[Specific occupational hazards and their health effects among dental technicians]

The authors describe specific hazards occurring at workplaces of dental technicians. Exposure to chemical and biological factors in particular and their health effects are presented in detail. Among chemical factors, a specific danger is associated with allergens (methyl metacrylate, metals, latex, tiurams), which may lead to the development of pneumoconiosis. In the authors' opinion, exposures to biological hazards need an extensive analysis. A thorough, hygiene and epidemiological study of occupational exposure and its health effects among dental technicians in Poland would be also very useful.

Mineral fiber problems and their management: UK 1890-1935

BACKGROUND

The first intimation that mineral fibers other than asbestos were biologically active, is generally identified with reports of experimental studies by Stanton and Wrench, and Pott and Friedrichs, in the early 1970s. In 1890 however, man-made mineral fiber was recognized to present human health hazards; in 1912 experimental study confirmed asbestos to be fibrogenic, and by 1935 other mineral fibers came to notice as potential lung hazards.

METHODS

Published and archival sources have been reviewed to trace the emergence between 1890 and 1935 of the awareness of the health hazards of various fibrous minerals, and the development of strategies for their control.

RESULTS

By the early 1900s there was evidence that the asbestos substituted for the man-made mineral fiber insulation material employed to improve the thermal efficiency of steam powered engines, presented a serious health problem. In the early 1930s, other mineral fibers came to be suspected of causing pneumoconiosis.

CONCLUSIONS

Containment, local exhaust ventilation and personal respiratory protection were instituted for the amelioration of asbestosis, but because of the limitations of what was perceived to be reasonably practicable on economic grounds, and what was feasible technologically, their benefits were severely limited. Initial and periodic medical examination were introduced as precautionary measures, based on hope rather than on experience. When in the early 1930s, the investigation of coal mine dust and siliceous dust, threw up the hypothesis that fibrous natural mineral dusts other than asbestos might be fibrogenic, this was ignored and no further investigations were pursued and no precautionary measures were set in train.

Dust concentrations and respiratory risks in coalminers: key risk estimates from the British Pneumoconiosis Field Research

To help inform the setting of dust control standards in coalmines, this brief review summarises the most recent and reliable exposure-response relations, for damaging respiratory effects, derived from the Pneumoconiosis Field Research (PFR). Collecting data over 38 years in the British coal industry, this was a programme of prospective research on the respiratory health of coal miners, characterised by regular health surveys and detailed measurements of dust and silica concentrations in the workplace. Exposure-response relations are presented for coal workers' simple pneumoconiosis category II, progressive massive fibrosis, defined deficits of lung function (FEV1), and category II silicosis. This simplified overview provides a guide to the most recent and most reliable estimates from the PFR of dust-related risks of substantial pulmonary disease, and to the magnitude of the effects. Control of dust sufficient to prevent category II simple pneumoconiosis should prevent most cases of progressive massive fibrosis and most dust related large lung function deficits. Where the dust contains high proportions of silica, control to low levels is essential, and even quite brief excursions of silica to high levels must be avoided.

Occupational Lung Disease in China

Occupational lung disease has been a major public health problem in China. The recently transformed industrial structure and expansion of the industrial labor force, accompanying the rapid industrialization and economic growth, pose both tremendous challenges and opportunities for occupational health policy and research. New occupational health problems are emerging, while the traditional occupational lung disease continued to occur. Simultaneously, relevant scientific research and professional activities have accelerated notably. The progress and achievement in occupational health research are creating more powerful forces in eliminating industrial hazards and protecting workers' health in China.

The fox guarding the chicken coop: monitoring exposure to respirable coal mine dust, 1969-2000

Following passage of the Coal Mine Health and Safety Act of 1969, underground coal mine operators were required to take air samples in order to monitor compliance with the exposure limit for respirable dust, a task essential for the prevention of pneumoconiosis among coal workers. Miners objected, claiming that having the mine operators perform this task was like "having the fox guard the chicken coop." This article is a historical narrative of mining industry corruption and of efforts to reform the program of monitoring exposure to coal mine dust. Several important themes common to the practice of occupational health are illustrated; most prominently, that employers should not be expected to regulate themselves.

