited due to their delayed effects. Therefore, electroconvulsive therapy (ECT) has been proposed as an alternative treatment. This approach is effective for treating most mental disorders associated with high suicide rates, including severe depression, bipolar disorder, and intractable psychotic disorders; ECT is also effective for Parkinson’s disease, which has the highest suicide rate among all disorders in Korea. The acute, long-term, and prophylactic effects of ECT on suicidality have been reported in the literature, and treatment guidelines outside of Korea recommend that ECT be used at an early stage for rapid reduction of suicide rates, as opposed to being applied as a treatment of last resort. However, only ~0.092 of every 10000 members of the Korean general population received ECT in 2018; this is much lower than the average rate worldwide, of 2.2 per 10000. Elimination of obstacles to the use of ECT, early crisis intervention involving administration of ECT for rapid stabilization, and maintenance ECT to prevent recurrence should reduce suicide rates.

Electroconvulsive Therapy for Psychiatric Disorders in Elderly Adults

Electroconvulsive therapy (ECT) is indicated for various mental disorders (e.g., major depressive disorder, schizophrenia, and bipolar disorder) and the behavioral and psychological symptoms of dementia in elderly patients. Furthermore, ECT is a useful first-line treatment in emergency and crisis situations such as suicide risk, violent behavior, catatonia, and food refusal, which are more frequent in elderly patients. ECT is also effective in the treatment of the motor symptoms of neurological disorders, such as Parkinson’s disease and Huntington’s disease. Due to the high risk of various physical diseases, the comorbid physical conditions of elderly patients should be individually controlled to optimize ECT treatment. Compared to young adults, in elderly patients the seizure threshold is higher, the seizure duration is shorter, and the anesthetic dose is lower. On the contrary, the response rate in the elderly is both faster and higher. Considering potential cognitive decline and the prevention of further deterioration of cognitive function in elderly patients, in the absence of significant comorbidities, twice weekly sessions and right unilateral electrode placement with a lower seizure threshold and less cognitive effect are preferred to bilateral electrode placement, which has a high risk of adverse cognitive effects. After an acute course of ECT, continuation and maintenance of ECT, combined with prescription of therapeutic drugs, may prevent possible relapse or recurrence of mental disorders. In conclusion, ECT can be used to treat mental disorders in elderly adults, with safety and effectiveness comparable to that in young adults.

The Electroconvulsive Therapy in the Prevention of Suicide Risks and Attempts

Suicidality is the most serious complication of mood disorders and psychosis; effective treatment should reduce suicide rates. The Organization for Economic Cooperation and Development age-standardized suicide rate in Korea was 22.6 in 2018, much higher compared to other countries worldwide. As mental and psychiatric problems are the main reasons for suicide attempts, accounting for 31.6% in 2018, targeting such problems should be the focus of efforts to reduce suicide rates. However, the ability of current pharmacotherapeutic and psychotherapeutic interventions to reduce suicide rates is limited due to their delayed effects. Therefore, electroconvulsive therapy (ECT) has been proposed as an alternative treatment. This approach is effective for treating most mental disorders associated with high suicide rates, including severe depression, bipolar disorder, and intractable psychotic disorders; ECT is also effective for Parkinson’s disease, which has the highest suicide rate among all disorders in Korea. The acute, long-term, and prophylactic effects of ECT on suicidality have been reported in the literature, and treatment guidelines outside of Korea recommend that ECT be used at an early stage for rapid reduction of suicide rates, as opposed to being applied as a treatment of last resort. However, only ~0.092 of every 10000 members of the Korean general population received ECT in 2018; this is much lower than the average rate worldwide, of 2.2 per 10000. Elimination of obstacles to the use of ECT, early crisis intervention involving administration of ECT for rapid stabilization, and maintenance ECT to prevent recurrence should reduce suicide rates.

The effect of shift work on high sensitivity C-reactive protein level among female workers

