In Appalachian states such as West Virginia, Kentucky, and Tennessee, underground coalmining is being edged out by mountaintop removal (MTR) mining, which is a form of surface mining and is sometimes referred to as such. This method uses explosives to remove mountain rock and gain access to coal seams, and the waste created in the process — including massive amounts of rock, soil, and vegetation — is then dumped into nearby valleys into what are called “valley fills.”1 Although less expensive and more efficient than conventional methods, opponents have criticized the adverse effects on both the environment and health associated with MTR across a range of studies.
In a study published in March 2019, researchers at Indiana University conducted a latent class analysis to examine relationships between symptoms of various diseases and proximity to MTR sites.2 Using data from cross-sectional surveys of households in 3 Appalachian states (N=2756), they identified 3 latent classes with low, intermediate, and high probability of symptoms across multiple organ systems. After controlling for covariates, the results demonstrated that the intermediate and high-symptom classes were significantly linked to residential proximity to MTR sites. The highest odds ratio (OR) was observed for the MTR condition vs controls for the high-symptom group (OR, 2.17; 95% CI, 1.80-2.61).
“MTR mining impacts the air, water, and soil and raises concerns about potential adverse health effects in neighboring communities,” as stated in a 2017 systematic review funded by the National Toxicology Program at the National Institute of Environmental Health Sciences, National Institutes of Health.1 Exposures “associated with MTR mining include particulate matter, polycyclic aromatic hydrocarbons, metals, hydrogen sulfide, and other recognized harmful substances.”
In this review of nearly 100 relevant studies, the authors noted adverse human health effects related to MTR mining, such as higher rates of mortality, birth defects, and cardiopulmonary effects. However, they concluded that the existing body of evidence is inconsistent because of the observational nature of the studies, methods used, and the lack of consideration for potentially confounding factors. While the authors acknowledged the plausibility of health consequences resulting from MTR exposure, they advised that more direct methods are needed “for assessing individual exposure levels tied to health effects, including early indicators of impacts such as cardiopulmonary function tests.”1
Noting the limitations associated with data derived from observational studies, the research group from Indiana University relied on a different approach to examine the effects of MTR on respiratory symptoms. In a 2015 study, they used propensity scores to “draw more confident causal inferences about mining effects on respiratory health using non-experimental data” from a survey of 682 adults living in 2 areas of Virginia where MTR mining takes place in one of these communities but not the other.3
Covariates used in estimating propensity scores included age, sex, obesity, smoking status, and other variables. The findings showed that the prevalence of respiratory symptoms and chronic obstructive pulmonary disease were significantly higher in the MTR group (P <.0001), and because of the study design, these results suggest that the respiratory impairment is a result of MTR exposure vs other risk factors.
In another study published in 2015, the same group found evidence of blood inflammation in people who resided near MTR mining activity compared with those residing further away; smokers, coalminers, and individuals with acute illness were excluded from the study.4 Significantly higher levels of C-reactive protein were observed in participants who lived near mining sites vs the comparison group (adjusted mean, 4.9 mg/L vs 0.6 mg/L; P <.03), and these individuals were also more likely to report cardiopulmonary disease and other illness symptoms.
Despite the growing evidence of MTR’s health effects, in 2017, the Trump administration halted a large study by the National Academies of Sciences, Engineering and Medicine, which was seeking to further elucidate health risks to residents living near MTR mining sites.5 The administration cited budget concerns as the main reason for terminating the study.