What Is Copper Chrome Arsenate (Cca) Timber Treatment?

Wood is an organic matter and, as such, it tends to break down over time due to being attacked by insects and fungus. To prevent this from occurring wood is treated with different timber treatments, but the most effective has proven to be the treatment with a copper chrome arsenate preservative.

This preservative has been used worldwide since the 1930s for many different purposes, but there have been concerns about the risks involved with arsenic leaching out of the timber, and it is not used as widely today because of this. For the use of house stumps by companies such as Black and White Houseraising and Restumping, this is a very effective timber treatment since usually the underside of the house is not frequented often by many people, so the risks associated are minimal.

What it Does

The components of this timber treatment include the chemicals copper, chromium and arsenic. The copper and arsenic are an effective preventative measure to protect the timber from insect and fungal attack. The chrome is added to hold the copper and arsenic into the wood to prevent it from leaching out. Wood that has been treated with the CCA timber treatment is usually identifiable because of its green hue.


The main risk associated with the use of the CCA timber treatment is the component of arsenic, which has been shown to leach out in small amounts over time, and can be swallowed or inhaled if the wood is burnt. It is for this reason that wood that has been treated with the CCA treatment will not be used for building children’s play equipment, patios, garden furniture, domestic decking, handrails, outdoor seating or picnic tables.

Risk Reduction

If you have been cutting or sanding wood that has been treated with the CCA treatment, clothing should be washed separately. CCA treated items should not be burnt in any wood fire as this could cause the arsenic to leach into the air where it could be inhaled, causing long-term damage to the human body. CCA treated wood should be disposed of through your local council or can be put into your regular garbage bin in small amounts. It should not be left unattended where it could be picked up by someone that is not aware of the risks involved. CCA treated timber should not be used for animal cages or any similar purpose that might involve it being chewed by animals.