Components of Coal Mine Dust Exposure and the Occurrence of Prestages of Pneumoconiosis

In the last 20 years the exposure of German coal miners to respirable dust has been lowered and controlled according to enacted dust standards. The incidence of coal workers' pneumoconiosis (CWP) dropped substantially, but the question remains whether the CWP risk has been eliminated. A historical cohort study was performed enrolling all hard coal miners at two typical collieries of the Ruhr area (Heinrich Robert, high rank coal: n = 564; Walsum, low rank coal: n = 693) and at all six collieries of the Saar area (n = 4521, special low rank coal) who began work underground without earlier exposure between 1974 and 1979 (Ruhr) or 1980 and 1986 (Saar). Thus all three typical stratigraphic horizons of German coal seams were considered. Complete individual data on shifts worked underground, exposures to respirable coal mine dust and quartz dust, and CWP development during time underground were compiled for each miner. Historical exposures were based mainly on 43,842 static gravimetric measurements. CW...