Truncating a disease. The reduction of silica hazards to silicosis at the 1930 international labor office conference on silicosis in Johannesburg (original) (raw)
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From silicosis to silica hazards: An experiment in medicine, history, and the social sciences
American Journal of Industrial Medicine, 2015
This special issue of the American Journal of Industrial Medicine looks back to the International Conference on silicosis that took place in Johannesburg 85 years ago [International Labour Office, 1930]. Held in 1930, this scientific gathering marked a turning point in the medical and economic history of pneumoconiosis. Moreover, this Conference, ground breaking in its own right, also laid the foundation for the International Labour Organization international convention on silicosis that followed four years later in 1934 [International Labour Office, 1934]. This meeting of experts from all over the industrialized world was convened by a most surprising duo: the Transvaal Chamber of Mines on the one hand, and the International Labour Office (ILO) on the other. The experts' charge was to define the nosology for and delineate the etiology of silicosis, but they were also called upon to determine the basis of financial compensation for the disease and to make recommendations for the best ways to "manage" silicotic workers who might be compromised by silicosis, yet still able to work. That the conference attracted representatives of virtually every industrialized nation, most traveling a great distance to South Africa just as the worldwide Depression had begun, also signaled the broad social and economic international importance of silicosis.
Frontiers in Public Health
Silicosis and other respirable crystalline silica-associated diseases, most notably tuberculosis, have long been substantial causes of morbidity and mortality in South Africa. For the mining and non-mining industries, silicosis elimination programmes have been developed with milestones regarding reduction of levels of exposure to respirable crystalline silica (RCS) and targets regarding the date of eradication. The present paper explores the feasibility of achieving these targets by investigating the evidence that levels of exposure and silicosis incidence rates have declined by an appraisal of the methods for data collection and reporting. In the mining industry the silicosis elimination programme is supported by the development and advocacy of leading practices to reduce the exposure. RCS exposure data are routinely collected according to a Code of Practice (CoP) and the results are reported to the Mine Health and Safety Inspectorate. As the CoP and the actual workplace practices have been demonstrated to have some flaws, there is some concern about the accuracy of the actual exposure data and the data interpretation. The annually reported levels of exposure suggest a decline, however, the actual levels of RCS as well as the number of exposed workers, were not reported over the last few years. With regard to the silicosis incidence rates, a steady decline of new cases is reported. However, there is a risk of under-diagnosis and-reporting especially in former miners. In the non-mining industries, a systematic baseline of RCS exposure levels and silicosis incidence is lacking. The reporting by industries on assigning of the workforce to exposure categories seems to be fragmented and incomplete. Consequently, any evidence of progress toward achieving the silicosis elimination target cannot be documented. Both the silicosis elimination target and the exposure milestone are aspirational but are unlikely to be achieved. Nevertheless, the formal mining industry may get close. Exposure control interventions, especially in the non-mining industries, should be developed and implemented and pragmatic methods need to be put in place to identify sources of new silicosis cases for targeted intervention.
Silicosis prevalence and exposure-response relations in South African goldminers
Occupational and Environmental Medicine, 2004
Aims: To measure the prevalence of silicosis among black migrant contract workers on a South African goldmine and to investigate exposure-response relations with silica dust. Methods: In a cross sectional study, 520 black goldminers (aged .37 years) were interviewed and had chest radiographs taken. Silicosis was defined as International Labour Organisation Classification radiological profusion of 1/1 or greater. Results: Mean length of service was 21.8 years (range 6.3-34.5). The mean intensity of respirable dust exposure was 0.37 mg/m 3 (range 0-0.70) and of quartz 0.053 mg/m 3 (range 0-0.095). The prevalence of silicosis was 18.3-19.9% depending on reader. Significant trends were found between the prevalence of silicosis and length of service, mean intensity of exposure, and cumulative exposure. Conclusion: Results confirm a large burden of silicosis among older black workers in the South African goldmining industry, which is likely to worsen as such miners spend longer periods in continuous employment in dusty jobs. An urgent need for improved dust control in the industry is indicated. If the assumption of stability of average dust concentrations on this mine over the working life of this group of workers is correct, these workers developed silicosis while exposed to a quartz concentration below the recommended occupational exposure limit (OEL) of 0.1 mg/m 3 . This accords with a mounting body of evidence that an OEL of 0.1 mg/m 3 is not protective against silicosis. Churchyard, Ehrlich, teWaterNaude, et al www.occenvmed.com
A Brief Review of Silicosis in the United States
Environmental Health Insights, 2010
Silicosis may be defined as the disease resulting from chronic occupational exposure to silica dust. Silica is primarily composed of quartz dust and has been classified since 2000 as a known human carcinogen by the U.S. government. Silicosis may lead to impairment of lung function resulting from fibrosis of the lungs. This may in turn lead to an increased susceptibility to the development of tuberculosis. Respirable particles are in the size range of less than one micrometer to as large as 30 micrometers. Silicosis is an untreatable, but preventable disease. This review explores the history of silicosis in the U.S. mining industry, including case studies of occupational silicosis.
