CCA H3.2 (Copper Chrome Arsenic) – Structural plywood is generally impregnated to H3.2 hazard class with CCA treatment to AS/NZS1604.3:2002. H3.2 hazard class is described as: “outside, above ground, subject to periodic, moderate wetting and leaching”. Green in appearance. (C and D Grades). CCA waterborne preservative is used for structural plywood. It has a green colour, and is dried following treatment so that the sheets may return to the correct dimensions and are at a moisture content suited to use in building.