In comparison to the HC³ pyrolisis and other waste-to-fuel processes have two disadvantages, effecting costs:

1. The higher pressure requires additional energy input, thus the net energy balance is not as high as the HC³'s.

2. As the processor works under the high pressure of 750 PSI, the machinery has to be built to pressure vessel standards, which means they have to fulfill all the regulations that a typical refinery for fossil fuels would require. Operational risks are therefore higher. This means higher construction costs, more sophisticated safety devices and higher insurance expenditures than the HC³ requires.
3. Leak in one of the pressurized vessels would free large amounts of dioxins into the atmosphere.

This means higher temperature/higher pressure systems have to fight with the same solid carbon problems as Fisher-Tropsch and "pure" Pyrolisis—with the use of surface heating, they produce elemental carbon, which is difficult to separate and scums the production facility.

With certain feedstocks containing chlorine, they will produce dioxins and furans, which limits the scope of application.