Black lung's back? How we became complacent with coal miners' pneumoconiosis

The name black lung says it all. When miners inhale excessive amounts of coal dust, the fine air filtration system of the lungs sieves out the dust, which then remains permanently in the lung. These deposits can even be seen with the naked eye if the lungs are removed from the body, hence the name.

The sinister part is the slow progressing breathing disorder that develops over many years due to excessive lung inflammation and scarring that is triggered by coal mine dust. This disease, coal workers' pneumoconiosis or black lung, is preventable and was widely considered a thing of the past in Australian miners.

But just before Christmas 2015, people were shocked to hear about newly confirmed cases of black lung in Queensland miners. Governments responded swiftly to investigate the problem, with inquiries established by the Queensland government and the federal senate.

The Department of Natural Resources and Mines has released some interim findings outlining poor documentation of confirmed cases, a lack of preventive measures taken where confirmed cases were found and too few screening tests being performed.

There is no cure for black lung. The review has recommended a greater focus on prevention and early detection, and ongoing surveillance.

Preventing black lung

Prevention involves managing exposure by monitoring dust levels and actively taking steps to reduce coal dust exposure in miners. Mining practices have progressively improved over the years, but overseas experience tells us not applying standards can result in cases of black lung.

There are no uniform standards for acceptable levels of dust exposure throughout Australia. Authorities permit Queensland miners to be exposed to coal dust levels higher than those in the United States, where the exposure limit is set at two micrograms per cubic metre.

Prevention also involves regular screening of exposed workers and having the results looked at by experts. The screening procedure requires imaging the lung with X-rays and assessing for possible lung impairment with breathing tests and focused clinical assessment. Each of these steps has to be quality controlled in order to successfully detect the subtle changes of black lung as early as possible.

The very early changes of black lung are an increase in dots and lines on the X-ray. The problem is the blood vessels and airways in the normal lung also show up as dots and lines, and so it takes expert training to tell when things become abnormal.

Fortunately, there are ongoing improvements in imaging technology, and there are now suggestions that a low-dose CT scan may make early detection easier and more reliable. Measuring impairment of lung capacity is very accurate when done in a quality controlled lung function laboratory, and this is the standard needed when trying to detect the changes of black lung as early as possible.

Of course, these assessments are useless if they’re not acted on. This means it is not only important to assess the results of individual workers, but to take a helicopter view of larger numbers of workers.

Given the significance of the issue and the potential implications, the peak professional body, the Thoracic Society of Australia and New Zealand believes this is best done at a national level, and independent of mining companies. There is also value in making the results of monitoring and screening accessible, so that the process is transparent.

Why has black lung returned?

Efforts in the 20th century to eradicate the disease including setting occupational exposure limits, introducing personal protective equipment, and improvements in dust management and health monitoring dramatically reduced the numbers of miners with black lung.

But in 2013, there were 25,000 deaths globally recorded from black lung. State-run mines in China now report black lung in between 4% and 17% of workers, and in Colombia, an growing coal producer, 36% of miners were recently found to have black lung.

Black lung is has been classified by Safe Work Australia as a deemed disease. This means the disease is caused by specific work-related activities, in this case prolonged exposure to coal dust. We don’t know exactly what has happened to cause black lung to reappear, but statements in the Queensland mines inspectorate report of 2014-15 indicating significant dust exposure above recommended limits are highly concerning.

There are now even recorded increases of black lung in the United States. It appears that just as the coal economy is a multinational activity, so are its risks. Black lung is just one of many diseases that can develop in miners. Conditions such as silicosis, occupational COPD (colloquially called emphysema), bronchitis and occupational lung cancer all require evaluation.