Abstract: Apparatus for in-situ treatment of contaminated soil that includes an elongated hollow drive shaft mounted for rotation about its axis while being supported in vertical orientation. The upper end of the drive shaft is connected for selective injection of fluid under pressure into the shaft. A drill is affixed to the lower end of the shaft for drilling a hole downwardly through the soil. The drill comprises a hollow sleeve mounted to the lower end of the shaft and extending therefrom coaxially with the shaft. A pair of drill blades are cantilevered from the sleeve, and extend outwardly therefrom at right angles diametrically opposite to and aligned with each other. Each blade is of identical uniform cross section and carries a plurality of radially spaced drill teeth oriented tangentially of the sleeve along a leading radial edge of the blade. A hollow pipe extends along the trailing edge of each blade, and has orifices for injecting fluid from the sleeve and the pipe into the earth as the blade is rotated.