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Copper chrome arsenic (CCA) treated timber is timber that has been treated with a preservative containing copper, chrome and arsenic. CCA treatment prolongs the life of wood, which is why CCA treated timber has so many common uses, including in playground equipment, fences, retaining walls and jetties. Recently concerns have been raised regarding the potential health risks of CCA treated timber.
The preservation process
The CCA process was pioneered in 1933 and is used worldwide. Copper and arsenic in the preservative protect the wood from insect and fungal attack. Chromium (chrome) ‘locks’ the copper and arsenic into the timber and reduces the risk of the chemicals leaching out. The CCA process gives the treated wood a green tint. New Zealand, the USA and Australia are the three highest consumers of CCA treated timber.
Arsenic
The main concerns about CCA treated timber relate to arsenic, which can be absorbed through the skin, inhaled (when CCA treated timber is burnt) or ingested (swallowed). Over time, small amounts of chemicals may leach from CCA treated timber, but research has found that the amount of leached arsenic is less than that found in common foods. Since the general population is exposed to naturally occurring arsenic in soil, water and food, the human body can tolerate small amounts of arsenic.
International concerns about CCA timber
Although the chemicals are fixed within the dry wood in CCA treated timber, there have been international concerns expressed about the potential for harm as small amounts of arsenic can leach out of the surface of the timber. The United States and Canada jointly decided to restrict the use of CCA treated timber in non-industrial settings after January 2004. In March 2005, the Australian Pesticides and Veterinary Medicines Authority (APVMA) reviewed the safety of CCA treated timber in the Australian context.
Australian recommendations
The APVMA concluded that:
- From March 2006, CCA treated timber is not permitted to be used in the construction of new garden furniture, picnic tables, exterior seating, children’s play equipment, patios, domestic decking and handrails.
- CCA treated timber can be used in other applications such as piling and other structure foundations, residential construction, industrial and commercial construction, rural and farm use, poles, fencing, landscaping timbers, fresh and salt water structures, signage and boat construction.
- It should be emphasised that these recommendations have been made as a precaution. There is no evidence to suggest that CCA timber is harmful when handled or used properly. Therefore, existing structures made from CCA treated timbers don’t need to be removed and replaced until they reach the end of their functional life.
How to reduce risk in your home workshop
While CCA treated timber appears to be a safe product, you should limit possible exposure to the chemicals as a precaution. While using CCA treated timber at home, you should:
- Select the correct timber for the job. The timbers are treated to different levels according to their intended end use. Observe warning labels on CCA treated timber.
- Cover any existing skin injuries such as cuts, wounds or abrasions before you work with CCA treated timber.
- Wear a dust mask labelled either as P1 or P2 to avoid inhaling sawdust.
- Wear eye goggles, gloves and appropriate clothing to prevent splinters.
- Keep food and drinks away from sawdust or CCA wood surfaces.
- Avoid sawing or sanding the wood in confined spaces. Work with CCA wood outdoors whenever possible.
- Reseal cut surfaces with a timber preservative.
- Use stainless steel or ‘hot-dip’ galvanised plates, bolts and nails.
- Wash your hands and face after working with the wood and before eating, drinking or any other activity that involves hand-to-mouth contact such as smoking.
- Clean sawdust from personal protective equipment before you use it again.
- Clean your workshop or garage thoroughly – don’t leave sawdust lying about.
Playground equipment
It has been proposed that children risk eating tiny amounts of arsenic from their hands after playing on CCA treated timber play equipment or swallowing the soil surrounding the equipment. However, the Australian Government’s Department of Health and Ageing states that there is insufficient evidence to demonstrate that CCA treated timber poses a health risk.
CCA treated timber has been in use for 30 years and no cases of adverse health effects have been reported in children playing on (or near) CCA treated timber play equipment.
Precautions to reduce children’s exposure include:
- Don’t allow food to come in contact with CCA treated timber play equipment.
- Make sure that children wash their hands after playing outside, and before eating and drinking.
There is no need to remove existing CCA treated timber play equipment from your backyard. It is unknown whether painting or sealing CCA treated timber play equipment is helpful. If you are planning to build play equipment on your property, talk to the staff at your local hardware store for information and guidance about treated timber products.
CCA timber and fire
In the event of a bushfire, the ash from burnt CCA treated timber can contain up to 10 per cent (by weight) arsenic, chromium and copper. Swallowing only a few grams of this ash can be harmful. Symptoms can include nausea and/or vomiting, diarrhoea, and a ‘pins and needles’ feeling in the skin.
Keep children and pets away from the CCA ash until it is removed, and see a doctor if you have or anyone in your family shows signs of having eaten CCA ash.
Risk reduction strategies – general suggestions
Suggestions include:
- Do wash your work clothes separately after cutting or sanding CCA timber.
- Don’t use CCA timber for kitchen cutting boards, kitchen countertops or food containers.
- Never burn CCA treated timber in fireplaces, barbecues, wood stoves or any wood fire.
- Ash from CCA treated timber can be double-bagged, sealed, and taken directly to your local landfill. Contact your local council for advice or requirements.
- When removing the ash, wear protective gloves, clothing, and a facemask to minimise exposure to dust.
- Don’t use sawdust in mulch, compost or animal feed.
- Don’t leave the timber where others may take it and use it for firewood; for example, don’t put it out on your nature strip.
- Do put small amounts of offcuts into your regular rubbish bin or dispose of CCA treated timber at approved landfill sites. Contact your local council for further information.
- Do be guided by the relevant timber associations but, generally speaking, it may not be advisable to use CCA treated timber for animal cages if the animal likes to chew on wood – for example, for bird cages.
- Don’t use CCA treated timber in the construction of fish ponds.
Where to get help
- Your doctor
- Your local council
- Environmental Health Unit, Department of Health Victoria Tel. 1300 761 874
- Plantation Timber Association Australia Tel. (03) 9859 2455
- Timber Preservers Association of Australia Tel. (03) 9597 0680
- EPA Victoria Tel. (03) 9695 2722
- Contact the Department of Human Services, Children’s Services Adviser in your region for information about CCA treated timber equipment in kindergartens and child care centres
- Contact the Department of Education and Training for information about CCA treated timber equipment in schools Tel. (03) 9637 2000
- Contact the Department of Primary Industries, Chemicals Standards Branch for information on permitted applications for CCA treated timber after March 2006 Tel. (03) 9210 9379
Things to remember
- Copper chrome arsenic (CCA) treated timber is timber that has been treated with a preservative containing copper, chrome and arsenic.
- While CCA treated timber can be considered a safe product when handled or used properly, you should limit possible exposure to the chemicals, especially for young children.
- Never burn CCA treated timber in fireplaces, barbecues, wood stoves or any wood fire.
- After a bushfire, keep children and pets away from the CCA ash until it is removed and follow safety precautions for clean-up.
You might also be interested in:
Asbestos and your health.
Cadmium.
Hazardous waste.
Lead poisoning.
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