Unexpectedly high concentrations of inorganic gases and volatile organic compounds (VOC) were released from the ventilation stack of tank 241-C-106 during sluicing operations on November 18, 1998. Workers experienced serious discomfort. They reported an obnoxious acrid odor and the 450 ppm VOC in ventilation stack 296-C-006 exceeded the level approved in the air discharge permit. Consequently, the operation was terminated. Subsequent analyses of samples collected opportunistically from the stack indicated many organic compounds including heptenes, heptanones, and normal paraffin hydrocarbons (NPH) and their remnants were present. Subsequently, a process test designed to avoid unnecessary worker exposure and enable collection of analytical samples from the stack, the breathing area, and the receiver tank was conducted on December 16, 1998. The samples obtained during that operation, in which the maximum VOC content of the stack was approximately 35 ppm, have been analyzed by teams at Pacific Northwest National Laboratory and Special Analytic Services (SAS). This report examines the results of these investigations. Future revisions of the report will examine the analytical results obtained for samples collected during sluicing operations in March. This report contains the available evidence about the source term for these emissions. Chapter 2 covers characterization work, including historical information about the layers of waste in the tank, the location of organic compounds in these layers, the total organic carbon (TOC) content and the speciation of organic compounds. Chapter 3 covers the data for the samples from the ventilation stack, which has the highest concentrations of organic compounds. Chapter 4 contains an interpretation of the information connecting the composition of the organic emissions with the composition of the original source term. Chapter 5 summarizes the characterization work, the sample data, and the interpretation of the results.
