An improved deep remediation injection system for in-situ remediation of contaminated soil and ground water. The system includes a soil penetrating lance for injecting at least two different highly-pressurized fluids taken from the group of air, gaseous oxygen, ozone, oxygenated liquid, hydrogen peroxide, surfactant-containing liquid, catalyst-containing liquid and suspended biologicals-containing liquids, or a liquid containing other chemicals, into said contaminated soil as said soil penetrating lance is inserted for penetration therein. The soil penetrating lance has at least an upper set of injection ports, the upper set of injection ports being generally radially spaced-apart on said lance, and at least one lower set of injection ports, the lance having an average width in the vicinity of the upper set of injection ports. The lance further includes substantially fluidically-independent first and second conduits leading, respectively, to the lower set of injection ports and the upper set of injection ports so as to permit delivery of separate pressurized fluid streams to the upper and lower sets of injection ports and then into the soil. The upper and lower sets of injection ports are spaced apart from each other on said lance a distance no farther than about three times the average width of said lance in the vicinity of the upper set of injection ports.