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Silicosis–An Ancient Disease

2022; Medknow; Volume: 26; Issue: 2 Linguagem: Inglês

10.4103/ijoem.ijoem_160_22

1998-3670

Prahlad K. Sishodiya,

Pleural and Pulmonary Diseases

Silicosis is an ancient disease caused by inhalation of silica dust. The disease must have occurred when man learned to break stone to make tools and build homes. Silicosis, an incurable, debilitating and often fatal disease, is totally preventable with available dust control measures. Silicosis still remains the most important occupational lung disease causing extensive morbidity and mortality among workers exposed to silica dust in most developing and many developed countries. The disease is reported from almost all occupations wherever silica dust exposure occurs; however, mining, mineral processing, tunnelling, stone carving, ceramics, glassmaking, foundries, building, and construction activities are the most affected industries. Recently, artificial stone manufacturing and processing have emerged as the new areas of concern. In India, silicosis was first reported by S Subba Rao, Senior Surgeon, Mysore Government in 1934.[1] A detailed investigation in Kolar Gold Fields from 1940 to 1946 by Chief Advisor of Factories involving 7653 mine workers found that 3402 (43.7%) workers were suffering from silicosis.[2] Sikand and Pamra (1949) were the first to report cases of silicosis in stone workers in India. They recorded 52.4% cases of silicosis among stone cutters and 12.5% among stone breakers.[3] They also reported higher prevalence of tuberculosis among workers. Since then, silicosis has been reported from gold, copper, uranium, mica, lead and zinc, sandstone and other mines, mineral processing, slate pencil, agate, and many other types of industries. Silicosis is a notified diseases under Mines Act, 1952, Factories Act 1948 and Building and Other Construction Workers (Regulation of Employment and Conditions of Service) Act 1996. It is also a compensable disease under Employees Compensation Act 1923 and Employees' State Insurance Act 1948. While Mines Act is implemented by the Central Government through Director General of Mines Safety, the Factories Act and Building and Other Construction Workers (Regulation of Employment and Conditions of Service) Acts are implemented by state governments through Chief Inspector of Factories. Following notification of silicosis under Mines Act 1952, large number of cases of silicosis were reported to then Chief Inspector of Mines [Figure 1], subsequently, redesignated as Director General of Mines Safety (DGMS). The improvement in mining technology, prohibition of dry drilling in mines and better enforcement of legislative measures, reduced incidence of silicosis in large and medium mines as reported to DGMS [Figure 2].[4] In last decade or so very few cases of silicosis have been reported to DGMS though it is likely that many cases of silicosis even from large and medium mines go undetected and unreported because of inadequate health surveillance.Figure 1: Number of silicosis cases notified to Chief Inspector of Mines (1954-1968). Data Source: Compiled from Annual Reports of Chief Inspector of MinesFigure 2: Number of silicosis cases notified to Director General of Mines Safety (1980-2004). Data Source: Compiled from Annual Reports of Director General of Mines SafetyIn most states, very few cases of silicosis are notified and in the absence of centralized national data base, very little information is available on occurrence of silicosis in factories and other occupations. Similarly, not much information is available on number of cases given compensation for silicosis by Employees' State Insurance and Employees Compensation Commissioners. While prevalence of silicosis has reduced in large and medium mines, the same cannot be said about small mines and mineral processing industry. Sporadic studies conducted in small and unorganized sector especially in sandstone mines and stone processing have reported high prevalence of silicosis among workers. Similarly, high prevalence of silicosis among workers in stone carving and sculpting has been reported from other countries. The health surveillance and diagnosis of silicosis is still based on chest radiography and lung function tests. Though, High-Resolution Computed Tomography (HRCT) detects silicosis at earlier stage, in view of the limited facilities, high cost, and higher radiation, it is mainly used as tool for excluding other pathologies with similar type opacities. Use of ILO International Classification of Chest Radiographs of Pneumoconioses still remains the most important tool for epidemiological studies. Efforts have been made to develop similar classification of HRCT images for epidemiological studies. A number of biomarkers with the potential to detect silicosis and other lung diseases have been investigated including, Club/Clara cell protein 16 (CC16), serum Heme Oxygenase -1 (HO-1), Tumor Necrosis Factor Alpha (TNFα), Interleukin - 6 & 8 (IL6 & IL8), Nephronectin (Npnt), and many others but limited success has been achieved. There have been some media reports of ICMR-NIOH, Ahmedabad having developed an early detection test for silicosis based on Clara Cell Protein 16 (CC-16); however, it is not yet available for clinical trials. Studies suggest that Exhaled Breath Condensate (EBC) can be used to assess respiratory health of pneumotoxic-exposed workers as a method of pulmonary biomarkers of exposure, effect, and susceptibility in the workplace. The measurement of exhaled Nitric Oxide (NO) and Volatile Organic Compounds (VOC) is also considered to be an inexpensive, safe, and easy-to-perform test that can also be used to assess peripheral lung inflammation, diagnosis, and prognosis.