The Persistent, and Rising, Threat of Black Lung Disease

Despite being on the decline after the 1970s, the prevalence of black lung has been on the rise over the last 2 decades,¹ and the federal government has issued a new rule on miners' safety.² With changes in mining technology, miners can dig deeper, exposing them more to silica, which is highly toxic and is driving rising rates of black lung.¹

Pneumoconiosis, which encompasses the family of interstitial lung diseases—those that cause progressive scarring of lung tissue and eventually a lack of oxygen in the blood³—can result from an autoimmune condition. It can also develop after an individual has inhaled either organic or nonorganic compounds that include bird and animal droppings, cotton or other fibers, silica, asbestos, diacetyl, beryllium, and talc.^3-5

Common forms of pneumoconiosis are asbestosis, silicosis, mixed-dust pneumoconiosis, and byssinosis, and they all are considered occupational lung diseases.^4-7 One of the most well-known types of pneumoconiosis and potentially the best-known occupational illness in the US⁸—perhaps infamous—is coal workers’ pneumoconiosis, also known as miner’s lung and black lung disease. As its eponymous name states, this subtype of pneumoconiosis results from inhalation of coal dust and is most often seen in coal miners.⁷ It entails both inflammation and fibrosis of the lung tissue, and cases can be simple or complicated.⁶

Described as far back as the 16th century as a blue-black marbling of the lung and in the 19th century as black pigmentation and darkening of the lungs, black lung disease is most often seen in miners of hard coal but can also be found among those who work in soft-coal or graphite mines.^8,9

Recent data show that per US county overall, there are 4.34 cases of black lung disease and 3.44 deaths as a direct result of it. This number indicates there are approximately 0.04 deaths per 1000 US population, and 4 deaths per 100,000 US population; for cases of black lung, 0.11 and 11, respectively. One of the most well-known areas with a high concentration of black lung disease is Appalachia, which stretches from southern New York state to northern Mississippi and all of West Virginia, comprising 423 counties; 206,000 square miles; and 26.4 million residents.^10,11 Here, among those with at least 25 years of mine work, approximately 20% of coal miners have black lung disease.^10,12 Further, more younger miners—those born after 1940 compared with those born in 1939 or earlier—have a higher risk of dying from this nonmalignant respiratory disease.¹²

Pneumoconiosis, better known as black lung disease or miner’s lung, is a progressive lung condition that involves both inflammation and fibrosis of lung tissue, and can remain asymptomatic for years | Image Credit: adam88xx-stock.adobe.com

While black lung disease can initially be asymptomatic, it is a progressive disease and can lead to a range of severe and debilitating symptoms that significantly impact daily life and overall quality of life. Over time, these symptoms can worsen, and they often require ongoing medical care and limit a person’s ability to work or engage in physical activities.

Symptomatic cases can take years to develop,^6,13,15 and there is no cure—treatment is palliative.¹³ Common symptoms of black lung include the following^6,13,16:

• Persistent and debilitating cough
• Shortness of breath
• Pain during breathing
• Chest tightness
• Black sputum
• Difficulty exercising
• Wheezing and crackling sounds in the lungs
• Progressive massive fibrosis
• Black spots on the lungs

There are many methods used to evaluate an individual for lung diseases that carry over into use among those with black lung disease. Principal imaging tests are chest x-rays, CT scans, and MRIs.¹⁷

A chest x-ray is a fast and painless method that involves investigating lung structures and damages to them. CT scans, also painless image, take that investigation further through the use of large amounts of detailed images (also known as slices) of both the lungs and of the chest, which then are used to form a comprehensive representation of the condition of the lungs and their structures. MRIs bring both chest x-rays and chest CT scans together by explaining what those test results may indicate. Although not painful, MRIs can be uncomfortable and very loud; they also pose a few risks for those with implanted devises and metal inside their bodies. MRIs frequently involve images first without contrast and then images with contrast.¹⁷ Essentially acting as a highlighter, a contrast is a gadolinium-based agent that helps to enhance the images taken during an MRI because it can align with the magnetic field and is harmless in injectable form; otherwise, it is a toxic rare earth metal,¹⁸ enabling the radiologist to more accurately make their diagnosis.¹⁹

Pulmonary function tests (PFTs), also known as lung function tests, are also incorporated when evaluating for black lung disease, and they are necessary if coal mine workers want to file for workers’ compensation.²⁰ Unlike imaging tests, which typically are used to diagnose, pulmonary function tests help to detect the degree of severity of the diagnosis,¹⁴ which includes total lung capacity, tidal volume, functional residual capacity, residual volume, and vital capacity—among many other indicators.²¹

There are 3 main types of PFTs. Spirometry evaluates how much and how fast an individual can exhale air, lung volume (also known as plethysmography) helps to tell how much air the lungs can hold and how much is left, and lung diffusion capacity gauges if it is easy for oxygen to enter the bloodstream.^21,22

Although black lung disease is progressive and the damage is irreversible, there are treatments to help alleviate symptoms, improve quality of life, and slow down the progression. Bronchodilators are used to keep airways open, and they can also help fight inflammation. Pulmonary rehabilitation comprises exercises that facilitate patients learning to breathe better. Supplemental oxygen is often be prescribed in more severe cases to help get more air into the lungs. Lung transplants are advised for very severe cases. Clinicians also recommend avoiding any more exposure to coal dust or other lung irritants, including cigarette smoke and vaping.^6,7,16

Black lung disease remains a serious and persistent occupational hazard, particularly for coal miners and others exposed to harmful organic or inorganic lung irritants. The ongoing prevalence of the devastating condition underscores the need for continued vigilance, early detection, and comprehensive care, and its irreversible nature highlights the importance of prevention and timely intervention. A strong commitment to protecting workers' health and improving conditions is essential to prevent future cases and support those already affected.

