Persistence and Shifts in Occupational Lung Diseases

Black lung disease and silicosis have roots in the industrial revolution, and beryllium disease dates to before World War II, but these conditions have not been consigned to the dustbin of history. In fact, changing work conditions, new industries, and even nearby environmental exposure have kept them relevant to respiratory practice, according to speakers at a session during the annual meeting of the American College of Chest Physicians (CHEST).

“The reality is they haven’t gone away, and they’re still very much active and part of our clinical practice,” said Maeve MacMurdo, MBChB, during her presentation.

She went on to discuss beryllium disease, which became a concern with its introduction in the 1930s and the development of the atomic bomb and aerospace applications due to its light weight, strength, and heat resistance. However, in the past 20 years, its use has shifted to non-traditional applications such as abrasive blasting, which strips paint from metal to prevent rusting. The practice previously used silica but switched to coal slag abrasives, which contain beryllium as a byproduct. “There’s been a lot of debate among the industry about whether this truly is a real health risk, and a lot of pressure to reconsider this, but the reality is that clinically, we are seeing sandblasters and shipbuilders with beryllium sensitization and chronic beryllium disease. This is a real exposure which many of these workers are not aware of, and there still is not [widespread] worker screening, even though it’s mandated by OSHA,” said MacMurdo, who is a staff physician at Cleveland Clinic.

She also cited a case series of beryllium disease in workers who had been exposed to beryllium because a nearby factory blew concrete dust into their area. “This is where a really thorough occupational history is key” to identify potential beryllium disease in a patient, according to MacMurdo.

Another example is military uses, where beryllium is employed in aircraft and ammunition. Military aircraft crashes can lead to exposures, as can wounds from beryllium-containing shrapnel or bullets. She pointed out that there are veterans diagnosed with sarcoidosis who very rarely get screened for chronic beryllium disease. “This is really one of those things where the exposure is there, but it’s often not well recognized, and there have been cases confirmed of chronic beryllium disease from these retained shrapnel and retained ammunition,” said MacMurdo.

Beryllium acts by triggering an autoimmune response that can lead to sensitization. Once sensitized, an individual is at heightened risk for chronic beryllium disease, which can occur long after exposure and even at low levels, though some never develop chronic beryllium disease at all. “There’s no magic bullet where if you get past 5 years of exposure, you’re now safe. Your risk is kind of constant,” said MacMurdo. Unfortunately, tests for beryllium sensitization aren’t very sensitive and can lead to false negatives, and the test is not widely available, she added.

The good news is that chronic beryllium disease is very treatable, particularly early in the disease. “They respond like sarcoidosis [patients], and so we use a lot of steroid medications, methotrexate, azathioprine — and in general, they work well,” said MacMurdo.

Beryllium exposure isn’t likely to go away even with the best engineering controls, she said. “We’re likely to still see beryllium sensitization, and the reality is that many of the workers we see do not have the best engineering controls and really are not aware of their exposure. But if we can find these at-risk workers early, we can start to screen and really find early disease and treat them before they become symptomatic and before they develop lifelong problems. This is where their occupational history is so important because if you don’t know you’re looking for it, you won’t spot it,” said MacMurdo.

Another lung disease that hasn’t gone away is silicosis, according to Jeremy Hua, MD, who spoke next. He cited the case of a 27-year-old man diagnosed with silicosis whose family had a business fabricating and installing engineered stone, also called artificial stone, which is commonly used for countertops. This newer material doesn’t have to be transported from quarries, can be customized, and is cheaper than natural stone. It has become very popular and sales are booming, according to Hua. However, its 90% silica content is much higher than other stone materials such as soapstone (50%-75%) or granite (20%-40%), which puts workers at greater silicosis risk, according to Hua. The first case of silicosis associated with the manufacture of these products was reported in Spain in 2010, and there are now case reports from at least 10 countries. “Unfortunately, it is probably under-recognized,” he said, citing a study of 544 active engineered stone workers that found 28.2% had been diagnosed with silicosis.

