CHARLESTON (AP) — Evidence suggesting black lung disease is on the rise among Appalachian coal miners who increasingly cut through rock containing silica is strong enough to warrant action by mine operators and regulators, federal officials said Wednesday.

The debilitating disease decreased for three decades in the U.S., but has been rising in parts of West Virginia, Kentucky, Virginia and, to a lesser degree, Pennsylvania over the past 10 years, said Michael Attfield, an epidemiologist for the National Institute for Occupational Safety and Health.

“We’re seeing six times as much simple pneumoconiosis ... and about 15 times as much severe disease,” Attfield said during a presentation at the West Virginia Coal Association annual mining symposium. “This should not be happening.”

Though NIOSH has been unable to pin down a cause, the agency suspects longer hours, greater silica exposure and increased productivity with fewer workers, among other things. Attfield called for tighter airborne dust standards, better efforts by mine operators to limit exposure and better technology for detecting and removing airborne dust.

The U.S. Mine Safety and Health Administration, meanwhile, suspects silica is playing a role. Dust samples collected in southern Appalachia show silica content often spikes above federal standards, even as the total amount of dust is within legal limits, said Bob Hardman, manager of MSHA’s southern West Virginia operations.

“It’s been around quite likely for a long period of time,” said Hardman, who took over MSHA’s southern West Virginia operations two-and-a-half years ago. “Our sampling shows we do have a problem.”

Attfield believes miners are kicking up more silica dust by cutting through rock more often now that thick coal seams are largely gone after more than a century of mining in the region. “This may come about because of the need to mine thinner seams,” he said.

Hardman has begun asking mines that have high silica readings to rewrite dust control plans the first time. If the problem recurs, Hardman is ordering rewrites.

It’s unclear whether other MSHA districts are requiring mines to rewrite dust control plans. However, the agency is pushing new technology for measuring dust levels.

For decades, the industry has relied on lab tests that take more than a week. A new device under consideration by MSHA measures dust almost instantly and allows quick action to lower exposure, said Joe Lamonica, a consultant for the Bituminous Coal Operators Association. Often overexposure can be corrected by simply moving a miner to a different location, he said.

Therein lies the key to controlling black lung, Attfield said.

“It’s entirely preventable,” he said. “Dust control is it.”