Prevalence of Black Lung Continues to Increase among U.S. Coal Miners
July 20, 2018
New Report Shows Increase Most Pronounced in central Appalachia
One in ten underground coal miners who have worked in mines for at least 25 years were identified as having black lung, according to a new report by the National Institute for Occupational Safety and Health (NIOSH) published in the American Journal of Public Health. Coal miners in central Appalachia are disproportionately affected with as many as 1 in 5 having evidence of black lung–the highest level recorded in 25 years.The data in this report come from NIOSH’s Coal Workers Health Surveillance Program (CWHSP). NIOSH has operated the CWHSP and tracked the burden of black lung disease in underground coal miners since 1970. Through the Program, coal miners are offered periodic chest x-rays to detect early signs of black lung. For this study, NIOSH researchers looked at x-ray data collected by the CWHSP from working underground miners during 1970 to 2017.
This latest national estimate of 10 percent is higher than the previous NIOSH estimate last reported using data from 2012, which found 7 percent of coal miners who worked more than 25 years in underground mines had evidence of black lung.
“Breathing coal mine dust is the sole cause of black lung, and it is entirely preventable,” said David Blackley, DrPH, epidemiologist and one of the study’s co-authors. “This study provides further evidence that effective dust control methods and protections to reduce coal mine dust exposure along with early detection of the disease are essential to protect miners’ health.”
A Steady Increase
By the late 1990s, the proportion of screened miners with black lung disease reached the lowest level on record. However, after that time, the trend reversed. Since 2000, the nationwide prevalence of black lung has increased. Recent NIOSH research indicates an unprecedented increase in progressive massive fibrosis (PMF), the most severe form of black lung disease, after the prevalence of PMF had fallen to 0.08% among all miners examined by NIOSH in the CWHSP in the late 1990s.
While this is the first published report of the prevalence of black lung in the central Appalachian region, a 2016 report showed an uptick in the number of cases of PMF among working coal miners in Kentucky, Virginia and West Virginia.
The current prevalence of severe black lung in this part of the country is as high as it’s been (5%) since record-keeping began in the early 1970s. Black lung disease is completely preventable and would not occur without hazardous coal mine dust exposures.
NIOSH Commitment
NIOSH is committed to addressing the current black lung epidemic and continues to work with partners to more fully define the scope of the problem and make recommendations. In addition to improving methods to control dust generated by mining activities, NIOSH scientists have recently worked to improve methods for detecting airborne coal mine dust to provide immediate warnings when dust levels are too high.
NIOSH continues to provide medical screening services to underground and surface coal miners so that they are informed of their health status and can take steps to protect it. Additionally, through its mobile outreach efforts, NIOSH is bringing medical screening to areas hit hardest by the epidemic.
For more information on the Coal Workers’ Health Surveillance Program and NIOSH’s Respiratory Health Division, please visit the NIOSH website.
NIOSH is the federal institute that conducts research and makes recommendations for preventing work-related injuries, illnesses, and deaths. For more information about NIOSH visit www.cdc.gov/niosh.
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Black lung disease on the rise
February 16, 2018 by Anna Allen And Carl Werntz, The Conversation
Underground mining is one of the most dangerous occupations in the United States. Risks include inhaling toxic gases, such as methane, carbon monoxide and hydrogen sulfide; being crushed by roof falls or mining equipment; drowning when tunnels fill with water; and injury in fires and explosions. Even if miners survive the workplace, they may suffocate to death years later.
Surface and underground mining is associated with two pneumoconioses, or dust diseases of the lung. Black lung disease, also known as coal workers' pneumoconiosis, comes from inhaling coal mine dust. The other disease, silicosis, is caused by inhaling silica dust from crushed rocks. Black lung and silicosis often appear together because coal seams are found between rock layers that contain silica.
When miners inhale dust, it deposits along their airways. Their bodies try to remove the dust by sending in special white blood cells called macrophages to engulf and chemically digest it. But the cells are unable to break down the dust, so they die and release enzymes that damage lung tissue. This causes problems that include chronic bronchitis, emphysema and fibrosis (scarring). In progressive massive fibrosis, the most severe version of black lung, scarring causes lung volume to shrink, further damaging adjacent lung tissue and making air exchange even worse.
