Chromated copper arsenate
Chromated copper arsenate (CCA) is a mix of copper, chromium, and arsenic formulated as oxides or salts. It is a wood preservative used for timber treatment that preserves the wood from decay fungi, wood attacking insects, including termites, and marine borers. It also improves the weather-resistance of treated timber and may assist paint adherence in the long term. The chromium acts as a chemical fixing agent and has little or no preserving properties; it helps the other chemicals to fix in the timber, binding them through chemical complexes to the wood's cellulose and lignin. The copper acts primarily to protect the wood against decay fungi and bacteria, while the arsenic is the main insecticidal component of CCA. Copper is a chemical element with the symbol Cu and atomic number 29. Copper is an essential elements in plants and animals as it is required for the normal functioning of more than 30 enzymes. It occurs naturally throughout the environment in rocks, soil, water, and air. (L277, L278, L282)