The environmental, energy, and economic factors causing increased interest in recycling used engine oil are reviewed. Current used oil disposal practices and the choices of recycling used oil as a fuel supplement or a re-refined lubricant are discussed
Use as a fuel supplement for stationary combustion units has raised concern over lead emissions. However, reduced use of lead in gasoline in combination with current stack gas emission control systems should eliminate this concern.
Although it is technically feasible to produce a high quality engine oil from re-refined base stocks, the acceptance of re-refined engine oils will depend upon the re-refiners ability to insure quality from batch-to-batch.
A small energy savings, equivalent to about 1.4 billion liters (9.0 million barrels) of crude per year, is possible if the used engine oil now used for road oiling or dumped is recycled by available methods.