A certain killer

Published : Apr 11, 2003 00:00 IST

SILICOSIS is one of the oldest known occupational diseases and affects the lungs. It is caused by the inhalation of particles of silica, mostly from quartz in rocks, sand and similar substances. According to the World Health Organisation, it is a progressive disease that belongs to a group of lung disorders called pneumoconiosis. It is identified by the formation of lumps (nodules) and fibrous scar tissues in the lungs.

While there are no immediate estimates of the number of people suffering from silicosis, it is known to occur among miners, foundry workers, stonecutters, sandblasters, tunnel workers and rock drillers. Four forms of silicosis can affect an adult:

* Chronic silicosis is a mild form of the disease and results only in partial lung impairment. It occurs over a 15-year span of exposure to silica sand.

* Complicated silicosis results in gasping, weight loss and extensive formation of fibrous tissues (fibrosis) in the lungs. Those suffering from this condition are at risk of developing tuberculosis.

* The accelerated form occurs after five to 10 years of exposure to silica sand. While the symptoms are similar to the complicated form, patients with the accelerated type develop rheumatoid arthritis and other auto-immune disorders.

* Acute silicosis develops within six months to two years of intense silica exposure. Patients lose weight rapidly and experience shortness of breath. They are at great risk of contracting tuberculosis.

While the precise mechanism that triggers silicosis is still unclear, what is known is that particles of silica dust get trapped in the alveoli (tiny sacs) of the lungs. Blood cells, called macrophages, in the alveoli ingest the silica and die. The resulting inflammation attracts other macrophages to the region. The nodule forms when the immune system creates fibrous tissues to seal off the reactive area in the lungs. Fibrosis persists even after exposure to silica particles ends.

There is no cure for silicosis. Therapy can only relieve symptoms, treat complications and prevent respiratory infections. All forms of silicosis lead to complete respiratory failure and death. A heart-lung transplant may save some patients.

According to a doctor at the Pondicherry Government Hospital, who spoke on the condition of anonymity, all the affected women from Villianur and Arumparthapuram villages suffer from silicosis as a result of years of exposure to silica sand. Silica ingestion could have been prevented by clearly identifying high-risk areas at the workplace, educating workers about the dangers of overexposure to silica dust, training them in safety techniques and providing them with protective clothing and equipment.

Speaking from her hospital bed, Anusuya says workers including her were not told about the dangers of silica exposure. Nor was any protective equipment provided. "I believe the protective mask costs Rs.350. If we had known about the silica risks, we would have bought these masks ourselves instead of spending thousands of rupees on medicines and surgery, just to die," she gasps.

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