BACKGROUND: This study assessed the association between shift work and high-sensitivity C-reactive protein (hs-CRP) level, a risk factor for cardiovascular disease (CVD), in female workers in electronics manufacturing services (EMS). METHODS: Female EMS workers who received special medical examinations for workers in Gyeongnam, Korea between January 2017 and December 2017 were enrolled in this study. Their age, marital status, education level, alcohol consumption, smoking habit, regular exercise, quality of sleep, work stress, and depression were investigated, and blood tests were conducted. The t- and χ2 tests were conducted to compare the general and biochemical characteristics between daytime and shift worker groups. Age-adjusted partial correlation analysis was performed to examine the linear relationship between hs-CRP level and other risk factors for CVDs. In addition, the difference in hs-CRP levels according to work schedule was analyzed by ANCOVA after adjusting for variables that could affect the hs-CRP level. RESULTS: Although the average hs-CRP levels did not differ significantly between daytime and shift workers (0.92 ± 1.87 and 1.07 ± 2.20 mg/dL, respectively), shift workers tended to show a higher hs-CRP level (p = 0.067). After adjusting for variables that can affect the hs-CRP level, the estimated average hs-CRP level was significantly higher in shift workers (1.325 ± 0.156 mg/dL) than that in daytime workers (0.652 ± 0.350 mg/dL) (p = 0.003). CONCLUSIONS: The results of this study identified a relationship between shift work and hs-CRP level increase in women. Because multiple studies have reported associations between increased hs-CRP and CVD, follow-up of hs-CRP may help early detection of CVD in shift workers.

Types and Health Hazards of Fibrous Materials Used as Asbestos Substitutes

Asbestos has been banned in many countries but many countries, including developing countries, are still using asbestos or materials containing asbestos. Substitute materials have been studied and developed over a long period of time because of the hazards of asbestos, and many people have recently shown interest in the hazards of substitute materials. However, comprehensive information about the types of asbestos substitutes, their use and health hazards, and references for the protection for the health of workers is limited. The purpose of this study is to provide people in the related industries with information on the types and health hazards of fibrous materials that can be used as asbestos substitutes. According to the patent resources from the United States and Europe, fibrous materials have been used to develop asbestos-free products since before 1980. Recently, the health hazards of asbestos substitutes have been assessed and many additional researches are required. However, only some of the substitute materials have been assessed for health hazards, and health hazard data has not been sufficient in many cases. Therefore, efforts should be made to minimize workers’ exposure to substitute materials that do not contain asbestos.

A Case of Recurrent Urticaria Due to Formaldehyde Release from Root-Canal Disinfectant

Although formaldehyde is well known to cause type 4 hypersensitivity, immunoglobulin E (IgE)-mediated hypersensitivity to formaldehyde is rare. Here, we report a case of recurrent generalized urticaria after endodontic treatment using a para-formaldehyde (PFA)-containing root canal sealant and present a review of previous studies describing cases of immediate hypersensitivity reactions to formaldehyde. A 50-year-old man visited our allergy clinic for recurrent generalized urticaria several hours after endodontic treatment. Prick tests to latex, lidocaine, and formaldehyde showed negative reactions. However, swelling and redness at the prick site continued for several days. The level of formaldehyde-specific IgE was high (class 4). Thus, the patient was deemed to have experienced an IgE-mediated hypersensitivity reaction caused by the PFA used in the root canal disinfectant. Accordingly, we suggest that physicians should pay attention to type I hypersensitivity reactions to root canal disinfectants, even if the symptoms occur several hours after exposure.

Failure of Conservative Treatment in Two Cases of Polyarteritis Nodosa with Superior Mesenteric Artery Involvement Presenting with Abdominal Pain

Polyarteritis nodosa (PAN) is a systemic necrotizing vasculitis affecting medium- or small-sized arteries. Its diagnosis may be delayed because it is a rare disease, and patients presenting with PAN demonstrate variable clinical manifestations and non-specific laboratory abnormalities. Gastrointestinal involvement occurs in 14~65% of patients with PAN and is a significant cause of morbidity and mortality. Thus, early diagnosis is very important in PAN with gastrointestinal involvement. We report two cases of rapidly progressive PAN presenting with abdominal pain, having failed conservative treatment.

Giant Brunner’s Gland Hamartoma of the Duodenal Bulb Presenting with Upper Gastrointestinal Bleeding and Obstruction

Brunner’s gland hamartomas are small benign lesions that are most commonly found in the bulb of the duodenum. They are very uncommon, and most are found incidentally during upper gastrointestinal series or esophagogastroduodenoscopy. The lesions tend to be asymptomatic, but patients may present with symptoms of duodenal obstruction or hemorrhage secondary to ulceration. Histologically, a Brunner's gland hamartoma consists of the components of Brunner's gland cells, as well as glandular, adipose and muscle cells. In this study, we report the case of a 30-year-old man who presented with upper gastrointestinal bleeding and obstructive symptoms due to a giant Brunner's gland hamartoma in the duodenal bulb. The hamartoma was successfully removed by endoscopic resection. No significant complications were observed. Microscopically, the lesion was found to be entirely composed of variable Brunner's glands and adipocytes.

