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Common Questions on CCA Treated Timber
What is CCA treated timber?
CCA treated timber contains forms of the chemicals Copper, Chromium and Arsenic. These are chemical preservatives used to protect non-durable wood from rotting and attack by fungi, termites or other wood boring insects. The treatment is applied under pressure in a controlled industrial environment and has been widely used to produce durable and economic outdoor building products for over 70 years.
Is it safe?
All treated timber manufactured by reputable companies and handled correctly is safe. CCA treated timber has been used world-wide for more than 70 years without evidence of harm to human or environmental health.
Along with the Australian review into CCA, there have been reviews in the USA, Canada, the EU and New Zealand and none have found any evidence that CCA has adverse human health impacts when handled correctly.
A Canadian Study compared arsenic levels on the hands of children playing in playgrounds constructed with CCA-treated wood with those found on the hands of children playing in other playgrounds without treated timber. They found the maximum amount of arsenic on children’s hands for all participants in the study was lower than the average daily intake of arsenic from water and food.
Kwon et all, 2005. Arsenic on the Hands of Children after Playing in Playgrounds.
Environmental Health Perspectives
A US analysis of cancer statistics from 1973 to 1999 concluded there has not been an increase in arsenic-associated cancers during the period of extensive use of CCA treated timber in the USA.
West, D C, 2004. Health Effects of Preserved Wood: Relationship Between CCA-Treated Wood and Incidence of Cancer in the United States.
Proceedings: Environmental Impacts of Preservative-Treated Wood, February 2004.
Correct Timber Handling
Wood dust from any timber, treated or untreated, can cause discomfort to skin, eyes and upper respiratory tracts. To protect yourself simply wear gloves, dust mask and goggles when building with timber.
Australian review of CCA treated timber – 2005
After a 2 year study the Australian Pesticides and Veterinary Medicines Authority (APVMA) stated in their report they found “… no compelling evidence from the available data to conclude that there was likely to be an unacceptable risk to public health from exposure to arsenic from CCA-treated timber.”
APVMA confirmed in its report that the level of arsenic in treated timber is lower than many sources found in water and food. Arsenic also occurs naturally in all soils.
APVMA Review of Copper Chrome Arsenate Treated Timber 2005
What changes were made as a result of the review?
As a precaution, timber used in “frequent contact areas” such as playgrounds, garden furniture, picnic tables, benches, handrails, and decking boards is no longer treated with CCA, for these applications alternative chemicals are used.
CCA treated timber is still suitable for all other applications such as the decking sub-structure, pergolas, fencing and landscaping.
Should existing playgrounds built with CCA treated timber be removed?
No regulatory authorities in the USA, Canada, Europe, Australia or New Zealand have recommended the dismantling of existing structures built with CCA treated timber.
An ENSIS (CSIRO) study investigated soils in three kindergarten playgrounds. All soil readings from the kindergartens were well below tolerable limits. According to ENSIS: “the results suggest that there is no need for the playground equipment at these kindergartens to be modified or removed.
Cookson, L J 205. Arsenic Content of Soil and Wood Chip Fines in Three Kindergartens,
ENSIS Technical Report No. 151.
Can the chemical leach into the soil?
Studies into treated timber used in vegetable gardens have shown the preservative CCA is not absorbed into food crops like grapes, tomatoes and cucumbers. Some root crops like carrots and beets have been reported to pick up small amounts of arsenic from CCA, but it is in an organic non-toxic form and in any case is largely removed by peeling the vegetables.
The APVMA found that, in general, if some preservative is leached from the timber, it is likely to remain in the soil close to CCA-treated wood and that plants and vegetable are not likely to take up significant amounts unless closely adjacent to treated timber.
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