Since its discovery in the late 19th century, pneumoconiosis has shaped the lives of thousands of miners. In some ways it became inextricably linked to the South Wales coal field and was a major public health threat to the men who worked in those mines. The disease was caused by the conditions of work and worsened the situation of many who were already living in poverty. This historical research account traces the miners' plight and touches on some of the public health issues raised by the disease.