The Relationship between Coronary Risk Factors and Coronary Calcium Score Detected by Computed Tomography Coronary Angiography in Korean Middle Aged Men / 農村醫學 地域保健

OBJECTIVES: The objective of this study was to investigate the relationship between coronary artery calcification and risk factors of cardiovascular disease with multidetector computed tomography. METHODS: Data were collected from 5,899 males between 30 and 59 years old by interview, survey, physical examination, blood test, and multidetector computed tomography in the university hospital from January 2010 to December 2011. We confirmed the coronary artery calcium scores of subjects by multidetector computed tomography and identified risk factors of cardiovascular disorders. We investigated the relationship between coronary artery calcification and risk factors of cardiovascular disorders. RESULTS: Mean calcium score of the coronary arteries in 5,899 participants was 8.20, and 773 participants (13.1%) exhibited coronary artery calcification. The presence of coronary artery calcification was correlated to risk factors of cardiovascular disease (age, blood pressure, triglyceride, HDL cholesterol, LDL cholesterol, glucose, Apolipoprotein A-1, Apolipoprotein B, body mass index, waist circumference) and risk assessment tools of cardiovascular disorders. Significant predicted factors of coronary artery calcification had different patterns in each age group (30-39, 40-49, 50-59 years old). CONCLUSIONS: We confirmed the relationship between coronary artery calcification and either typical risk factors of cardiovascular disease or risk assessment tools of cardiovascular disease. In addition, we also observed that the pattern of these factors varied according to age. Therefore, age-related variation needs to be considered in management strategies to prevent cardiovascular disease.

Effects of a Discharge Education Program using Computerized Animation Video for Post-operative Colon Cancer Patients / 재활간호학회지

PURPOSE: This study was to identify the effects of a nurse-led education program using computerized animation video for post-operative colon cancer patients. METHODS: a total of 163 patients and 51 nurses were participated in this study. With a non-equivalent control group post-test design, patients were divided into three groups (77 got traditional education, 46 were applying brochure, 40 were watching video). Twelve-item animation video and brochure about the management after discharge for post-operative colon cancer patients were developed based on patient survey and the items of Korea Healthcare Accreditation. RESULTS: The computerized video watching group had better satisfaction than the others, but there was no significant difference about comprehension. When video was applied, satisfaction, usefulness, application, and perceived patients' comprehension of nurses were all increased. CONCLUSION: This video education program was developed by nurses and it had a special thing for patient to access the same program even after discharge using the authorization system. It would be helpful for nurses to be more concentrated on the direct care for hospitalized patients as well as for patients to provide self-care at home. This program would be adjusted into more various diseases and settings.

The Relationship of Serum Vitamin D Levels and the Framingham Risk Score among Male Workers in the Manufacturing Sector / 대한산업의학회지

OBJECTIVES: A growing body of evidence states that vitamin D deficiencies may adversely affect cardiovascular disease, however data from Korean workers are lacking. The purpose of this study was to investigate the vitamin D level of the Korean worker and the relationship between vitamin D levels and the Framingham Risk Score. METHODS: 11,448 male workers who visited a university hospital for health screening between March 2010 and August 2011, were enrolled in the study. We measured their of serum vitamin D(25(OH)D) levels and calculated their Framingham Risk Score. RESULTS: The mean serum vitamin D(25(OH)D) level of the surveyed workers was 13.03+/-6.47 ng/mL. 12.4% of the total workers had adequate vitamin D levels. It was found that the lower the vitamin D level, the higher the risk of cardiovascular disease. The Framingham Risk Score and vitamin D levels were found to be significantly related (OR=1.39, 95% CI 1.14~1.68) through a multivariate logistic regression analysis. CONCLUSIONS: 87.6% of workers possessed inappropriate vitamin D levels. Management for this high risk group in regards to cardiovascular disease should be included in the evaluation and vitamin D levels should be corrected.

Persistent Complete Atrioventricular Block after Recovery from Acute Fulminant Myocarditis / 대한내과학회지

Acute myocarditis can be caused by viral, bacterial, or protozoal infection, or drug toxicity. Fulminant myocarditis progresses rapidly and frequently leads to cardiogenic shock, so patients should be supported by extracorporeal membrane oxygenation (ECMO), an intra-aortic balloon pump (IABP), mechanical ventilation, or a temporary pacemaker to maintain hemodynamic status. Most patients recover with supportive therapy. However, a few patients have persistent atrioventricular (AV) block. We report the case of a 34-year-old male with persistent complete atrioventricular block after the regression of acute myocarditis. Ultimately, a permanent pacemaker was implanted.

