[en] In late October and early November of 1991, single-shell tank (SST) 241-T-111 (on the Organic Watch List) was sampled and analyses were conducted on the materials obtained to complete Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement) Milestone M-10-00 to sample and analyze two cores from each tank. Other objectives that these measurements and inventory estimates support are as follows: Obtain estimates of both the concentration and total quantity of key analytes relating to safety issues, such as organics and radionuclides; Provided input to risk assessment-based disposal decisions for the waste; and Implement physical property measurements, such as rheology, bulk density, and particle size. These measurements are necessary for the design and fabrication of retrieval, pretreatment, and vitrification systems. The purpose of the tank characterization report is to describe and characterize the waste in SST 241-T-111, based on information from various sources. This report summarizes the available information regarding the waste in tank 241-T-111, and arranges this information in a format useful to support management and technical decisions concerning this waste tank