[Black lung](http://en.wikipedia.org/wiki/Black_lung “Wikipedia”) disease is posing a greater threat to coal miners in far southwest Virginia, and scientists arent sure why.

A report released by the U.S. Centers for Disease Control and Prevention shows that the number of cases of black lung disease is rising in Lee and Wise counties and that the cases are more severe.

Researchers examined 328, or 31 percent, of some 1,055 coal miners who were working underground in Lee and Wise in March and May of this year. They ranged in age from 21 to 63 and had worked in the mines for an average of 23 years.

Thirty of the miners had evidence of black lung, and 11 of the cases were advanced. The miners with the advanced cases had an average age of 51 and had spent an average of 31 years working in underground coal mines.

[Read](http://www.wtopnews.com/?nid=106&sid=882650 “Read the Story”) (AP via WTOP)