Applies to insulating oil containing less than ppm of PCB, which is considered to be non-PCB oil only. Discusses the significance of oil-spillage regulations and their applicability to electric supply substations; identifies the sources of oil spills; discusses typical designs and methods for dealing with oil containment and control of oil spills; and provides guidelines for preparation of a typical Spill Prevention Control and Countermeasure (SPCC) plan.