Requests for information were placed in 20 local and free papers throughout South Wales. Eighteen replies were received from individuals who forwarded either written or taped statements. The written information included in this study was publicly available. Respondents were self-selecting and were assured that their answers would remain anonymous. The diseases caused by dust, pneumoconiosis and silicosis, first came under the close investigation of the medical profession in the first part of the 19th century.
Pneumoconiosis comprises two disease processes.
In its first and simple form, it is due to the retention in the lungs of small particles of coal and rock dust. This dust is not exhaled and accumulates in the lungs in small discrete deposits which harden, fibrose and cause extremes of breathlessness, especially on exertion. The second form is called progressive massive fibrosis and is due to the combination of simple dust disease and massive fibrosis of the lung tissue. This is nearly always progressive and independent of continued dust exposure. There were also those who believed that coal dust itself was not harmful.