[en] A joint Operations and Engineering Contractor and Research and Development Contractor team was assembled early in fiscal year 1985 by the Operations and Engineering Contractor to address issues and problems associated with characterization of single-shell tank wastes located on the Hanford Site. This multidisciplinary team was asked to address both the requirements of characterizing single-shell tank wastes and the most effective methods of conducting this characterization. These team efforts continued throughout fiscal years 1985, 1986, and 1987 and are expected to continue until single-shell tank waste characterization has been satisfactorily completed. This document summarizes the initial characterization strategy developed by the team; describes the team's, activities during fiscal years 1985, 1986 and 1987; presents the significant results of the single-shell tank waste characterization activities; and identifies changes in characterization strategy resulting from both team activities and other relevant information. The Single-Shell Tank Waste Characterization Team addressed and documented statistical requirements of estimating the inventory of single-shell tanks by tank sampling, evaluated model validity and model predictions of SST contents, defined the statistical requirements of model calibration and validation, assessed the technical requirements of characterization efforts, defined the performance assessment requirements of characterizing the single-shell tank wastes, and developed a characterization plan for single-shell tank wastes that recognizes additional information is required to obtain a final single-shell tank waste characterization strategy. 4 figs