The present work embodies the results of scientific investigation involving the use of safe radiolysis process for degradation of PCBs; persistent organic pollutants present in used oils by gamma radiation using Co-60 as a radiation source. The work reports the salient aspects of ship breaking activity in India, gamma irradiation of PCBs, gamma irradiation of various oils, method development and validation, determination of PCBs in thermic oils using GC-MS, etc. The aim is to assess the level of destruction of PCBs in standards and oils by gamma irradiation and to determine the optimum dose of irradiation for this purpose. The studies are also directed towards effects of gamma irradiation on properties of oils. The properties of oils before and after irradiation have been studied. The study led to some useful and interesting conclusions which are covered in this book. The development and validation of method of analysis of various PCBs at their trace levels in oils is also the notable achievement of this study.