A program involving exploratory and analytical studies of the concept of retrofilling askarel insulated transformers with polydimethylsiloxanes (silicone oil) has generated concerns regarding the practicality and economic feasibility of this concept. This paper identifies and discusses technical and economic problems associated with the retrofilling concept. The following conclusions are given. (1) While transformers specifically designed around the characteristics of silicone fluid appear to be a logical successor to askarel filled units, the two fluids are not one-to-one substitutes in existing transformers. Reliability and load capacity of an askarel transformer retrofilled with silicone will be decreased. (2) It is economically impractical to remove all the PCB's in an askarel transformer to the point where no environmental problems exist via the drain and flush method.