Number of black lung cases rising again

Early-stage pneumoconiosis, commonly called black lung disease, can be asymptomatic, but advanced cases often lead to disability and premature death, according to the National Institute for Occupational Safety and Health.

From 1998 through 2007, coal workers' pneumoconiosis played a role, among other health factors, in 8,111 deaths, according to NIOSH statistics. In about 40% of those cases, black lung initiated a string of health events leading directly to the death.

In 1998, there were 1,103 coal worker deaths to which pneumoconiosis contributed, according NIOSH. That number dropped annually to 525 in 2007. But NIOSH also has reported that the number of black lung cases has begun to increase again, particularly among younger miners in the Appalachia region.