A Threat to Public Health in the Past and the Future : Silicosis
2017
Silicosis is a disease caused by inhaling respirable silica particles primarily composed of quartz dust and has been recognised, since the 2000’s, as a human carcinogen. Chronic, accelerated and acute types of silicosis have been described. The most commonly diagnosed chronic silicosis develops after 10 or more years of exposure to relatively low dust concentrations. Silicosis leads to fibrosis and impairment of lung function. It is a preventable disease that is not easily treatable. Despite political and industrial debates, many workers worldwide are still exposed to silica dust. This review emphasizes that silicosis will continue to threaten public health in the future, if adequate preventive measures and widescale case studies of occupational silicosis are not carried out.
American Journal of Industrial Medicine, 2015
The 1930 International Labour Office Conference on silicosis in Johannesburg identified silicosis by setting a medicolegal framework to its nosology: as with other occupational illnesses, its medical content was fixed under economic pressure. This article follows a reading of all the proceedings of this conference (debates and reports of experts) to examine their potential impact on the etiology and nosology of other diseases, specifically sarcoidosis and pulmonary alveolar proteinosis (PAP), "idiopathic" diseases in which inorganic particles may be involved. We propose renewed study of the role of inorganic particles in these diseases. To do this, we propose to mobilize detection means such as mineralogical analysis and electron microscopy and in depth interviewing that are currently seldom used in France, in order to establish diagnosis and the potential occupational and environmental origin of these diseases.
Silicotuberculosis and silicosis as occupational diseases: Report of two cases
Srpski arhiv za celokupno lekarstvo, 2011
Introduction. Silicosis, the most prevalent of the pneumoconioses, is caused by inhalation of crystalline silica particles. Silica-exposed workers are at increased risk for tuberculosis and other mycobacterium-related diseases. The risk of a patient with silicosis developing tuberculosis is higher (2.8 to 39 fold higher, depending on the severity of silicosis) than that found in healthy controls. Outline of Cases. The first patient was a 52-year-old male who was admitted in 2002 for the second time with dyspnoea, wheezing and fatigue over the last 11 years. He had worked in an iron smelting factory and was exposed to silica dust for 20 years. First hospitalization chest radiography showed bilateral pleural adhesions, diffuse lung fibrosis with signs of a specific lung process. Second hospitalization chest radiography showed bilateral massive irregular, non-homogenous calcified changes in the upper and middle parts of lungs. The patient died due to respiratory failure and chronic pul...
Silicosis: A former occupational disease with new occupational exposure scenarios
Revista clínica española, 2019
Background: Recent studies have shown an increase in the prevalence of silicosis due to the use of artificial quartz aggregates (AQA). The aim of this study was to assess the cases of silicosis in our area reported to the Healthcare Information System for Occupational Epidemiological Surveillance of the Autonomous Community of Valencia to detect new agents of exposure to silica and working conditions that promote its onset. Material and method: A descriptive study was conducted of cases of silicosis reported to the Healthcare Information System for Occupational Epidemiological Surveillance of the Autonomous Community of Valencia from January 2009 to September 2016. The data sources include epidemiological-occupational surveys and medical reports. Results: Nineteen cases of silicosis were reported, 74% of which were diagnosed using highresolution computed tomography. Some 68.4% of the cases were related to the handling of AQA, as assemblers/cutters/sanders of countertops. The subgroup's mean age was 46.62 ± 13.33 years, and the mean exposure was 11.00 ± 3.58 years. The rest of the patients worked in companies with no AQA exposure, with a mean age of 62.33 ± 16.22 years and a mean exposure of 27.16 ± 8.44 years (p < 0.05). Four cases presented complicated forms (3 exposed to AQA). Conclusions: The work of assembling/cutting/sanding AQA countertops presents a high risk of developing the disease. The mean age at onset and the exposure time for this group is lower, and the percentage of complicated clinical forms is higher. Improvements need to be made in preventive planning for companies with exposure to these new agents.