References

1. Cohen RA, Rose CS, Go LHT, et al. Pathology and mineralogy demonstrate respirable crystalline silica is a major cause of severe pneumoconiosis in U.S. coal miners. Ann Am Thorac Soc. 2022;19(9):1469-1478. doi:10.1513/AnnalsATS.202109-1064OC

2. Daly M, Willingham L. Coal miners have long faced risk of black lung disease. Now they’re getting new protections. AP. April 16, 2024. Accessed August 26, 2024. https://apnews.com/article/coal-miners-black-lung-disease-silica-dust-05071eec125cb5be706604aa0fd99299

3. Mayo Clinic staff. Interstitial lung disease. Mayo Clinic. April 25, 2023. Accessed August 23, 2024. https://www.mayoclinic.org/diseases-conditions/interstitial-lung-disease/symptoms-causes/syc-20353108

4. Pneumoconiosis. Johns Hopkins Medicine. Accessed August 23, 2024. https://www.hopkinsmedicine.org/health/conditions-and-diseases/pneumoconiosis#:~:text=Pneumoconiosis%20is%20one%20of%20a,usually%20take%20years%20to%20develop

5. Pneumoconiosis. In: DeLight N, Sachs H. StatPearls. StatPearls Publishing LLC; 2024. https://www.ncbi.nlm.nih.gov/books/NBK555902/#:~:text=Pneumoconiosis%20is%20any%20lung%20disease,known%20as%20an%20occupational%20disease

6. Black lung disease (coal workers’ pneumoconiosis). Cleveland Clinic. Accessed August 23, 2024. https://my.clevelandclinic.org/health/diseases/25135-black-lung-disease

7. Coal worker’s pneumoconiosis (black lung disease). American Lung Association. Accessed August 23, 2024. https://www.lung.org/lung-health-diseases/lung-disease-lookup/black-lung

8. Black lung disease. Britannica. Updated July 28, 2024. Accessed August 23, 2024. https://www.britannica.com/science/black-lung

9. Donaldson K, Wallace WA, Elliot TA, Henry C. Coal worker’s pneumoconiosis (black lung disease). J R Coll Physicians Edinb. 2017;47(3):296-302. doi:10.4997/JRCPE.2017.317 https://pubmed.ncbi.nlm.nih.gov/29465110/

10. Summit Consulting. Black Lung Incidence Study Final Report. US Department of Labor. October 2023. Accessed August 23, 2024. https://www.dol.gov/sites/dolgov/files/OASP/evaluation/pdf/Black-Lung-Incidence-Study-Final-Report-508.pdf

11. About the Appalachian region. Accessed August 23, 2024. https://www.arc.gov/about-the-appalachian-region/

12. Maher K. Black lung resurgence prompts new mining rules. The Wall Street Journal. August 28, 2023. Accessed August 24, 2024. https://www.wsj.com/health/healthcare/black-lung-resurgence-prompts-new-mining-rules-8e4c1629

13. Coal worker’s pneumoconiosis symptoms and diagnosis. American Lung Association. Updated June 7, 2024. Accessed August 23, 2024. https://www.lung.org/lung-health-diseases/lung-disease-lookup/black-lung/symptoms-diagnosis

14. About Pneumoconioses. National Institute for Occupational Safety and Health (NIOSH). Accessed August 23, 2024. https://www.cdc.gov/niosh/pneumoconioses/about/index.html

15. Nunez K. What is black lung disease? Healthline. June 30, 2022. Accessed August 23, 2024.https://www.healthline.com/health/black-lung

16. Coal worker's pneumoconiosis. Penn Medicine. Accessed August 24, 2024. https://www.pennmedicine.org/for-patients-and-visitors/patient-information/conditions-treated-a-to-z/coal-workers-pneumoconiosis

17. Tests for lung disease. National Heart, Blood, and Lung Institute. Accessed August 24, 2024. https://www.nhlbi.nih.gov/health/lung-tests#:~:text=A%20chest%20X%2Dray%20is,lung%20tissue%20scarring%2C%20called%20fibrosis.

18. Haederle M. Contrast caution. The University of New Mexico Health Sciences. February 24, 2022. Accessed August 24, 2024. https://hsc.unm.edu/news/2022/02/doctor-researches-toxic-side-effects-rare-earth-metals-mri.html

19. Ferris N, Goergen S. Gadolinium contrast medium (MRI contrast agents). Inside Radiology. Accessed August 24, 2024. https://www.insideradiology.com.au/gadolinium-contrast-medium/

20. Instructions for black lung physical examination (guide to completing form Cm-988). US Department of Labor. Updated August 2017. Accessed August 24, 2024. https://www.dol.gov/agencies/owcp/dcmwc/CM-988A

21. Pulmonary function tests. Johns Hopkins Medicine. Accessed August 24, 2024. https://www.hopkinsmedicine.org/health/treatment-tests-and-therapies/pulmonary-function-tests#:~:text=Pulmonary%20function%20tests%20(PFTs)%20are,treatment%20of%20certain%20lung%20disorders

22. Pulmonary function tests (PFTs). City of Hope. Updated September 27, 2022. Accessed August 24, 2024. https://www.cancercenter.com/cancer-types/lung-cancer/diagnosis-and-detection/pulmonary-function-tests#:~:text=The%20three%20main%20PFT%20types,testing%20and%20lung%20diffusion%20capacity