A more thorough explanation:

Black-lung disease is a chronic lung disease caused or worsened by exposure to coal dust during coal mining. It is also known as pneumoconiosis, which is a medical condition characterized by respiratory and pulmonary impairments.

The disease is usually latent, meaning it may not show symptoms until after the exposure to coal dust has ended. Clinical pneumoconiosis is any medically recognized condition caused by coal-dust exposure while working in a coal mine. Some examples of clinical pneumoconioses are:

• Silicosis or silicotuberculosis
• Massive pulmonary fibrosis
• Anthrosilicosis

These conditions are caused by the permanent deposits of particulate matter in the lungs, coupled with the lung tissue's fibrotic reaction. Legal pneumoconiosis is any chronic restrictive or obstructive pulmonary disease or impairment and related conditions arising out of coal-mine employment.

For example, a coal miner who has been exposed to coal dust for many years may develop black-lung disease, which can cause breathing difficulties, coughing, and chest pain. This condition can be debilitating and may require medical treatment.