A thermal insulation article for placement in a shipping container to hold an item includes a multi-section thermally insulating pad shaped to be positioned in a cavity of a rectangular prism shipping container. The pad includes a plurality of solid compostable panel sections formed primarily of grain starch, and a water-proof polyethylene film forming a pocket enclosing the plurality of panel sections. Each panel section holds together as a single unit, and each panel section provides a rectangular plate dimensioned to substantially span whichever of the floor, plurality of side walls or cover that the rectangular plate is adjacent. The pad is configured to be foldable at a right angle along a boundary between the panel sections. The film provides both an interior and an exterior surface of the pad where the pad is folded.