About this story:

Our stories about black lung were jointly reported by the Center for Public Integrity and NPR News as part of Hard Labor, an occasional series on health, safety and economic threats to U.S. workers. Additional reporting was provided by Ken Ward Jr. of the Charleston Gazette.

Hear more about black lung Monday, July 9, on NPR's "All Things Considered" and Tuesday, July 10, on NPR's "Morning Edition."  Additional NPR stories are available at www.npr.org.