[Analyses of 1003 death cases of pneumoconiosis from Xuzhou coal mines]

In order to investigate the general rules concerning attack, development and death of pneumoconiosis for providing scientific evidences for preventing, 1003 death cases of pneumoconiosis from Xuzhou coal mine factory were analyzed. Results showed that: (1) The death causes was in the sequence of pneumoconiosis, lung tuberculosis, chronic cor pulmonale, pulmonary carcinoma, etc., and changed into pneumoconiosis, chronic cor pulmonale, pulmonary carcinoma, cerebrovascular accident, etc. since 1990s. Lung tuberculosis would no longer be the main death cause of pneumoconiosis; (2) The accumulative death percentage of the death cases about pneumoconiosis was correlated to the length of dust exposure. The accumulative death percentage increased rapidly in a beeline within 5 to 20 years; (3) The length of service of episode and mean life of digging or mining workers were significantly shorter than that of others (P < 0.01); (4) The mean life and the course of diseases became more and more longer than ever since 1970s. Therefore, it can be concluded that the key for preventing and controlling pneumoconiosis was to decrease the concentration of dust in workplace and to limit the length of service of dust exposure.

[Dust exposure in a pottery plant assessed by using GRIMM dust monitor]

In one of the pottery plants in which pneumoconiosis was the only certified occupational disease (16 cases during the years 1984-1997), the concentrations of dust in inhalable, thoracic and respirable fractions were measured at most characteristic workplaces. The highest concentrations in all the three fractions was found in the slip house; the mean concentrations were as follows: inhalable dust-7231.8 mg/m3; thoracic fraction--4834.9 mg/m3; and respirable fraction 1402.2 mg/m3. High concentrations of all the dust fractions were also observed at the workplace of the intershop transport worker who removed the waste body from cast and throw shops. The largest number of pneumoconiosis (7) cases was found among the workers of the slip house (20 persons employed); this was followed by the intershop transport workers-4 cases (4 persons employed). At the other workplaces (cast shop, throw shop and firing), concentrations of inhalable dust ranged from 1175 to 3232 mg/m3; thoracic from 726 to 2001 mg/m3; and respirable from 146 to 549 mg/m3. The contents of free crystalline silica (SiO2) in the air dust ranged from 3% in firing to 50% in slip house, in the latter mostly in the form of quartz or cristobalite. The main fraction of inhalable dust was the tracheobronchial fraction, ranging from 43.1 to 48.2%, the extrathoracic fraction ranged from 32.8 to 42.3% and respirable fraction from 11.8 to 21.6%. On the basis of the graphic record, such activities as pouring of raw materials into grinding mill and reloading of the waste body were identified at the workplaces of slip making and internship transport as those associated with the highest dust emission.

[Activities of the regional occupational health center under present-day conditions]

The authors represented experience of contemporary activities of Occupational center in Rostov region, demonstrated efficiency of thorough medical examinations carried by mobile clinical and diagnostic laboratories, suggested 4-levels structure of occupational service organization.

[Study on the prevention, control and elimination of pneumoconiosis in fluorite mine]

OBJECTIVE

To prevent pneumoconiosis by strengthening comprehensive dust-proof and controlling its pathogenesis, and to discuss feasibility of pneumoconiosis elimination in our country.

METHODS

Comprehensive dust-proof was used for reducing the concentration of dust. Epidemiological investigation of pneumoconiosis was employed for evaluating the efficiency of pneumoconiosis prevention. Prospective tracking investigation was used for identifying the feasibility of the pneumoconiosis elimination.

RESULTS

The outcomes of dynamic observation of 35 years from 1962 to 1996 and results of prospective thirty years tracking investigation showed that after comprehensive dustp-roof, the average dust concentration and time weighted mean dust concentration in workers' operating conditions decreased from 366.0 mg/m3 and 163.4 mg/m3 to 1.2 mg/m3 and 1.3 mg/m3 respectively, and the declined rates reached 99.7% and 92.1%, respectively. After controlling pneumoconiosis pathogensis, the incidence rate of pneumoconiosis, its prevalence rate and mortality rate decreased from 24.8%, 85.5% and 5.9% to zero respectively.

CONCLUSION

The thirty years prospective tracking investigation validated that the incidence of pneumoconiosis was zero. So the goal to eliminate pneumoconiosis was achieved.

