摘要:

AbstractThe vermiculite ore and concentrate of a mine and mill near Libby, Montana, was found to be contaminated with fibrous tremolite‐actinolite. Of 599 fibers (length greater than 5 μm and width greater than 0.45 μm) counted in eight airborne membrane filter samples, 96% had an aspect ratio greater than 10 and 16% had an aspect ratio greater than 50. Additionally, 73% of the fibers were longer than 10 μm, 36% were longer than 20 μm, and 10% were longer than 40 μm. Estimates of exposure before 1964 in the dry mill were 168 fibers/cc for working areas, 182 fibers/cc for sweepers, 88 fibers/cc for skipping, and 13 fibers/cc for the quality control laboratory. In 1964–1971, exposure estimates for these areas were 33, 36, 17, and 3 fibers/cc, respectively. Estimates of exposures in the mine before 1971 ranged from 9–23 fibers/cc for drillers and were less than 2 fibers/cc for nondrilling jobs. All 8‐hr TWA job exposure estimates decreased from 1972‐1976, and from 1977‐1982 were less

ISSN:0271-3586    

DOI:10.1002/ajim.4700110102

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

年代:1987

数据来源: WILEY

摘要:

AbstractThe vermiculite ore and concentrate of a mine and mill located near Libby, Montana was found to be contaminated with a fiber of the tremolite/actinolite series. A study was conducted to estimate the exposure‐response relationship for mortality for 575 men who had been hired prior to 1970 and employed at least 1 year at the Montana site. Individual cumulative fiber exposure (fiber‐years) was calculated. Results indicated that mortality from nonmalignant respiratory disease (NMRD) and lung cancer was significantly increased compared to the U.S. white male population. For those workers more than 20 years since hire, the standard mortality rate (SMR) for lung cancer (ICDA 162–163) was 84.7, 225.1, 109.3, and 671.3 for less than 50, 50–99, 100–399, and more than 399 fiber‐years respectively. Corresponding results for NMRD (ICDA 460–519) were 327.8, 283.5, 0, and 278.4. Based on a linear model for greater than 20 years since hire, the estimated percentage increase in lung cancer mortality risk was 0.6% for each fiber‐year of exposure. At 5 fiber‐years, the estimated percentage was 2.9% from an unrestricted (nonthreshold) linear model and 0.6% from

ISSN:0271-3586    

DOI:10.1002/ajim.4700110103

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

年代:1987

数据来源: WILEY

摘要:

AbstractA study was conducted to estimate the exposure‐response relationship for tremolite‐actinolite fiber exposure and radiographic findings among 184 men employed at a Montana vermiculite mine and mill. Workers were included if they had been employed during 1975–1982 and had achieved at least 5 years tenure at the Montana site. Past fiber exposure was associated with an increased prevalence of parenchymal and pleural radiographic abnormalities. Smoking was not significantly related to the prevalence of small opacities. However, the number of workers who had never smoked was small, and this prevented measurement of the smoking effect. Under control for smoking and age, the prevalence of small opacities was significantly greater for vermiculite workers with greater than 100 fiber/cc‐years exposure than for comparison groups (cement workers, blue collar workers, and coal miners) who had no known occupational fiber exposure. A logistic model predicted an increase of 1.3% in the odds ratio for small opacities at an additional exposure of 5 fibe

ISSN:0271-3586    

DOI:10.1002/ajim.4700110104

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

年代:1987

数据来源: WILEY

摘要:

AbstractThe possible bronchocarcinogenic effects of fumes released during the shielded metal arc welding of stainless steel and the thermal spraying of chromium oxide (Cr2O3) have been studied on the rat. The fume particles were shown to contain tri‐ and hexavalent chromium in soluble and low soluble forms; they were collected and implanted as pellets in the bronchi of groups of 100 rats by the method of Laskin et al. A negative control group of 100 rats was included, as well as positive controls receiving pellets containing benz(a)pyrene. The experiment was continued for 34 months; no differences of biological significance were noted between the growth rates, survival times, and terminal organ weights of the test and negative control groups. At autopsy, the macroscopic and microscopic appearance of the organs in the three groups, including the local reaction to the implanted pellet, were similar. No precancerous changes were observed at the implantation sites; one rat, who received a pellet containing welding fumes, showed squamous cell carcinoma remote from the implantation site and not associated with the bronchus. It had the appearance of a metastasis. All three benz(a)pyrene control rats developed cancer at the implantation site. The occupational health implications of these findings are discusse

ISSN:0271-3586    

DOI:10.1002/ajim.4700110105

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

年代:1987

数据来源: WILEY

摘要:

AbstractTo investigate further the relationships of asbestos exposure, cigarette smoking, and airflow limitation, we have obtained detailed pulmonary function tests (PFT) in 331 long‐term Canadian chrysotile workers, 34 of whom were lifetime nonsmokers. Three disease categories were defined on the bases of standard diagnostic criteria, gallium‐67 lung uptake, and the lung pressure‐volume curve. Category A was composed of workers without changes suggestive of alveolitis or asbestosis. There were eight nonsmokers (ns), among whom we found a statistically significant 30% reduction in airflow conductance (Gus) at low lung volume, which is consistent with the concept of an asbestos airway lesion. The 85 smokers (sm) of category A had reduction of Gusat both high and low lung volumes. Category B was composed of workers without asbestosis but with evidence of asbestos alveolitis. In the six ns, Guswas significantly reduced to 50% normal at low lung volume. The 59 sm had reduction of Gusat both high and low lung volumes but less severely than sm in category A. Category C was composed of workers with asbestosis. The 20 ns had restrictive pattern of lung function, and Guswas decreased to 39% normal at 50% TLC. The 153 sm in C had airflow reduction comparable to sm in B. We concluded that asbestos exposure, which leads to asbestos airway disease, asbestos peribronchiolar alveolitis, and asbestosis, causes airflow limitation at low lung volume but does not reduce the expiratory flow rates on the flow‐volume curve in lifetime nonsmokers. In the smoking asbestos workers with alveolitis or asbestosis, the major component of airflow limitation is a smoking effect. In these smoking workers, rigidity of the lung lessens airflow obstruction associated with smoking at the expense of increased work of br

