‘Silicosis is a silent epidemic’

Despite affecting millions of workers across industries, silicosis remains underdiagnosed and mismanaged, exacerbating India’s tuberculosis burden and threatening occupational health, says Mihir Prafulbhai Rupani, a scientist specialising in silicosis at the Health Sciences Division of the National Institute of Occupational Health in Ahmedabad, Gujarat. Rupani says reducing silicosis burden is crucial for India to meet its target of eliminating tuberculosis by 2025. Excerpts:

Bhagirath Srivas (BS): What is the current status of silicosis and silicotuberculosis in India?

Mihir Prafulbhai Rupani (MPR): Silicosis remains a significant occupational health challenge in India, predominantly affecting workers exposed to silica dust across a wide range of industries. For example, silicosis prevalence among stone mine workers ranges from 38 to 79 per cent, while among agate workers, who polish stones into beads and other decorative items, it spans from 18 to 69 per cent. Slate pencil workers are similarly affected, with prevalence rates between 25 and 55 per cent.

Silicotuberculosis, the co-occurrence of silicosis and tuberculosis (TB), presents an even more serious health risk. In affected worker populations, silicotuberculosis prevalence rates range from 5 to 25 per cent. About 52 million workers are expected to be in jobs that expose them to silica dust by 2025. A key challenge in addressing the diseases is that the high percentage of India’s workforce (92 per cent) is employed in the informal sector, which lacks adequate regulatory oversight and occupational health protections.

BS: Which are the high-risk regions?

MPR: High-risk regions are located in states with industries heavily reliant on silica-rich materials, such as mining, quarrying and construction. Rajasthan is one of the most affected states, with extensive stone mining and stone carving industries in Jodhpur, Jaisalmer and Udaipur. In Madhya Pradesh, stone mining and slate pencil manufacturing, especially around Mandsaur, contribute to silicosis. Gujarat is another critical state, with agate stone processing centred in Khambhat, tile manufacturing in Morbi and Himmatnagar, and mining activities in Surendranagar. Andhra Pradesh’s slate stone processing industries, particularly in Markapur, place many at elevated risk for silicosis. Additionally, West Bengal, Tamil Nadu and Jharkhand report elevated silicosis risks.

BS: Why is silicosis often wrongly treated for TB?

MPR: As the symptoms of TB and silicosis are very similar—cough, weight loss and fever—it is easy to confuse the two diseases. In India, doctors are trained to look for TB first, as it is more common, and there is a strong focus on TB in national health programmes. One major reason for misdiagnosis is that doctors often do not ask enough about the patient’s job and exposure to dust. A clear way to distinguish between these diseases is through a high-resolution CT scan, but these are costly and not available at primary or community health centres. Some centres can only conduct simple sputum tests for TB, which increases the chance of misdiagnosis.

BS: What measures should be taken to prevent deaths due to silicosis and provide relief to the victims?

MPR: The most important step to prevent silicosis deaths is to reduce silica dust exposure. Employers can achieve this through engineering controls, such as physical barriers to prevent dust from spreading, the use of exhaust fans, and rotating workers in dusty areas to limit exposure.

The next step is raising awareness about the dangers of silica dust in relation to both silicosis and TB. Awareness efforts should target workers, employers and all levels of healthcare. Doctors need training to recognise silicosis on X-rays and should take detailed histories to understand whether patients are exposed to silica dust. Telemedicine can also help doctors in rural areas consult with specialists.

Employers have a duty to support workers who develop silicosis by moving them to safer roles or providing financial assistance. India needs a comprehensive national health programme for silicosis.

BS: With the high silicosis burden, can India meet its target of eliminating TB by 2025?

MPR: Silicosis is one of the key conditions linked to TB, along with HIV and diabetes, and it requires focused attention in India’s TB elimination efforts. However, it still does not receive the attention it deserves. There is a misconception that silicosis primarily affects mining areas, but silica dust exposure occurs in many industries, including construction, where granite and tiles are cut. Almost every district in India has construction activity, which means silicosis can affect workers nationwide. Controlling silicosis is essential if India is to meet its TB elimination goal by 2025.

BS: What important facts about silicosis have you uncovered in your study?

MPR: Silicosis increases the risk of adverse TB treatment outcomes, leading to a higher likelihood of treatment failure and mortality.

It also raises the risk of drug-resistant TB and the need for TB re-treatment. We recommend treating silicosis as a major risk factor in India’s differentiated TB care strategy, which currently includes HIV and diabetes. All TB patients with silica exposure should be screened for silicosis, and all patients with silicosis, as well as all silica-exposed workers with TB symptoms, should be screened for active TB. We also propose replacing silicosis with silica dust exposure as the high-risk group for systematic TB testing and preventive treatment in national guidelines.

(The opinions and insights expressed are solely the expert’s and do not represent the views of the National Institute of Occupational Health, the Indian Council of Medical Research (ICMR), or the Department of Health Research) 

This was first published as part of a cover story on silicosis titled ‘Dust To Dust’ in the 1-15 April, 2025 print edition of Down To Earth