He's one of a handful of miners on an April afternoon to move through the RV parked at the fire department in Wharton. Inside, a team of NIOSH workers shepherds them from station to station: medical history, questionnaire, breathing test, chest X-ray. Foster hopes the tests will provide evidence he can use to submit a claim for benefits. Other miners are still working and want to make sure their lungs are clear.
It is from this rolling medical unit, in part, that NIOSH has documented the return of black lung. For decades, miners have been entitled to free X-rays every five years, and this has helped track the drop in the disease's prevalence. After the data started showing a reversal, NIOSH sent its RV out to gather more data in 2005.
What these researchers found, combined with data from routine medical monitoring, was worrisome: From the 1970s through the 1990s, the proportion of miners with signs of black lung among those who submitted X-rays dropped from 6.5 percent to 2.1 percent. During the most recent decade, it jumped to 3.2 percent.
In a triangle of Appalachia - southern West Virginia, eastern Kentucky and western Virginia - the numbers were even higher. The NIOSH unit found a disease prevalence of 9 percent in Kentucky from 2005 to 2009, for example.
Prevalence of the most severe form of black lung has tripled between the 1980s and the 2000s and has almost reached the levels of the 1970s.
A wake-up call for some came after the Upper Big Branch explosion in southern West Virginia in April 2010, which killed 29 miners. Of the 24 who had enough lung tissue for an autopsy, 17 had signs of black lung. Some had as few as 10 years of experience in mines; they ranged in age from 25 to 61.
Black lung leaves miners' lungs scarred, shriveled and black. They struggle to do routine tasks and are eventually forced to choose between eating and breathing.
"No human being should have to go through the misery that dying of [black lung] entails," said Dr. Edward Petsonk, who treats patients with black lung and works with NIOSH. "It is like a screw being slowly tightened across your throat. It is really almost a diabolical torture."
Underpinnings of an epidemic
There are theories about why the disease has returned, but no definitive answers. One likely explanation: Miners are breathing a more potent mix of dust. Coal seams are surrounded by rock, much of which contains the mineral silica. When ground up, silica is more toxic to the lungs than coal dust and can cause faster-progressing disease.
With larger coal seams becoming mined out, companies are turning to thinner seams surrounded by more rock. At the same time, because of the price of coal and advances in mining equipment, it now makes more sense economically for companies to cut through large amounts of rock to get at the coal.
NIOSH research suggests this may be having an effect. A particular marker on an X-ray is often indicative of silica-related disease. Comparing miners' X-rays taken from 2000 to 2008 with those taken from 1980-1999, researchers found that the proportion bearing these markers had nearly quadrupled and, in central Appalachia, had increased almost eight times over.
Rules are supposed to limit the amount of silica in the air in mines, but a Center for Public Integrity analysis of MSHA's dust sampling database, obtained under the Freedom of Information Act, shows that the agency has long failed to control silica dust. In each of the past 25 years, the analysis found, the average valid silica sample has been above the allowed level.
Another possible explanation for black lung's resurgence: The number of hours worked by miners has steadily increased over the past three decades, MSHA data show. Longer hours mean more exposure to dust and less recovery time.
At the same time, production has increased, thanks in part to powerful new equipment. A longwall shearer, for example, can carve out huge swaths of coal in little time.
Mark McCowan ran one of these behemoths for the final years of his career. "By the time I was 40 years old, I had mined more coal than most miners mine in a lifetime," he recalled, sitting in his living room in Pounding Mill, Va.
McCowan was diagnosed with black lung at age 40. His disease has progressed to the most severe form; now 47, he finds it harder and harder to breathe. He pointed to a photo of a beaming, blond-haired 2-year-old on his wall - his grandson, Haiden. McCowan sees him two or three times a week and plays with him for as long as his lungs can take. "My biggest fear," he said, "is I won't live long enough for him to remember me."
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 Charleston Gazette staff writer Ken Ward Jr.
Read more in Monday's Gazette and on the CPI website, http://www.iwatchnews.org/.Hear more about black lung Monday on NPR's All Things Considered and Tuesday on NPR's Morning Edition. Additional NPR stories are available at www.npr.org.