[5] Silicosis is invariably asymptomatic at early stage and often go undetected till symptoms like persistent cough, breathlessness on exertion and other associated symptoms develops. Development of Progressive Massive Fibrosis and recurrent pneumothorax invariable indicate poor prognosis. Further, exposure to silica dust and occurrence of silicosis predisposes to Pulmonary Tuberculosis and often complicates the treatment. Experience in Rajasthan suggests that 25 to 40% of silicosis cases from sand stone mines and stone carving industries have radiological evidence of active or healed Pulmonary Tuberculosis. The initial results from an ongoing study by National Institute of Occupational Health, Ahmedabad, suggests that Pulmonary Tuberculosis when associated with silicosis has 2.5 times failure of treatment outcome in comparison to simple Pulmonary Tuberculosis. As silicosis is a major occupational lung disease in the country and in the absence of comprehensive policy and programme for prevention, control and rehabilitation, Public Interest Litigations (PILs) have been filed in Honourable Supreme Court and High Courts by NGOs and voluntary organizations to draw attention of the government to the plight of silicosis affected persons. Honourable Supreme Court has issued directions to National Human Rights Commission (NHRC) and various state governments for prevention and control of silicosis and providing monetary relief to victims. National Human Rights Commission in its report on silicosis submitted to the Parliament in 2010 drew attention to the plight of silicosis victims and suggested measures for prevention and control of the disease and providing relief to the silicosis affected persons.[6] National Human Rights Commission also identified Gujrat, Jharkhand, Karnataka, Madhya Pradesh, Rajasthan, and West Bengal as endemic states for silicosis. DEVELOPMENT OF RAJASTHAN MODEL OF DETECTION, RELIEF, AND REHABILITATION OF SLICOSIS VICTIMS Though silicosis had been reported from Lead and Zinc Mines in 1961 and Mica Mines in 1963 from Rajasthan, like many other states very little information was available on prevalence of silicosis in Rajasthan. There had been few reports of occurrence of silicosis among sandstone mine workers in Jodhpur, Karauli, and some other districts. The cases of silicosis were often misdiagnosed as Pulmonary Tuberculosis by medical professionals. It was common belief among workers and medical professionals that workers who worked dusty industries such as mining and construction died of Pulmonary Tuberculosis. It was series of reports on detection of silicosis among sandstone mine and stone carving workers in Karauli, Dausa, and Dhaulpur districts based on medical records of workers by National Institute of Miners' Health, Nagpur, under Ministry of Mines which drew attention of the state government and media on occurrence of silicosis in Rajasthan. The reports indicated high prevalence of silicosis varying from 38.4% to 78.5% in Karauli district among sandstone mine workers and 100% prevalence among worker who worked for more than 20 years in stone mines.[7] Suo-moto action taken by Rajasthan State Human Rights Commission and its "Special Report on Silicosis" submitted to Rajasthan State Assembly with comprehensive recommendations on detection, prevention, control, relief, and rehabilitation.[8] The report galvanized the state government to formulate and implement the comprehensive "Rajasthan Policy on Pneumoconiosis including Silicosis Detection, Prevention, Control and Rehabilitation – 2019" and make silicosis grant disbursement as flagship scheme of the government. Even before formulation of comprehensive policy, BOCW Welfare Board and Mines Department started schemes for providing relief to silicosis victims. The government amended the Rajasthan Employee Compensation (Occupational Diseases) Rules, 1965 and constituted Pneumoconiosis Board in every district and Appellate Pneumoconiosis Boards in government medical colleges. It also declared silicosis as reportable diseases under Rajasthan Epidemic Diseases Act 1957 and identified 19 of 33 as important mining and mineral processing districts. An online system for registration, certification, and payment of relief to victims was also started. Building and Other Construction Workers' (BOCW) Welfare Board, Labour Department organised silicosis detection camps in various districts and identified hotspots for occurrence of silicosis. In 137 screening camps for silicosis organized between August 2015 and August 2021, 6809 persons were examined and 3410 cases of silicosis were detected. The board also provided relief to 6758 cases including 1055 cases of death due to silicosis and disbursed an amount of 133.74 crores (US$ 17.83 million) as relief to victims. Analysis of data of silicosis victims provided relief BOCW Welfare Board revealed that there was significant difference in occurrence of silicosis and deaths due to silicosis among districts where mining and stone processing were prevalent. In stone carving districts, silicosis and death due to silicosis occurred at much younger age than mining districts. While in case of mining districts, the prevalence of silicosis and deaths due to silicosis increased with age peaking in the age group of 46 to 50 and 51 to 55 years, respectively, in case of stone carving districts, the prevalence of silicosis reached its peak in the age group of 31 to 35 and deaths in the age group of 36 to 40, respectively. The Figures 3 and 4 show age-groupwise distribution of comparative percentage of silicosis patients and deaths due to silicosis in mining and stone carving districts, respectively.Figure 3: Comparative trend of silicosis patients in stone carving and mining districts (Original)Figure 4: Comparative trend of silicosis deaths in stone carving and mining districts (Original)SALIENT FEATURES OF RAJASTHAN POLICY FOR PNEUMOCONIOSIS INCLUDING SILICOSIS DETECTION, PREVENTION CONTROL, AND REHABILITATION[9] Mission of the policy on pneumoconiosis "The mission of pneumoconiosis policy of Rajasthan is prevention and control of pneumoconiosis as an occupational disease with the ultimate aim of elimination and to provide relief and rehabilitation to affected persons." The goals and objectives of the policy include: Establishing an efficient system for detection, certification and treatment of Pneumoconiosis cases Upgrading screening