From quartz hazard to quartz risk: the coal mines revisited

Following the classification of quartz as a human carcinogen by the IARC, many standard-setting committees are currently trying to convert this hazard into their national or EU standards. Since human data to set a safe exposure limit for quartz are limited, we hypothesized that lung burden data on quartz in coal miners' lungs after lifetime exposure could be used to set a non-carcinogenic lung burden of quartz, and that this might be valid for other groups occupationally exposed to quartz. A review of data shows that lungs of coal miners with simple coal workers' pneumoconiosis (sCWP) typically contain up to 30 g of dust, and in one specific study lung burdens between 0.7 and 1.7 g of quartz were associated with macules only, and no sCWP. Assuming independent actions of coal and quartz and no clearance of quartz, and sCWP as a prerequisite for lung cancer due to quartz exposure in coal mine dust, a simple kinetic approach was applied. A no observed adverse effect level (NOAEL) for quartz of between 0.03 and 0.13 mg/m3 (40 yr exposure) is derived, but it is concluded that more refined physiologically based pharmacokinetic modelling is needed for a better estimate, also including interindividual differences in lung clearance. Considering the independent effects of, and the well-known interaction between coal and quartz, these data could be important to other workplaces with usual mixed-dust exposure.

Disturbance of respiratory system in workers in smelter plants

Workers from smelter plants are at high risk from lung injuries due to exposure to quartz sand, clay, resin, loams, airborne metals etc. The aim of this study was to investigate the relevance of the problem and the risk of occupational pathology in metallurgy at "ELMA" plant--Troyan. The study revealed decreased number of occupational lung diseases but the percentage rate (about 10%) of registered new cases with occupational lung diseases was maintained. No new cases with mixed silicosis were recorded. The results were compared to respective national data. Slowly evolving forms of diffusely outlined lung chart with late functional breathing disturbances were prevailing. Chronic bronchitis are presented as a polyetiologic paraoccupational disease.

The Medical Research Council Pneumoconiosis Research Unit, 1945-1985: a short history and tribute

The Pneumoconiosis Research Unit (PRU) was set up to obtain the information needed to eliminate pneumoconiosis of coal workers. To this end, instruments and procedures were developed for dust sampling, delivering dust to animals, testing lung function, reading chest radiographs, conducting respiratory surveys and extracting the relevant information. A provisional estimate of safe working conditions was made using data from four pits. The National Coal Board extended the research to an additional 20 pits, refined the estimate and applied it nationally. Meanwhile at PRU aspects of treatment were explored, immunological techniques were added to the repertoire of skills, other occupational disorders were highlighted and new information obtained on biological variation in lung function and blood pressure. The work laid the foundations for medical epidemiology and evidence-based medicine. Starting in 1959, the Unit took the lead in a world campaign to control lung diseases due to asbestos. This account indicates how these successes were achieved, what were the failures, some tensions which developed and what might have been if some events had been handled differently. If there is a message, it is that for success in research the problem under consideration should be the prime focus of attention and resources.

[Occupational medicine in aluminum and copper alloy production]

Workers engaged into aluminum alloys production demonstrated high prevalence of occupational respiratory diseases caused by dust--pneumoconiosis and dust bronchitis, workers of copper alloys production were diagnosed as having early stage of chronic lead intoxication.

The past and present of pneumoconioses

Pneumoconioses are still a common cause of chronic lung disease. In industrialized countries, improvements in working conditions and dust control measures have led to a decrease in the incidence of severe forms of silicosis, coal worker pneumoconiosis, and parenchymal asbestosis. However, the diversity of settings in which silica and asbestos are used fuels a continued input of cases, and the burden of cases related to remote exposures is still considerable. Overall, the clinical picture of the classic pneumoconioses and their complications has not changed substantially. However, their limits and links have expanded toward systemic and connective tissue disease, idiopathic pulmonary fibrosis, and antineutrophil cytoplasmic autoantibody-positive vasculitides. Immunologically mediated occupational lung diseases have emerged, such as berylliosis and hard-metal disease. Advances in imaging, mineralogic analysis of bronchoalveolar lavage fluid, and immunologic techniques have been instrumental in describing new patterns of disease and are helpful in litigious or difficult cases.

Mixed dust fibrosis and tuberculosis in comparison with silicosis and macular pneumoconiosis

BACKGROUND

To assess the relationship between mixed dust fibrosis (MDF) and tuberculosis.

METHODS

We performed a comparative analysis with MDF, silicosis, and macular pneumoconiosis (Mac), using autopsy records from 1975 to 1994.

RESULTS

Prevalences of having tuberculosis among MDF, silicosis, and Mac were not significantly different, albeit a tendency of higher prevalence in silicosis. Cure rates of tuberculosis were, in order, silicosis < MDF < Mac (P=0. 085). Death rates associated with tuberculosis were, in order, silicosis > MDF=Mac (P=0.911). With respect to the two types of association with tuberculosis, i.e., combined type (tuberculopneumoconiosis) and complicated one (pneumoconiosis with tuberculosis); the former was significantly dominant in silicosis, the latter was significantly dominant in Mac, and intermediate in MDF. As a whole, the complicated type had a tendency of a higher cure rate than the combined type (P=0.071). Although the differences of profiles between the combined and complicated types were not statistically significant, the combined type had a tendency to have longer duration of exposure to dusts, earlier registration for treatment, higher profusion score, and earlier death compared with the complicated type.

