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Federal Fix for Silica Dust Understates That Thousands of Coal Miners Are Still Sick and Dying



September 6, 2023 - The gravesite in Danny Smith’s vast and verdant yard is shaded by hulking trees.

Danny Smith

Photo: Elaine McMillion Sheldon/PBS Frontline

His parents’ graves are adjacent and marked by a massive headstone. In summer, crickets chirp, birds sing, and leaves rustle in the breeze.

It is a peaceful spot for Smith’s final resting place. And it’s ready.


“I honestly never imagined it would get this bad,” Smith, 51, wrote recently in a text message from his home in the coalfields of eastern Kentucky.

His breathing is so labored now, he said, that he wasn’t sure he could get through a phone call. “I have a hard time just walking to the kitchen without losing breath,” he wrote. “I stay so tired and exhausted.”

Smith’s lungs are riddled with fibrotic tissue. When NPR and PBS Frontline last visited in 2018, he tried to mow his lawn, but a fit of heavy hacking forced him to his knees. Coughing violently, he spit out what looked like moist and crusty bits of dark gray paper with black streaks. That’s dead lung tissue, his respiratory therapist said later.

Smith suffers from progressive massive fibrosis (PMF), an incurable, fatal and advanced stage of black lung disease. It plagues thousands of sick and dying coal miners like him. The likely cause, studies conclude, is exposure to clouds of silica dust while mining coal, and digging through solid rock to get to coal seams and prepare them for mining. Silica, one of the most abundant minerals on earth, is 20 times more toxic than coal dust alone. It wreaks havoc on lung tissue when inhaled repeatedly.

“As bad as I feel now, and I never thought I would say it,” Smith wrote, “I so wish I had never stepped foot inside a mine.”

Smith worked just 12 years underground and was diagnosed with PMF at 39. Both are shocking numbers because it used to take decades of mining for coal miners much older to get as sick as this.

A crackdown on silica dust. Or is it?

Now, after decades of delay, the federal Mine Safety and Health Administration (MSHA) is finally getting serious about overexposure to silica in the nation’s mines.

The agency is proposing a silica dust exposure limit twice as tough as it is now. MSHA would also directly regulate excessive silica exposures, something it hasn’t previously done, making citations and fines possible for putting miners at risk.

“Our current standard as it relates to regulating silica in the nation’s mines … does not adequately protect miners’ health,” Christopher Williamson, the Assistant Secretary of Labor for Mine Safety and Health, acknowledged in an interview.

But there are questions about how effective even these measures will be, beginning with MSHA’s assumptions on potential lives saved and disease avoided.

An investigation by Public Health Watch, Louisville Public Media and Mountain State Spotlight shows that the plan’s purported benefits understate the silica risk to coal miners and the urgent need for immediate action. The news organizations documented cases of PMF not mentioned in MSHA’s plan or included in the calculation of how many lives the proposed rule could save and how much disease it could prevent.

The results are staggering: more than 4,000 cases of PMF identified by black lung clinics and the National Institute for Occupational Safety and Health (NIOSH) since 2010; more than 1,500 diagnoses in the last five years alone.

Understating the risk potentially weakens MSHA’s case as its proposed rule faces possible challenges from the mining industry.

“The scale of human tragedy is profound,” said Kirsten Almberg, an epidemiologist at the Black Lung Data and Resource Center at the University of Illinois Chicago. Almberg tracks the occurrence of PMF as reported by federally funded black lung clinics.

The news organizations’ investigation surveyed both independent and government-supported clinics that test coal miners for black lung disease. Also obtained, through the Freedom of Information Act, were unpublished counts of disease from the federally funded clinics.

“There’s really no way to quantify … the individual tragedy that happens in each of these cases, with lives cut short, careers cut short, communities reeling and families falling apart,” Almberg said. “It’s just devastating.”

These thousands of cases of disease, suffering and death are not included anywhere in the 168 pages of MSHA’s proposed rule on silica dust exposure. They’re not part of the agency’s prediction of how many lives its new regulation might save (just 63 over 60 years) and how much disease might be avoided (244 cases of black lung over 60 years).

