Work-related dermatitis (WRD) represents a broad range of skin conditions such as irritant (ICD) and allergic contact dermatitis (ACD), as well as atopic eczema, that are either caused by or exacerbated by activities at work. In 2010, WRD affected 15.2 million American workers, representing 9.8% of the US working population. In 2016, we conducted the first “Congo Coltan Miners’ Health Study.” The present report comprises findings related to WRD. Here, data from 398 workers (199 coltan miners matched to 199 unexposed office workers) are reported. Workstation air quality (PM2.5 and volatile organic compounds or VOC levels) was monitored using BRAMC Air Quality Monitor BR-AIR-329. Each participant answered two questionnaires related to skin and respiratory health. Higher PM2.5 levels were detected at coltan miners’ workstations as compared with control sites (range, 180–210 μg/m3 vs. 19–44 μg/m3, respectively; p < 0.001); similarly, higher VOC levels were also found in coltan miners’ workstations (range, 1.4–2.3 vs. 0.5–0.8, respectively; p < 0.05). Additionally, markedly higher proportion of miners reported dermatitis for the last 12-month period (37% vs. 7%) and in the previous years as compared with controls (36.2% vs. 7%, respectively; p < 0.001). Furthermore, coltan mining work was strongly associated with WRD in the last 12-month period (aOR = 4.88 ± 1.15; 95% CI, 2.06–11.33) and in the previous years (aOR = 9.48 ± 12.3; 95% CI, 3.74–120.49). This first study on African informal coltan miners’ health showed striking results, with high dust exposure levels (PM2.5, VOC) and high frequency of WRD, suggesting the necessity to implement dust control measures to improve occupational safety in coltan mining settings.