CONCLUSIONS

From our findings, MDF takes an intermediate position between silicosis and Mac regarding the relationship with tuberculosis. The type of association with tuberculosis rather than the kind of background pneumoconiosis seemed to be more important in light of responsiveness to the treatment.

Occurrence and prevention of coal miners' pneumoconiosis in Poland

BACKGROUND

Coal production is one of the largest industries in Poland and incidence of coal miners' pneumoconiosis is high.

METHODS

Data concerning the epidemiology of coal miners' pneumoconiosis stem from the national register and previous investigations performed in Poland. Improvements in medical and technical methodologies for the prevention of pneumoconiosis is discussed.

RESULTS

Analysis of the dust concentration measurements shows that TLV values are exceeded in 90% of underground workplaces. The number of new pneumoconiosis cases diagnosed annually ranges from 400-800 and has been showing a diminishing tendency in the last five years. Recently, a new system of medical and technical prevention has been introduced in seven collieries.

CONCLUSIONS

The current epidemiological situation of coal miners pneumoconiosis in Poland is unfavorable and needs vast improvement.

[Metabolism of serum phospholipids in coal miners]

The studies covered metabolism of serum phospholipids during lipids peroxidation and hydrolysis by phospholipase A2. Metabolism of serum phospholipids appeared to depend on duration of exposure to mine dust and on coal pneumoconiosis stage. Lipids peroxidation becomes activated after 20 and more years of service, intensifies with anthracosilicosis development on background of higher catalase activity that is low on early stages of the disease. Activity of phospholi pase A2 increases with pulmonary fibrosis progression.

Between a rock and a healthy place

The Federal Mine Safety and Health Act of 1977 consolidated all federal health and safety regulations of the mining industry-coal as well as noncoal mining-under a single mandate administered by the Mine Safety and Health Administration (MSHA). Today, the agency is striving to reduce the environmental health risks associated with mining.

Occupational lung diseases and global occupational health on the Net

Occupational lung disease is a major area of concern in occupational health, exhibiting a diverse panorama across countries. While pneumoconiosis is deemed to be the most common occupational disease in many developing countries, emphasis is shifting towards asbestos-related lung diseases and occupational asthma in industrialized countries. Following the Occupational Health for All strategies set forth by the World Health Organization, we propose that a model system based upon the Global Health Network can serve as an effective vehicle towards the prevention of occupational lung diseases on a global scale. It has the potential to: (1) enhance transmission of data and collaboration with the primary health care system in disease surveillance; (2) strengthen research and information transfer and (3) promote education and training at all levels of prevention, with a possible application to the interpretation of chest radiograms.

[Experimental study on prevention of pneumoconiosis complicating with tuberculosis by Mycobacterium vaccae]

OBJECTIVE

To explore the role of Mycobacterium vaccae in prevention of pneumoconiosis complicating with tuberculosis.

METHOD

Mycobacterium vaccae was injected into rats which had been exposed to quartz for 2 weeks, and H37Rv was injected into their tail veins 1 month later. All the rats were killed 3 months later. Indexes for evaluation in the study included tuberculous lesion pathological change index, Mycobacterium tuberculosis culture in a fixed amount in lung tissues, count of Mycobacterium tuberculosis and histopathological changes in alveolar macrophages.

RESULT

Tuberculous lesion pathological change index, Mycobacterium tuberculosis culture in a fixed amount in lung tissues and count of Mycobacterium tuberculosis in alveolar macrophages were 2.6 +/- 0.5, (4.40 +/- 4.00) x 10(4) CFU and 7.2 +/- 3.2 respectively in pneumoconiosis complicated with tuberculosis and injecting Mycobacterium vaccae group, while 3.1 +/- 0.3, (18.9 +/- 18.2) x 10(4) CFU and 12.5 +/- 6.3 respectively in the control group. And statistically significant differences were found between the two groups (P < 0.05, 0.01, 0.05 respectively). The histopathological analysis revealed that proliferative and lymphoid nodules were predominant in the pneumoconiosis complicated with tuberculosis and injecting Mycobacterium vaccae group, while necrotic nodules in the control group.

CONCLUSION

Mycobacterium vaccae might play a role in prevention of pneumoconiosis complicating with tuberculosis.