Residents in the town of Washington, when glancing to the north this past summer, may have caught a glimpse of multiple individuals decked out in Hazmat suits attached to rock-climbing ropes repelling down a sheer cliff to the canyon floor below. While the vision might have echoes of post-apocalyptic zombie movies currently in vogue, it was actually the culmination of a complex environmental clean-up project conducted by the U.S. Forest Service in conjunction with the state of California and the Nevada County Department of Public Health. From 1955 until 1979, Relief Hill Dump, located down a steep precipice about a …