The Howe Sound Company's Holden Mine was profitable in part by making few outlays for the impacts of its on-site operations. For example, the low-grade copper ore was concentrated and the tailings were dumped next to the mine portal, covering many acres of wetlands. Although this practice was not unusual for its time, it took place within a remote and otherwise untouched area subsequently surrounded on 3 sides by federally designated wilderness (The Glacier Peak Wilderness Area). Modern regulations put into place after the mine's closure prohibited such practices, and ultimately the U.S. Environmental Protection Agency declared the Holden Mine area as a Superfund site. The impact from the former mining operations at Holden are only mild compared to other Superfund sites in the United States in terms of their impact on human populations because the area is so remote from population centers. The waters of Railroad Creek flow directly past the tailing piles, which introduces significant amounts of iron to the water, reducing the stream's biodiversity as well as cementing the stream bed.