Miners typically work 10 to 12 hours a day and up to seven days a week. This increases their exposure time and decreases the recovery time their bodies need to heal damage from silica and coal dust particles. Traditionally, black lung was associated with miners who had been working for at least 20 years, with symptoms often appearing after retirement. The recent trend is that black lung, including progressive massive fibrosis, is occurring after a shorter time in mining – as little as five years mining underground.
The "hot spot" described in the JAMA study is in parts of western Virginia, southern West Virginia and eastern Kentucky. This area includes three of the federal Mine Safety and Health Administration enforcement districts – areas where the agency inspects coal mines and investigates accidents and complaints from miners.
We see patients in Morgantown in north-central West Virginia and Cabin Creek in south-central West Virginia. We have noticed increased severity of disease in patients in the southern part of the state. During our first year, from June 2016 to May 2017, working in Cabin Creek providing federally authorized black lung exams, the incidence was 16 percent for black lung and about 6 percent for progressive massive fibrosis. In contrast, the same exams in our Morgantown clinic found black lung in less than 3 percent of cases, and only a few progressive massive fibrosis cases in four years.
What do you think could be causing more cases of black lung disease?
The increase is likely the result of several factors. Much of the coal in the area of the JAMA study is so-called "low coal," with seams that are only 20 to 36 inches high. This "low coal" is hard to mine but profitable because it is metallurgical coal, which has high value for steel production.
Manufacturers stopped producing shorter machines designed for mining "low coal" in about 1990 due to quality control problems. Now mines use taller machines designed for seams that are 32 to 36 inches high. As these machines cut coal from the seam, they must remove at least 12 to 16 inches of sandstone adjacent to the coal.
Cutting that much sandstone significantly increases miners' exposure to silica dust from the crushed rock. Newer machines also cut through coal and rock much more quickly than older models, generating more dust. Generally, what we call black lung is primarily silicosis in a coal miner, so silica exposure is significant to the development and progression of disease.
Working in "low coal" also involves more physical effort than mining "high coal." Crawling and stooping while carrying mining gear and operating equipment requires more physical effort. Miners breathe more heavily and frequently, which can increase dust exposure. And it is hard to keep air flowing smoothly through these smaller mines, so dust concentrations may be higher in some spots.
What does the coal industry do to prevent black lung?
Screening is available to current miners through the federal government's Coal Workers' Health Surveillance Program, which uses x-rays to detect early changes in the lungs. This information is shared with miners so they can decide whether to continue working in coal mining, but is kept private from their employers.
The main way to prevent black lung is to keep miners from inhaling dust. After 20 years of debate, recent changes in federal law decreased the allowed exposure from 2.0 milligrams per cubic meter of air to 1.5 milligrams. Continuous personal dust sampling has also been implemented so that miners can have real-time data on their exposures. This information is then used to determine whether a mine requires more frequent inspections.
To decrease dust exposure, mine operators can spray water to knock dust out of the air, increase air flow in tunnels to move dust out more quickly, or require miners to wear respirators.
Black lung diagnosis can be complicated. Some of the most common symptoms include shortness of breath, decreased exercise tolerance, chronic cough, coughing up phlegm and inability to breathe lying flat. Other diseases can cause similar symptoms, so it is important for miners to talk to their primary care doctors.
Some states have workers compensation programs that offer benefits to workers diagnosed with black lung. The Federal Black Lung Program provides medical coverage for eligible miners with lung diseases related to pneumoconiosis, along with benefits for those who are totally disabled by it, and for families of miners who die of black lung disease.
There is no cure for black lung disease – we can only treat symptoms. Medications, such as inhaled steroids, can help patients breathe more easily. More severe cases can require oxygen and possibly lung transplants. One step patients can take is to stop smoking, which also destroys lung tissue. Smoking does not cause black lung, but it can make the symptoms more severe.