ISSN:0271-3586    

DOI:10.1002/ajim.4700110106

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

年代:1987

数据来源: WILEY

摘要:

AbstractThe content of chromium was measured in organs of six chromate workers who had worked in a chromate chemical manufacturing plant, had been exposed to a considerable amount of chromiun for over 10 years, and had died of lung cancer. The chromium in the lungs of workers averaged 51.5 μg/g (range 24.8–210 μg/g), while levels in the lungs of non‐exposed controls were 0.07–1.01 μg/g. Organs other than the lungs of the workers also had more chromium than those of the controls. Moreover, it was apparent that the metal remained in the lungs long after exposure to chromate ha

ISSN:0271-3586    

DOI:10.1002/ajim.4700110107

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

年代:1987

数据来源: WILEY

摘要:

AbstractWe have studied the mortality between 1950 and 1980 of a cohort of 1,143 workers in an electrochemical plant producing cobalt and sodium. The mortality of the whole cohort is significantly lower than in the French population for all causes of death (SMR = 0.77), and especially for deaths from circulatory system diseases (SMR = 0.59). However, among cobalt production workers, there is a relative over‐mortality, especially from lung cancers (SMR = 4.66, 4 cases). The relationship between cobalt production and lung cancer mortality was supported by a case‐control study nested in the cohort study. The authenticity of the occupational origin of this risk could not be established due to the low number of cases and because the role of tobacco consumption could not be taken into account. Other studies should be carried out in plants producing or using cob

ISSN:0271-3586    

DOI:10.1002/ajim.4700110108

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

年代:1987

数据来源: WILEY

摘要:

AbstractRespiratory health variables were studied cross‐sectionally in 227 employees of a plastics molding facility where numerous complaints had been apparently associated with the use of azodicarbonamide foaming agent in injection molding. Pre‐ and postshift respiratory status measures and azodicarbonamide concentrations were also obtained for 17 employees. Cross‐sectional pulmonary function differences by injection molding status were not observed. Modest decrements in pulmonary function measures were observed between start and end of shift but with no dose‐effect relationship. A strong association was observed for injection molding workers for eye/nose/throat irritation, cough, and wheezing. Additionally, wheezing, chest tightness, and symptoms of chronic bronchitis were strongly associated with work in injection molding during periods in which azodicarbonamide was in use. These results suggest respiratory symptom causation by some combination of azodicarbonamide itself, reaction products of azodicarbonamide formed during injection molding, or other unidentified agents uniquely associated with the process of injection molding with azodicarbonamide foamin

ISSN:0271-3586    

DOI:10.1002/ajim.4700110109

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

年代:1987

数据来源: WILEY

摘要:

AbstractMin‐U‐Sil5, a form of alpha quartz, has been shown to induce peripheral lung tumors in rats exposed to the dust by inhalation. The animals were exposed to a nominal particle concentration of 12.4 mg/m3for 8 hr/day, 4 days/week, for 2 years. The induced tumors were large and peripheral, and, when examined by electron microscopy, were found to be composed predominantly of alveolar type II cells. These cells were found in papillary, acinar, and solid forms of the tumors and were characterized by lamellar inclusion bodies. This is in contrast to the mouse, in which the papillary form was associated with Clara cells and the acinar form was linked with the type II cell. In this study, the Clara cell was a minor component of the tumor mass. No clear risk is established in man linking silica exposure to increased lung tumor ra

ISSN:0271-3586    

DOI:10.1002/ajim.4700110110

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

年代:1987

数据来源: WILEY

摘要:

AbstractDuring analyses of alkali digested lung tissue for asbestos bodies, we observed that the number of asbestos bodies in the discarded waste frequently exceeded the number in the filtered residue, the number reported in the standard diagnostic method. This observation led to the exploration of alternative techniques that would optimize the recovery of asbestos bodies. We describe a new, simple, and rapid method for extracting asbestos bodies from digested lung tissue using a cytocentrifuge, in which the waste extraction and filtration steps are eliminated. Samples of digested lung tissue are ready for light microscopy after 10 minutes of cytocentrifugation directly onto a glass slide. The standard method was compared with the cytocentrifuge technique using lung tissue from four asbestos‐exposed workers and four controls with no known history of exposure. The number of asbestos bodies extracted by the centrifuge method was, on average, seven times higher than the number found with the standard method. A detailed quantitative study was made of the case that had the most asbestos bodies (comparison of the number of asbestos bodies counted in both “residue” and “waste”, applying the filtration and cytocentrifuge methods). The number of asbestos bodies found in the discarded waste significantly exceeded the number in the “reportable” fil

ISSN:0271-3586    

DOI:10.1002/ajim.4700110111

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

年代:1987

数据来源: WILEY