Tony Daviesis a retired professor of occupational health who has focused on lung diseases for many of his 50 years working in central and southern Africa.
He served as director of South Africa’s National Institute of Occupational Health from 1985 to 2002 and has published more than 100 articles, many on subjects related to health in the mining industry.
Q: Why does exposure to quartz dust predispose miners to tuberculosis of the lungs?
A: Small particles of quartz (silica) reach the depths of the lungs and damage the cells that remove foreign material from the air spaces. These cells are the first line of defense against tuberculosis. Once the lungs are thoroughly dusted with silica, the increased risk of contracting tuberculosis persists throughout life. Silicosis commonly progresses or develops after workers retire. It impedes breathing and can eventually lead to heart failure.
Q: What makes the situation in South African mines so serious?
A: Uncontrolled exposure to quartz dust has been associated with high levels of tuberculosis for a very long time, but in South Africa a poor tuberculosis control service and the uncontrolled spread of HIV/AIDS have pushed the level of new infections to unprecedented levels.
Q: What is the key to reversing the epidemic?
A: The key is dust control – and in fact most occupational disease originates from aerosols in the workplace. The interaction of quartz dust, tuberculosis and HIV has proved disastrous for South Africa. Mines must become more conscious about controlling dust. Respiratory protection isn’t always enough, especially for regular full shift work. Source control can’t be underestimated, whether it’s the use of wet methods, engineering controls like local ventilation or specialized systems and equipment.