CCA-treated timber is timber preserved with Copper Chrome Arsenate (CCA) or Chromated Copper Arsenate, as it is known in some countries. The copper (23-25%) and arsenic (30-37%) in CCA act as fungicides and insecticides, while the chromium (38-45%) fixes the chemicals into the wood (APVMA, 2003e; Greaves 2003). The chemical mixture is injected into the wood under pressure so that the wood is saturated with the chemicals.