“The difference in scale is striking,” Almberg added, after comparing the actual count of PMF cases and MSHA’s predictions.

“I don’t have a lot of faith in the modeling,” said Dr. Drew Harris, a University of Virginia pulmonologist who is medical director for black lung clinics operated by Stone Mountain Health Services in southwest Virginia.


“Not factoring into their risk prediction the amount of disease that is currently happening and had been happening for 10 to 15 years, I think, is not acceptable,” Harris said.

A fraught history of failure to protect

The proposed crackdown on silica follows a fraught history of MSHA inattention and decades of failure to protect miners from the toxic dust.

A 2018 NPR/PBS Frontline investigation found that MSHA had measured dangerous exposure to silica dust in coal mines for 30 years but did nothing effective in response. There were 21,000 excessive silica dust exposures from 1986 to 2016, according to MSHA’s own data.

More than twice that many dust samples (52,000) exceeded silica levels first recommended by NIOSH in 1974 and by the U.S. Department of Labor’s own special advisory committee on black lung in 1996. That stricter limit has applied to all industries except mining since 2016.

That long-recommended limit (50 micrograms of silica per cubic meter of dust) is precisely the limit MSHA is proposing now.

Just since 2016, the investigation found, MSHA’s silica dust samples from coal mines exceeded the newly proposed limit more than 5,300 times. Overexposure to silica dust has been and continues to be a persistent threat.

It’s not like the agency was completely in the dark. As far back as 1996, internal MSHA memos acknowledged the problem, including a cluster of severe black lung disease linked to silica dust exposure.

MSHA’s Williamson cited the 2018 NPR/PBS Frontline investigation and subsequent studies and reports in proposing tougher limits on silica.

“The timing was absolutely right to do this,” he said. “The science is solid … What currently exists is not protective enough.”

So many miners dead and dying

That’s evident at black lung clinics like Stone Mountain and pulmonary rehab centers focused on miners with PMF. Marcy Martinez is a respiratory therapist at New Beginnings Pulmonary Rehab, which has two centers in Virginia and Kentucky. She said her caseload alone defies MSHA’s projections for avoided death and disease.

“It’s ridiculous to think that that’s the biggest impact this new rule will have … I don’t think they have a concept of what the reality is out there …,” Martinez said, fighting back tears.

“Just seeing the sick ones, just seeing the severity, just seeing the deaths … We lost 11 men in the last seven months … 147 deaths have occurred in my clinics, from black lung, in 10 years. And that is heartbreaking.”

One small clinic alone in eastern Kentucky has identified far more cases of advanced black lung disease in less than a decade than MSHA predicts it will avoid in six decades with the new rule in place.

“As of now, we are almost at 700 cases of complicated black lung,” said Dr. Brandon Crum, a radiologist specializing in black lung X-ray assessments at United Medical Group in Pikeville, Ky. That’s Crum’s count of PMF cases at his clinic from 2015 through 2023 so far.

“I’m surprised that we continue to see that much disease and the severity of the disease,” Crum added. “We’re seeing younger and younger miners get it … Men in their thirties, forties and fifties on a regular basis.”

MSHA deferred questions about its risk analysis, and its failure to include the thousands of cases of disease among American miners, until after the public comment period on the proposed rule ends Sept. 11.

“MSHA encourages all interested parties to provide comments on the proposed rule, including the preliminary risk analysis, and relevant data for the Agency’s consideration,” the agency said in a statement to Public Health Watch.

Almberg, at the University of Illinois Chicago, believes she knows why MSHA would not include in its risk analysis the actual number of PMF cases recorded by clinics and NIOSH since 2010. The analysis depends on knowing precisely how much silica dust exposure sick miners experienced, Almberg said, and that detail is not available for the cases reported by clinics and NIOSH.

“I do think it is an underestimate,” Almberg said. MSHA said so in its proposal, she added, though there still was no mention of thousands of documented cases of disease in the last decade.