All fluids are infinitely compressible at the critical point.
Fluids in the vicinity of the critical point can therefore be orders of magnitude denser than gases at ambient conditions, and at the same much more compressible. These and other properties of supercritical fluids can be exploited for a variety of purposes, including the production of novel materials, the destruction of hazardous wastes, and the replacement of toxic solvents for industrial cleaning operations. Scientifically, supercritical fluids are interesting because their properties are governed by structure and correlations occurring over widely different length scales. On the other hand, long-ranged correlations, characteristic of fluids near their critical point, govern the compressibility, and the extreme sensitivity of thermophysical properties to small changes in temperature and pressure. The properties of supercritical fluids can be conveniently exploited for the production of microparticles of interest in the pharmaceutical industry.