On 6 April 1993 a major radiological accident occurred at a plutonium extraction facility at a location then known as Tomsk-7, Russian Federation. The accident blew the concrete cover off the reaction vessel and led to widespread contamination of the site and the surrounding area up to a distance of 28 km. The report describes the events leading up to the accident and the radiological consequences. It provides a detailed description of the decontamination and recovery operations and gives an analysis of their effectiveness. Contents: Preamble; 1. Introduction; 2. Background information; 3. Fuel reprocessing at the radiochemical works; 4. The accident and its cause; 5. Radiological situation after the accident; 6. SCE site; 7. Surrounding area; 8. Recommendations.