ISSN:0271-3586    

DOI:10.1002/ajim.4700280602

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractThis study tested the hypothesis that fabrication room (fab) work in the silicon‐based semiconductor industry is associated with an increased risk of spontaneous abortion (SAB). The study was conducted nationwide at 14 companies representing a spectrum of large to small manufacturers. A small increase in risk of SAB was observed among fab workers compared with nonfabrication room (nonfab) workers in two cohorts, historical (adjusted RR = 1.43, 95% confidence interval [CI] 0.95–2.09) and prospective (adjusted RR = 1.25, 95% CI = 0.63–1.76). Analysis of specific fab exposures in the historical cohort showed a consistent, dose‐response association of SAB with photoresist and developer solvents, whose major component was ethylene‐based glycol ethers. The consistency of our findings and the toxicological data for these agents suggest that this is a causal association. Independent associations of SAB with self‐reported stress and with etching fluorides were observed and require further research. No significant decrease in fertility was observed among men or women working in fabs, but reduced fecundability was suggested for some women

ISSN:0271-3586    

DOI:10.1002/ajim.4700280603

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractThe Semiconductor Health Study included 14 U.S. companies with 82 silicon‐based wafer‐fabrication rooms and a complex array of processes and chemicals. Its epidemiologic components were a historical examination of spontaneous abortion rates among 902 women, a prospective evaluation of reproductive outcomes in 483 women, and a cross‐sectional review of MAle fertility and of respiratory, ergonomic, neurologic, or gastrointestinal problems among 3,175 men and women. Designing an exposure assessment strategy presented unique problems, and multiple agents had to be evaluated. A three‐tiered approach to exposure assessment was developed to reflect increasing specificity of exposures. At the first tier, employees were divided into fabrication and nonfabrication groups. At the second tier, work groups with qualitatively different exposures were determined. At the third tier, intensity of exposures to specific chemical, physical, and ergonomic agents was evaluated. Evaluations were based on worker reports of tasks performed, moderated by fabrication‐specific factors observed by study industrial hygienists during si

ISSN:0271-3586    

DOI:10.1002/ajim.4700280604

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractInformation on chemical use and exposure control between 1986 and 1990 was collected from 14 companies participating in the Semiconductor Health Study. Questionnaires and site visits provided data used to develop exposure categories for three epidemiological studies: prospective, historical, and cross‐sectional. Patterns of use of target chemicals were compiled for 82 silicon‐wafer fabrication rooms (fabs), including 47 from which subjects were selected for study. Chemical use was examined by operation, year, and epidemiological component. Target agents for epidemiological analyses were present in more than 50% of fabs. Use of these agents was fairly constant from 1986 to 1990, except for a moderate increase in use of propylene glycol monomethyl ether acetate, a solvent being substituted for ethylene‐based glycol ethers (EGE) in photoresists. The distribution of personal protective equipment, engineering controls, and other factors potentially affecting employee exposure was also examined. Controls designed to MAnage processes or high acute toxicity were present in most fabs; their prevalence remained unchanged from 1986 through 1990. Controls designed to reduce exposures to chemicals with low acute toxicity were less widely distributed; their prevalence increased moderately from 1986 to

ISSN:0271-3586    

DOI:10.1002/ajim.4700280605

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractFor exposure assessment in a series of epidemiologic studies of semiconductor industry workers, estimates of potential personal exposures to selected chemical agents were developed using a set of algorithms. A worker's total exposure to each agent was defined as the sum of task scores for each task using that agent. Task scores were calculated as the intensity and frequency score for each task, modified by a factor indicating degree of presence of the target agent and a process‐specific emission factor representing degree of emission control present for that process. The algorithms used multiple sources of information to generate an exposure score for each worker‐process‐agent combination. Exposure scores were then placed into ordinal categories of exposure (0–3) for use in the epidemiologic a

ISSN:0271-3586    

DOI:10.1002/ajim.4700280606

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractThe fabrication of integrated circuits in the semiconductor industry involves worker exposures to multiple chemical and physical agents. The potential for a high degree of correlation among exposure variables was of concern in the Semiconductor Health Study. Hierarchical cluster analysis was used to identify groups or “clusters” of correlated variables. Several variations of hierarchical cluster analysis were performed on 14 chemical and physical agents, using exposure data on 882 subjects from the historical cohort of the epidemiological studies. Similarity between agent pairs was determined by calculating two metrics of dissimilarity, and hierarchical trees were constructed using three clustering methods. Among subjects exposed to ethylene‐based glycol ethers (EGE), xylene, or n‐butyl acetate (nBA), 83% were exposed to EGE and xylene, 86% to EGE and nBA, and 94% to xylene and nBA, suggesting that exposures to EGE, xylene, and nBA were highly correlated. A high correlation was also found for subjects exposed to boron and phosphorus (80%). The trees also revealed cluster groups containing agents associated with work‐group exposure categories developed for the epidemiologic

