A 2026 systematic review in Public Health analyzed 45 U.S. studies and found consistent associations between residential and occupational coal exposure and higher cancer mortality, with all 18 residential studies showing statistical significance. This observational evidence base, lacking RCTs due to ethical constraints on exposure trials, highlights patterns missed by narrower incident-focused research: post-2003 occupational studies uniformly linked coal work to increased deaths, while incidence findings remained mixed. Limitations such as healthy worker bias and ecological fallacy underscore the need for caution, yet the mortality signal persists across designs. Synthesizing this with Nogueira et al.'s findings and a 2021 Environmental Research study on Appalachian coal counties (n>50,000, observational cohort) reveals underreported synergies with PM2.5 and heavy metals driving lung and colorectal cancers beyond direct mining. A 2019 International Journal of Environmental Research and Public Health analysis of 12 states further ties proximity to operations with 15-20% excess mortality, exposing gaps in original coverage that overlooked economic burdens like rising healthcare costs in low-income areas. These patterns indicate industrial pollution as a modifiable driver with broad implications for policy, as rollback of protections could accelerate carcinogen exposure in vulnerable populations.