July 12, 2016 Kim Krisberg 0Comment

Mining is one of the most dangerous jobs in America, with more than 600 workers dying in fatal workplace incidents between 2004 and the beginning of July. And many more miners die long after they’ve left the mines from occupational illnesses such as black lung disease, while others live with the debilitating aftermath of workplace injuries. Today, researchers know a great deal about the health risks miners face on the job, but some pretty big gaps remain.

Kristin Yeoman and her colleagues at the National Institute for Occupational Safety and Health (NIOSH) hope to begin closing that knowledge gap with a new focus on the health of metal and nonmetal (MNM) miners. In an article published earlier this year in Archives of Environmental & Occupational Health, the researchers outlined current knowledge on MNM miner health and potential sources of new data, with the ultimate goal of developing a health surveillance program specifically focused on MNM mine workers.

“What we really want to do with this article is figure out what information is out there so we can better understand what we know and don’t know,” Yeoman, a medical officer in NIOSH’s Western States Division, told me. “We believe a surveillance program would be an excellent tool to help us analyze trends and outcomes and measure the effectiveness of interventions…but right now, we need to understand what information we need and how to collect it.”

Today, there are no comprehensive health surveillance systems in place to monitor the health of MNM miners. Still, such surveillance isn’t new for NIOSH — the agency has been operating the Coal Workers’ Health Surveillance Program for more than four decades in accordance with the Federal Coal Mine Health and Safety Act of 1969. In fact, NIOSH is now set to expand its coal miner health program as part of a larger effort to end black lung disease, which kills about 1,500 former coal miners every year. MNM miners face many of the same or similar hazards that coal miners do — noise, heat, silica and other dangerous dusts, chemical fumes, repetitive stress, diesel exhaust — but the current health status of MNM miners remains unknown.

Yeoman said the renewed focus on MNM miners comes, in part, from an expansion of NIOSH’s Western States Division. In turn, she said researchers now have an opportunity to focus more on occupations particularly prevalent in the American West, such as MNM mining. Yeoman and co-authors C.N. Halldin, J. Wood, E. Storey, D. Johns and A.S. Laney write:

Substantial gaps exist in our understanding of the current health status of MNM miners. Although data regarding general health status, chronic diseases, and some occupational illnesses in the general mining industry can be obtained from national health surveys such as (National Health Interview Surveys), health data specific to each mining sector are not collected. Very little information is available regarding chronic disease risk factors, occupational diseases, as well as nonfatal illnesses that cause substantial morbidity among MNM miners. Many of the cohort studies evaluating MNM miner health status were performed in other countries, and the representativeness of these miners’ working conditions to those of U.S. miners is questionable. Current surveillance systems are inadequate to monitor the health of this population.

Metal mining involves both precious and nonprecious metals, such as gold, silver, copper and zinc, while nonmetal mining can include commodities such as gypsum, silicates, aluminum oxides and potash, which is mostly used for fertilizer. MNM mining, which includes both underground and surface mining, employed more than 66,000 workers as of 2012, not including contractors, the journal article reported. Every year between 2004 and 2013, more 1,000 MNM miners sustained work-related injuries that required time away from work.

In conducting a literature review on MNM miner health, Yeoman and her colleagues found that a substantial portion is focused on lung cancer — some of that research has found “excess lung cancer deaths” among MNM miners who spent longer durations underground or who faced greater lifetime exposures to radon and diesel exhaust. Prior research on MNM miners has also examined nonmalignant respiratory diseases; increased silicosis risks; excess mortality from esophageal and stomach cancers; heat illness; and cardiovascular-related deaths. However, the article found that “methodologic issues and a narrow focus limit the ability to use current literature to effectively understand the health status of the MNM mining population.”

Yeoman and fellow researchers also reviewed national health and labor surveys as well as state health department data to see how those sources contribute to knowledge about MNM miner health. They reported that the National Survey of the Mining Population doesn’t include health questions and its labor force data might not be representative of the entire MNM mining sector. The National Health Interview Surveys provide some “useful” information on mine workers in general, but they don’t differentiate between different types of mining.

The National Occupational Mortality Surveillance System includes useful information on causes of death among MNM miners, but it’s not as useful in developing interventions targeting nonfatal conditions, such as arthritis and hearing loss. The Mine Safety and Health Administration collects data on mining-related injuries and diseases, but its data is limited by under-reporting of illnesses, many of which have a long latency period. Finally, most public health agencies do not have health data on mine workers, the article found. In fact, 10 western state health departments reported no specific data on miner health status.

“What stands out to me is that when you look at the literature on MNM miner health, it’s focused on respiratory disease and cancer and much of it is focused on mortality rather than morbidity,” Yeoman told me. “But we don’t have good information on nonfatal illnesses like musculoskeletal disorders that can lead to disability.”

In the article, Yeoman and colleagues concluded that with such big knowledge gaps, a “surveillance system focused specifically on (MNM miners) is necessary.” Such an effort would ideally gather information from sources that already have data on MNM miner health and would include active health surveillance in the form of a mobile health clinic at MNM mines and in mining communities. Other data sources could be primary care and clinical occupational health providers as well as employer-sponsored health programs.

Yeoman emphasized that plans for a MNM miner health surveillance system are in their very earliest stages. At the moment, she said, researchers are focused on gathering as much existing information as possible and reaching out to new collaborators. For example, she said an early step will be partnering with individual mines to develop research programs and identify priority health issues among MNM miners. She said NIOSH researchers also hope to collaborate with public health organizations, community-based groups, health care facilities, employers, and labor and trade organizations.

“We’re interested in hearing from any group that interacts with MNM miners,” Yeoman told me. “We want to hear suggestions, we want to know about miner health data we might not know about. Right now, it’s more about getting as much information on MNM miners as we can and figuring out who’s out there and who’s interested. …As we expand NIOSH’s reach in western states, we need to look at this industry and do whatever we can to keep MNM miners as healthy as we can.”

If you have information on MNM miner health or are interested in collaborating, email Yeoman at kyeoman@cdc.gov. For a copy of the full journal article, visit Archives of Environmental & Occupational Health.

Kim Krisberg is a freelance public health writer living in Austin, Texas, and has been writing about public health for nearly 15 years.

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