His group is building a database of affected workers, which includes 169 cases to date, with 32% having progressive massive fibrosis. The workers also seemingly had more aggressive silicosis, as more than in 1 in 5 workers (21%) had autoimmune disease. Many of the workers are younger with less experience and are disproportionately migrant or non-native speakers, and they are often contractors with fewer medical and legal protections than employees.

Hua also noted that while some believe that silicosis has few treatment options, “there’s actually a lot that can be done, including screening for some of these other silicosis-related conditions, and one of the most impactful questions you can ask your patient is whether or not that have they have workers compensation coverage because that can actually protect them in a lot of different ways,” he said.

For both silicosis and black lung disease, an occupational history combined with imaging is enough for a diagnosis, with no need for invasive testing. “Importantly, though, if you do make a diagnosis, that starts a clock for statutes of limitations for legal protection, so working with someone who has familiarity with the occupational medicine world can be helpful,” said Hua.

Next, Drew Harris, MD, an associate professor of pulmonary and critical care at the University of Virginia, discussed black lung disease among coal miners. He said that exposure to coal mine dust is a risk factor for developing chronic obstructive pulmonary disease (COPD). “I think that’s very underappreciated amongst many pulmonologists,” said Harris.

He showed a slide summarizing a study comparing 600 coal miners with 100 controls that found a relationship between coal dust exposure and risk and severity of developing emphysema. “This is independent of smoking, and it shows the effect of coal mine dust is about the same as smoking for the development and severity of emphysema,” said Harris.

Another study, which included the National Institute for Occupational Safety and Health Coal Workers’ Health Surveillance Program, found that of never-smoker miners who underwent pulmonary function tests throughout their careers, 7.7% developed COPD. The heightened rate occurred even among miners who worked for less than 10 years.

Black lung disease has a wide spectrum of severity, according to Harris, and he cited a patient he had who has undergone various COPD treatments, including inhaled therapies, azithromycin, roflumilast, and dupilumab. “So I think there are lots of things we can do for lots of these miners,” he said.

Black lung disease often resembles idiopathic pulmonary fibrosis, and dust-related fibrosis can be progressive. There are treatment options for progressive fibrosis, and patients can also be referred for lung transplants. In fact, more lung transplants were performed on coal miners in 2023 than any previous year, according to unpublished data. “I think this speaks to two things. Number one is that there’s really an ongoing crisis of black lung, predominantly in Central Appalachia. But also that some of these miners are more recognized and getting referred to tertiary level care, which is challenging in rural environments, and so I think that speaks to the success for some access to care in a really geographically isolated community,” said Harris.

One evolving factor in black lung disease is that many of the larger coal deposits have already been depleted and are no longer mined. Instead, miners are spending more time working thinner coal seams, often in confined spaces close to rock layers that lead to more exposure to rock dust. One study of 5064 US mines showed that this leads to an increased risk for silica exposure.

Coal miners may also develop symptoms long after they stop working in the mines. A study of 130 retired coal miners showed that 31% had significant radiographic progression of disease on X-rays taken at retirement and again an average of 3.6 years later, with 9% developing progressive massive fibrosis only after retirement. “I think this speaks to the importance of ongoing follow-up for folks who have left the mines, even if it’s been decades after they’ve left the mines,” said Harris. He referred to a larger epidemic illustrated by a study he published in January, which examined 1177 patients who had developed progressive, massive fibrosis, in the past 5 years. Most lived in Central Appalachia, and most worked underground, and in 31.6%-34.9% of cases X-rays showed r-type small opacities that reflect silica dust exposure.

Harris also discussed his efforts to help miners with black lung disease receive worker’s compensation benefits. The Federal Back Lung Program provides comprehensive healthcare coverage, including lung transplants if necessary. “It’s really life-changing for people. It also provides a small monthly stipend, which can also be super important,” said Harris.

MacMurdo, Hua, and Harris had no relevant financial disclosures.