A legacy of CCA-contaminated sites

Significant risks to the environment, and indirectly to humans, are being posed by chromated copper arsenate (CCA) timber treatment sites, Green Party Co-Leader Jeanette Fitzsimons warned today.

This is in addition to the risks posed by direct human contact with CCA-treated timber, especially in children's playgrounds, house balconies and outdoor furniture.

Ms Fitzsimons said the toxicity of CCA had been known for many years. "Arsenic, copper and chromium are heavy metals that never break down in the environment," she said.

"Timber is impregnated with CCA in a pressure vessel. In the past, these have frequently blown out and dumped their contents into the environment. Stacks of treated timber drying outside also dripped CCA on to the ground and rain washed off more. These processes have caused very high soil concentrations of CCA in some places, creating contaminated sites. These are a shocking legacy for future generations," Ms Fitzsimons said.

Often these sites were located near the coast, and CCA could contaminate coastal waters and fisheries. Practices have improved over the past decade, but the code of practice and guidelines are still voluntary. All operators should be brought up to the same best practice standard, Ms Fitzsimons said.

"There is also the question of disposing of unwanted treated timber. Offcuts from construction are sometimes burned in domestic fires, leading to arsenic in the air and in the ash, which is often put on gardens. Old fence posts and CCA-treated timber from demolitions are also an environmental hazard if they are burned."

Reports that the Building Industry Authority was considering making timber treated to H3-level mandatory for house framing were very worrying, Ms Fitzsimons said.

"H3 is usually (though not always) CCA-treated, unlike H1 which was used in the past. H1 is treated with much less-toxic boron. The risk of H3 in house framing is not to the inhabitants, as the timber will not be exposed, but in expanding the total use of CCA and therefore the risks to the environment and people who are indirectly contaminated by the treatment sites," Ms Fitzsimons said.

"H3 treatment of framing would also not solve the leaky houses problem - it's small comfort to have your framing still sound if your carpets are rotting, your ceilings and wall linings are sagging and your furnishings are growing mould."

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