This paper reports investigations into coal's viability as an alternative filler to wood flour in wood plastic composites (WPCs)a class of materials used in building applications in lieu of pressure-treated wood coal plastic composites (CPCs) were fabricated with 15−60 wt % coal combined with high-density polyethylene and their physical (mechanical, water absorption, and metal leaching) and chemical (oxidative degradation and flammability) properties were compared with commercial WPCs. In addition, mass and energy balances (10 ton/h basis) and life cycle analyses (60 wt % filler and 1 ton basis) were conducted on CPCs and WPCs to assess environmental impact during manufacturing. At 60 wt %, CPCs had higher flexural strength, slower oxidative degradation and burn rate, and lower water absorption in comparison to commercial WPCs, suggesting better performance and stability in building applications. Furthermore, CPC manufacturing showed 44% lower greenhouse gas emissions and 62% less energy usage in comparison with WPC. These results indicate that the direct utilization of coal as a filler in construction composite applications may yield lower-cost products with lower associated emissions and energy demand compared to that of existing WPC materials, potentially yielding a more sustainable end use for coal than current uses such as power production.