Abstract: A system and method for delivering volatile corrosion inhibitor (VCI) for protecting against external corrosion to the bottom, soil-side, surface of a storage tank is disclosed. The VCI delivery system can include a transport material buried underneath the tank and a carrier structure for containing the transport material. VCI can be supplied to the transport material from an external VCI storage tank and the supply regulated by a control valve. The transport material is configured to adaptively and controllably release VCI into the soil in response an external stimulus. The transport material can passively adjust the VCI release rate as a function of a stimulus including pH or soil potential. Additionally, a control system can monitor soil conditions and generate the stimulus that triggers the release of the VCI. Also disclosed are systems and methods for deploying the VCI delivery system under the tank using horizontal drilling techniques.