The upland (dry-land) contamination source area of the CRMS. OU-1 is undergoing continued management and monitoring to assure public protection from mine wastes. The most significant health risk in OU-1 is direct contact and ingestion of contaminated soils. OU-2 is defined as the water, sediment and biologic resources of the Carson River, Lahontan Reservoir, Washoe Lakes, Steamboat Creek, associated Irrigation Ditches and Stillwater Wildlife Refuge. EPA Contractor and USGS are continuing studies of OU-2 areas and will be producing a (RI/FS). The most significant health risk posed by mercury in OU-2 is consumption of fish and waterfowl from affected lake & river systems. In the 1990s the EPA compelled several limited area cleanups to be completed by third parties and completed cleanup on a half dozen areas themselves. The cleanups occurred primarily in residential areas of Dayton. The remainder of the site has not undergone cleanup and due to the size and scope of the area impacted; most likely never will. Since complete site cleanup is not economically viable. A Long Term Sampling and Response Plan (LTSRP) was developed to manage site contamination into the future. The LTSRP provides guidance for land development activities (both commercial and residential) to help assure site CoC's do not impact human health and the environment. Typically, soil sampling is required to verify developed area soils do not contain CoC's at levels which may cause harm to human health.