Silicosis: What is it and how common is it in the US?

I recently read a report from India about miners in certain areas of the country coming down with a condition called silicosis. Demand from India's booming construction industry for granite, sandstone and other minerals has seen the commissioning of more and more stone quarries and people to work in the quarries. What is silicosis and how common is it here in the United States? Joining me today to talk about silicosis is Cedric "Jamie" Rutland, M.D., Dr Rutland is a Pulmonary and Critical Care Physician and a National Volunteer Medical Spokesperson for the American Lung Association.