Abstract: A load box for containing liquid spillage has a container; with an upper access opening with a cover, attachable to a wall of a containment structure containing a liquid storage tank. An input opening configured to receive a discharge end of a tank conduit, and an output opening is configured to receive a suction end of a transport conduit. The container encloses a releasable connection between the suction end of the transport conduit and the discharge end of the tank conduit. An overflow opening is located such that liquid rising in the container flows through the overflow opening before rising to a level where liquid flows through one of the input and output openings, and an overflow conduit attached to the overflow opening is configured such that when a liquid level in the container rises to the overflow opening, liquid flows through the overflow conduit into the structure interior.