The possibility of worker exposure to radioactive materials during accidents at nuclear facilities is a principal concern of the DOE. The KBERT analysis tool has been developed at Sandia National Laboratories under DOE support to address this issue by assisting in the estimation of risks posed by accidents at chemical and nuclear facilities. KBERT is an acronym for Knowledge-Based system for Estimating hazards of Radioactive material release Transients. KBERT's primary purpose is to predict doses to in-facility workers due to accidental releases of radioactivity. Models are also in KBERT for predicting doses to the public based upon plume dispersal models. This report gives detailed instructions on how a user, starting with knowledge of design, layout and potential hazards of a facility, can use KBERT to assess the risks to workers in that facility and to the public as a result of releases from the facility. A key feature of KBERT is the inclusion of the non-facility-specific material release, radioactive decay, and dose databases (i.e., knowledge bases) that might also be needed for such an assessment. The material release characteristics are based on the 1994 DOE Handbook for airborne release fractions/rates and respirable fractions for nonreactor nuclear facilities. Another important feature of KBERTis the inclusion of a transparent interface between KBERTand the Nuclear Regulatory Commission's CONTAIN code. This interface enables KBERT to use the validated and proven flow models in CONTAIN to predict inter-room airflows. Potential applications of KBERT include the evaluation of the consequences of evacuation practices, the effect of personal protection equipment, and the degree of containment of hazardous materials.