Exposure to Volatile Organic Compounds and Possibility of Exposure to By-product Volatile Organic Compounds in Photolithography Processes in Semiconductor Manufacturing Factories

OBJECTIVES: The purpose of this study was to measure the concentration of volatile organic compound (VOC)s originated from the chemicals used and/or derived from the original parental chemicals in the photolithography processes of semiconductor manufacturing factories. METHODS: A total of four photolithography processes in 4 Fabs at three different semiconductor manufacturing factories in Korea were selected for this study. This study investigated the types of chemicals used and generated during the photolithography process of each Fab, and the concentration levels of VOCs for each Fab. RESULTS: A variety of organic compounds such as ketone, alcohol, and acetate compounds as well as aromatic compounds were used as solvents and developing agents in the processes. Also, the generation of by-products, such as toluene and phenol, was identified through a thermal decomposition experiment performed on a photoresist. The VOC concentration levels in the processes were lower than 5% of the threshold limit value (TLV)s. However, the air contaminated with chemical substances generated during the processes was re-circulated through the ventilation system, thereby affecting the airborne VOC concentrations in the photolithography processes. CONCLUSION: Tens of organic compounds were being used in the photolithography processes, though the types of chemical used varied with the factory. Also, by-products, such as aromatic compounds, could be generated during photoresist patterning by exposure to light. Although the airborne VOC concentrations resulting from the processes were lower than 5% of the TLVs, employees still could be exposed directly or indirectly to various types of VOCs.

A Study of the Results of Sputum Cytology as a Special Health Examination / 대한산업의학회지

OBJECTIVES: This study aims investigate the results of sputum cytology, which began its test period from 2009 as a special health examination for individuals whose lungs have been exposed to carcinogens. METHODS: 22,215 cases of sputum results were classified into six categories through Papanicolau classification. The sputum results were analyzed according to age, exposure degree to welding fumes and smoking status. Chi-square tests and logistic regression analysis were used to compare and analyze the associations between sputum results and smoking status, exposure degree and age classifications. RESULTS: The number of class I cases was 20,784 with a frequency of (93.6%), class II had 1,076 cases (4.8%), class III had 69 cases (0.3%), and the inadequate class had 286 cases (1.3%) and there were no cases in class VI and V. Patients in class III received CT scans of their chest for further evaluation, but no cancer patients were found from that. There were 2.48 times (95% CI 1.12~5.53) more smokers than non-smokers in class III and 1.70 times (95% CI 1.43~2.02) more in class II. The number of ex-smokers was 2.46 times (95% CI 1.01~5.99) larger than the number of non-smokers in class III and 1.28 times (95% CI 1.03~1.60) larger than the number of non-smokers in class II. There were 1.54 times (95% CI 1.28~1.85) more patients from the mid-exposure group than the low exposure group in class II. There were 1.62 times (95% CI 1.31~1.99) more patients from the high-exposure group than the low-exposure group in class II. CONCLUSIONS: As a screening test for lung cancer, the usefulness of sputum cytology is limited. However, the precancerous cells (class II, class III) varied according to welding fume exposure degree and smoking status.

Cases Series of Malignant Lymphohematopoietic Disorder in Korean Semiconductor Industry

OBJECTIVES: Seven cases of malignant lymphohematopoietic (LHP) disorder were claimed to have developed from occupational exposure at two plants of a semiconductor company from 2007 to 2010. This study evaluated the possibility of exposure to carcinogenic agents for the cases. METHODS: Clinical courses were reviewed with assessing possible exposure to carcinogenic agents related to LHP cancers. Chemicals used at six major semiconductor companies in Korea were reviewed. Airborne monitoring for chemicals, including benzene, was conducted and the ionizing radiation dose was measured from 2008 to 2010. RESULTS: The latency of seven cases (five leukemiae, a Non-Hodgkin's lymphoma, and an aplastic anemia) ranged from 16 months to 15 years and 5 months. Most chemical measurements were at levels of less than 10% of the Korean Occupational Exposure Limit value. No carcinogens related to LHP cancers were used or detected. Complete-shielded radiation-generating devices were used, but the ionizing radiation doses were 0.20-0.22 uSv/hr (background level: 0.21 microSv/hr). Airborne benzene was detected at 0.31 ppb when the detection limit was lowered as low as possible. Ethylene oxide and formaldehyde were not found in the cases' processes, while these two were determined to be among the 263 chemicals in the list that was used at the six semiconductor companies at levels lower than 0.1%. Exposures occurring before 2002 could not be assessed because of the lack of information. CONCLUSION: Considering the possibility of exposure to carcinogenic agents, we could not find any convincing evidence for occupational exposure in all investigated cases. However, further study is needed because the semiconductor industry is a newly developing one.