This Corrective Action Decision Document/Closure Report has been prepared for Corrective Action Unit 266, Area 25 Building 3124 Leachfield, in accordance with the Federal Facility Agreement and Consent Order. Corrective Action Site 25-05-09 is the only Corrective Action Site within Corrective Action Unit 266. Data collected during the field investigation activities showed evidence of contamination at this site in the soil, septic tank, and distribution box. The Corrective Action Decision Document and Closure Report have been combined into one report because the contaminants of concern were either not present in the soil, or present at concentrations not requiring corrective action. Contaminants identified within the septic tank and distribution box have been adequately addressed.