ISSN:0271-3586    

DOI:10.1002/ajim.4700280607

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractA model was created to assess occupational exposure to extremely low‐frequency MAgnetic fields (ELF‐MF) among semiconductor fabrication‐room (fab) workers. This model was based on the assumption that each subject's exposure arose from being near identifiable ELF‐MF sources or being in areas with high ELF‐MF levels. To assess ELF‐MF exposures, the model superimposed subjects' time‐activity patterns (patterns of how and where they spent their time) with measurements of MAgnetic‐field levels from devices and work areas. This model, which was validated by personal dosimetry on 192 persons in three fabs, predicted actual time‐weighted average exposures with a correlation coefficient of 0.62. The inability of the model to predict individual exposures more accurately was attributed to unforeseen sources of elevated ELF‐MF (transformers, distribution panels, sources in adjacent rooms) or to errors in subjects' judgments of time spent near devices. These unpredictable errors are intrinsic to the method used t

ISSN:0271-3586    

DOI:10.1002/ajim.4700280608

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractThe risk of spontaneous abortion (SAB) in the semiconductor industry was examined in a historical cohort study of pregnancies at 14 companies. We identified Female employees who had worked for at least 6 months and whose ages ranged from 18 to 44 years during the 1986–1989 study period. Using company records, we included all fabrication‐room (fab) employees and an Approximately equal number of nonfabrication (non‐fab) employees, for a total sample of 7,269. Telephone interviews with 6,088 women (84%) identified 904 eligible pregnancies and 113 SABs. Exposure classification was based on questionnaire and industrial hygiene assessments of tasks the women performed during the first trimester of pregnancy. Using logistic regression to control for age, smoking, ethnicity, education, income, year of pregnancy, and stress, we found a higher risk of SAB in fab employees than in nonfab employees (15.0% of fab pregnancies ended in SAB vs. 10.4% of nonfab pregnancies, adjusted relative risk [RR] = 1.43, 95% CI = 0.95‐2.09). Analysis of fab work groups showed that the highest relative risk was in MAsking employees (17.5% SAB rate, adjusted RR = 1.78, 95% CI = 1.17‐2.62 in comparison with nonfab employees). Within MAsking, the highest risk was found in etching‐related process employees (22.2% SAB rate, adjusted RR = 2.08, 95% CI = 1.27‐3.19 in comparison to non

ISSN:0271-3586    

DOI:10.1002/ajim.4700280609

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractRisk of spontaneous abortion (SAB) was examined in relation to chemical and physical agents in a retrospective study of employees of 14 seminconductor MAnufacturers: After screening over 6,000 employees, 506 current and 385 former workers were eligible. If a woman had multiple eligible pregnancies, one was selected at random. Telephone interviews provided data on demographics and occupational and other exposures during the first trimester. Two groups of chemicals accounted for the 45% excess risk of SAB among fabrication‐room (fab) workers: photoresist and developed solvents (PDS), including glycol ethers, and fluoride compounds used in etching. Women exposed to high levels of both these agents were at greater risk (RR = 3.21, 95% confidence interval [CI] = 1.29–5.96). In fab workers without these exposures, SAB rates were not elevated (adjusted relative risk [RR]= 0.98, 95% CI = 0.55‐1.69). An association was seen with workplace stress, which was not limited to women exposed to PDS or fluoride, nor did stress explain the associations between these chemicals an

ISSN:0271-3586    

DOI:10.1002/ajim.4700280610

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractLaboratory methods were adapted or developed to analyze approximately 70,000 daily urine samples collected during more than 2,500 menstrual cycles from 448 women working in the semiconductor industry. An immunoenzymometric assay (IEMA) for Human chorionic gonadotropin (hCG) was employed for screening cycles in order to optimize laboratory resources and to reduce the number of samples requiring analysis by less efficient methods. The presence of hCG in urine was confirmed by the definitive immunoradiometric assay (IRMA). The screening assay eliminated 78% of cycles from further analysis because there was no evidence of conception. Thirty‐eight of 448 cycles identified as having significant levels of hCG with the IEMA were confirmed as hCG positive with the IRMA. HCG‐positive cycles were further evaluated by examination of daily diary data and by laboratory assays for ovarian and pituitary hormones. As a result of these evaluations, 17 of the 38 cycles identified by the IRMA as positive for hCG were found to be nonconceptive cycles. These results demonstrate the effectiveness of screening assays for hCG, as well as the importance of using multiple urinary biomarkers for the detection of early fetal loss with daily urine samp

ISSN:0271-3586    

DOI:10.1002/ajim.4700280611

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY