Other Names: Black lung disease; Pneumoconiosis; Anthrosilicosis; CWP. Caplan Syndrome is a related condition.
Hospital: Report by phone, fax, or mail
Lab: Report by phone, fax, or mail
Physician/Health care providers: Report by phone, fax, or mail
Medical Examiners: Report by phone, fax, or mail
Poison Control Centers: Report by phone, fax, or mail
Occupational Nurses: Report by phone, fax, or mail
Local Public Health Agency (LPHA): No follow-up required, unless outbreak occurrence
Report to the IDPH Division of Environmental Health:
Iowa Department of Public Health
Division of Environmental Health
Lucas State Office Building
321 E. 12th Street
Des Moines, Iowa 50319-0075
Phone (Mon-Fri 8 am - 4:30 pm): 800-972-2026
24-hour Disease Reporting Hotline: (For use outside of EH office hours) 800-362-2736
Coal worker's pneumoconiosis (CWP) is a lung disease that results from breathing in dust from coal, graphite, or man-made carbon over a long period of time. CWP results from >10 years of occupational exposure.
A. Clinical Description
CWP occurs in two forms: simple and complicated (progressive massive fibrosis or PMF). The simple form is usually not disabling, but the complicated form often is, and also causes premature death.
Early CWP does not usually cause symptoms. Most chronic pulmonary symptoms in coal miners are caused by other conditions, such as industrial bronchitis from coal dust or coincident emphysema from smoking. Cough can be chronic and problematic in patients even after they leave the workplace, even in those who do not smoke. PMF causes progressive dyspnea. Occasionally, patients cough up black sputum (melanoptysis), which occurs as a result of rupture of PMF lesions into the airways. PMF often progresses to pulmonary hypertension with right ventricular and respiratory failure and premature death.
B. Sources of Exposure
Coal workers pneumoconiosis is caused by the inhalation of dust from coal, graphite, or man-made carbon.
C. Population at Risk
Chronic lung diseases, such as pneumoconiosis (black lung) were once common in miners, leading to reduced life expectancy. In some mining countries, CWP is still common, with approximately 4,000 new cases every year in the USA (4% of workers annually) and 10,000 new cases every year in China (0.2% of workers).
The incidence and rate of CWP progression is related to the amount of respirable coal dust to which miners were exposed during their working lifetime. Most affected workers are over the age of 50, and have over 20 years of exposure history, although some workers have been diagnosed after as few as 10 years of exposure
To characterize the impact of premature mortality attributed to CWP in the United States, CDC's National Institute for Occupational Safety and Health (NIOSH) analyzed annual underlying cause of death data from 1968--2006, the most recent years for which complete data were available.
During 1968--2006, CWP was identified as the underlying cause of death for 28,912 decedents aged =25 years. Of these, 3,983 (13.8%) were aged 25--64 years, including four (0.1%) aged 25--34 years, 40 (1.0%) aged 35--44 years, 494 (12.4%) aged 45--54 years, and 3,445 (86.5%) aged 55--64 years. Among CWP decedents aged 25--64 years, 3,954 (99.3%) were male and 3,891 (97.7%) were white.
Overall, CWP deaths among U.S. residents aged =25 years declined 73%, from an average of 1,106 per year during 1968--1972 to 300 per year during 2002—2006. Age-adjusted death rates among residents aged 25--64 years declined 96%, from 1.78 per million in 1968 to 0.07 in 2006; age-adjusted death rates among residents aged =65 years declined 84%, from 6.24 per million in 1968 to 1.02 in 2006.
Years of potential life lost before age 65 years (YPLL), and mean YPLL were calculated using standard methodology, and was reported in a December 2009 MMWR report. It described the results of that analysis, which indicate that during 1968--2006, a total of 22,625 YPLL were attributed to CWP (mean per decedent: 5.7). Annual YPLL attributed to CWP decreased 91.2%, from an average of 1,484 YPLL per year during 1968--1972 to 154 per year during 2002--2006. However, annual YPLL from CWP have been increasing since 2002, from 135 in that year to 169 YPLL in 2006, suggesting a need for strengthening CWP prevention measures.
D. Diagnosis, Treatment, and Prognosis
Diagnosis depends on a history of exposure and chest x-ray or chest CT appearance. In patients with CWP, x-ray or CT reveals diffuse, small, rounded opacities or nodules. The finding of at least one opacity > 10 mm suggests PMF. The specificity of the chest x-ray for PMF is low, because up to 1/3 of the lesions identified as being PMF turn out to be cancers, scars, or other disorders. Chest CT is more sensitive than chest x-ray for detecting coalescing nodules, early PMF, and cavitation.
Treatment is rarely necessary in simple CWP, although smoking cessation and tuberculosis (TB) surveillance are recommended. Patients with pulmonary hypertension, hypoxemia, or both are given supplemental oxygen therapy. Pulmonary rehabilitation can help more severely affected workers carry out activities of daily living. Workers with CWP, especially those with PMF, should be restricted from further exposure, especially to high concentrations of dust. TB is treated in accordance with current recommendations.
The outcome for the simple form of coal workers pneumoconiosis is usually good. However, the complicated form may become a disabling illness that may include cor pulmonale, or failure of the right side of the heart, pulmonary tuberculosis, and premature death.
E. Prevention of Exposure
CWP can be prevented by suppressing coal dust at the coal face. Despite long-standing regulations, exposures continue to occur in the mining trade. Respiratory masks provide only limited protection. Preventive measures include eliminating exposure, stopping smoking, and giving pneumococcal and influenza vaccinations.
Medical surveillance is critical to detect coal workers’ pneumoconiosis as early as possible, to guide intervention, and to keep the disease from advancing to stages in which it becomes progressively debilitating and life-threatening. Because patients with CWP often have had exposure to both silica dust as well as coal dust, surveillance for TB is usually done utilizing annual tuberculin skin testing. In those with positive test results, sputum culture and cytology, CT, and bronchoscopy may be needed to confirm TB.
In light of an observed onset of advanced pneumoconiosis among younger coal miners, and the apparent regional clustering of rapidly progressive cases, the National Institute for Occupational Safety and Health (NIOSH), in collaboration with the Department of Labor Mine Safety Health Administration (MSHA), has developed, staffed, and implemented the ECWHSP. Additional information is available at www.cdc.gov/niosh/topics/surveillance/ords/ecwhsp.html.
Coal mineralogy, mining conditions, respirable dust and silica exposure concentrations, mining and dust control strategies, and other relevant data in regions with disease clusters are being collected under a separate NIOSH project entitled, "Dust Control Technology for Black Lung Hot Spots." Outreach and awareness resources are available through the NIOSH website.