An emergency administrative order was issued to the Oglala Sioux Tribe as owner of the Northwest Housing Standing Pipe, part of the Oglala Sioux Rural Water System, after the EPA determined that conditions existed at the facility that may present an immenent and substantial endangerment to the health of persons served by the Oglala Rural Water System. The EPA made this determination based on a tank inspection report that identified contamination in the Northwest Housing Standpipe storage tank. [The Tribe was required to complete repairs of the tank, then disinfect the tank. No final cost of repairs and other required work is available.]