The Historical Site Assessment (HSA) is a detailed investigation of historical information from Area IV. The HSA is an evaluation that identifies sites (i.e., numbered structures) that may have contained regulated radioactive material and classifies the sites as radiologically impacted or non-impacted. The HSA describes the final status surveys performed for those impacted sites that have been released for unrestricted use by the appropriate regulatory agencies.
Impacted sites (both buildings and building footprints) requiring further sampling are identified in the HSA. The HSA is divided into two volumes (methodology and site summaries).