Direct Push Injection (DPI) is a technique used for the in-situ delivery of chemical amendments or remedial agents into the subsurface at contaminated sites. This technique involves the use of direct-push technology (DPT), which is a vehicle-mounted drilling system that utilizes hydraulic or pneumatic pressure to advance a drill rod and tool string into the subsurface. During DPI, the drill rod and tool string are advanced into the subsurface to a predetermined depth. The drill rod is then held stationary while the remedial agent is injected into the subsurface through a series of injection ports or screened intervals in the tool string. The DPI technique can be used to deliver a range of remedial agents, including slurries, chemical oxidants, reductants, and bioaugmentation products directly into the subsurface to target the contaminant source or plume.