An apparatus and method for tarpless fumigation of containerized cargo within a shipping container is disclosed. A portable fumigation containment door is installed in covering relation with main rear opening of a standard cargo container. Pneumatic cylinders are actuated to secure the door in place, and an inflatable gasket extending around the perimeter of the containment door and is inflated to create an airtight seal between the cargo container and the containment door. The door is provided with a series of connection ports for receiving fumigant injection and sampling lines necessary for performing the fumigation process.
