The phase-out of CFCs has caused many companies to reevaluate petroleum based hydrocarbons. Generally speaking, the petroleum based hydrocarbons are less costly but not quite as effective as terpenes for a wide range of contaminants. Several disadvantages are associated with some semi-aqueous cleaning products. The biggest concern is flammability. Several semi-aqueous cleaners have low flash points and become extremely volatile when sprayed.
Health effects associated with the use of terpenes are still unclear.
Several terpenes have been found to be a carcinogens among certain laboratory animals, but results are inconclusive for humans. A new process on the market is vacuum deoiling, an operation that removes surface oils from parts without using ozone-depleting or hazardous chemicals, water or detergents. Thermal and vacuum technology remove the oil residue on parts through vaporization. Once the parts have been loaded the heater and pump are actuated to warm and evacuate the unit's chamber. The oil's boiling point falls with pressure so heating it in a slight vacuum dries the part quickly.