Oligomers of chlorotrifluoroethylene (POLYCTFE) have been found to possess excellent properties as lubricants and hydraulic fluids. The 3l1 oil, consisting primarily of oligomers of 3 and 4 units, is a candidate base stock for nonflammable hydraulic fluids for advanced aircraft. Unfortunately, ultrastructural studies of the livers from rats exposed to vapors of POLYCTFE for 90-days revealed an increase in the number of peroxisomes, dose-dependent mitochondrial swelling and a dose-dependent increase ...