[en] This document presents the results of an engineering evaluation/cost analysis (EE/CA) that was conducted to evaluate alternatives for addressing final disposition of contaminated buildings and structures in the 100-N Area of the Hanford Site. The Hanford Site is located in southeastern Washington State and is owned by the U.S. Government and operated by the U.S. Department of Energy, Richland Operations Office (RL). In November 1989, the 100 Area of the Hanford Site (as well as the 200, 300, and 1100 Areas) was placed on the U.S. Environmental Protection Agency's National Priorities List (NPL) under the Comprehensive Environmental Response, Compensation, and Liability Act of 1980. The 100 Area NPL includes the 100-N Area, which is in various stages of the remediation process. It has been determined by RL that hazardous substances in the 100-N Area ancillary facilities may present a potential threat to human health or the environment, and that a non-time critical removal action at these facilities is warranted. To help determine the most appropriate action, RL, in cooperation with the Washington State Department of Ecology (Ecology) and the EPA, has prepared this EE/CA. The scope of the evaluation includes the inactive contaminated ancillary facilities in the 100-N Area, the facilities residing in the buffer zone, and the Hanford Generating Plant (HGP) and the solid waste management units (SWMUs) inside HGP support facilities. The 105-N Reactor and 109-N Heat Exchange facilities are excluded from this EE/CA evaluation