Figure 1From: Role of pyrite in formation of hydroxyl radicals in coal: possible implications for human healthCorrelation between sulfur that is associated with pyrite in coal and prevalence of coal workers pneumoconiosis. The data is from Huang et al., 2005 [25] who have compiled extensive data from the USGS coal quality database [53] and the first National Study of Coal Workers' Pneumoconiosis [54].Back to article page