Changes in health conditions in the Huainan coal mine in the past three decades.

Health conditions in the Huainan Coal Mine have improved greatly since 1950. In particular, the work and living environments, the underground dust concentration, the water supply and waste disposal systems, and the nutritional value of miners' food have become much better. Thus the rates of occupational, infectious, and parasitic diseases and nutritional deficiency diseases have decreased considerably among miners. The decreases in the prevalence of anthracosilicosis and hookworm have been especially striking.