and treatment facilities in selected Community Health Centers and district hospitals with high prevalence of pneumoconiosis. Establishing system for providing Relief and Rehabilitation to persons affected with Pneumoconiosis. Identification of Pneumoconiosis prone industries, mines, factories, other establishments, and adjacent areas. Implementation and enforcement of measures for prevention and control of Pneumoconiosis Implementing awareness and training programs and build capacity of all stake holders', that is, medical doctors, government officials, employers, workers, elected representatives, and people at large. Implementing state wise comprehensive program for detection, prevention, control, and elimination of Pneumoconiosis in Rajasthan. Following features of policy have already been implemented as on March 2020 for all persons suffering from silicosis/pneumoconiosis; Online registration portal for screening, certification, and disbursement of relief to cases of pneumoconiosis One-time financial assistance of Rs. 300,000 (US$ 4000) to any person suffering from silicosis/pneumoconiosis and further Rs. 200,000 (US$ 2667) to the dependent in the event of death of the silicosis victim. Rs. 10,000 (US$ 135) as funeral expenses in case of death of silicosis patient Disability Pension of Rs. 1500 (US$ 20) per month for the victim. Free treatment and medicines for victims. Benefits of other welfare schemes of the state such as Below Poverty Line (BPL) for family, Palanhar for children, scholarships for education, etc. Quarterly monitoring and review committee under chairmanship of Chief Secretary, Rajasthan. PROCESS OF DETECTION, CERTIFICATION, AND DISBURSEMENT OF RELIEF IN SILICOSIS The government started an online portal for registration of persons for certification and disbursement of relief. The initial screening of the person is conducted at Community Health Centre and if suspected, the case is referred to the district pneumoconiosis board for certification. The district pneumoconiosis board consisting of one radiologist, one chest physician, and one general physician examines the person in detail and based on chest radiograph and other investigations, certifies silicosis. The details are sent to district authorities for validation followed by payment of relief to the victim from centralized "Pneumoconiosis Fund" setup by contribution from BOCW Welfare Board, District Mining Foundation Trusts (DMFT), and the state government. The whole process is online with minimum human interface. As on May 31, 2022, 1,81,687 persons had registered for silicosis screening examination. The district pneumoconiosis boards have certified 23,436 cases of silicosis after the system became online including 6876 cases of deaths due to silicosis.[10] Additionally, 17,687 cases were certified prior to start of online system till May 2019 including 1857 cases of death due to silicosis. A total of 30,293 silicosis affected persons have been disbursed relief and 31,121 silicosis victims have registered for disability pension. Though, exact figures are not available but it is estimated that more than 550 crores (US$ 73.3 million) have been paid as a relief to the silicosis victims. The state government is also setting up a Project Monitoring Unit for implementation of policy and has allocated 5 crores (US$ 670,000) for prevention and research for silicosis. LESSONS FROM IMPLEMENTATION OF RAJASTHAN SILICOSIS POLICY Prevalence of silicosis is much higher than what is generally believed or suggested by the official statistics and large number of cases go undetected. Most cases of silicosis are undiagnosed or misdiagnosed as Pulmonary Tuberculosis. Participation of all stakeholders, workers, NGOs, unions, media, and state government is extremely important in effective formulation and implementation of policy. Monetary relief to silicosis victims is very important for participation by the affected persons and successful implementation of the policy. Policy implementation should be financed through cess on the industry and must be independent or only partially dependent of government budgetary provision. Ease of registration for detection, certification, and disbursement of relief for silicosis victims are important aspects of policy implementation. Training of medical doctors is important for uniform standards for detection and certification of silicosis Online portal for registration, certification, and disbursement of relief are effective way of implementation of policy. Media play an important role in creating awareness among public and other stakeholders. Much has been achieved in successful implementation of relief to silicosis victims in Rajasthan; however, prevention and control measures for dust in small mines and industries remains a major shortcoming though greater awareness among all stake holders has marginally improved working conditions. The hotspots for dust prone industries and mines have been identified in various districts and enforcement is being improved. The states of Haryana, West Bengal, and Jharkhand have also formulated state policies on silicosis relief and rehabilitation. It would be prudent to learn from experiences of Rajasthan model for implementation by other states and developing countries. As mining and mineral processing are important industries for economic development and employment generation and sandstone mining and stone carving are carried out in one form or another all over the country, silicosis, and other dust diseases are likely to be prevalent in most states and throughout the country. Therefore, it is necessary that a National Program for Elimination of Silicosis and other dust disease on the line of National Tuberculosis Elimination Program is formulated and implemented. In view of the large number of silicosis cases also have associated Pulmonary Tuberculosis and are more prone to having adverse outcome and treatment failure, elimination of Pulmonary Tuberculosis as envisaged in national programme by 2030 may prove to be a distant dream without controlling silicosis and other dust-related diseases.